Vulkan-Hpp/VulkanHppGenerator.cpp

// Copyright(c) 2015-2016, NVIDIA CORPORATION. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <cassert>
#include <algorithm>
#include <fstream>
#include <functional>
#include <iterator>
#include <sstream>
#include <exception>
#include <regex>
#include <iterator>
#include "VulkanHppGenerator.hpp"

const size_t INVALID_INDEX = (size_t)~0;

const std::string vkNamespace = R"(
#if !defined(VULKAN_HPP_NAMESPACE)
#define VULKAN_HPP_NAMESPACE vk
#endif

#define VULKAN_HPP_STRINGIFY2(text) #text
#define VULKAN_HPP_STRINGIFY(text) VULKAN_HPP_STRINGIFY2(text)
#define VULKAN_HPP_NAMESPACE_STRING VULKAN_HPP_STRINGIFY(VULKAN_HPP_NAMESPACE)

namespace VULKAN_HPP_NAMESPACE
{
)";

const std::string constExprHeader = R"(
#if defined(_MSC_VER) && (_MSC_VER <= 1800)
# define VULKAN_HPP_CONSTEXPR
#else
# define VULKAN_HPP_CONSTEXPR constexpr
#endif
)";

const std::string exceptionHeader = R"(
#if defined(_MSC_VER) && (_MSC_VER == 1800)
# define noexcept _NOEXCEPT
#endif

  class ErrorCategoryImpl : public std::error_category
  {
    public:
    virtual const char* name() const noexcept override { return VULKAN_HPP_NAMESPACE_STRING"::Result"; }
    virtual std::string message(int ev) const override { return to_string(static_cast<Result>(ev)); }
  };

#if defined(_MSC_VER) && (_MSC_VER == 1800)
# undef noexcept
#endif

  VULKAN_HPP_INLINE const std::error_category& errorCategory()
  {
    static ErrorCategoryImpl instance;
    return instance;
  }

  VULKAN_HPP_INLINE std::error_code make_error_code(Result e)
  {
    return std::error_code(static_cast<int>(e), errorCategory());
  }

  VULKAN_HPP_INLINE std::error_condition make_error_condition(Result e)
  {
    return std::error_condition(static_cast<int>(e), errorCategory());
  }
)";

const std::string exceptionClassesHeader = R"(
#if defined(_MSC_VER) && (_MSC_VER == 1800)
# define noexcept _NOEXCEPT
#endif

  class Error
  {
    public:
    virtual ~Error() = default;

    virtual const char* what() const noexcept = 0;
  };

  class LogicError : public Error, public std::logic_error
  {
    public:
    explicit LogicError( const std::string& what )
      : Error(), std::logic_error(what) {}
    explicit LogicError( char const * what )
      : Error(), std::logic_error(what) {}
    virtual ~LogicError() = default;

    virtual const char* what() const noexcept { return std::logic_error::what(); }
  };

  class SystemError : public Error, public std::system_error
  {
    public:
    SystemError( std::error_code ec )
      : Error(), std::system_error(ec) {}
    SystemError( std::error_code ec, std::string const& what )
      : Error(), std::system_error(ec, what) {}
    SystemError( std::error_code ec, char const * what )
      : Error(), std::system_error(ec, what) {}
    SystemError( int ev, std::error_category const& ecat )
      : Error(), std::system_error(ev, ecat) {}
    SystemError( int ev, std::error_category const& ecat, std::string const& what)
      : Error(), std::system_error(ev, ecat, what) {}
    SystemError( int ev, std::error_category const& ecat, char const * what)
      : Error(), std::system_error(ev, ecat, what) {}
    virtual ~SystemError() = default;

    virtual const char* what() const noexcept { return std::system_error::what(); }
  };

#if defined(_MSC_VER) && (_MSC_VER == 1800)
# undef noexcept
#endif

)";

const std::string flagsHeader = R"(
  template <typename FlagBitsType> struct FlagTraits
  {
    enum { allFlags = 0 };
  };

  template <typename BitType, typename MaskType = VkFlags>
  class Flags
  {
  public:
    VULKAN_HPP_CONSTEXPR Flags()
      : m_mask(0)
    {
    }

    Flags(BitType bit)
      : m_mask(static_cast<MaskType>(bit))
    {
    }

    Flags(Flags<BitType> const& rhs)
      : m_mask(rhs.m_mask)
    {
    }

    explicit Flags(MaskType flags)
      : m_mask(flags)
    {
    }

    Flags<BitType> & operator=(Flags<BitType> const& rhs)
    {
      m_mask = rhs.m_mask;
      return *this;
    }

    Flags<BitType> & operator|=(Flags<BitType> const& rhs)
    {
      m_mask |= rhs.m_mask;
      return *this;
    }

    Flags<BitType> & operator&=(Flags<BitType> const& rhs)
    {
      m_mask &= rhs.m_mask;
      return *this;
    }

    Flags<BitType> & operator^=(Flags<BitType> const& rhs)
    {
      m_mask ^= rhs.m_mask;
      return *this;
    }

    Flags<BitType> operator|(Flags<BitType> const& rhs) const
    {
      Flags<BitType> result(*this);
      result |= rhs;
      return result;
    }

    Flags<BitType> operator&(Flags<BitType> const& rhs) const
    {
      Flags<BitType> result(*this);
      result &= rhs;
      return result;
    }

    Flags<BitType> operator^(Flags<BitType> const& rhs) const
    {
      Flags<BitType> result(*this);
      result ^= rhs;
      return result;
    }

    bool operator!() const
    {
      return !m_mask;
    }

    Flags<BitType> operator~() const
    {
      Flags<BitType> result(*this);
      result.m_mask ^= FlagTraits<BitType>::allFlags;
      return result;
    }

    bool operator==(Flags<BitType> const& rhs) const
    {
      return m_mask == rhs.m_mask;
    }

    bool operator!=(Flags<BitType> const& rhs) const
    {
      return m_mask != rhs.m_mask;
    }

    explicit operator bool() const
    {
      return !!m_mask;
    }

    explicit operator MaskType() const
    {
        return m_mask;
    }

  private:
    MaskType  m_mask;
  };

  template <typename BitType>
  Flags<BitType> operator|(BitType bit, Flags<BitType> const& flags)
  {
    return flags | bit;
  }

  template <typename BitType>
  Flags<BitType> operator&(BitType bit, Flags<BitType> const& flags)
  {
    return flags & bit;
  }

  template <typename BitType>
  Flags<BitType> operator^(BitType bit, Flags<BitType> const& flags)
  {
    return flags ^ bit;
  }

)";

const std::string optionalClassHeader = R"(
  template <typename RefType>
  class Optional
  {
  public:
    Optional(RefType & reference) { m_ptr = &reference; }
    Optional(RefType * ptr) { m_ptr = ptr; }
    Optional(std::nullptr_t) { m_ptr = nullptr; }

    operator RefType*() const { return m_ptr; }
    RefType const* operator->() const { return m_ptr; }
    explicit operator bool() const { return !!m_ptr; }

  private:
    RefType *m_ptr;
  };
)";

const std::string arrayProxyHeader = R"(
#ifndef VULKAN_HPP_DISABLE_ENHANCED_MODE
  template <typename T>
  class ArrayProxy
  {
  public:
    VULKAN_HPP_CONSTEXPR ArrayProxy(std::nullptr_t)
      : m_count(0)
      , m_ptr(nullptr)
    {}

    ArrayProxy(T & ptr)
      : m_count(1)
      , m_ptr(&ptr)
    {}

    ArrayProxy(uint32_t count, T * ptr)
      : m_count(count)
      , m_ptr(ptr)
    {}

    template <size_t N>
    ArrayProxy(std::array<typename std::remove_const<T>::type, N> & data)
      : m_count(N)
      , m_ptr(data.data())
    {}

    template <size_t N>
    ArrayProxy(std::array<typename std::remove_const<T>::type, N> const& data)
      : m_count(N)
      , m_ptr(data.data())
    {}

    template <class Allocator = std::allocator<typename std::remove_const<T>::type>>
    ArrayProxy(std::vector<typename std::remove_const<T>::type, Allocator> & data)
      : m_count(static_cast<uint32_t>(data.size()))
      , m_ptr(data.data())
    {}

    template <class Allocator = std::allocator<typename std::remove_const<T>::type>>
    ArrayProxy(std::vector<typename std::remove_const<T>::type, Allocator> const& data)
      : m_count(static_cast<uint32_t>(data.size()))
      , m_ptr(data.data())
    {}

    ArrayProxy(std::initializer_list<T> const& data)
      : m_count(static_cast<uint32_t>(data.end() - data.begin()))
      , m_ptr(data.begin())
    {}

    const T * begin() const
    {
      return m_ptr;
    }

    const T * end() const
    {
      return m_ptr + m_count;
    }

    const T & front() const
    {
      VULKAN_HPP_ASSERT(m_count && m_ptr);
      return *m_ptr;
    }

    const T & back() const
    {
      VULKAN_HPP_ASSERT(m_count && m_ptr);
      return *(m_ptr + m_count - 1);
    }

    bool empty() const
    {
      return (m_count == 0);
    }

    uint32_t size() const
    {
      return m_count;
    }

    T * data() const
    {
      return m_ptr;
    }

  private:
    uint32_t  m_count;
    T *       m_ptr;
  };
#endif
)";

const std::string structureChainHeader = R"(

  template <typename X, typename Y> struct isStructureChainValid { enum { value = false }; };

  template <typename P, typename T>
  struct TypeList
  {
    using list = P;
    using last = T;
  };

  template <typename List, typename X>
  struct extendCheck
  {
    static const bool valid = isStructureChainValid<typename List::last, X>::value || extendCheck<typename List::list,X>::valid;
  };

  template <typename T, typename X>
  struct extendCheck<TypeList<void,T>,X>
  {
    static const bool valid = isStructureChainValid<T, X>::value;
  };

  template <typename X>
  struct extendCheck<void,X>
  {
    static const bool valid = true;
  };

  template <class Element>
  class StructureChainElement
  {
  public:
    explicit operator Element&() { return value; }
    explicit operator const Element&() const { return value; }
  private:
    Element value;
  };

  template<typename ...StructureElements>
  class StructureChain : private StructureChainElement<StructureElements>...
  {
  public:
    StructureChain()
    {
      link<void, StructureElements...>();  
    }

    StructureChain(StructureChain const &rhs)
    {
      linkAndCopy<void, StructureElements...>(rhs);
    }

    StructureChain(StructureElements const &... elems)
    {
      linkAndCopyElements<void, StructureElements...>(elems...);
    }

    StructureChain& operator=(StructureChain const &rhs)
    {
      linkAndCopy<void, StructureElements...>(rhs);
      return *this;
    }

    template<typename ClassType> ClassType& get() { return static_cast<ClassType&>(*this);}

  private:
    template<typename List, typename X>
    void link()
    {
      static_assert(extendCheck<List, X>::valid, "The structure chain is not valid!");
    }

    template<typename List, typename X, typename Y, typename ...Z>
    void link()
    {
      static_assert(extendCheck<List,X>::valid, "The structure chain is not valid!");
      X& x = static_cast<X&>(*this);
      Y& y = static_cast<Y&>(*this);
      x.pNext = &y;
      link<TypeList<List, X>, Y, Z...>();
    }

    template<typename List, typename X>
    void linkAndCopy(StructureChain const &rhs)
    {
      static_assert(extendCheck<List, X>::valid, "The structure chain is not valid!");
      static_cast<X&>(*this) = static_cast<X const &>(rhs);
    }

    template<typename List, typename X, typename Y, typename ...Z>
    void linkAndCopy(StructureChain const &rhs)
    {
      static_assert(extendCheck<List, X>::valid, "The structure chain is not valid!");
      X& x = static_cast<X&>(*this);
      Y& y = static_cast<Y&>(*this);
      x = static_cast<X const &>(rhs);
      x.pNext = &y;
      linkAndCopy<TypeList<List, X>, Y, Z...>(rhs);
    }

    template<typename List, typename X>
    void linkAndCopyElements(X const &xelem)
    {
      static_assert(extendCheck<List, X>::valid, "The structure chain is not valid!");
      static_cast<X&>(*this) = xelem;
    }

    template<typename List, typename X, typename Y, typename ...Z>
    void linkAndCopyElements(X const &xelem, Y const &yelem, Z const &... zelem)
    {
      static_assert(extendCheck<List, X>::valid, "The structure chain is not valid!");
      X& x = static_cast<X&>(*this);
      Y& y = static_cast<Y&>(*this);
      x = xelem;
      x.pNext = &y;
      linkAndCopyElements<TypeList<List, X>, Y, Z...>(yelem, zelem...);
    }
  };

)";

const std::string versionCheckHeader = R"(
#if !defined(VULKAN_HPP_HAS_UNRESTRICTED_UNIONS)
# if defined(__clang__)
#  if __has_feature(cxx_unrestricted_unions)
#   define VULKAN_HPP_HAS_UNRESTRICTED_UNIONS
#  endif
# elif defined(__GNUC__)
#  define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#  if 40600 <= GCC_VERSION
#   define VULKAN_HPP_HAS_UNRESTRICTED_UNIONS
#  endif
# elif defined(_MSC_VER)
#  if 1900 <= _MSC_VER
#   define VULKAN_HPP_HAS_UNRESTRICTED_UNIONS
#  endif
# endif
#endif
)";

const std::string inlineHeader = R"(
#if !defined(VULKAN_HPP_INLINE)
# if defined(__clang___)
#  if __has_attribute(always_inline)
#   define VULKAN_HPP_INLINE __attribute__((always_inline)) __inline__
#  else
#    define VULKAN_HPP_INLINE inline
#  endif
# elif defined(__GNUC__)
#  define VULKAN_HPP_INLINE __attribute__((always_inline)) __inline__
# elif defined(_MSC_VER)
#  define VULKAN_HPP_INLINE inline
# else
#  define VULKAN_HPP_INLINE inline
# endif
#endif
)";

const std::string explicitHeader = R"(
#if defined(VULKAN_HPP_TYPESAFE_CONVERSION)
# define VULKAN_HPP_TYPESAFE_EXPLICIT
#else
# define VULKAN_HPP_TYPESAFE_EXPLICIT explicit
#endif
)";

const std::string resultValueHeader = R"(
  template <typename T>
  struct ResultValue
  {
    ResultValue( Result r, T & v )
      : result( r )
      , value( v )
    {}

    ResultValue( Result r, T && v )
      : result( r )
      , value( std::move( v ) )
    {}

    Result  result;
    T       value;

    operator std::tuple<Result&, T&>() { return std::tuple<Result&, T&>(result, value); }
  };

  template <typename T>
  struct ResultValueType
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    typedef ResultValue<T>  type;
#else
    typedef T               type;
#endif
  };

  template <>
  struct ResultValueType<void>
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    typedef Result type;
#else
    typedef void   type;
#endif
  };
)";

const std::string createResultValueHeader = R"(
  VULKAN_HPP_INLINE ResultValueType<void>::type createResultValue( Result result, char const * message )
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    VULKAN_HPP_ASSERT( result == Result::eSuccess );
    return result;
#else
    if ( result != Result::eSuccess )
    {
      throwResultException( result, message );
    }
#endif
  }

  template <typename T>
  VULKAN_HPP_INLINE typename ResultValueType<T>::type createResultValue( Result result, T & data, char const * message )
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    VULKAN_HPP_ASSERT( result == Result::eSuccess );
    return ResultValue<T>( result, data );
#else
    if ( result != Result::eSuccess )
    {
      throwResultException( result, message );
    }
    return std::move( data );
#endif
  }

  VULKAN_HPP_INLINE Result createResultValue( Result result, char const * message, std::initializer_list<Result> successCodes )
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    VULKAN_HPP_ASSERT( std::find( successCodes.begin(), successCodes.end(), result ) != successCodes.end() );
#else
    if ( std::find( successCodes.begin(), successCodes.end(), result ) == successCodes.end() )
    {
      throwResultException( result, message );
    }
#endif
    return result;
  }

  template <typename T>
  VULKAN_HPP_INLINE ResultValue<T> createResultValue( Result result, T & data, char const * message, std::initializer_list<Result> successCodes )
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    VULKAN_HPP_ASSERT( std::find( successCodes.begin(), successCodes.end(), result ) != successCodes.end() );
#else
    if ( std::find( successCodes.begin(), successCodes.end(), result ) == successCodes.end() )
    {
      throwResultException( result, message );
    }
#endif
    return ResultValue<T>( result, data );
  }

#ifndef VULKAN_HPP_NO_SMART_HANDLE
  template <typename T, typename D>
  VULKAN_HPP_INLINE typename ResultValueType<UniqueHandle<T,D>>::type createResultValue( Result result, T & data, char const * message, typename UniqueHandleTraits<T,D>::deleter const& deleter )
  {
#ifdef VULKAN_HPP_NO_EXCEPTIONS
    VULKAN_HPP_ASSERT( result == Result::eSuccess );
    return ResultValue<UniqueHandle<T,D>>( result, UniqueHandle<T,D>(data, deleter) );
#else
    if ( result != Result::eSuccess )
    {
      throwResultException( result, message );
    }
    return UniqueHandle<T,D>(data, deleter);
#endif
  }
#endif

)";

const std::string uniqueHandleHeader = R"(
#ifndef VULKAN_HPP_NO_SMART_HANDLE

  template <typename Type, typename Dispatch> class UniqueHandleTraits;

  template <typename Type, typename Dispatch>
  class UniqueHandle : public UniqueHandleTraits<Type,Dispatch>::deleter
  {
  private:
    using Owner = typename UniqueHandleTraits<Type,Dispatch>::owner;
    using Deleter = typename UniqueHandleTraits<Type,Dispatch>::deleter;
  public:

    explicit UniqueHandle( Type const& value = Type() )
      : UniqueHandle(value, Deleter())
    {}

    explicit UniqueHandle( Type const& value, Deleter const& deleter = Deleter() )
      : Deleter( deleter)
      , m_value( value )
    {}

    explicit UniqueHandle( Type const& value, Owner const& owner = Owner() )
      : Deleter( owner)
      , m_value( value )
    {}

    UniqueHandle( UniqueHandle const& ) = delete;

    UniqueHandle( UniqueHandle && other )
      : Deleter( std::move( static_cast<Deleter&>( other ) ) )
      , m_value( other.release() )
    {}

    ~UniqueHandle()
    {
      if ( m_value ) this->destroy( m_value );
    }

    UniqueHandle & operator=( UniqueHandle const& ) = delete;

    UniqueHandle & operator=( UniqueHandle && other )
    {
      reset( other.release() );
      *static_cast<Deleter*>(this) = std::move( static_cast<Deleter&>(other) );
      return *this;
    }

    explicit operator bool() const
    {
      return m_value.operator bool();
    }

    Type const* operator->() const
    {
      return &m_value;
    }

    Type * operator->()
    {
      return &m_value;
    }

    Type const& operator*() const
    {
      return m_value;
    }

    Type & operator*()
    {
      return m_value;
    }

    const Type & get() const
    {
      return m_value;
    }
    
    Type & get()
    {
      return m_value;
    }

    void reset( Type const& value = Type() )
    {
      if ( m_value != value )
      {
        if ( m_value ) this->destroy( m_value );
        m_value = value;
      }
    }

    Type release()
    {
      Type value = m_value;
      m_value = nullptr;
      return value;
    }

    void swap( UniqueHandle<Type,Dispatch> & rhs )
    {
      std::swap(m_value, rhs.m_value);
      std::swap(static_cast<Deleter&>(*this), static_cast<Deleter&>(rhs));
    }

  private:
    Type    m_value;
  };

  template <typename Type, typename Dispatch>
  VULKAN_HPP_INLINE void swap( UniqueHandle<Type,Dispatch> & lhs, UniqueHandle<Type,Dispatch> & rhs )
  {
    lhs.swap( rhs );
  }
#endif

)";

const std::string deleterClassString = R"(
  struct AllocationCallbacks;

  template <typename OwnerType, typename Dispatch>
  class ObjectDestroy
  {
    public:
      ObjectDestroy( OwnerType owner = OwnerType(), Optional<const AllocationCallbacks> allocator = nullptr, Dispatch const &dispatch = Dispatch() )
        : m_owner( owner )
        , m_allocator( allocator )
        , m_dispatch( &dispatch )
      {}

      OwnerType getOwner() const { return m_owner; }
      Optional<const AllocationCallbacks> getAllocator() const { return m_allocator; }

    protected:
      template <typename T>
      void destroy(T t)
      {
        m_owner.destroy( t, m_allocator, *m_dispatch );
      }

    private:
      OwnerType m_owner;
      Optional<const AllocationCallbacks> m_allocator;
      Dispatch const* m_dispatch;
  };

  class NoParent;

  template <typename Dispatch>
  class ObjectDestroy<NoParent,Dispatch>
  {
    public:
      ObjectDestroy( Optional<const AllocationCallbacks> allocator = nullptr, Dispatch const &dispatch = Dispatch() )
        : m_allocator( allocator )
        , m_dispatch( &dispatch )
      {}

      Optional<const AllocationCallbacks> getAllocator() const { return m_allocator; }

    protected:
      template <typename T>
      void destroy(T t)
      {
        t.destroy( m_allocator, *m_dispatch );
      }

    private:
      Optional<const AllocationCallbacks> m_allocator;
      Dispatch const* m_dispatch;
  };

  template <typename OwnerType, typename Dispatch>
  class ObjectFree
  {
    public:
      ObjectFree( OwnerType owner = OwnerType(), Optional<const AllocationCallbacks> allocator = nullptr, Dispatch const &dispatch = Dispatch() )
        : m_owner( owner )
        , m_allocator( allocator )
        , m_dispatch( &dispatch )
      {}

      OwnerType getOwner() const { return m_owner; }
      Optional<const AllocationCallbacks> getAllocator() const { return m_allocator; }

    protected:
      template <typename T>
      void destroy(T t)
      {
        m_owner.free( t, m_allocator, *m_dispatch );
      }

    private:
      OwnerType m_owner;
      Optional<const AllocationCallbacks> m_allocator;
      Dispatch const* m_dispatch;
  };

  template <typename OwnerType, typename PoolType, typename Dispatch>
  class PoolFree
  {
    public:
      PoolFree( OwnerType owner = OwnerType(), PoolType pool = PoolType(), Dispatch const &dispatch = Dispatch() )
        : m_owner( owner )
        , m_pool( pool )
        , m_dispatch( &dispatch )
      {}

      OwnerType getOwner() const { return m_owner; }
      PoolType getPool() const { return m_pool; }

    protected:
      template <typename T>
      void destroy(T t)
      {
        m_owner.free( m_pool, t, *m_dispatch );
      }

    private:
      OwnerType m_owner;
      PoolType m_pool;
      Dispatch const* m_dispatch;
  };

)";


std::string replaceWithMap(std::string const &input, std::map<std::string, std::string> replacements)
{
  // This will match ${someVariable} and contain someVariable in match group 1
  std::regex re(R"(\$\{([^\}]+)\})");
  auto it = std::sregex_iterator(input.begin(), input.end(), re);
  auto end = std::sregex_iterator();

  // No match, just return the original string
  if (it == end)
  {
    return input;
  }

  std::string result = "";
  while (it != end)
  {
    std::smatch match = *it;
    auto itReplacement = replacements.find(match[1].str());
    assert(itReplacement != replacements.end());

    result += match.prefix().str() + ((itReplacement != replacements.end()) ? itReplacement->second : match[0].str());
    ++it;

    // we've passed the last match. Append the rest of the orignal string
    if (it == end)
    {
      result += match.suffix().str();
    }
  }
  return result;
}


bool beginsWith(std::string const& text, std::string const& prefix);
void checkAttributes(std::map<std::string, std::string> const& attributes, int line, std::map<std::string, std::set<std::string>> const& required, std::map<std::string, std::set<std::string>> const& optional);
void checkElements(std::vector<tinyxml2::XMLElement const*> const& elements, std::set<std::string> const& values);
void checkEmptyElement(tinyxml2::XMLElement const* element);
void checkOrderedElements(std::vector<tinyxml2::XMLElement const*> const& elements, std::vector<std::string> const& values);
std::string createEnumValueName(std::string const& name, std::string const& prefix, std::string const& postfix, bool bitmask, std::string const& tag);
bool endsWith(std::string const& text, std::string const& postfix);
void enterProtect(std::ostream &os, std::string const& protect);
std::string extractTag(std::string const& name);
std::string findTag(std::string const& name, std::set<std::string> const& tags);
std::string generateEnumNameForFlags(std::string const& name);
std::map<std::string, std::string> getAttributes(tinyxml2::XMLElement const* element);
std::vector<tinyxml2::XMLElement const*> getChildElements(tinyxml2::XMLElement const* element);
bool isErrorEnum(std::string const& enumName);
void leaveProtect(std::ostream &os, std::string const& protect);
std::string readArraySize(tinyxml2::XMLNode const* node, std::string& name);
std::string startUpperCase(std::string const& input);
std::string startLowerCase(std::string const& input);
std::string strip(std::string const& value, std::string const& prefix, std::string const& postfix = std::string());
std::string stripErrorEnumPrefix(std::string const& enumName);
std::string stripPluralS(std::string const& name);
std::vector<std::string> tokenize(std::string tokenString, char separator);
std::string trim(std::string const& input);
std::string trimEnd(std::string const& input);
std::string toCamelCase(std::string const& value);
std::string toUpperCase(std::string const& name);
void writeFunctionHeaderName(std::ostream & os, std::string const& name, bool singular, bool unique);
void writeReinterpretCast(std::ostream & os, bool leadingConst, bool vulkanType, std::string const& type, bool trailingPointerToConst);
void writeStandardOrEnhanced(std::ostream & os, std::string const& standard, std::string const& enhanced);
void writeTypesafeCheck(std::ostream & os, std::string const& typesafeCheck);
void writeVersionCheck(std::ostream & os, std::string const& version);
#if !defined(NDEBUG)
void skipFeatureRequire(tinyxml2::XMLElement const* element);
void skipImplicitExternSyncParams(tinyxml2::XMLElement const* element);
void skipTypeEnum(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes);
void skipTypeInclude(tinyxml2::XMLElement const* element);
#endif

bool beginsWith(std::string const& text, std::string const& prefix)
{
  return !prefix.empty() && text.substr(0, prefix.length()) == prefix;
}

// check the validity of an attributes map
// attributes : the map of name/value pairs of the encountered attributes
// line       : the line in the xml file where the attributes are listed
// required   : the required attributes, with a set of allowed values per attribute
// optional   : the optional attributes, with a set of allowed values per attribute
void checkAttributes(std::map<std::string, std::string> const& attributes, int line, std::map<std::string, std::set<std::string>> const& required, std::map<std::string, std::set<std::string>> const& optional)
{
  std::stringstream ss;
  ss << line;
  std::string lineNumber = ss.str();

  // check if all required attributes are included and if there is a set of allowed values, check if the actual value is part of that set
  for (auto const& r : required)
  {
    auto attributesIt = attributes.find(r.first);
    if (attributesIt == attributes.end())
    {
      throw std::runtime_error("Spec error on line " + lineNumber + ": missing attribute <" + r.first + ">");
    }
    if (!r.second.empty() && (r.second.find(attributesIt->second) == r.second.end()))
    {
      throw std::runtime_error("Spec error on line " + lineNumber + ": unexpected attribute value <" + attributesIt->second + "> in attribute <" + r.first + ">");
    }
  }
  // check if all not required attributes or optional, and if there is a set of allowed values, check if the actual value is part of that set
  for (auto const& a : attributes)
  {
    if (required.find(a.first) == required.end())
    {
      auto optionalIt = optional.find(a.first);
      if (optionalIt == optional.end())
      {
        std::cerr << "warning: " << "Unknown attribute " + a.first + " in line " + lineNumber + "!" << std::endl;
        continue;
      }
      if (!optionalIt->second.empty())
      {
        std::vector<std::string> values = tokenize(a.second, ',');
        for (auto const& v : values)
        {
          if (optionalIt->second.find(v) == optionalIt->second.end())
          {
            throw std::runtime_error("Spec error on line " + lineNumber + ": unexpected attribute value <" + v + "> in attribute <" + a.first + ">");
          }
        }
      }
    }
  }
}

void checkElements(std::vector<tinyxml2::XMLElement const*> const& elements, std::set<std::string> const& values)
{
  for (auto e : elements)
  {
    if (values.find(e->Value()) == values.end())
    {
      std::stringstream ss;
      ss << e->GetLineNum();
      std::string lineNumber = ss.str();
      std::cerr << "warning: Unknown element in spec on line: " << lineNumber << " " << e->Value() << "!" << std::endl;
    }
  }
}

void checkEmptyElement(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), {}, {});
  checkElements(getChildElements(element), {});
}

void checkOrderedElements(std::vector<tinyxml2::XMLElement const*> const& elements, std::vector<std::string> const& values)
{
  for (size_t i = 0; i < elements.size(); i++)
  {
    std::stringstream ss;
    ss << elements[i]->GetLineNum();
    std::string lineNumber = ss.str();

    if (values.size() <= i)
    {
      throw std::runtime_error("Spec error on line " + lineNumber + ": unexpected surplus element <" + elements[i]->Value() + ">");
    }
    if (values[i] != elements[i]->Value())
    {
      throw std::runtime_error("Spec error on line " + lineNumber + ": unexpected element <" + elements[i]->Value() + ">, expected <" + values[i] + ">");
    }
  }
}

std::string createEnumValueName(std::string const& name, std::string const& prefix, std::string const& postfix, bool bitmask, std::string const& tag)
{
  std::string result = "e" + toCamelCase(strip(name, prefix, postfix));
  if (bitmask)
  {
    size_t pos = result.find("Bit");
    if (pos != std::string::npos)
    {
      result.erase(pos, 3);
    }
  }
  if (!tag.empty() && (result.substr(result.length() - tag.length()) == toCamelCase(tag)))
  {
    result = result.substr(0, result.length() - tag.length()) + tag;
  }
  return result;
}

bool endsWith(std::string const& text, std::string const& postfix)
{
  return !postfix.empty() && (postfix.length() < text.length()) && (text.substr(text.length() - postfix.length()) == postfix);
}

void enterProtect(std::ostream &os, std::string const& protect)
{
  if (!protect.empty())
  {
    os << "#ifdef " << protect << std::endl;
  }
}

std::string extractTag(std::string const& name)
{
  // the name is supposed to look like: VK_<tag>_<other>
  size_t start = name.find('_');
  assert((start != std::string::npos) && (name.substr(0, start) == "VK"));
  size_t end = name.find('_', start + 1);
  assert(end != std::string::npos);
  return name.substr(start + 1, end - start - 1);
}

std::string findTag(std::string const& name, std::set<std::string> const& tags)
{
  // find the tag in a name, return that tag or an empty string
  auto tagIt = std::find_if(tags.begin(), tags.end(), [&name](std::string const& t)
  {
    size_t pos = name.find(t);
    return (pos != std::string::npos) && (pos == name.length() - t.length());
  });
  return tagIt != tags.end() ? *tagIt : "";
}

std::string generateEnumNameForFlags(std::string const& name)
{
  // create a string, where the substring "Flags" is replaced by "FlagBits"
  std::string generatedName = name;
  size_t pos = generatedName.rfind("Flags");
  assert(pos != std::string::npos);
  generatedName.replace(pos, 5, "FlagBits");
  return generatedName;
}

std::map<std::string, std::string> getAttributes(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes;
  for (auto attribute = element->FirstAttribute(); attribute; attribute = attribute->Next())
  {
    assert(attributes.find(attribute->Name()) == attributes.end());
    attributes[attribute->Name()] = attribute->Value();
  }
  return attributes;
}

std::vector<tinyxml2::XMLElement const*> getChildElements(tinyxml2::XMLElement const* element)
{
  std::vector<tinyxml2::XMLElement const*> childElements;
  for (tinyxml2::XMLElement const* childElement = element->FirstChildElement(); childElement; childElement = childElement->NextSiblingElement())
  {
    childElements.push_back(childElement);
  }
  return childElements;
}

bool isErrorEnum(std::string const& enumName)
{
  return (enumName.substr(0, 6) == "eError");
}

void leaveProtect(std::ostream &os, std::string const& protect)
{
  if (!protect.empty())
  {
    os << "#endif /*" << protect << "*/" << std::endl;
  }
}

std::string readArraySize(tinyxml2::XMLNode const* node, std::string& name)
{
  std::string arraySize;
  if (name.back() == ']')
  {
    // if the parameter has '[' and ']' in its name, get the stuff inbetween those as the array size and erase that part from the parameter name
    assert(!node->NextSibling());
    size_t pos = name.find('[');
    assert(pos != std::string::npos);
    arraySize = name.substr(pos + 1, name.length() - 2 - pos);
    name.erase(pos);
  }
  else
  {
    // otherwise look for a sibling of this node
    node = node->NextSibling();
    if (node && node->ToText())
    {
      assert(node->Value());
      std::string value = trimEnd(node->Value());
      if (value == "[")
      {
        // if this node has '[' as its value, the next node holds the array size, and the node after that needs to hold ']', and there should be no more siblings
        node = node->NextSibling();
        assert(node && node->ToElement() && (strcmp(node->Value(), "enum") == 0));
        arraySize = node->ToElement()->GetText();
        node = node->NextSibling();
        assert(node && node->ToText() && (trimEnd(node->Value()) == "]"));
      }
      else
      {
        // otherwise, the node holds '[' and ']', so get the stuff in between those as the array size
        assert((value.front() == '[') && (value.back() == ']'));
        arraySize = value.substr(1, value.length() - 2);
      }
      assert(!node->NextSibling() || ((strcmp(node->NextSibling()->Value(), "comment") == 0) && !node->NextSibling()->NextSibling()));
    }
  }
  return arraySize;
}

std::string startUpperCase(std::string const& input)
{
  return static_cast<char>(toupper(input[0])) + input.substr(1);
}

std::string startLowerCase(std::string const& input)
{
  return input.empty() ? "" : static_cast<char>(tolower(input[0])) + input.substr(1);
}

std::string strip(std::string const& value, std::string const& prefix, std::string const& postfix)
{
  std::string strippedValue = value;
  if (beginsWith(strippedValue, prefix))
  {
    strippedValue.erase(0, prefix.length());
  }
  if (endsWith(strippedValue, postfix))
  {
    strippedValue.erase(strippedValue.length() - postfix.length());
  }
  return strippedValue;
}

std::string stripErrorEnumPrefix(std::string const& enumName)
{
  assert(isErrorEnum(enumName));
  return strip(enumName, "eError");
}

std::string stripPluralS(std::string const& name)
{
  std::string strippedName(name);
  size_t pos = strippedName.rfind('s');
  assert(pos != std::string::npos);
  strippedName.erase(pos, 1);
  return strippedName;
}

std::vector<std::string> tokenize(std::string tokenString, char separator)
{
  std::vector<std::string> tokens;
  size_t start = 0, end;
  do
  {
    end = tokenString.find(separator, start);
    tokens.push_back(tokenString.substr(start, end - start));
    start = end + 1;
  } while (end != std::string::npos);
  return tokens;
}

std::string trim(std::string const& input)
{
  std::string result = input;
  result.erase(result.begin(), std::find_if(result.begin(), result.end(), [](char c) { return !std::isspace(c); }));
  result.erase(std::find_if(result.rbegin(), result.rend(), [](char c) { return !std::isspace(c); }).base(), result.end());
  return result;
}

std::string trimEnd(std::string const& input)
{
  std::string result = input;
  result.erase(std::find_if(result.rbegin(), result.rend(), [](char c) { return !std::isspace(c); }).base(), result.end());
  return result;
}

std::string toCamelCase(std::string const& value)
{
  assert(!value.empty() && (isupper(value[0]) || isdigit(value[0])));
  std::string result;
  result.reserve(value.size());
  result.push_back(value[0]);
  for (size_t i = 1; i < value.size(); i++)
  {
    if (value[i] != '_')
    {
      if ((value[i - 1] == '_') || isdigit(value[i - 1]))
      {
        result.push_back(value[i]);
      }
      else
      {
        result.push_back(static_cast<char>(tolower(value[i])));
      }
    }
  }
  return result;
}

std::string toUpperCase(std::string const& name)
{
  std::string convertedName;

  for (size_t i = 0; i<name.length(); i++)
  {
    if (isupper(name[i]) && ((i == 0) || islower(name[i - 1]) || isdigit(name[i - 1])))
    {
      convertedName.push_back('_');
    }
    convertedName.push_back(static_cast<char>(toupper(name[i])));
  }
  return convertedName;
}

void writeFunctionHeaderName(std::ostream & os, std::string const& name, bool singular, bool unique)
{
  os << (singular ? stripPluralS(name) : name);
  if (unique)
  {
    os << "Unique";
  }
}

void writeReinterpretCast(std::ostream & os, bool leadingConst, bool vulkanType, std::string const& type, bool trailingPointerToConst)
{
  os << "reinterpret_cast<";
  if (leadingConst)
  {
    os << "const ";
  }
  if (vulkanType)
  {
    os << "Vk";
  }
  os << type;
  if (trailingPointerToConst)
  {
    os << "* const";
  }
  os << "*>";
}

void writeStandardOrEnhanced(std::ostream & os, std::string const& standard, std::string const& enhanced)
{
  if (standard == enhanced)
  {
    // standard and enhanced string are equal -> just use one of them and we're done
    os << standard;
  }
  else
  {
    // standard and enhanced string differ -> use both, wrapping the enhanced by !VULKAN_HPP_DISABLE_ENHANCED_MODE
    // determine the argument list of that standard, and compare it with that of the enhanced
    // if they are equal -> need to have just one; if they differ -> need to have both
    size_t standardStart = standard.find('(');
    size_t standardCount = standard.find(')', standardStart) - standardStart;
    size_t enhancedStart = enhanced.find('(');
    bool unchangedInterface = (standard.substr(standardStart, standardCount) == enhanced.substr(enhancedStart, standardCount));
    if (unchangedInterface)
    {
      os << "#ifdef VULKAN_HPP_DISABLE_ENHANCED_MODE" << std::endl;
    }
    os << standard
      << (unchangedInterface ? "#else" : "#ifndef VULKAN_HPP_DISABLE_ENHANCED_MODE") << std::endl
      << enhanced
      << "#endif /*VULKAN_HPP_DISABLE_ENHANCED_MODE*/" << std::endl;
  }
}

void writeTypesafeCheck(std::ostream & os, std::string const& typesafeCheck)
{
  os << "// 32-bit vulkan is not typesafe for handles, so don't allow copy constructors on this platform by default." << std::endl
    << "// To enable this feature on 32-bit platforms please define VULKAN_HPP_TYPESAFE_CONVERSION" << std::endl
    << typesafeCheck << std::endl
    << "# if !defined( VULKAN_HPP_TYPESAFE_CONVERSION )" << std::endl
    << "#  define VULKAN_HPP_TYPESAFE_CONVERSION" << std::endl
    << "# endif" << std::endl
    << "#endif" << std::endl;
}

void writeVersionCheck(std::ostream & os, std::string const& version)
{
  os << "static_assert( VK_HEADER_VERSION == " << version << " , \"Wrong VK_HEADER_VERSION!\" );" << std::endl
    << std::endl;
}

#if !defined(NDEBUG)
void skipFeatureRequire(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {}, { { "name",{} } });
  checkElements(getChildElements(element), {});
}

void skipImplicitExternSyncParams(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), {}, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkOrderedElements(children, { "param" });
  checkEmptyElement(children[0]);
}

void skipTypeEnum(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category",{ "enum" } } }, { { "alias", {} }, { "name",{} } });
  checkElements(getChildElements(element), {});
}

void skipTypeInclude(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), { { "category",{ "include" } } }, { { "name",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "name" });

  for (auto child : children)
  {
    checkEmptyElement(child);
  }
}
#endif

template <typename T>
void VulkanHppGenerator::checkAlias(std::map<std::string, T> const& data, std::string const& name, int line)
{
  if (data.find(name) == data.end())
  {
    std::stringstream ss;
    ss << line;
    std::string lineNumber = ss.str();

    throw std::runtime_error("Spec error on line " + lineNumber + ": missing alias <" + name + ">");
  }
}

bool VulkanHppGenerator::containsUnion(std::string const& type, std::map<std::string, StructData> const& structs)
{
  // a simple recursive check if a type is or contains a union
  std::map<std::string, StructData>::const_iterator sit = structs.find(type);
  bool found = (sit != structs.end());
  if (found)
  {
    found = sit->second.isUnion;
    for (std::vector<MemberData>::const_iterator mit = sit->second.members.begin(); mit != sit->second.members.end() && !found; ++mit)
    {
      found = (mit->type == mit->pureType) && containsUnion(mit->type, structs);
    }
  }
  return found;
}

std::map<std::string, std::string> VulkanHppGenerator::createDefaults()
{
  std::map<std::string, std::string> defaultValues;
  for (auto const& dependency : m_dependencies)
  {
    assert(defaultValues.find(dependency.name) == defaultValues.end());
    switch (dependency.category)
    {
    case DependencyData::Category::BITMASK:
    case DependencyData::Category::HANDLE:
    case DependencyData::Category::STRUCT:
    case DependencyData::Category::UNION:        // just call the default constructor for bitmasks, handles, structs, and unions (which are mapped to classes)
      defaultValues[dependency.name] = dependency.name + "()";
      break;
    case DependencyData::Category::COMMAND:    // commands should never be asked for defaults
      break;
    case DependencyData::Category::ENUM:
      assert(m_enums.find(dependency.name) != m_enums.end());
      setDefault(dependency.name, defaultValues, m_enums.find(dependency.name)->second);
      break;
    case DependencyData::Category::FUNC_POINTER: // func_pointers default to nullptr
      defaultValues[dependency.name] = "nullptr";
      break;
    case DependencyData::Category::REQUIRED:     // all required default to "0"
    case DependencyData::Category::SCALAR:       // all scalars default to "0"
      defaultValues[dependency.name] = "0";
      break;
    default:
      assert(false && "Unhandled exception category");
      break;
    }
  }
  return defaultValues;
}

void VulkanHppGenerator::determineEnhancedReturnType(CommandData & commandData)
{
  std::string returnType;
  // if there is a return parameter of type void or Result, and if it's of type Result it either has just one success code
  // or two success codes, where the second one is of type eIncomplete and it's a two-step process
  // -> we can return that parameter
  if ((commandData.returnParam != INVALID_INDEX)
    && ((commandData.returnType == "void")
      || ((commandData.returnType == "Result")
        && ((commandData.successCodes.size() == 1)
          || ((commandData.successCodes.size() == 2)
            && (commandData.successCodes[1] == "eIncomplete")
            && commandData.twoStep)))))
  {
    if (commandData.vectorParams.find(commandData.returnParam) != commandData.vectorParams.end())
    {
      // the return parameter is a vector-type parameter
      if (commandData.params[commandData.returnParam].pureType == "void")
      {
        // for a vector of void, we use a vector of uint8_t, instead
        commandData.enhancedReturnType = "std::vector<uint8_t,Allocator>";
      }
      else
      {
        // for the other parameters, we use a vector of the pure type
        commandData.enhancedReturnType = "std::vector<" + commandData.params[commandData.returnParam].pureType + ",Allocator>";
      }
    }
    else
    {
      // it's a simple parameter -> get the type and just remove the trailing '*' (originally, it's a pointer)
      assert(commandData.params[commandData.returnParam].type.back() == '*');
      assert(commandData.params[commandData.returnParam].type.find("const") == std::string::npos);
      commandData.enhancedReturnType = commandData.params[commandData.returnParam].type;
      commandData.enhancedReturnType.pop_back();
    }
  }
  else if ((commandData.returnType == "Result") && (commandData.successCodes.size() == 1))
  {
    // an original return of type "Result" with just one successCode is changed to void, errors throw an exception
    commandData.enhancedReturnType = "void";
  }
  else
  {
    // the return type just stays the original return type
    commandData.enhancedReturnType = commandData.returnType;
  }
}

void VulkanHppGenerator::determineReducedName(CommandData & commandData)
{
  commandData.reducedName = commandData.fullName;
  std::string searchName = commandData.params[0].pureType;
  size_t pos = commandData.fullName.find(searchName);
  if ((pos == std::string::npos) && isupper(searchName[0]))
  {
    searchName[0] = static_cast<char>(tolower(searchName[0]));
    pos = commandData.fullName.find(searchName);
  }
  if (pos != std::string::npos)
  {
    commandData.reducedName.erase(pos, searchName.length());
  }
  else if ((searchName == "commandBuffer") && (commandData.fullName.find("cmd") == 0))
  {
    commandData.reducedName.erase(0, 3);
    pos = 0;
  }
  if ((pos == 0) && isupper(commandData.reducedName[0]))
  {
    commandData.reducedName[0] = static_cast<char>(tolower(commandData.reducedName[0]));
  }
}

void VulkanHppGenerator::determineReturnParam(CommandData & commandData)
{
  // for return types of type Result or void, we can replace determine a parameter to return
  if ((commandData.returnType == "Result") || (commandData.returnType == "void"))
  {
    for (size_t i = 0; i < commandData.params.size(); i++)
    {
      if ((commandData.params[i].type.find('*') != std::string::npos)
        && (commandData.params[i].type.find("const") == std::string::npos)
        && std::find_if(commandData.vectorParams.begin(), commandData.vectorParams.end(), [i](std::pair<size_t, size_t> const& vp) { return vp.second == i; }) == commandData.vectorParams.end())
      {
        // it's a non-const pointer and not a vector-size parameter
        std::map<size_t, size_t>::const_iterator vpit = commandData.vectorParams.find(i);
        if ((vpit == commandData.vectorParams.end()) || commandData.twoStep || (commandData.vectorParams.size() > 1) || (vpit->second == INVALID_INDEX) || (commandData.params[vpit->second].type.find('*') != std::string::npos))
        {
          // it's not a vector parameter, or a two-step process, or there is at least one more vector parameter, or the size argument of this vector parameter is not an argument, or the size argument of this vector parameter is provided by a pointer
          // -> look for another non-cost pointer argument
          auto paramIt = std::find_if(commandData.params.begin() + i + 1, commandData.params.end(), [](ParamData const& pd)
          {
            return (pd.type.find('*') != std::string::npos) && (pd.type.find("const") == std::string::npos);
          });
          // if there is another such argument, we can't decide which one to return -> return INVALID_INDEX
          // otherwise return the index of the selcted parameter
          commandData.returnParam = paramIt != commandData.params.end() ? ~0 : i;
        }
      }
    }
  }
}

void VulkanHppGenerator::determineSkippedParams(CommandData & commandData)
{
  // the size-parameters of vector parameters are not explicitly used in the enhanced API
  std::for_each(commandData.vectorParams.begin(), commandData.vectorParams.end(), [&commandData](std::pair<size_t, size_t> const& vp) { if (vp.second != INVALID_INDEX) commandData.skippedParams.insert(vp.second); });
  // and the return parameter is also skipped
  if (commandData.returnParam != INVALID_INDEX)
  {
    commandData.skippedParams.insert(commandData.returnParam);
  }
}

void VulkanHppGenerator::determineTemplateParam(CommandData & commandData)
{
  for (size_t i = 0; i < commandData.params.size(); i++)
  {
    // any vector parameter on the pure type void is templatized in the enhanced API
    if ((commandData.vectorParams.find(i) != commandData.vectorParams.end()) && (commandData.params[i].pureType == "void"))
    {
#if !defined(NDEBUG)
      for (size_t j = i + 1; j < commandData.params.size(); j++)
      {
        assert((commandData.vectorParams.find(j) == commandData.vectorParams.end()) || (commandData.params[j].pureType != "void"));
      }
#endif
      commandData.templateParam = i;
      break;
    }
  }
  assert((commandData.templateParam == INVALID_INDEX) || (commandData.vectorParams.find(commandData.templateParam) != commandData.vectorParams.end()));
}

void VulkanHppGenerator::determineVectorParams(CommandData & commandData)
{
  // look for the parameters whose len equals the name of an other parameter
  for (auto it = commandData.params.begin(), begin = it, end = commandData.params.end(); it != end; ++it)
  {
    if (!it->len.empty())
    {
      auto findLambda = [it](ParamData const& pd) { return pd.name == it->len; };
      auto findIt = std::find_if(begin, it, findLambda);                        // look for a parameter named as the len of this parameter
      assert((std::count_if(begin, end, findLambda) == 0) || (findIt < it));    // make sure, there is no other parameter like that

      // add this parameter as a vector parameter, using the len-name parameter as the second value (or INVALID_INDEX if there is nothing like that)
      commandData.vectorParams.insert(std::make_pair(std::distance(begin, it), findIt < it ? std::distance(begin, findIt) : INVALID_INDEX));
      assert((commandData.vectorParams[std::distance(begin, it)] != INVALID_INDEX)
        || (it->len == "null-terminated")
        || (it->len == "pAllocateInfo::descriptorSetCount")
        || (it->len == "pAllocateInfo::commandBufferCount"));
    }
  }
}

std::string VulkanHppGenerator::generateCall(CommandData const& commandData, bool firstCall, bool singular)
{
  std::ostringstream call;
  writeCall(call, commandData, firstCall, singular);
  return call.str();
}

std::string const& VulkanHppGenerator::getTypesafeCheck() const
{
  return m_typesafeCheck;
}

std::string const& VulkanHppGenerator::getVersion() const
{
  return m_version;
}

std::string const& VulkanHppGenerator::getVulkanLicenseHeader() const
{
  return m_vulkanLicenseHeader;
}

bool VulkanHppGenerator::isSubStruct(std::pair<std::string, StructData> const& nsd, std::string const& name, StructData const& structData)
{
  if ((nsd.first != name) && (nsd.second.members.size() < structData.members.size()) && (structData.members[0].name != "sType"))
  {
    bool equal = true;
    for (size_t i = 0; i < nsd.second.members.size() && equal; i++)
    {
      equal = (nsd.second.members[i].type == structData.members[i].type) && (nsd.second.members[i].name == structData.members[i].name);
    }
    if (equal)
    {
      return true;
    }
  }
  return false;
}

void VulkanHppGenerator::linkCommandToHandle(CommandData & commandData)
{
  // first, find the handle named like the type of the first argument
  // if there is no such handle, look for the unnamed "handle", that gathers all the functions not tied to a specific handle
  assert(!commandData.params.empty());
  std::map<std::string, HandleData>::iterator hit = m_handles.find(commandData.params[0].pureType);
  if (hit == m_handles.end())
  {
    hit = m_handles.find("");
  }
  assert(hit != m_handles.end());

  // put the command into the handle's list of commands, and store the handle in the commands className
  hit->second.commands.push_back(commandData.fullName);
  commandData.className = hit->first;

  // add the dependencies of the command to the dependencies of the handle
  DependencyData const& commandDD = m_dependencies.back();
  std::list<DependencyData>::iterator handleDD = std::find_if(m_dependencies.begin(), m_dependencies.end(), [hit](DependencyData const& dd) { return dd.name == hit->first; });
  assert((handleDD != m_dependencies.end()) || hit->first.empty());
  if (handleDD != m_dependencies.end())
  {
    std::copy_if(commandDD.dependencies.begin(), commandDD.dependencies.end(), std::inserter(handleDD->dependencies, handleDD->dependencies.end()), [hit](std::string const& d) { return d != hit->first; });
  }
}

bool VulkanHppGenerator::readCommandParam(tinyxml2::XMLElement const* element, std::set<std::string> & dependencies, std::vector<ParamData> & params)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {}, { { "externsync",{} },{ "len",{} },{ "noautovalidity",{ "true" } },{ "optional",{ "false", "true" } } });
  checkElements(getChildElements(element), { "name", "type" });

  ParamData param;

  bool isTwoStep = false;
  auto lenAttribute = attributes.find("len");
  if (lenAttribute != attributes.end())
  {
    param.len = lenAttribute->second;
    auto pit = std::find_if(params.begin(), params.end(), [&param](ParamData const& pd) { return param.len == pd.name; });
    if (pit != params.end())
    {
      isTwoStep = (pit->type.find('*') != std::string::npos);
    }
  }

  // get the type of the parameter, and put it into the list of dependencies
  tinyxml2::XMLNode const* child = readCommandParamType(element->FirstChild(), param);
  dependencies.insert(param.pureType);

  assert(child->ToElement());
  tinyxml2::XMLElement const* nameElement = child->ToElement();
  checkEmptyElement(nameElement);
  param.name = child->ToElement()->GetText();

  param.arraySize = readArraySize(child, param.name);

  auto optionalAttribute = attributes.find("optional");
  param.optional = (optionalAttribute != attributes.end()) && (optionalAttribute->second == "true");

  params.push_back(param);

  assert(!isTwoStep || (param.type.substr(0, 6) != "const "));
  return isTwoStep;
}

tinyxml2::XMLNode const* VulkanHppGenerator::readCommandParamType(tinyxml2::XMLNode const* node, ParamData& param)
{
  assert(node);
  if (node->ToText())
  {
    // start type with "const" or "struct", if needed
    std::string value = trim(node->Value());
    assert((value == "const") || (value == "struct") || (value == "const struct"));
    param.type = value + " ";
    node = node->NextSibling();
    assert(node);
  }

  // get the pure type
  assert(node->ToElement());
  tinyxml2::XMLElement const* typeElement = node->ToElement();
  checkEmptyElement(typeElement);
  std::string type = strip(node->ToElement()->GetText(), "Vk");
  param.unchangedType = param.type + node->ToElement()->GetText();
  param.type += type;
  param.pureType = type;

  // end with "*", "**", or "* const*", if needed
  node = node->NextSibling();
  assert(node);
  if (node->ToText())
  {
    std::string value = trimEnd(node->Value());
    assert((value == "*") || (value == "**") || (value == "* const*"));
    param.type += value;
    param.unchangedType += value;
    node = node->NextSibling();
  }

  return node;
}

void VulkanHppGenerator::readCommands(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {}, { { "comment",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "command" });

  for (auto child : children)
  {
    readCommandsCommand(child);
  }
}

void VulkanHppGenerator::readCommandsCommand(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {},
  { { "alias", {} },
    { "cmdbufferlevel",{ "primary", "secondary" } },
    { "comment",{} },
    { "errorcodes",{} },
    { "name", {} },
    { "pipeline",{ "compute", "graphics", "transfer" } },
    { "queues",{ "compute", "graphics", "sparse_binding", "transfer" } },
    { "renderpass",{ "both", "inside", "outside" } },
    { "successcodes",{} }
  });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);

  CommandData commandData;
  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    // for command aliases, create a copy of the aliased command
    checkAttributes(attributes, element->GetLineNum(), { { "alias",{} },{ "name",{} } }, {});    // re-check on alias type!
    checkElements(children, {});

    std::string alias = startLowerCase(strip(aliasIt->second, "vk"));
    checkAlias(m_commands, alias, element->GetLineNum());

    auto commandsIt = m_commands.find(alias);
    assert(commandsIt != m_commands.end());
    commandData = commandsIt->second;
    commandData.fullName = startLowerCase(strip(attributes.find("name")->second, "vk"));
    commandData.isAlias = true;
    determineReducedName(commandData);
    linkCommandToHandle(commandData);

    // add a DependencyData to this name
    m_dependencies.push_back(DependencyData(DependencyData::Category::COMMAND, commandData.fullName));
    m_dependencies.back().dependencies.insert(alias);
  }
  else
  {
    checkElements(children, { "implicitexternsyncparams", "param", "proto" });

    // read the success codes
    auto successcodesAttribute = attributes.find("successcodes");
    if (successcodesAttribute != attributes.end())
    {
      commandData.successCodes = tokenize(successcodesAttribute->second, ',');
      for (auto & code : commandData.successCodes)
      {
        std::string tag = findTag(code, m_tags);
        // on each success code: prepend 'e', strip "VK_" and a tag, convert it to camel case, and add the tag again
        code = std::string("e") + toCamelCase(strip(code, "VK_", tag)) + tag;
      }
    }

    for (auto child : children)
    {
      std::string value = child->Value();
      if (value == "param")
      {
        commandData.twoStep |= readCommandParam(child, m_dependencies.back().dependencies, commandData.params);
      }
      else if (value == "proto")
      {
        readCommandProto(child, commandData.returnType, commandData.unchangedReturnType, commandData.fullName);
      }
#if !defined(NDEBUG)
      else
      {
        assert(value == "implicitexternsyncparams");
        skipImplicitExternSyncParams(child);
      }
#endif
    }

    determineReducedName(commandData);
    linkCommandToHandle(commandData);
    registerDeleter(commandData);
    determineVectorParams(commandData);
    determineReturnParam(commandData);
    determineTemplateParam(commandData);
    determineEnhancedReturnType(commandData);
    determineSkippedParams(commandData);
  }

  // insert the commandData into the commands-map,
  assert(m_commands.find(commandData.fullName) == m_commands.end());
  m_commands.insert(std::make_pair(commandData.fullName, commandData));
}

void VulkanHppGenerator::readCommandProto(tinyxml2::XMLElement const* element, std::string & returnType, std::string & unchangedReturnType, std::string & fullName)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), {}, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkOrderedElements(children, { "type", "name" });

  // get return type and name of the command
  returnType = strip(children[0]->GetText(), "Vk");
  unchangedReturnType = children[0]->GetText();
  fullName = startLowerCase(strip(children[1]->GetText(), "vk"));

  // add an empty DependencyData to this name
  m_dependencies.push_back(DependencyData(DependencyData::Category::COMMAND, fullName));
}

void VulkanHppGenerator::readComment(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), {}, {});
  checkElements(getChildElements(element), {});

  assert(element->GetText());
  std::string text = element->GetText();
  if (text.find("\nCopyright") == 0)
  {
    assert(m_vulkanLicenseHeader.empty());
    m_vulkanLicenseHeader = text;

    // erase the part after the Copyright text
    size_t pos = m_vulkanLicenseHeader.find("\n\n------------------------------------------------------------------------");
    if (pos != std::string::npos) {
      m_vulkanLicenseHeader.erase(pos);
    }

    // replace any '\n' with "\n// "
    for (pos = m_vulkanLicenseHeader.find('\n'); pos != std::string::npos; pos = m_vulkanLicenseHeader.find('\n', pos + 1))
    {
      m_vulkanLicenseHeader.replace(pos, 1, "\n// ");
    }

    // and add a little message on our own
    m_vulkanLicenseHeader += "\n\n// This header is generated from the Khronos Vulkan XML API Registry.";
  }

  m_vulkanLicenseHeader.erase(m_vulkanLicenseHeader.begin(), std::find_if(m_vulkanLicenseHeader.begin(), m_vulkanLicenseHeader.end(), [](char c) { return !std::isspace(c); }));
}

void VulkanHppGenerator::readDisabledExtensionRequire(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), {}, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "command", "enum", "type" });

  for (auto child : children)
  {
    checkElements(getChildElements(child), {});

    std::string value = child->Value();
    if ((value == "command") || (value == "type"))
    {
      std::map<std::string, std::string> attributes = getAttributes(child);
      checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, {});

      // disable a command or a type !
      auto nameAttribute = attributes.find("name");
      std::string name = (value == "command") ? startLowerCase(strip(nameAttribute->second, "vk")) : strip(nameAttribute->second, "Vk");

      // search this name in the dependencies list and remove it
      std::list<DependencyData>::const_iterator depIt = std::find_if(m_dependencies.begin(), m_dependencies.end(), [&name](DependencyData const& dd) { return(dd.name == name); });
      assert(depIt != m_dependencies.end());
      m_dependencies.erase(depIt);

      // erase it from all dependency sets
      for (auto & dep : m_dependencies)
      {
        dep.dependencies.erase(name);
      }

      if (value == "command")
      {
        // first unlink the command from its class
        auto commandsIt = m_commands.find(name);
        assert(commandsIt != m_commands.end());
        assert(!commandsIt->second.className.empty());
        auto handlesIt = m_handles.find(commandsIt->second.className);
        assert(handlesIt != m_handles.end());
        auto it = std::find(handlesIt->second.commands.begin(), handlesIt->second.commands.end(), name);
        assert(it != handlesIt->second.commands.end());
        handlesIt->second.commands.erase(it);

        // then remove the command
        m_commands.erase(name);
      }
      else
      {
        // a type simply needs to be removed from the structs and vkTypes sets
        assert((m_structs.find(name) != m_structs.end()) && (m_vkTypes.find(name) != m_vkTypes.end()));
        m_structs.erase(name);
        m_vkTypes.erase(name);
      }
    }
    else
    {
      assert(value == "enum");
      std::map<std::string, std::string> attributes = getAttributes(child);
      checkAttributes(attributes, child->GetLineNum(), { { "name",{} } }, { { "bitpos", {} }, { "extends",{} },{ "offset",{} },{ "value",{} } });
    }
  }
}

void VulkanHppGenerator::readEnums(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, { { "comment",{} },{ "type",{ "bitmask", "enum" } } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "comment", "enum", "unused" });

  std::string name = strip(attributes.find("name")->second, "Vk");

  if (name == "API Constants")
  {
    for (auto child : children)
    {
      assert(strcmp(child->Value(), "enum") == 0);
      readEnumsConstant(child);
    }
  }
  else
  {
    checkAttributes(attributes, element->GetLineNum(), { { "name",{} },{ "type",{ "bitmask", "enum" } } }, { { "comment",{} } });   // re-check with type as required

    if (std::find_if(m_dependencies.begin(), m_dependencies.end(), [&name](DependencyData const& dd) { return dd.name == name; }) == m_dependencies.end())
    {
      // add an empty DependencyData on this name into the dependencies list
      m_dependencies.push_back(DependencyData(DependencyData::Category::ENUM, name));

      // add this enum to the set of Vulkan data types
      assert(m_vkTypes.find(name) == m_vkTypes.end());
      m_vkTypes.insert(name);
    }

    // ad an empty EnumData on this name into the enums map
    std::map<std::string, EnumData>::iterator it = m_enums.insert(std::make_pair(name, EnumData(name))).first;
    assert(it->second.postfix.empty() && it->second.prefix.empty() && it->second.protect.empty() && it->second.values.empty());

    if (name == "Result")
    {
      // special handling for VKResult, as its enums just have VK_ in common
      it->second.prefix = "VK_";
    }
    else
    {
      std::string type = attributes.find("type")->second;
      it->second.bitmask = (type == "bitmask");
      if (it->second.bitmask)
      {
        // for a bitmask enum, start with "VK", cut off the trailing "FlagBits", and convert that name to upper case
        // end that with "Bit"
        size_t pos = name.find("FlagBits");
        assert(pos != std::string::npos);
        it->second.prefix = "VK" + toUpperCase(name.substr(0, pos)) + "_";
      }
      else
      {
        // for a non-bitmask enum, start with "VK", and convert the name to upper case
        it->second.prefix = "VK" + toUpperCase(name) + "_";
      }

      // if the enum name contains a tag move it from the prefix to the postfix to generate correct enum value names.
      for (std::set<std::string>::const_iterator tit = m_tags.begin(); tit != m_tags.end(); ++tit)
      {
        if ((tit->length() < it->second.prefix.length()) && (it->second.prefix.substr(it->second.prefix.length() - tit->length() - 1) == (*tit + "_")))
        {
          it->second.prefix.erase(it->second.prefix.length() - tit->length() - 1);
          it->second.postfix = "_" + *tit;
          break;
        }
        else if ((tit->length() < it->second.name.length()) && (it->second.name.substr(it->second.name.length() - tit->length()) == *tit))
        {
          it->second.postfix = "_" + *tit;
          break;
        }
      }
    }

    // read the names of the enum values
    for (auto child : children)
    {
      std::string value = child->Value();
      if (value == "enum")
      {
        readEnumsEnum(child, it->second, "");
      }
#if !defined(NDEBUG)
      else
      {
        assert((value == "comment") || (value == "unused"));
      }
#endif
    }
  }
}

void VulkanHppGenerator::readEnumsEnum(tinyxml2::XMLElement const* element, EnumData & enumData, std::string const& tag)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, { {"alias", {} }, { "bitpos",{} },{ "comment",{} },{ "value",{} } });
  assert((attributes.find("alias") != attributes.end()) + (attributes.find("bitpos") != attributes.end()) + (attributes.find("value") != attributes.end()) == 1);
  checkElements(getChildElements(element), {});
  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    auto enumIt = std::find_if(enumData.values.begin(), enumData.values.end(), [&aliasIt](EnumValueData const& evd) { return evd.value == aliasIt->second; });
    assert((enumIt != enumData.values.end()) && enumIt->alias.empty());
    enumIt->alias = createEnumValueName(attributes.find("name")->second, enumData.prefix, enumData.postfix, enumData.bitmask, tag);
  }
  else
  {
    enumData.addEnumValue(attributes.find("name")->second, tag, m_nameMap);
  }
}

void VulkanHppGenerator::readEnumsConstant(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, { { "alias", {}}, { "comment",{} }, { "value",{} } });
  checkElements(getChildElements(element), {});
  std::string name = attributes.find("name")->second;
  assert(m_constants.find(name) == m_constants.end());

  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    checkAttributes(attributes, element->GetLineNum(), { {"alias", {}}, { "name", {}} }, {});    // re-check on alias type
    checkAlias(m_constants, aliasIt->second, element->GetLineNum());
    m_constants[name] = m_constants.find(aliasIt->second)->second;
  }
  else
  {
    checkAttributes(attributes, element->GetLineNum(), { { "name",{} }, { "value", {}} }, { {"comment", {} } });    // re-check on non-alias type
    m_constants[name] = attributes.find("value")->second;
  }
}

void VulkanHppGenerator::readExtensionCommand(tinyxml2::XMLElement const* element, std::string const& protect)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, {});
  checkElements(getChildElements(element), {});

  // just add the protect string to the CommandData
  if (!protect.empty())
  {
    std::string name = startLowerCase(strip(attributes.find("name")->second, "vk"));
    std::map<std::string, CommandData>::iterator cit = m_commands.find(name);
    assert(cit != m_commands.end());
    cit->second.protect = protect;
  }
}

void VulkanHppGenerator::readExtensionEnum(tinyxml2::XMLElement const* element, std::string const& tag)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(),
  {
    { "name", {} }
  },
  {
    { "alias", {} },
    { "bitpos", {} },
    { "comment", {} },
    { "dir", { "-" } },
    { "extends", {} },
    { "extnumber", {} },
    { "offset", {} },
    { "value", {} }
  });
  checkElements(getChildElements(element), {});

  // TODO process enums which don't extend existing enums
  auto extendsIt = attributes.find("extends");
  if (extendsIt != attributes.end())
  {
    std::string extends = strip(extendsIt->second, "Vk");
    auto enumIt = m_enums.find(extends);
    assert(enumIt != m_enums.end());

    auto aliasIt = attributes.find("alias");
    if (aliasIt != attributes.end())
    {
      checkAttributes(attributes, element->GetLineNum(), { { "alias", {} }, { "extends", {} }, { "name", {} } }, { { "comment",{} } });
      std::string alias = createEnumValueName(aliasIt->second, enumIt->second.prefix, enumIt->second.postfix, enumIt->second.bitmask, tag);
      auto evdIt = std::find_if(enumIt->second.values.begin(), enumIt->second.values.end(), [&alias](EnumValueData const& evd) { return evd.name == alias; });
      assert(evdIt != enumIt->second.values.end());
      evdIt->alias = createEnumValueName(attributes.find("name")->second, enumIt->second.prefix, enumIt->second.postfix, enumIt->second.bitmask, tag);
      if (evdIt->name == evdIt->alias)
      {
        // skip alias, that would result in the very same enum name
        evdIt->alias.clear();
      }
    }
    else
    {
      assert((attributes.find("bitpos") != attributes.end()) + (attributes.find("offset") != attributes.end()) + (attributes.find("value") != attributes.end()) == 1);
      enumIt->second.addEnumValue(attributes.find("name")->second, tag, m_nameMap);
    }
  }
}

void VulkanHppGenerator::readExtensionRequire(tinyxml2::XMLElement const* element, std::string const& protect, std::string const& tag)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {}, { { "extension",{} },{ "feature",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "command", "comment", "enum", "type" });

  for (auto child : children)
  {
    std::string value = child->Value();

    if (value == "command")
    {
      readExtensionCommand(child, protect);
    }
    else if (value == "enum")
    {
      readExtensionEnum(child, tag);
    }
    else if (value == "type")
    {
      readExtensionType(child, protect);
    }
#if !defined(NDEBUG)
    else
    {
      assert(value == "comment");
      checkEmptyElement(child);
    }
#endif
  }
}

void VulkanHppGenerator::readExtensions(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "comment",{} } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "extension" });

  for (auto child : children)
  {
    readExtensionsExtension(child);
  }
}

void VulkanHppGenerator::readExtensionsExtension(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(),
  {
    { "name",{} },
    { "number",{} },
    { "supported",{ "disabled", "vulkan" } }
  },
  {
    { "author",{} },
    { "comment", {} },
    { "contact",{} },
    { "deprecatedby", {} },
    { "obsoletedby", {} },
    { "platform",{} },
    { "promotedto", {} },
    { "provisional", {} },
    { "protect",{} },
    { "requires",{} },
    { "requiresCore",{} },
    { "type",{ "device", "instance" } }
  });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "require" });

  if (attributes.find("supported")->second == "disabled")
  {
    // kick out all the disabled stuff we've read before !!
    for (tinyxml2::XMLElement const* child = element->FirstChildElement(); child; child = child->NextSiblingElement())
    {
      assert(strcmp(child->Value(), "require") == 0);
      readDisabledExtensionRequire(child);
    }
  }
  else
  {
    std::string name = attributes.find("name")->second;
    std::string tag = extractTag(name);
    assert(m_tags.find(tag) != m_tags.end());

    auto protectAttribute = attributes.find("protect");
    auto platformAttribute = attributes.find("platform");
    std::string protect;
    if (protectAttribute != attributes.end())
    {
      protect = protectAttribute->second;
    }
    else if (platformAttribute != attributes.end())
    {
      auto authorAttribute = attributes.find("author");
      assert(authorAttribute != attributes.end());
      protect = "VK_USE_PLATFORM_" + toUpperCase(platformAttribute->second) + "_" + authorAttribute->second;
    }

#if !defined(NDEBUG)
    assert(m_extensions.find(name) == m_extensions.end());
    ExtensionData & extension = m_extensions.insert(std::make_pair(name, ExtensionData())).first->second;
    extension.protect = protect;
    auto requiresAttribute = attributes.find("requires");
    if (requiresAttribute != attributes.end())
    {
      extension.requires = tokenize(requiresAttribute->second, ',');
    }
#endif

    for (auto child : children)
    {
      readExtensionRequire(child, protect, tag);
    }
  }
}

void VulkanHppGenerator::readExtensionType(tinyxml2::XMLElement const* element, std::string const& protect)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, {});
  checkElements(getChildElements(element), {});

  // add the protect-string to the appropriate type: enum, flag, handle, scalar, or struct
  if (!protect.empty())
  {
    std::string name = strip(attributes.find("name")->second, "Vk");
    std::map<std::string, BitmaskData>::iterator bitmasksIt = m_bitmasks.find(name);
    if (bitmasksIt != m_bitmasks.end())
    {
      bitmasksIt->second.protect = protect;

      // if the enum of this flags is auto-generated, protect it as well
      std::string enumName = generateEnumNameForFlags(name);
      std::map<std::string, EnumData>::iterator enumsIt = m_enums.find(enumName);
      assert(enumsIt != m_enums.end());
      if (enumsIt->second.values.empty())
      {
        enumsIt->second.protect = protect;
      }
    }
    else
    {
      std::map<std::string, EnumData>::iterator eit = m_enums.find(name);
      if (eit != m_enums.end())
      {
        eit->second.protect = protect;
      }
      else
      {
        std::map<std::string, HandleData>::iterator hait = m_handles.find(name);
        if (hait != m_handles.end())
        {
          hait->second.protect = protect;
        }
        else
        {
          std::map<std::string, ScalarData>::iterator scit = m_scalars.find(name);
          if (scit != m_scalars.end())
          {
            scit->second.protect = protect;
          }
          else
          {
            std::map<std::string, StructData>::iterator stit = m_structs.find(name);
            if (stit != m_structs.end())
            {
              stit->second.protect = protect;
            }
            else
            {
              assert(m_defines.find(name) != m_defines.end());
            }
          }
        }
      }
    }
  }
}

void VulkanHppGenerator::readFeature(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "api",{ "vulkan" } },{ "comment",{} },{ "name",{} },{ "number",{} } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "require" });

  for (auto child : children)
  {
    readFeatureRequire(child);
  }
}

void VulkanHppGenerator::readFeatureRequire(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {}, { { "comment",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "command", "comment", "enum", "type" });

  for (auto child : children)
  {
    std::string value = child->Value();
    if (value == "enum")
    {
      readFeatureRequireEnum(child);
    }
#if !defined(NDEBUG)
    else
    {
      assert((value == "command") || (value == "comment") || (value == "type"));
      skipFeatureRequire(child);
    }
#endif
  }
}

void VulkanHppGenerator::readFeatureRequireEnum(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(),
  {
    { "name",{} }
  },
  {
    { "bitpos",{} },
    { "comment",{} },
    { "dir", { "-" } },
    { "extends",{} },
    { "extnumber", {} },
    { "offset", {} },
    { "value",{} }
  });
  checkElements(getChildElements(element), {});

  auto extendsAttribute = attributes.find("extends");
  if (extendsAttribute != attributes.end())
  {
    assert(strncmp(extendsAttribute->second.c_str(), "Vk", 2) == 0);
    std::string extends = strip(extendsAttribute->second, "Vk");
    auto enumIt = m_enums.find(extends);
    assert(enumIt != m_enums.end());
    enumIt->second.addEnumValue(attributes.find("name")->second, "", m_nameMap);
  }
}

void VulkanHppGenerator::readTags(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), { { "comment",{} } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "tag" });

  for (auto child : children)
  {
    std::string value = child->Value();
    assert(value == "tag");
    readTag(child);
  }
}

void VulkanHppGenerator::readTag(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "author",{} },{ "contact",{} },{ "name",{} } }, {});
  checkElements(getChildElements(element), {});

  for (auto const& attribute : attributes)
  {
    std::string name = attribute.first;
    if (name == "name")
    {
      std::string value = attribute.second;
      m_tags.insert(value);
    }
    else
    {
      assert((name == "author") || (name == "contact"));
    }
  }
}

void VulkanHppGenerator::readType(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);

  auto categoryIt = attributes.find("category");
  if (categoryIt != attributes.end())
  {
    if (categoryIt->second == "basetype")
    {
      readTypeBasetype(element, attributes);
    }
    else if (categoryIt->second == "bitmask")
    {
      readTypeBitmask(element, attributes);
    }
    else if (categoryIt->second == "define")
    {
      readTypeDefine(element, attributes);
    }
    else if (categoryIt->second == "funcpointer")
    {
      readTypeFuncpointer(element, attributes);
    }
    else if (categoryIt->second == "handle")
    {
      readTypeHandle(element, attributes);
    }
    else if (categoryIt->second == "struct")
    {
      readTypeStruct(element, false, attributes);
    }
    else if (categoryIt->second == "union")
    {
      readTypeStruct(element, true, attributes);
    }
#if !defined(NDEBUG)
    else if (categoryIt->second == "enum")
    {
      skipTypeEnum(element, attributes);
    }
    else if (categoryIt->second == "include")
    {
      skipTypeInclude(element);
    }
    else
#else
    else if ((categoryIt->second != "enum") && (categoryIt->second != "include"))
#endif
    {
      std::stringstream ss;
      ss << element->GetLineNum();
      std::string lineNumber = ss.str();

      throw std::runtime_error("Spec error on line " + lineNumber + ": unknown category <" + categoryIt->second + ">");
    }
  }
  else
  {
    assert(attributes.find("name") != attributes.end());
    readTypeName(element, attributes);
  }
}

void VulkanHppGenerator::readTypeBasetype(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category",{ "basetype" } } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkOrderedElements(children, { "type", "name" });
  checkEmptyElement(children[0]);
  checkEmptyElement(children[1]);

  std::string type = children[0]->GetText();
  assert((type == "uint32_t") || (type == "uint64_t"));

  std::string name = strip(children[1]->GetText(), "Vk");

  // skip "Flags",
  if (name != "Flags")
  {
    m_dependencies.push_back(DependencyData(DependencyData::Category::SCALAR, name));
    m_dependencies.back().dependencies.insert(type);
  }
  else
  {
    assert(type == "uint32_t");
  }
}

void VulkanHppGenerator::readTypeBitmask(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category", { "bitmask" } } }, { { "alias", {} }, { "name", {}}, { "requires", {} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);

  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    checkAttributes(attributes, element->GetLineNum(), { { "alias", {} }, { "category", {"bitmask"} }, { "name", {} } }, {});   // re-check on alias type!
    checkElements(children, {});

    std::string alias = strip(aliasIt->second, "Vk");
    checkAlias(m_bitmasks, alias, element->GetLineNum());

    std::string name = strip(attributes.find("name")->second, "Vk");

    auto bitmasksIt = m_bitmasks.find(alias);
    assert((bitmasksIt != m_bitmasks.end()) && bitmasksIt->second.alias.empty());
    bitmasksIt->second.alias = name;
  }
  else
  {
    checkOrderedElements(children, { "type", "name" });
    checkEmptyElement(children[0]);
    checkEmptyElement(children[1]);

    assert(strcmp(children[0]->GetText(), "VkFlags") == 0);

    std::string name = strip(children[1]->GetText(), "Vk");

    std::string requires;
    auto requiresIt = attributes.find("requires");
    if (requiresIt != attributes.end())
    {
      requires = strip(requiresIt->second, "Vk");
    }
    else
    {
      // Generate FlagBits name, add a DependencyData for that name, and add it to the list of enums and vulkan types
      requires = generateEnumNameForFlags(name);
      assert(std::find_if(m_dependencies.begin(), m_dependencies.end(), [&requires](DependencyData const& dd) { return dd.name == requires; }) == m_dependencies.end());
      m_dependencies.push_back(DependencyData(DependencyData::Category::ENUM, requires));
      assert(m_enums.find(requires) == m_enums.end());
      m_enums.insert(std::make_pair(requires, EnumData(requires, true)));
      assert(m_vkTypes.find(requires) == m_vkTypes.end());
      m_vkTypes.insert(requires);
    }

    // add a DependencyData for the bitmask name, with the required type as its first dependency
    m_dependencies.push_back(DependencyData(DependencyData::Category::BITMASK, name));
    m_dependencies.back().dependencies.insert(requires);

    m_bitmasks.insert(std::make_pair(name, BitmaskData()));

    assert(m_vkTypes.find(name) == m_vkTypes.end());
    m_vkTypes.insert(name);
  }
}

void VulkanHppGenerator::readTypeDefine(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category",{ "define" } } }, { { "name",{} } });

  auto nameIt = attributes.find("name");
  if (nameIt != attributes.end())
  {
    assert(!element->FirstChildElement());
    assert(nameIt->second == "VK_DEFINE_NON_DISPATCHABLE_HANDLE");

    // filter out the check for the different types of VK_DEFINE_NON_DISPATCHABLE_HANDLE
    std::string text = element->LastChild()->ToText()->Value();
    size_t start = text.find("#if defined(__LP64__)");
    size_t end = text.find_first_of("\r\n", start + 1);
    m_typesafeCheck = text.substr(start, end - start);
  }
  else if (element->GetText() && (trim(element->GetText()) == "struct"))
  {
    tinyxml2::XMLElement const* child = element->FirstChildElement();
    assert(child && (strcmp(child->Value(), "name") == 0) && child->GetText());
    m_defines.insert(child->GetText());
    m_dependencies.push_back(DependencyData(DependencyData::Category::REQUIRED, child->GetText()));
  }
  else
  {
    tinyxml2::XMLElement const* child = element->FirstChildElement();
    assert(child && !child->FirstAttribute() && (strcmp(child->Value(), "name") == 0) && child->GetText());
    std::string text = trim(child->GetText());
    if (text == "VK_HEADER_VERSION")
    {
      m_version = trimEnd(element->LastChild()->ToText()->Value());
    }
    // ignore all the other defines
    assert(!child->NextSiblingElement() || (child->NextSiblingElement() && !child->NextSiblingElement()->FirstAttribute() && (strcmp(child->NextSiblingElement()->Value(), "type") == 0) && !child->NextSiblingElement()->NextSiblingElement()));
  }
}

void VulkanHppGenerator::readTypeFuncpointer(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category",{ "funcpointer" } } }, { { "requires",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "name", "type" });
  assert(!children.empty());
  checkEmptyElement(children[0]);

  assert((strcmp(children[0]->Value(), "name") == 0) && children[0]->GetText());
  m_dependencies.push_back(DependencyData(DependencyData::Category::FUNC_POINTER, children[0]->GetText()));

#if !defined(NDEBUG)
  for (size_t i = 1; i < children.size(); i++)
  {
    checkEmptyElement(children[i]);
  }
#endif
}

void VulkanHppGenerator::readTypeHandle(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "category",{ "handle" } } }, { { "alias",{} }, { "name",{} }, { "parent",{} } });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);

  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    checkAttributes(attributes, element->GetLineNum(), { { "alias",{} },{ "category",{ "handle" } },{ "name",{} } }, {});   // re-check on alias type!
    checkElements(children, {});

    std::string alias = strip(aliasIt->second, "Vk");
    checkAlias(m_handles, alias, element->GetLineNum());

    std::string name = strip(attributes.find("name")->second, "Vk");

    auto handlesIt = m_handles.find(alias);
    assert((handlesIt != m_handles.end()) && handlesIt->second.alias.empty());
    handlesIt->second.alias = name;
  }
  else
  {
    checkOrderedElements(children, { "type", "name" });
    checkEmptyElement(children[0]);
    checkEmptyElement(children[1]);

#if !defined(NDEBUG)
    std::string type = children[0]->GetText();
    assert((type.find("VK_DEFINE_HANDLE") == 0) || (type.find("VK_DEFINE_NON_DISPATCHABLE_HANDLE") == 0));
#endif

    std::string name = strip(children[1]->GetText(), "Vk");

    m_dependencies.push_back(DependencyData(DependencyData::Category::HANDLE, name));

    assert(m_vkTypes.find(name) == m_vkTypes.end());
    m_vkTypes.insert(name);
    assert(m_handles.find(name) == m_handles.end());
    m_handles.insert(std::make_pair(name, HandleData()));
  }
}

void VulkanHppGenerator::readTypeName(tinyxml2::XMLElement const* element, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(), { { "name",{} } }, { { "requires",{} } });
  checkElements(getChildElements(element), {});

  auto nameIt = attributes.find("name");
  assert(nameIt != attributes.end());
  m_dependencies.push_back(DependencyData(DependencyData::Category::REQUIRED, nameIt->second));
}

void VulkanHppGenerator::readTypes(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), { { "comment",{} } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "comment", "type" });

  for (auto child : children)
  {
    std::string value = child->Value();
    if (value == "type")
    {
      readType(child);
    }
#if !defined(NDEBUG)
    else
    {
      assert(value == "comment");
      checkEmptyElement(child);
    }
#endif
  }
}

void VulkanHppGenerator::readTypeStruct(tinyxml2::XMLElement const* element, bool isUnion, std::map<std::string, std::string> const& attributes)
{
  checkAttributes(attributes, element->GetLineNum(),
  {
    { "category",{ isUnion ? "union" : "struct" } },
    { "name",{} }
  },
  {
    { "alias", {} },
    { "comment",{} },
    { "returnedonly",{ "true" } },
    { "structextends",{} }
  });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "comment", "member" });

  std::string name = strip(attributes.find("name")->second, "Vk");

  auto aliasIt = attributes.find("alias");
  if (aliasIt != attributes.end())
  {
    checkAttributes(attributes, element->GetLineNum(), { { "alias", {}}, {"category", {"struct"}}, { "name", {}} }, {});    // re-check on alias type!

    std::string alias = strip(aliasIt->second, "Vk");
    checkAlias(m_structs, alias, element->GetLineNum());

    auto structsIt = m_structs.find(alias);
    assert((structsIt != m_structs.end()) && structsIt->second.alias.empty());
    structsIt->second.alias = name;
  }
  else
  {
    m_dependencies.push_back(DependencyData(isUnion ? DependencyData::Category::UNION : DependencyData::Category::STRUCT, name));

    assert(m_structs.find(name) == m_structs.end());
    std::map<std::string, StructData>::iterator it = m_structs.insert(std::make_pair(name, StructData())).first;
    it->second.returnedOnly = (attributes.find("returnedonly") != attributes.end());
    it->second.isUnion = isUnion;

    auto attributesIt = attributes.find("structextends");
    if (attributesIt != attributes.end())
    {
      std::vector<std::string> structExtends = tokenize(attributesIt->second, ',');
      for (auto const& s : structExtends)
      {
        assert(s.substr(0, 2) == "Vk");
        std::string strippedName = s.substr(2);
        it->second.structExtends.push_back(strippedName);
        m_extendedStructs.insert(strippedName);
      }
      assert(!it->second.structExtends.empty());
    }

    for (auto child : children)
    {
      assert(child->Value());
      std::string value = child->Value();
      if (value == "member")
      {
        readTypeStructMember(child, it->second);
      }
#if !defined(NDEBUG)
      else
      {
        assert(value == "comment");
        checkEmptyElement(child);
      }
#endif
    }

    for (auto const& s : m_structs)
    {
      if (isSubStruct(s, name, it->second))
      {
        it->second.subStruct = s.first;
        break;    // just take the very first candidate as a subStruct, skip any possible others!
      }
    }
  }

  assert(m_vkTypes.find(name) == m_vkTypes.end());
  m_vkTypes.insert(name);
}

void VulkanHppGenerator::readTypeStructMember(tinyxml2::XMLElement const* element, StructData & structData)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), {},
  {
    { "altlen",{} },
    { "externsync",{ "true" } },
    { "len",{} },
    { "noautovalidity",{ "true" } },
    { "optional",{ "false", "true" } },
    { "values",{} }
  });
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "comment", "enum", "name", "type" });
  for (auto child : children)
  {
    checkEmptyElement(child);
  }

  structData.members.push_back(MemberData());
  MemberData & member = structData.members.back();

  auto valuesAttribute = attributes.find("values");
  if (valuesAttribute != attributes.end())
  {
    member.values = valuesAttribute->second;
  }

  tinyxml2::XMLNode const* child = element->FirstChild();
  assert(child);
  if (child->ToText())
  {
    std::string value = trim(child->Value());
    assert((value == "const") || (value == "struct") || value == "const struct");
    member.type = value + " ";
    child = child->NextSibling();
    assert(child);
  }

  assert(child->ToElement());
  tinyxml2::XMLElement const* typeElement = child->ToElement();
  assert((strcmp(typeElement->Value(), "type") == 0) && typeElement->GetText());
  member.pureType = strip(typeElement->GetText(), "Vk");
  member.type += member.pureType;

  child = typeElement->NextSibling();
  assert(child);
  if (child->ToText())
  {
    std::string value = trimEnd(child->Value());
    assert((value == "*") || (value == "**") || (value == "* const*"));
    member.type += value;
    child = child->NextSibling();
  }

  m_dependencies.back().dependencies.insert(member.pureType);

  assert(child->ToElement());
  tinyxml2::XMLElement const* nameElement = child->ToElement();
  assert((strcmp(nameElement->Value(), "name") == 0) && nameElement->GetText());
  member.name = nameElement->GetText();

  member.arraySize = readArraySize(nameElement, member.name);
}

void VulkanHppGenerator::registerDeleter(CommandData const& commandData)
{
  if ((commandData.fullName.substr(0, 7) == "destroy") || (commandData.fullName.substr(0, 4) == "free"))
  {
    std::string key;
    size_t valueIndex;
    switch (commandData.params.size())
    {
    case 2:
    case 3:
      assert(commandData.params.back().pureType == "AllocationCallbacks");
      key = (commandData.params.size() == 2) ? "" : commandData.params[0].pureType;
      valueIndex = commandData.params.size() - 2;
      break;
    case 4:
      key = commandData.params[0].pureType;
      valueIndex = 3;
      assert(m_deleters.find(commandData.params[valueIndex].pureType) == m_deleters.end());
      m_deleters[commandData.params[valueIndex].pureType].pool = commandData.params[1].pureType;
      break;
    default:
      assert(false);
      valueIndex = 0;
    }
    assert(m_deleterTypes[key].find(commandData.params[valueIndex].pureType) == m_deleterTypes[key].end());
    m_deleterTypes[key].insert(commandData.params[valueIndex].pureType);
    m_deleters[commandData.params[valueIndex].pureType].call = commandData.reducedName;
  }
}

void VulkanHppGenerator::setDefault(std::string const& name, std::map<std::string, std::string> & defaultValues, EnumData const& enumData)
{
  defaultValues[name] = name + (enumData.values.empty() ? "()" : ("::" + enumData.values.front().name));
}

void VulkanHppGenerator::sortDependencies()
{
  std::set<std::string> listedTypes = { "VkFlags" };
  std::list<DependencyData> sortedDependencies;

  while (!m_dependencies.empty())
  {
    bool found = false;
    for (std::list<DependencyData>::iterator it = m_dependencies.begin(); it != m_dependencies.end(); ++it)
    {
      // check if all dependencies of it are already listed
      if (std::find_if(it->dependencies.begin(), it->dependencies.end(), [&listedTypes](std::string const& d) { return listedTypes.find(d) == listedTypes.end(); }) == it->dependencies.end())
      {
        // add it to the end of the sorted list and the set of listed types, remove it from the list of dependencies to handle and start over with the next dependency
        sortedDependencies.push_back(*it);
        listedTypes.insert(it->name);

        // if it is a struct, add any alias of it to the list of encountered types
        if (it->category == DependencyData::Category::STRUCT)
        {
          std::map<std::string, StructData>::const_iterator sit = m_structs.find(it->name);
          assert(sit != m_structs.end());
          if (!sit->second.alias.empty())
          {
            assert(listedTypes.find(sit->second.alias) == listedTypes.end());
            listedTypes.insert(sit->second.alias);
          }
        }
        m_dependencies.erase(it);
        found = true;
        break;
      }
    }
    if (!found)
    {
      // at least one dependency of it is not yet listed -> resolve direct circular dependencies
      for (std::list<DependencyData>::iterator it = m_dependencies.begin(); !found && it != m_dependencies.end(); ++it)
      {
        for (std::set<std::string>::const_iterator dit = it->dependencies.begin(); dit != it->dependencies.end(); ++dit)
        {
          std::list<DependencyData>::const_iterator depIt = std::find_if(m_dependencies.begin(), m_dependencies.end(), [&dit](DependencyData const& dd) { return(dd.name == *dit); });
          if (depIt != m_dependencies.end())
          {
            if (depIt->dependencies.find(it->name) != depIt->dependencies.end())
            {
              // we only have two cases, for now!
              assert((depIt->category == DependencyData::Category::STRUCT) && ((it->category == DependencyData::Category::HANDLE) || (it->category == DependencyData::Category::STRUCT)));
              it->forwardDependencies.insert(*dit);
              it->dependencies.erase(*dit);
              found = true;
              break;
            }
          }
#if !defined(NDEBUG)
          else
          {
            // here, only already sorted dependencies should occur, or structs that are aliased and sorted
            std::list<DependencyData>::const_iterator sdit = std::find_if(sortedDependencies.begin(), sortedDependencies.end(), [&dit](DependencyData const& dd) { return(dd.name == *dit); });
            if (sdit == sortedDependencies.end())
            {
              std::map<std::string, StructData>::const_iterator sit = std::find_if(m_structs.begin(), m_structs.end(), [&dit](std::pair<std::string, StructData> const& sd) { return sd.second.alias == *dit; });
              assert(sit != m_structs.end());
              assert(std::find_if(sortedDependencies.begin(), sortedDependencies.end(), [name = sit->first](DependencyData const& dd) { return dd.name == name; }) != sortedDependencies.end());
            }
          }
#endif
        }
      }
    }
    assert(found);
  }

  m_dependencies.swap(sortedDependencies);
}

void VulkanHppGenerator::writeArguments(std::ostream & os, CommandData const& commandData, bool firstCall, bool singular, size_t from, size_t to)
{
  assert(from <= to);

  // get the parameter indices of the counter for vector parameters
  std::map<size_t, size_t> countIndices;
  for (std::map<size_t, size_t>::const_iterator it = commandData.vectorParams.begin(); it != commandData.vectorParams.end(); ++it)
  {
    countIndices.insert(std::make_pair(it->second, it->first));
  }

  bool encounteredArgument = false;
  for (size_t i = from; i < to; i++)
  {
    if (encounteredArgument)
    {
      os << ", ";
    }

    std::map<size_t, size_t>::const_iterator it = countIndices.find(i);
    if (it != countIndices.end())
    {
      writeCallCountParameter(os, commandData, singular, it);
    }
    else if ((it = commandData.vectorParams.find(i)) != commandData.vectorParams.end())
    {
      writeCallVectorParameter(os, commandData, firstCall, singular, it);
    }
    else if (m_vkTypes.find(commandData.params[i].pureType) != m_vkTypes.end())
    {
      writeCallVulkanTypeParameter(os, commandData.params[i]);
    }
    else
    {
      writeCallPlainTypeParameter(os, commandData.params[i]);
    }
    encounteredArgument = true;
  }
}

void VulkanHppGenerator::writeBitmaskToString(std::ostream & os, std::string const& bitmaskName, EnumData const &enumData)
{
  // the helper functions to make strings out of flag values
  enterProtect(os, enumData.protect);
  os << "  VULKAN_HPP_INLINE std::string to_string(" << bitmaskName << (enumData.values.empty() ? ")" : " value)") << std::endl
    << "  {" << std::endl;
  if (enumData.values.empty())
  {
    // no flags values in this enum -> return "{}"
    os << "    return \"{}\";" << std::endl;
  }
  else
  {
    os << "    if (!value) return \"{}\";" << std::endl
      << "    std::string result;" << std::endl;

    // 'or' together all the bits in the value
    for (auto valuesIt = enumData.values.begin(); valuesIt != enumData.values.end(); ++valuesIt)
    {
      os << "    if (value & " << enumData.name << "::" << valuesIt->name << ") result += \"" << valuesIt->name.substr(1) << " | \";" << std::endl;
    }
    // cut off the last three characters from the result (being " | ")
    os << "    return \"{\" + result.substr(0, result.size() - 3) + \"}\";" << std::endl;
  }
  os << "  }" << std::endl;
  leaveProtect(os, enumData.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeCall(std::ostream & os, CommandData const& commandData, bool firstCall, bool singular)
{
  // the original function call
  os << "d.vk" << startUpperCase(commandData.fullName) << "( ";

  if (!commandData.className.empty())
  {
    // if it's member of a class -> the first argument is the member variable, starting with "m_"
    assert(commandData.className == commandData.params[0].type);
    os << "m_" << startLowerCase(commandData.className);
    if (1 < commandData.params.size())
    {
      os << ", ";
    }
  }

  writeArguments(os, commandData, firstCall, singular, commandData.className.empty() ? 0 : 1, commandData.params.size());
  os << " )";
}

void VulkanHppGenerator::writeCallCountParameter(std::ostream & os, CommandData const& commandData, bool singular, std::map<size_t, size_t>::const_iterator it)
{
  // this parameter is a count parameter for a vector parameter
  if ((commandData.returnParam == it->second) && commandData.twoStep)
  {
    // the corresponding vector parameter is the return parameter and it's a two-step algorithm
    // -> use the pointer to a local variable named like the counter parameter without leading 'p'
    os << "&" << startLowerCase(strip(commandData.params[it->first].name, "p"));
  }
  else
  {
    // the corresponding vector parameter is not the return parameter, or it's not a two-step algorithm
    if (singular)
    {
      // for the singular version, the count is just 1.
      os << "1 ";
    }
    else
    {
      // for the non-singular version, the count is the size of the vector parameter
      // -> use the vector parameter name without leading 'p' to get the size (in number of elements, not in bytes)
      os << startLowerCase(strip(commandData.params[it->second].name, "p")) << ".size() ";
    }
    if (commandData.templateParam == it->second)
    {
      // if the vector parameter is templatized -> multiply by the size of that type to get the size in bytes
      os << "* sizeof( T ) ";
    }
  }
}

void VulkanHppGenerator::writeCallPlainTypeParameter(std::ostream & os, ParamData const& paramData)
{
  // this parameter is just a plain type
  if (paramData.type.back() == '*')
  {
    // it's a pointer
    std::string parameterName = startLowerCase(strip(paramData.name, "p"));
    if (paramData.type.find("const") != std::string::npos)
    {
      // it's a const pointer
      if (paramData.pureType == "char")
      {
        // it's a const pointer to char -> it's a string -> get the data via c_str()
        os << parameterName;
        if (paramData.optional)
        {
          // it's optional -> might use nullptr
          os << " ? " << parameterName << "->c_str() : nullptr";
        }
        else
        {
          os << ".c_str()";
        }
      }
      else
      {
        // it's const pointer to something else -> just use the name
        assert(!paramData.optional);
        os << paramData.name;
      }
    }
    else
    {
      // it's a non-const pointer, and char is the only type that occurs -> use the address of the parameter
      assert(paramData.type.find("char") == std::string::npos);
      os << "&" << parameterName;
    }
  }
  else
  {
    // it's a plain parameter -> just use its name
    os << paramData.name;
  }
}

void VulkanHppGenerator::writeCallVectorParameter(std::ostream & os, CommandData const& commandData, bool firstCall, bool singular, std::map<size_t, size_t>::const_iterator it)
{
  // this parameter is a vector parameter
  assert(commandData.params[it->first].type.back() == '*');
  if ((commandData.returnParam == it->first) && commandData.twoStep && firstCall)
  {
    // this parameter is the return parameter, and it's the first call of a two-step algorithm -> just just nullptr
    os << "nullptr";
  }
  else
  {
    std::string parameterName = startLowerCase(strip(commandData.params[it->first].name, "p"));
    std::set<std::string>::const_iterator vkit = m_vkTypes.find(commandData.params[it->first].pureType);
    if ((vkit != m_vkTypes.end()) || (it->first == commandData.templateParam))
    {
      // CHECK for !commandData.params[it->first].optional

      // this parameter is a vulkan type or a templated type -> need to reinterpret cast
      writeReinterpretCast(os, commandData.params[it->first].type.find("const") == 0, vkit != m_vkTypes.end(), commandData.params[it->first].pureType, commandData.params[it->first].type.rfind("* const") != std::string::npos);
      os << "( ";
      if (singular)
      {
        // in singular case, strip the plural-S from the name, and use the pointer to that thing
        os << "&" << stripPluralS(parameterName);
      }
      else
      {
        // in plural case, get the pointer to the data
        os << parameterName << ".data()";
      }
      os << " )";
    }
    else if (commandData.params[it->first].pureType == "char")
    {
      // the parameter is a vector to char -> it might be optional
      // besides that, the parameter now is a std::string -> get the pointer via c_str()
      os << parameterName;
      if (commandData.params[it->first].optional)
      {
        os << " ? " << parameterName << "->c_str() : nullptr";
      }
      else
      {
        os << ".c_str()";
      }
    }
    else
    {
      // this parameter is just a vetor -> get the pointer to its data
      os << parameterName << ".data()";
    }
  }
}

void VulkanHppGenerator::writeCallVulkanTypeParameter(std::ostream & os, ParamData const& paramData)
{
  // this parameter is a vulkan type
  if (paramData.type.back() == '*')
  {
    // it's a pointer -> needs a reinterpret cast to the vulkan type
    std::string parameterName = startLowerCase(strip(paramData.name, "p"));
    writeReinterpretCast(os, paramData.type.find("const") != std::string::npos, true, paramData.pureType, false);
    os << "( ";
    if (paramData.optional)
    {
      // for an optional parameter, we need also a static_cast from optional type to const-pointer to pure type
      os << "static_cast<const " << paramData.pureType << "*>( " << parameterName << " )";
    }
    else
    {
      // other parameters can just use the pointer
      os << "&" << parameterName;
    }
    os << " )";
  }
  else
  {
    // a non-pointer parameter needs a static_cast from vk::-type to vulkan type
    os << "static_cast<Vk" << paramData.pureType << ">( " << paramData.name << " )";
  }
}

void VulkanHppGenerator::writeEnumsToString(std::ostream & os, EnumData const& enumData)
{
  // the helper functions to make strings out of enum values
  enterProtect(os, enumData.protect);
  os << "  VULKAN_HPP_INLINE std::string to_string(" << enumData.name << (enumData.values.empty() ? ")" : " value)") << std::endl
    << "  {" << std::endl;
  if (enumData.values.empty())
  {
    // no enum values in this enum -> return "(void)"
    os << "    return \"(void)\";" << std::endl;
  }
  else
  {
    // otherwise switch over the value and return the a stringized version of that value (without leading 'e')
    os << "    switch (value)" << std::endl
      << "    {" << std::endl;
    for (auto const& value : enumData.values)
    {
      os << "    case " << enumData.name << "::" << value.name << ": return \"" << value.name.substr(1) << "\";" << std::endl;
    }
    os << "    default: return \"invalid\";" << std::endl
      << "    }" << std::endl;
  }
  os << "  }" << std::endl;
  leaveProtect(os, enumData.protect);
  os << std::endl;
}

// Intended only for `enum class Result`!
void VulkanHppGenerator::writeExceptionsForEnum(std::ostream & os, EnumData const& enumData)
{
  std::string templateString =
    R"(  class ${className} : public SystemError
  {
  public:
    ${className}( std::string const& message )
      : SystemError( make_error_code( ${enumName}::${enumMemberName} ), message ) {}
    ${className}( char const * message )
      : SystemError( make_error_code( ${enumName}::${enumMemberName} ), message ) {}
  };
)";

  enterProtect(os, enumData.protect);
  for (size_t i = 0; i < enumData.values.size(); i++)
  {
    if (!isErrorEnum(enumData.values[i].name))
    {
      continue;
    }
    os << replaceWithMap(templateString,
    { { "className", stripErrorEnumPrefix(enumData.values[i].name) + "Error" },
    { "enumName", enumData.name },
    { "enumMemberName", enumData.values[i].name }
    });
  }
  leaveProtect(os, enumData.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeFunction(std::ostream & os, std::string const& indentation, CommandData const& commandData, bool definition, bool enhanced, bool singular, bool unique, bool isStructureChain)
{
  writeFunctionHeaderTemplate(os, indentation, commandData, enhanced, unique, !definition, isStructureChain);

  os << indentation << (definition ? "VULKAN_HPP_INLINE " : "");
  writeFunctionHeaderReturnType(os, commandData, enhanced, singular, unique, isStructureChain);
  if (definition && !commandData.className.empty())
  {
    os << commandData.className << "::";
  }
  writeFunctionHeaderName(os, commandData.reducedName, singular, unique);
  writeFunctionHeaderArguments(os, commandData, enhanced, singular, !definition);
  os << (definition ? "" : ";") << std::endl;

  if (definition)
  {
    // write the function body
    os << indentation << "{" << std::endl;
    if (enhanced)
    {
      writeFunctionBodyEnhanced(os, indentation, commandData, singular, unique, isStructureChain);
    }
    else
    {
      writeFunctionBodyStandard(os, indentation, commandData);
    }
    os << indentation << "}" << std::endl;
  }
}

void VulkanHppGenerator::writeFunctionBodyEnhanced(std::ostream & os, std::string const& indentation, CommandData const& commandData, bool singular, bool unique, bool isStructureChain)
{
  if (unique && !singular && (commandData.vectorParams.find(commandData.returnParam) != commandData.vectorParams.end()))    // returns a vector of UniqueStuff
  {
    std::string const stringTemplate =
R"(${i}  static_assert( sizeof( ${type} ) <= sizeof( Unique${type} ), "${type} is greater than Unique${type}!" );
${i}  std::vector<Unique${type}, Allocator> ${typeVariable}s;
${i}  ${typeVariable}s.reserve( ${vectorSize} );
${i}  ${type}* buffer = reinterpret_cast<${type}*>( reinterpret_cast<char*>( ${typeVariable}s.data() ) + ${vectorSize} * ( sizeof( Unique${type} ) - sizeof( ${type} ) ) );
${i}  Result result = static_cast<Result>(d.vk${command}( m_device, ${arguments}, reinterpret_cast<Vk${type}*>( buffer ) ) );

${i}  ${Deleter}<${DeleterTemplate},Dispatch> deleter( *this, ${deleterArg}, d );
${i}  for ( size_t i=0 ; i<${vectorSize} ; i++ )
${i}  {
${i}    ${typeVariable}s.push_back( Unique${type}( buffer[i], deleter ) );
${i}  }

${i}  return createResultValue( result, ${typeVariable}s, VULKAN_HPP_NAMESPACE_STRING "::${class}::${function}Unique" );
)";

    std::string type = (commandData.returnParam != INVALID_INDEX) ? commandData.params[commandData.returnParam].pureType : "";
    std::string typeVariable = startLowerCase(type);
    std::ostringstream arguments;
    writeArguments(arguments, commandData, true, singular, 1, commandData.params.size() - 1);

    std::map<std::string, DeleterData>::const_iterator ddit = m_deleters.find(type);
    assert(ddit != m_deleters.end());

    bool isCreateFunction = (commandData.fullName.substr(0, 6) == "create");
    os << replaceWithMap(stringTemplate, std::map<std::string, std::string>
    {
      { "i", indentation },
      { "type", type },
      { "typeVariable", typeVariable },
      { "vectorSize", isCreateFunction ? "createInfos.size()" : "allocateInfo." + typeVariable + "Count" },
      { "command", startUpperCase(commandData.fullName) },
      { "arguments", arguments.str() },
      { "Deleter", ddit->second.pool.empty() ? "ObjectDestroy" : "PoolFree" },
      { "DeleterTemplate", ddit->second.pool.empty() ? commandData.className : commandData.className + "," + ddit->second.pool },
      { "deleterArg", ddit->second.pool.empty() ? "allocator" : "allocateInfo." + startLowerCase(ddit->second.pool) },
      { "class", commandData.className },
      { "function", commandData.reducedName }
    });
  }
  else
  {
    if (1 < commandData.vectorParams.size())
    {
      writeFunctionBodyEnhancedMultiVectorSizeCheck(os, indentation, commandData);
    }

    std::string returnName;
    if (commandData.returnParam != INVALID_INDEX)
    {
      returnName = writeFunctionBodyEnhancedLocalReturnVariable(os, indentation, commandData, singular, isStructureChain);
    }

    if (commandData.twoStep)
    {
      assert(!singular);
      writeFunctionBodyEnhancedLocalCountVariable(os, indentation, commandData);

      // we now might have to check the result, resize the returned vector accordingly, and call the function again
      std::map<size_t, size_t>::const_iterator returnit = commandData.vectorParams.find(commandData.returnParam);
      assert(returnit != commandData.vectorParams.end() && (returnit->second != INVALID_INDEX));
      std::string sizeName = startLowerCase(strip(commandData.params[returnit->second].name, "p"));

      if (commandData.returnType == "Result")
      {
        if (1 < commandData.successCodes.size())
        {
          writeFunctionBodyEnhancedCallTwoStepIterate(os, indentation, returnName, sizeName, commandData);
        }
        else
        {
          writeFunctionBodyEnhancedCallTwoStepChecked(os, indentation, returnName, sizeName, commandData);
        }
      }
      else
      {
        writeFunctionBodyEnhancedCallTwoStep(os, indentation, returnName, sizeName, commandData);
      }
    }
    else
    {
      if (commandData.returnType == "Result")
      {
        writeFunctionBodyEnhancedCallResult(os, indentation, commandData, singular);
      }
      else
      {
        writeFunctionBodyEnhancedCall(os, indentation, commandData, singular);
      }
    }

    if ((commandData.returnType == "Result") || !commandData.successCodes.empty())
    {
      writeFunctionBodyEnhancedReturnResultValue(os, indentation, returnName, commandData, singular, unique);
    }
    else if ((commandData.returnParam != INVALID_INDEX) && (commandData.returnType != commandData.enhancedReturnType))
    {
      // for the other returning cases, when the return type is somhow enhanced, just return the local returnVariable
      os << indentation << "  return " << returnName << ";" << std::endl;
    }
  }
}

void VulkanHppGenerator::writeFunctionBodyEnhanced(std::ostream &os, std::string const& templateString, std::string const& indentation, CommandData const& commandData, bool singular)
{
  os << replaceWithMap(templateString, {
    { "call", generateCall(commandData, true, singular) },
    { "i", indentation }
  });
}

void VulkanHppGenerator::writeFunctionBodyTwoStep(std::ostream & os, std::string const &templateString, std::string const& indentation, std::string const& returnName, std::string const& sizeName, CommandData const& commandData)
{
  std::map<std::string, std::string> replacements = {
    { "sizeName", sizeName },
    { "returnName", returnName },
    { "call1", generateCall(commandData, true, false) },
    { "call2", generateCall(commandData, false, false) },
    { "i", indentation }
  };

  os << replaceWithMap(templateString, replacements);
}

std::string VulkanHppGenerator::writeFunctionBodyEnhancedLocalReturnVariable(std::ostream & os, std::string const& indentation, CommandData const& commandData, bool singular, bool isStructureChain)
{
  std::string returnName = startLowerCase(strip(commandData.params[commandData.returnParam].name, "p"));

  // there is a returned parameter -> we need a local variable to hold that value
  if (commandData.returnType != commandData.enhancedReturnType)
  {
    // the returned parameter is somehow enhanced by us
    os << indentation << "  ";
    if (singular)
    {
      if (isStructureChain)
      {
        std::string const &pureType = commandData.params[commandData.returnParam].pureType;
        // For StructureChains use the template parameters
        os << "StructureChain<X, Y, Z...> structureChain;" << std::endl;
        returnName = stripPluralS(returnName);
        os << indentation << "  " << pureType << "& " << returnName << " = structureChain.template get<" << pureType << ">()";
        returnName = "structureChain";
      }
      else
      {
        // in singular case, just use the return parameters pure type for the return variable
        returnName = stripPluralS(returnName);
        os << commandData.params[commandData.returnParam].pureType << " " << returnName;
      }
    }
    else
    {
      // in non-singular case, use the enhanced type for the return variable (like vector<...>)
      if (isStructureChain)
      {
        std::string const &returnType = commandData.enhancedReturnType;
        // For StructureChains use the template parameters
        os << "StructureChain<X, Y, Z...> structureChain;" << std::endl;
        os << indentation << "  " << returnType << "& " << returnName << " = structureChain.template get<" << returnType << ">()";
        returnName = "structureChain";
      }
      else
      {
        os << commandData.enhancedReturnType << " " << returnName;
      }

      std::map<size_t, size_t>::const_iterator it = commandData.vectorParams.find(commandData.returnParam);
      if (it != commandData.vectorParams.end() && !commandData.twoStep)
      {
        // if the return parameter is a vector parameter, and not part of a two-step algorithm, initialize its size
        std::string size;
        if (it->second == INVALID_INDEX)
        {
          assert(!commandData.params[commandData.returnParam].len.empty());
          // the size of the vector is not given by an other parameter, but by some member of a parameter, described as 'parameter::member'
          // -> replace the '::' by '.' and filter out the leading 'p' to access that value
          size = startLowerCase(strip(commandData.params[commandData.returnParam].len, "p"));
          size_t pos = size.find("::");
          assert(pos != std::string::npos);
          size.replace(pos, 2, ".");
        }
        else
        {
          // the size of the vector is given by an other parameter
          // first check, if that size has become the size of some other vector parameter
          // -> look for it and get it's actual size
          for (auto const& vectorParam : commandData.vectorParams)
          {
            if ((vectorParam.first != it->first) && (vectorParam.second == it->second))
            {
              size = startLowerCase(strip(commandData.params[vectorParam.first].name, "p")) + ".size()";
              break;
            }
          }
          if (size.empty())
          {
            // otherwise, just use that parameter
            size = commandData.params[it->second].name;
          }
        }
        assert(!size.empty());
        os << "( " << size << " )";
      }
    }
    os << ";" << std::endl;
  }
  else
  {
    // the return parameter is not enhanced -> the type is supposed to be a Result and there are more than one success codes!
    assert((commandData.returnType == "Result") && (1 < commandData.successCodes.size()));
    os << indentation << "  " << commandData.params[commandData.returnParam].pureType << " " << returnName << ";" << std::endl;
  }

  return returnName;
}

void VulkanHppGenerator::writeFunctionBodyEnhancedCall(std::ostream &os, std::string const& indentation, CommandData const& commandData, bool singular)
{
  std::string const templateString = "${i}  return ${call};\n";
  std::string const templateStringVoid = "${i}  ${call};\n";
  writeFunctionBodyEnhanced(os, commandData.returnType == "void" ? templateStringVoid : templateString, indentation, commandData, singular);
}

void VulkanHppGenerator::writeFunctionBodyEnhancedCallResult(std::ostream &os, std::string const& indentation, CommandData const& commandData, bool singular)
{
  std::string const templateString = "${i}  Result result = static_cast<Result>( ${call} );\n";
  writeFunctionBodyEnhanced(os, templateString, indentation, commandData, singular);
}

void VulkanHppGenerator::writeFunctionBodyEnhancedCallTwoStep(std::ostream & os, std::string const& indentation, std::string const& returnName, std::string const& sizeName, CommandData const& commandData)
{
  std::string const templateString =
    R"(${i}  ${call1};
${i}  ${returnName}.resize( ${sizeName} );
${i}  ${call2};
)";
  writeFunctionBodyTwoStep(os, templateString, indentation, returnName, sizeName, commandData);
}

void VulkanHppGenerator::writeFunctionBodyEnhancedCallTwoStepIterate(std::ostream & os, std::string const& indentation, std::string const& returnName, std::string const& sizeName, CommandData const& commandData)
{
  std::string const templateString =
    R"(${i}  Result result;
${i}  do
${i}  {
${i}    result = static_cast<Result>( ${call1} );
${i}    if ( ( result == Result::eSuccess ) && ${sizeName} )
${i}    {
${i}      ${returnName}.resize( ${sizeName} );
${i}      result = static_cast<Result>( ${call2} );
${i}    }
${i}  } while ( result == Result::eIncomplete );
${i}  VULKAN_HPP_ASSERT( ${sizeName} <= ${returnName}.size() );
${i}  ${returnName}.resize( ${sizeName} );
)";
  writeFunctionBodyTwoStep(os, templateString, indentation, returnName, sizeName, commandData);
}

void VulkanHppGenerator::writeFunctionBodyEnhancedCallTwoStepChecked(std::ostream & os, std::string const& indentation, std::string const& returnName, std::string const& sizeName, CommandData const& commandData)
{
  std::string const templateString =
    R"(${i}  Result result = static_cast<Result>( ${call1} );
${i}  if ( ( result == Result::eSuccess ) && ${sizeName} )
${i}  {
${i}    ${returnName}.resize( ${sizeName} );
${i}    result = static_cast<Result>( ${call2} );
${i}  }
)";
  writeFunctionBodyTwoStep(os, templateString, indentation, returnName, sizeName, commandData);
}

void VulkanHppGenerator::writeFunctionBodyEnhancedLocalCountVariable(std::ostream & os, std::string const& indentation, CommandData const& commandData)
{
  // local count variable to hold the size of the vector to fill
  assert(commandData.returnParam != INVALID_INDEX);

  std::map<size_t, size_t>::const_iterator returnit = commandData.vectorParams.find(commandData.returnParam);
  assert(returnit != commandData.vectorParams.end() && (returnit->second != INVALID_INDEX));
  assert((commandData.returnType == "Result") || (commandData.returnType == "void"));

  // take the pure type of the size parameter; strip the leading 'p' from its name for its local name
  os << indentation << "  " << commandData.params[returnit->second].pureType << " " << startLowerCase(strip(commandData.params[returnit->second].name, "p")) << ";" << std::endl;
}

void VulkanHppGenerator::writeFunctionBodyEnhancedMultiVectorSizeCheck(std::ostream & os, std::string const& indentation, CommandData const& commandData)
{
  std::string const templateString =
    R"#(#ifdef VULKAN_HPP_NO_EXCEPTIONS
${i}  VULKAN_HPP_ASSERT( ${firstVectorName}.size() == ${secondVectorName}.size() );
#else
${i}  if ( ${firstVectorName}.size() != ${secondVectorName}.size() )
${i}  {
${i}    throw LogicError( VULKAN_HPP_NAMESPACE_STRING "::${className}::${reducedName}: ${firstVectorName}.size() != ${secondVectorName}.size()" );
${i}  }
#endif  // VULKAN_HPP_NO_EXCEPTIONS
)#";


  // add some error checks if multiple vectors need to have the same size
  for (std::map<size_t, size_t>::const_iterator it0 = commandData.vectorParams.begin(); it0 != commandData.vectorParams.end(); ++it0)
  {
    if (it0->first != commandData.returnParam)
    {
      for (std::map<size_t, size_t>::const_iterator it1 = std::next(it0); it1 != commandData.vectorParams.end(); ++it1)
      {
        if ((it1->first != commandData.returnParam) && (it0->second == it1->second))
        {
          os << replaceWithMap(templateString, std::map<std::string, std::string>({
            { "firstVectorName", startLowerCase(strip(commandData.params[it0->first].name, "p")) },
            { "secondVectorName", startLowerCase(strip(commandData.params[it1->first].name, "p")) },
            { "className", commandData.className },
            { "reducedName", commandData.reducedName },
            { "i", indentation }
          }));
        }
      }
    }
  }
}

void VulkanHppGenerator::writeFunctionBodyEnhancedReturnResultValue(std::ostream & os, std::string const& indentation, std::string const& returnName, CommandData const& commandData, bool singular, bool unique)
{
  std::string type = (commandData.returnParam != INVALID_INDEX) ? commandData.params[commandData.returnParam].pureType : "";
  std::string returnVectorName = (commandData.returnParam != INVALID_INDEX) ? strip(commandData.params[commandData.returnParam].name, "p", "s") : "";

  if (unique)
  {
    // the unique version needs a Deleter object for destruction of the newly created stuff
    // get the DeleterData corresponding to the returned type
    std::map<std::string, DeleterData>::const_iterator ddit = m_deleters.find(type);
    assert(ddit != m_deleters.end() && ddit->second.pool.empty());

    // special handling for "createDevice", as Device is created from PhysicalDevice, but destroyed on its own
    bool noParent = commandData.className.empty() || (commandData.fullName == "createDevice");
    os << std::endl
      << indentation << ((commandData.fullName == "allocateMemory") ? "  ObjectFree<" : "  ObjectDestroy<") << (noParent ? "NoParent" : commandData.className) << ",Dispatch> deleter( " << (noParent ? "" : "*this, ") << "allocator, d );" << std::endl
      << indentation << "  return createResultValue<" << type << ",Dispatch>( result, ";
  }
  else
  {
    os << indentation << "  return createResultValue( result, ";
  }

  // if the return type is "Result" or there is at least one success code, create the Result/Value construct to return
  if (commandData.returnParam != INVALID_INDEX)
  {
    // if there's a return parameter, list it in the Result/Value constructor
    os << returnName << ", ";
  }

  // now the function name (with full namespace) as a string
  os << "VULKAN_HPP_NAMESPACE_STRING\"::" << (commandData.className.empty() ? "" : commandData.className + "::") << (singular ? stripPluralS(commandData.reducedName) : commandData.reducedName) << (unique ? "Unique" : "") << "\"";

  if (!commandData.twoStep && (1 < commandData.successCodes.size()))
  {
    // and for the single-step algorithms with more than one success code list them all
    os << ", { Result::" << commandData.successCodes[0];
    for (size_t i = 1; i < commandData.successCodes.size(); i++)
    {
      os << ", Result::" << commandData.successCodes[i];
    }
    os << " }";
  }

  if (unique)
  {
    os << ", deleter";
  }

  os << " );" << std::endl;
}

void VulkanHppGenerator::writeFunctionBodyStandard(std::ostream & os, std::string const& indentation, CommandData const& commandData)
{
  os << indentation << "  ";
  bool castReturn = false;
  if (commandData.returnType != "void")
  {
    // there's something to return...
    os << "return ";

    castReturn = (m_vkTypes.find(commandData.returnType) != m_vkTypes.end());
    if (castReturn)
    {
      // the return-type is a vulkan type -> need to cast to vk::-type
      os << "static_cast<" << commandData.returnType << ">( ";
    }
  }

  // call the original function
  os << "d.vk" << startUpperCase(commandData.fullName) << "( ";

  if (!commandData.className.empty())
  {
    // the command is part of a class -> the first argument is the member variable, starting with "m_"
    assert(commandData.className == commandData.params[0].type);
    os << "m_" << startLowerCase(commandData.className);
  }

  // list all the arguments
  for (size_t i = commandData.className.empty() ? 0 : 1; i < commandData.params.size(); i++)
  {
    if (0 < i)
    {
      os << ", ";
    }

    if (m_vkTypes.find(commandData.params[i].pureType) != m_vkTypes.end())
    {
      // the parameter is a vulkan type
      if (commandData.params[i].type.back() == '*')
      {
        // it's a pointer -> need to reinterpret_cast it
        writeReinterpretCast(os, commandData.params[i].type.find("const") == 0, true, commandData.params[i].pureType, commandData.params[i].type.find("* const") != std::string::npos);
      }
      else
      {
        // it's a value -> need to static_cast ist
        os << "static_cast<Vk" << commandData.params[i].pureType << ">";
      }
      os << "( " << commandData.params[i].name << " )";
    }
    else
    {
      // it's a non-vulkan type -> just use it
      os << commandData.params[i].name;
    }
  }
  os << " )";

  if (castReturn)
  {
    // if we cast the return -> close the static_cast
    os << " )";
  }
  os << ";" << std::endl;
}

void VulkanHppGenerator::writeFunctionHeaderArguments(std::ostream & os, CommandData const& commandData, bool enhanced, bool singular, bool withDefaults)
{
  os << "(";
  if (enhanced)
  {
    writeFunctionHeaderArgumentsEnhanced(os, commandData, singular, withDefaults);
  }
  else
  {
    writeFunctionHeaderArgumentsStandard(os, commandData, withDefaults);
  }
  os << ")";
  if (!commandData.className.empty())
  {
    os << " const";
  }
}

void VulkanHppGenerator::writeFunctionHeaderArgumentsEnhanced(std::ostream & os, CommandData const& commandData, bool singular, bool withDefaults)
{
  // check if there's at least one argument left to put in here
  if (commandData.skippedParams.size() + (commandData.className.empty() ? 0 : 1) < commandData.params.size())
  {
    // determine the last argument, where we might provide some default for
    size_t lastArgument = INVALID_INDEX;
    for (size_t i = commandData.params.size() - 1; i < commandData.params.size(); i--)
    {
      if (commandData.skippedParams.find(i) == commandData.skippedParams.end())
      {
        lastArgument = i;
        break;
      }
    }

    os << " ";
    bool argEncountered = false;
    for (size_t i = commandData.className.empty() ? 0 : 1; i < commandData.params.size(); i++)
    {
      if (commandData.skippedParams.find(i) == commandData.skippedParams.end())
      {
        if (argEncountered)
        {
          os << ", ";
        }
        std::string strippedParameterName = startLowerCase(strip(commandData.params[i].name, "p"));

        std::map<size_t, size_t>::const_iterator it = commandData.vectorParams.find(i);
        size_t rightStarPos = commandData.params[i].type.rfind('*');
        if (it == commandData.vectorParams.end())
        {
          // the argument ist not a vector
          if (rightStarPos == std::string::npos)
          {
            // and its not a pointer -> just use its type and name here
            os << commandData.params[i].type << " " << commandData.params[i].name;
            if (!commandData.params[i].arraySize.empty())
            {
              os << "[" << commandData.params[i].arraySize << "]";
            }

            if (withDefaults && (lastArgument == i))
            {
              // check if the very last argument is a flag without any bits -> provide some empty default for it
              std::map<std::string, BitmaskData>::const_iterator bitmasksIt = m_bitmasks.find(commandData.params[i].pureType);
              if (bitmasksIt != m_bitmasks.end())
              {
                // get the enum corresponding to this flag, to check if it's empty
                std::list<DependencyData>::const_iterator depIt = std::find_if(m_dependencies.begin(), m_dependencies.end(), [&bitmasksIt](DependencyData const& dd) { return(dd.name == bitmasksIt->first); });
                assert((depIt != m_dependencies.end()) && (depIt->dependencies.size() == 1));
                std::map<std::string, EnumData>::const_iterator enumIt = m_enums.find(*depIt->dependencies.begin());
                assert(enumIt != m_enums.end());
                if (enumIt->second.values.empty())
                {
                  // there are no bits in this flag -> provide the default
                  os << " = " << commandData.params[i].pureType << "()";
                }
              }
            }
          }
          else
          {
            // the argument is not a vector, but a pointer
            assert(commandData.params[i].type[rightStarPos] == '*');
            if (commandData.params[i].optional)
            {
              // for an optional argument, trim the trailing '*' from the type, and the leading 'p' from the name
              os << "Optional<" << trimEnd(commandData.params[i].type.substr(0, rightStarPos)) << "> " << strippedParameterName;
              if (withDefaults)
              {
                os << " = nullptr";
              }
            }
            else if (commandData.params[i].pureType == "void")
            {
              // for void-pointer, just use type and name
              os << commandData.params[i].type << " " << commandData.params[i].name;
            }
            else if (commandData.params[i].pureType != "char")
            {
              // for non-char-pointer, change to reference
              os << trimEnd(commandData.params[i].type.substr(0, rightStarPos)) << " & " << strippedParameterName;
            }
            else
            {
              // for char-pointer, change to const reference to std::string
              os << "const std::string & " << strippedParameterName;
            }
          }
        }
        else
        {
          // the argument is a vector
          // it's optional, if it's marked as optional and there's no size specified
          bool optional = commandData.params[i].optional && (it->second == INVALID_INDEX);
          assert((rightStarPos != std::string::npos) && (commandData.params[i].type[rightStarPos] == '*'));
          if (commandData.params[i].type.find("char") != std::string::npos)
          {
            // it's a char-vector -> use a std::string (either optional or a const-reference
            if (optional)
            {
              os << "Optional<const std::string> " << strippedParameterName;
              if (withDefaults)
              {
                os << " = nullptr";
              }
            }
            else
            {
              os << "const std::string & " << strippedParameterName;
            }
          }
          else
          {
            // it's a non-char vector (they are never optional)
            assert(!optional);
            if (singular)
            {
              // in singular case, change from pointer to reference
              os << trimEnd(commandData.params[i].type.substr(0, rightStarPos)) << " & " << stripPluralS(strippedParameterName);
            }
            else
            {
              // otherwise, use our ArrayProxy
              bool isConst = (commandData.params[i].type.find("const") != std::string::npos);
              os << "ArrayProxy<" << ((commandData.templateParam == i) ? (isConst ? "const T" : "T") : trimEnd(commandData.params[i].type.substr(0, rightStarPos))) << "> " << strippedParameterName;
            }
          }
        }
        argEncountered = true;
      }
    }

    if (argEncountered)
    {
      os << ", ";
    }
  }
  os << "Dispatch const &d";
  if (withDefaults)
  {
    os << " = Dispatch()";
  }

  os << " ";
}

void VulkanHppGenerator::writeFunctionHeaderArgumentsStandard(std::ostream & os, CommandData const& commandData, bool withDefaults)
{
  // for the standard case, just list all the arguments as we've got them
  bool argEncountered = false;

  // determine the last argument, where we might provide some default for
  size_t lastArgument = commandData.params.size() - 1;

  for (size_t i = commandData.className.empty() ? 0 : 1; i < commandData.params.size(); i++)
  {
    if (argEncountered)
    {
      os << ",";
    }

    os << " " << commandData.params[i].type << " " << commandData.params[i].name;
    if (!commandData.params[i].arraySize.empty())
    {
      os << "[" << commandData.params[i].arraySize << "]";
    }

    if (withDefaults && (lastArgument == i))
    {
      // check if the very last argument is a flag without any bits -> provide some empty default for it
      std::map<std::string, BitmaskData>::const_iterator flagIt = m_bitmasks.find(commandData.params[i].pureType);
      if (flagIt != m_bitmasks.end())
      {
        // get the enum corresponding to this flag, to check if it's empty
        std::list<DependencyData>::const_iterator depIt = std::find_if(m_dependencies.begin(), m_dependencies.end(), [&flagIt](DependencyData const& dd) { return(dd.name == flagIt->first); });
        assert((depIt != m_dependencies.end()) && (depIt->dependencies.size() == 1));
        std::map<std::string, EnumData>::const_iterator enumIt = m_enums.find(*depIt->dependencies.begin());
        assert(enumIt != m_enums.end());
        if (enumIt->second.values.empty())
        {
          // there are no bits in this flag -> provide the default
          os << " = " << commandData.params[i].pureType << "()";
        }
      }
    }
    argEncountered = true;
  }
  if (argEncountered)
  {
    os << ", ";
  }

  os << "Dispatch const &d";
  if (withDefaults)
  {
    os << " = Dispatch() ";
  }
}

void VulkanHppGenerator::writeFunctionHeaderReturnType(std::ostream & os, CommandData const& commandData, bool enhanced, bool singular, bool unique, bool isStructureChain)
{
  std::string templateString;
  std::string returnType;
  if (enhanced)
  {
    // the enhanced function might return some pretty complex return stuff
    if (isStructureChain || (!singular && (commandData.enhancedReturnType.find("Allocator") != std::string::npos)))
    {
      // for the non-singular case with allocation, we need to prepend with 'typename' to keep compilers happy
      templateString = "typename ";
    }
    if (unique)
    {
      // the unique version returns something prefixed with 'Unique'; potentially a vector of that stuff
      // it's a vector, if it's not the singular version and the return parameter is a vector parameter
      bool returnsVector = !singular && (commandData.vectorParams.find(commandData.returnParam) != commandData.vectorParams.end());

      templateString += returnsVector ? "ResultValueType<std::vector<UniqueHandle<${returnType},Dispatch>,Allocator>>::type " : "typename ResultValueType<UniqueHandle<${returnType},Dispatch>>::type ";
      returnType = isStructureChain ? "StructureChain<X, Y, Z...>" : commandData.params[commandData.returnParam].pureType;
    }
    else if ((commandData.enhancedReturnType != commandData.returnType) && (commandData.returnType != "void"))
    {
      // if the enhanced return type differs from the original return type, and it's not void, we return a ResultValueType<...>::type
      templateString += "ResultValueType<${returnType}>::type ";

      assert(commandData.returnType == "Result");
      // in singular case, we create the ResultValueType from the pure return type, otherwise from the enhanced return type
      if (isStructureChain)
      {
        returnType = "StructureChain<X, Y, Z...>";
      }
      else
      {
        returnType = singular ? commandData.params[commandData.returnParam].pureType : commandData.enhancedReturnType;
      }
    }
    else if ((commandData.returnParam != INVALID_INDEX) && (1 < commandData.successCodes.size()))
    {
      // if there is a return parameter at all, and there are multiple success codes, we return a ResultValue<...> with the pure return type
      assert(commandData.returnType == "Result");
      templateString = "ResultValue<${returnType}> ";
      returnType = isStructureChain ? "StructureChain<X, Y, Z...>" : commandData.params[commandData.returnParam].pureType;
    }
    else
    {
      // and in every other case, we just return the enhanced return type.
      templateString = "${returnType} ";
      returnType = isStructureChain ? "StructureChain<X, Y, Z...>" : commandData.enhancedReturnType;
    }
  }
  else
  {
    // the non-enhanced function just uses the return type
    templateString = "${returnType} ";
    returnType = commandData.returnType;
  }
  os << replaceWithMap(templateString, { { "returnType", returnType } });
}

void VulkanHppGenerator::writeFunctionHeaderTemplate(std::ostream & os, std::string const& indentation, CommandData const& commandData, bool enhanced, bool unique, bool withDefault, bool isStructureChain)
{
  std::string dispatch = withDefault ? std::string("typename Dispatch = DispatchLoaderStatic") : std::string("typename Dispatch");
  if (enhanced && isStructureChain)
  {
    os << indentation << "template <typename X, typename Y, typename ...Z, " << dispatch << ">" << std::endl;
  }
  else if (enhanced && (commandData.templateParam != INVALID_INDEX) && ((commandData.templateParam != commandData.returnParam) || (commandData.enhancedReturnType == "Result")))
  {
    // if there's a template parameter, not being the return parameter or where the enhanced return type is 'Result' -> templatize on type 'T'
    assert(commandData.enhancedReturnType.find("Allocator") == std::string::npos);
    os << indentation << "template <typename T, " << dispatch << ">" << std::endl;
  }
  else if (enhanced && (commandData.enhancedReturnType.find("Allocator") != std::string::npos))
  {
    // otherwise, if there's an Allocator used in the enhanced return type, we templatize on that Allocator
    assert((commandData.enhancedReturnType.substr(0, 12) == "std::vector<") && (commandData.enhancedReturnType.find(',') != std::string::npos) && (12 < commandData.enhancedReturnType.find(',')));
    os << indentation << "template <typename Allocator";
    if (withDefault)
    {
      // for the default type get the type from the enhancedReturnType, which is of the form 'std::vector<Type,Allocator>'
      os << " = std::allocator<" << (unique ? "Unique" : "") << commandData.enhancedReturnType.substr(12, commandData.enhancedReturnType.find(',') - 12) << ">";
    }
    os << ", " << dispatch;
    os << "> " << std::endl;
  }
  else
  {
    os << indentation << "template<" << dispatch << ">" << std::endl;
  }
}

void VulkanHppGenerator::writeResultEnum(std::ostream & os)
{
  std::list<DependencyData>::const_iterator it = std::find_if(m_dependencies.begin(), m_dependencies.end(), [](DependencyData const& dp) { return dp.name == "Result"; });
  assert(it != m_dependencies.end());
  writeTypeEnum(os, m_enums.find(it->name)->second);
  writeEnumsToString(os, m_enums.find(it->name)->second);
  os << "#ifndef VULKAN_HPP_NO_EXCEPTIONS";
  os << exceptionHeader;
  os << exceptionClassesHeader;
  writeExceptionsForEnum(os, m_enums.find(it->name)->second);
  writeThrowExceptions(os, m_enums.find(it->name)->second);
  os << "#endif" << std::endl;
  m_dependencies.erase(it);
}

void VulkanHppGenerator::writeStructConstructor(std::ostream & os, std::string const& name, StructData const& structData, std::map<std::string, std::string> const& defaultValues)
{
  // the constructor with all the elements as arguments, with defaults
  std::string ctorOpening = "    " + name + "( ";
  size_t indentSize = ctorOpening.size();
  os << ctorOpening;

  bool listedArgument = false;
  for (size_t i = 0; i < structData.members.size(); i++)
  {
    listedArgument = writeStructConstructorArgument(os, listedArgument, indentSize, structData.members[i], defaultValues);
  }
  os << " )" << std::endl;

  // copy over the simple arguments
  bool firstArgument = true;
  for (size_t i = 0; i < structData.members.size(); i++)
  {
    // skip members 'pNext' and 'sType' are directly set by initializers
    if ((structData.members[i].name != "pNext") && (structData.members[i].name != "sType") && (structData.members[i].arraySize.empty()))
    {
      // here, we can only handle non-array arguments
      std::string templateString = "      ${sep} ${member}( ${value} )\n";
      std::string sep = firstArgument ? ":" : ",";
      std::string member = structData.members[i].name;
      std::string value = structData.members[i].name + "_";   // the elements are initialized by the corresponding argument (with trailing '_', as mentioned above)

      os << replaceWithMap(templateString, { { "sep", sep },{ "member", member },{ "value", value } });
      firstArgument = false;
    }
  }

  // the body of the constructor, copying over data from argument list into wrapped struct
  os << "    {" << std::endl;
  for (size_t i = 0; i < structData.members.size(); i++)
  {
    if (!structData.members[i].arraySize.empty())
    {
      // here we can handle the arrays, copying over from argument (with trailing '_') to member
      // size is arraySize times sizeof type
      std::string member = structData.members[i].name;
      std::string arraySize = structData.members[i].arraySize;
      std::string type = structData.members[i].type;
      os << replaceWithMap("      memcpy( &${member}, ${member}_.data(), ${arraySize} * sizeof( ${type} ) );\n",
      { { "member", member },{ "arraySize", arraySize },{ "type", type } });
    }
  }
  os << "    }\n\n";

  if (!structData.subStruct.empty())
  {
    auto const& subStruct = m_structs.find(structData.subStruct);
    assert(subStruct != m_structs.end());

    std::string subStructArgumentName = startLowerCase(strip(subStruct->first, "vk"));
    ctorOpening = "    explicit " + name + "( ";
    indentSize = ctorOpening.size();

    os << ctorOpening << subStruct->first << " const& " << subStructArgumentName;

    for (size_t i = subStruct->second.members.size(); i < structData.members.size(); i++)
    {
      writeStructConstructorArgument(os, true, indentSize, structData.members[i], defaultValues);
    }
    os << " )" << std::endl;

    firstArgument = true;
    std::string templateString = "      ${sep} ${member}( ${value} )\n";
    for (size_t i = 0; i < subStruct->second.members.size(); i++)
    {
      assert(structData.members[i].arraySize.empty());
      std::string sep = firstArgument ? ":" : ",";
      std::string member = structData.members[i].name;
      std::string value = subStructArgumentName + "." + subStruct->second.members[i].name;

      os << replaceWithMap(templateString, { { "sep", sep },{ "member", member },{ "value", value } });
      firstArgument = false;
    }
    for (size_t i = subStruct->second.members.size(); i < structData.members.size(); i++)
    {
      assert(structData.members[i].arraySize.empty());
      std::string member = structData.members[i].name;
      std::string value = structData.members[i].name + "_";   // the elements are initialized by the corresponding argument (with trailing '_', as mentioned above)

      os << replaceWithMap(templateString, { { "sep", "," },{ "member", member },{ "value", value } });
    }
    os << "    {}" << std::endl << std::endl;
  }

  std::string templateString =
    R"(    ${name}( Vk${name} const & rhs )
    {
      memcpy( this, &rhs, sizeof( ${name} ) );
    }

    ${name}& operator=( Vk${name} const & rhs )
    {
      memcpy( this, &rhs, sizeof( ${name} ) );
      return *this;
    }
)";

  os << replaceWithMap(templateString, { { "name", name } });
}

void VulkanHppGenerator::writeIndentation(std::ostream & os, size_t indentLength)
{
  for(size_t i = 0; i < indentLength; i++)
  {
    os << " ";
  }
}

bool VulkanHppGenerator::writeStructConstructorArgument(std::ostream & os, bool listedArgument, size_t indentLength, MemberData const& memberData, std::map<std::string, std::string> const& defaultValues)
{
  if (listedArgument)
  {
    os << ",\n";
    writeIndentation(os, indentLength);
  }

  // skip members 'pNext' and 'sType', as they are never explicitly set
  if ((memberData.name != "pNext") && (memberData.name != "sType"))
  {
    // find a default value for the given pure type
    std::map<std::string, std::string>::const_iterator defaultIt = defaultValues.find(memberData.pureType);
    assert(defaultIt != defaultValues.end());

    if (memberData.arraySize.empty())
    {
      // the arguments name get a trailing '_', to distinguish them from the actual struct members
      // pointer arguments get a nullptr as default
      os << memberData.type << " " << memberData.name << "_ = " << (memberData.type.back() == '*' ? "nullptr" : defaultIt->second);
    }
    else
    {
      // array members are provided as const reference to a std::array
      // the arguments name get a trailing '_', to distinguish them from the actual struct members
      // list as many default values as there are elements in the array
      os << "std::array<" << memberData.type << "," << memberData.arraySize << "> const& " << memberData.name << "_ = { { " << defaultIt->second;
      size_t n = atoi(memberData.arraySize.c_str());
      assert(0 < n);
      for (size_t j = 1; j < n; j++)
      {
        os << ", " << defaultIt->second;
      }
      os << " } }";
    }
    listedArgument = true;
  }
  return listedArgument;
}

void VulkanHppGenerator::writeStructSetter(std::ostream & os, std::string const& structureName, MemberData const& memberData)
{
  if (memberData.type != "StructureType") // filter out StructureType, which is supposed to be immutable !
  {
    // the setters return a reference to the structure
    os << "    " << structureName << "& set" << startUpperCase(memberData.name) << "( ";
    if (memberData.arraySize.empty())
    {
      os << memberData.type << " ";
    }
    else
    {
      os << "std::array<" << memberData.type << "," << memberData.arraySize << "> ";
    }
    // add a trailing '_' to the argument to distinguish it from the structure member
    os << memberData.name << "_ )" << std::endl
      << "    {" << std::endl;
    // copy over the argument, either by assigning simple data, or by memcpy array data
    if (memberData.arraySize.empty())
    {
      os << "      " << memberData.name << " = " << memberData.name << "_";
    }
    else
    {
      os << "      memcpy( &" << memberData.name << ", " << memberData.name << "_.data(), " << memberData.arraySize << " * sizeof( " << memberData.type << " ) )";
    }
    os << ";" << std::endl
      << "      return *this;" << std::endl
      << "    }" << std::endl
      << std::endl;
  }
}

void VulkanHppGenerator::writeStructureChainValidation(std::ostream & os)
{
  // write all template functions for the structure pointer chain validation
  for (auto it = m_dependencies.begin(); it != m_dependencies.end(); ++it)
  {
    if (it->category == DependencyData::Category::STRUCT)
    {
      writeStructureChainValidation(os, *it);
    }
  }
}

void VulkanHppGenerator::writeStructureChainValidation(std::ostream & os, DependencyData const& dependencyData)
{
  std::map<std::string, StructData>::const_iterator it = m_structs.find(dependencyData.name);
  assert(it != m_structs.end());

  if (!it->second.structExtends.empty())
  {
    enterProtect(os, it->second.protect);

    // write out allowed structure chains
    for (auto extendName : it->second.structExtends)
    {
      std::map<std::string, StructData>::const_iterator itExtend = m_structs.find(extendName);
      if (itExtend == m_structs.end()) {
        std::stringstream errorString;
        errorString << extendName << " does not specify a struct in structextends field.";

        // check if symbol name is an alias to a struct
        auto itAlias = std::find_if(m_structs.begin(), m_structs.end(), [&extendName](std::pair<std::string, StructData> const &it) -> bool {return it.second.alias == extendName;});
        if (itAlias != m_structs.end())
        {
          errorString << " The symbol is an alias and maps to " << itAlias->first << ".";
        }

        errorString << std::endl;
        throw std::runtime_error(errorString.str());
      }
      enterProtect(os, itExtend->second.protect);

      os << "  template <> struct isStructureChainValid<" << extendName << ", " << dependencyData.name << ">{ enum { value = true }; };" << std::endl;

      leaveProtect(os, itExtend->second.protect);
    }
    leaveProtect(os, it->second.protect);
  }
}

void VulkanHppGenerator::writeThrowExceptions(std::ostream & os, EnumData const& enumData)
{
  enterProtect(os, enumData.protect);
  os <<
    R"(  VULKAN_HPP_INLINE void throwResultException( Result result, char const * message )
  {
    switch ( result )
    {
)";
  for (size_t i = 0; i<enumData.values.size(); i++)
  {
    if (!isErrorEnum(enumData.values[i].name))
    {
      continue;
    }
    const std::string strippedExceptionName = stripErrorEnumPrefix(enumData.values[i].name);
    os << "    case " << enumData.name << "::" << enumData.values[i].name << ": "
      << "throw " << strippedExceptionName << "Error ( message );" << std::endl;
  }
  os <<
    R"(    default: throw SystemError( make_error_code( result ) );
    }
  }
)";
  leaveProtect(os, enumData.protect);
}

void VulkanHppGenerator::writeToStringFunctions(std::ostream & os)
{
  // write all the to_string functions for enums and flags
  for (auto it = m_dependencies.begin(); it != m_dependencies.end(); ++it)
  {
    switch (it->category)
    {
      case DependencyData::Category::BITMASK:
        writeBitmaskToString(os, it->name, m_enums.find(*it->dependencies.begin())->second);
        break;
      case DependencyData::Category::ENUM:
        assert(m_enums.find(it->name) != m_enums.end());
        writeEnumsToString(os, m_enums.find(it->name)->second);
        break;
      default:
        break;
    }
  }
}

void VulkanHppGenerator::writeTypeBitmask(std::ostream & os, std::string const& bitmaskName, BitmaskData const& bitmaskData, EnumData const& enumData)
{
  enterProtect(os, bitmaskData.protect);

  // each Flags class is using on the class 'Flags' with the corresponding FlagBits enum as the template parameter
  os << "  using " << bitmaskName << " = Flags<" << enumData.name << ", Vk" << bitmaskName << ">;" << std::endl;

  std::stringstream allFlags;
  for (size_t i = 0; i < enumData.values.size(); i++)
  {
    if (i != 0)
    {
      allFlags << " | ";
    }
    allFlags << "VkFlags(" << enumData.name << "::" << enumData.values[i].name << ")";
  }

  if (!enumData.values.empty())
  {
    const std::string templateString = R"(
  VULKAN_HPP_INLINE ${bitmaskName} operator|( ${enumName} bit0, ${enumName} bit1 )
  {
    return ${bitmaskName}( bit0 ) | bit1;
  }

  VULKAN_HPP_INLINE ${bitmaskName} operator~( ${enumName} bits )
  {
    return ~( ${bitmaskName}( bits ) );
  }

  template <> struct FlagTraits<${enumName}>
  {
    enum
    {
      allFlags = ${allFlags}
    };
  };
)";
    os << replaceWithMap(templateString, { { "bitmaskName", bitmaskName },{ "enumName", enumData.name },{ "allFlags", allFlags.str() } });
  }

  if (!bitmaskData.alias.empty())
  {
    os << std::endl
      << "  using " << bitmaskData.alias << " = " << bitmaskName << ";" << std::endl;
  }

  leaveProtect(os, bitmaskData.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeTypeCommand(std::ostream & os, DependencyData const& dependencyData)
{
  assert(m_commands.find(dependencyData.name) != m_commands.end());
  CommandData const& commandData = m_commands.find(dependencyData.name)->second;
  if (commandData.className.empty())
  {
    if (commandData.fullName == "createInstance")
    {
      // special handling for createInstance, as we need to explicitly place the forward declarations and the deleter classes here
#if !defined(NDEBUG)
      auto deleterTypesIt = m_deleterTypes.find("");
      assert((deleterTypesIt != m_deleterTypes.end()) && (deleterTypesIt->second.size() == 2));
      assert(deleterTypesIt->second.find("Instance") != deleterTypesIt->second.end());
#endif

      writeUniqueTypes(os, std::make_pair<std::string, std::set<std::string>>("", { "Instance" }));
      writeTypeCommand(os, "  ", commandData, false);
    }
    else
    {
      writeTypeCommand(os, "  ", commandData, false);
    }
    writeTypeCommand(os, "  ", commandData, true);
    os << std::endl;
  }
}

void VulkanHppGenerator::writeTypeCommand(std::ostream & os, std::string const& indentation, CommandData const& commandData, bool definition)
{
  enterProtect(os, commandData.protect);

  bool isStructureChain = m_extendedStructs.find(commandData.enhancedReturnType) != m_extendedStructs.end();

  // first create the standard version of the function
  std::ostringstream standard;
  writeFunction(standard, indentation, commandData, definition, false, false, false, false);

  // then the enhanced version, composed by up to five parts
  std::ostringstream enhanced;
  writeFunction(enhanced, indentation, commandData, definition, true, false, false, false);

  if (isStructureChain)
  {
    writeFunction(enhanced, indentation, commandData, definition, true, false, false, true);
  }

  // then a singular version, if a sized vector would be returned
  std::map<size_t, size_t>::const_iterator returnVector = commandData.vectorParams.find(commandData.returnParam);
  bool singular = (returnVector != commandData.vectorParams.end()) &&
                  (returnVector->second != INVALID_INDEX) &&
                  (commandData.params[returnVector->first].pureType != "void") &&
                  (commandData.params[returnVector->second].type.back() != '*');
  if (singular)
  {
    writeFunction(enhanced, indentation, commandData, definition, true, true, false, false);
  }

  // special handling for createDevice and createInstance !
  bool specialWriteUnique = (commandData.reducedName == "createDevice") || (commandData.reducedName == "createInstance");

  // and then the same for the Unique* versions (a Deleter is available for the commandData's class, and the function starts with 'allocate' or 'create')
  if (((m_deleters.find(commandData.className) != m_deleters.end()) || specialWriteUnique) && ((commandData.reducedName.substr(0, 8) == "allocate") || (commandData.reducedName.substr(0, 6) == "create")))
  {
    enhanced << "#ifndef VULKAN_HPP_NO_SMART_HANDLE" << std::endl;
    writeFunction(enhanced, indentation, commandData, definition, true, false, true, false);

    if (singular)
    {
      writeFunction(enhanced, indentation, commandData, definition, true, true, true, false);
    }
    enhanced << "#endif /*VULKAN_HPP_NO_SMART_HANDLE*/" << std::endl;
  }

  // and write one or both of them
  writeStandardOrEnhanced(os, standard.str(), enhanced.str());

  leaveProtect(os, commandData.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeTypeEnum(std::ostream & os, EnumData const& enumData)
{
  // a named enum per enum, listing all its values by setting them to the original Vulkan names
  enterProtect(os, enumData.protect);
  os << "  enum class " << enumData.name << std::endl
    << "  {" << std::endl;
  for (size_t i = 0; i<enumData.values.size(); i++)
  {
    os << "    " << enumData.values[i].name << " = " << enumData.values[i].value;
    if (!enumData.values[i].alias.empty())
    {
      os << "," << std::endl
        << "    " << enumData.values[i].alias << " = " << enumData.values[i].value;
    }
    if (i < enumData.values.size() - 1)
    {
      os << ",";
    }
    os << std::endl;
  }
  os << "  };" << std::endl;

  leaveProtect(os, enumData.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeTypeHandle(std::ostream & os, DependencyData const& dependencyData, HandleData const& handleData)
{
  enterProtect(os, handleData.protect);

  // check if there are any forward dependenices for this handle -> list them first
  if (!dependencyData.forwardDependencies.empty())
  {
    os << "  // forward declarations" << std::endl;
    for (std::set<std::string>::const_iterator it = dependencyData.forwardDependencies.begin(); it != dependencyData.forwardDependencies.end(); ++it)
    {
      assert(m_structs.find(*it) != m_structs.end());
      os << "  struct " << *it << ";" << std::endl;
    }
    os << std::endl;
  }

  // then write any forward declaration of Deleters used by this handle
  std::map<std::string, std::set<std::string>>::const_iterator deleterTypesIt = m_deleterTypes.find(dependencyData.name);
  if (deleterTypesIt != m_deleterTypes.end())
  {
    writeUniqueTypes(os, *deleterTypesIt);
  }
  else if (dependencyData.name == "PhysicalDevice")
  {
    // special handling for class Device, as it's created from PhysicalDevice, but destroys itself
    writeUniqueTypes(os, std::make_pair<std::string, std::set<std::string>>("", { "Device" }));
  }

  const std::string memberName = startLowerCase(dependencyData.name);
  const std::string templateString =
    R"(  class ${className}
  {
  public:
    VULKAN_HPP_CONSTEXPR ${className}()
      : m_${memberName}(VK_NULL_HANDLE)
    {}

    VULKAN_HPP_CONSTEXPR ${className}( std::nullptr_t )
      : m_${memberName}(VK_NULL_HANDLE)
    {}

    VULKAN_HPP_TYPESAFE_EXPLICIT ${className}( Vk${className} ${memberName} )
      : m_${memberName}( ${memberName} )
    {}

#if defined(VULKAN_HPP_TYPESAFE_CONVERSION)
    ${className} & operator=(Vk${className} ${memberName})
    {
      m_${memberName} = ${memberName};
      return *this; 
    }
#endif

    ${className} & operator=( std::nullptr_t )
    {
      m_${memberName} = VK_NULL_HANDLE;
      return *this;
    }

    bool operator==( ${className} const & rhs ) const
    {
      return m_${memberName} == rhs.m_${memberName};
    }

    bool operator!=(${className} const & rhs ) const
    {
      return m_${memberName} != rhs.m_${memberName};
    }

    bool operator<(${className} const & rhs ) const
    {
      return m_${memberName} < rhs.m_${memberName};
    }

${commands}

    VULKAN_HPP_TYPESAFE_EXPLICIT operator Vk${className}() const
    {
      return m_${memberName};
    }

    explicit operator bool() const
    {
      return m_${memberName} != VK_NULL_HANDLE;
    }

    bool operator!() const
    {
      return m_${memberName} == VK_NULL_HANDLE;
    }

  private:
    Vk${className} m_${memberName};
  };

  static_assert( sizeof( ${className} ) == sizeof( Vk${className} ), "handle and wrapper have different size!" );

)";

  std::ostringstream commands;
  // now list all the commands that are mapped to members of this class
  for (size_t i = 0; i < handleData.commands.size(); i++)
  {
    std::map<std::string, CommandData>::const_iterator cit = m_commands.find(handleData.commands[i]);
    assert((cit != m_commands.end()) && !cit->second.className.empty());
    writeTypeCommand(commands, "    ", cit->second, false);

    // special handling for destroy functions which are not aliased.
    if (!cit->second.isAlias && (((cit->second.fullName.substr(0, 7) == "destroy") && (cit->second.reducedName != "destroy")) || (cit->second.fullName.substr(0, 4) == "free")))
    {
      CommandData shortenedCommand = cit->second;
      shortenedCommand.reducedName = (cit->second.fullName.substr(0, 7) == "destroy") ? "destroy" : "free";
      writeTypeCommand(commands, "    ", shortenedCommand, false);
    }
  }

  os << replaceWithMap(templateString, {
    { "className", dependencyData.name },
    { "memberName", memberName },
    { "commands", commands.str() }
  });

  // and finally the commands, that are member functions of this handle
  for (size_t i = 0; i < handleData.commands.size(); i++)
  {
    std::string commandName = handleData.commands[i];
    std::map<std::string, CommandData>::const_iterator cit = m_commands.find(commandName);
    assert((cit != m_commands.end()) && !cit->second.className.empty());
    std::list<DependencyData>::const_iterator dep = std::find_if(m_dependencies.begin(), m_dependencies.end(), [commandName](DependencyData const& dd) { return dd.name == commandName; });
    assert(dep != m_dependencies.end() && (dep->name == cit->second.fullName));
    writeTypeCommand(os, "  ", cit->second, true);

    // special handling for destroy functions
    if (!cit->second.isAlias && (((cit->second.fullName.substr(0, 7) == "destroy") && (cit->second.reducedName != "destroy")) || (cit->second.fullName.substr(0, 4) == "free")))
    {
      CommandData shortenedCommand = cit->second;
      shortenedCommand.reducedName = (cit->second.fullName.substr(0, 7) == "destroy") ? "destroy" : "free";
      writeTypeCommand(os, "  ", shortenedCommand, true);
    }
  }

  if (!handleData.alias.empty())
  {
    os << "  using " << handleData.alias << " = " << dependencyData.name << ";" << std::endl
      << std::endl;
  }

  leaveProtect(os, handleData.protect);
}

void VulkanHppGenerator::writeTypes(std::ostream & os, std::map<std::string, std::string> const& defaultValues)
{
  assert(m_deleterTypes.find("") != m_deleterTypes.end());

  for (std::list<DependencyData>::const_iterator it = m_dependencies.begin(); it != m_dependencies.end(); ++it)
  {
    switch (it->category)
    {
    case DependencyData::Category::BITMASK:
      assert(m_bitmasks.find(it->name) != m_bitmasks.end());
      writeTypeBitmask(os, it->name, m_bitmasks.find(it->name)->second, m_enums.find(generateEnumNameForFlags(it->name))->second);
      break;
    case DependencyData::Category::COMMAND:
      writeTypeCommand(os, *it);
      break;
    case DependencyData::Category::ENUM:
      assert(m_enums.find(it->name) != m_enums.end());
      writeTypeEnum(os, m_enums.find(it->name)->second);
      break;
    case DependencyData::Category::FUNC_POINTER:
    case DependencyData::Category::REQUIRED:
      // skip FUNC_POINTER and REQUIRED, they just needed to be in the dependencies list to resolve dependencies
      break;
    case DependencyData::Category::HANDLE:
      assert(m_handles.find(it->name) != m_handles.end());
      writeTypeHandle(os, *it, m_handles.find(it->name)->second);
      break;
    case DependencyData::Category::SCALAR:
      writeTypeScalar(os, *it);
      break;
    case DependencyData::Category::STRUCT:
      writeTypeStruct(os, *it, defaultValues);
      break;
    case DependencyData::Category::UNION:
      assert(m_structs.find(it->name) != m_structs.end());
      writeTypeUnion(os, *it, defaultValues);
      break;
    default:
      assert(false);
      break;
    }
  }
}

void VulkanHppGenerator::writeTypeScalar(std::ostream & os, DependencyData const& dependencyData)
{
  assert(dependencyData.dependencies.size() == 1);
  os << "  using " << dependencyData.name << " = " << *dependencyData.dependencies.begin() << ";" << std::endl
    << std::endl;
}

void VulkanHppGenerator::writeTypeStruct(std::ostream & os, DependencyData const& dependencyData, std::map<std::string, std::string> const& defaultValues)
{
  std::map<std::string, StructData>::const_iterator it = m_structs.find(dependencyData.name);
  assert(it != m_structs.end());

  enterProtect(os, it->second.protect);
  os << "  struct " << dependencyData.name << std::endl
    << "  {" << std::endl;

  // only structs that are not returnedOnly get a constructor!
  if (!it->second.returnedOnly)
  {
    writeStructConstructor(os, dependencyData.name, it->second, defaultValues);
  }

  // create the setters
  if (!it->second.returnedOnly)
  {
    for (size_t i = 0; i < it->second.members.size(); i++)
    {
      writeStructSetter(os, dependencyData.name, it->second.members[i]);
    }
  }

  // the implicit cast-operators to the native type
  os << "    operator Vk" << dependencyData.name << " const&() const" << std::endl
    << "    {" << std::endl
    << "      return *reinterpret_cast<const Vk" << dependencyData.name << "*>(this);" << std::endl
    << "    }" << std::endl
    << std::endl
    << "    operator Vk" << dependencyData.name << " &()" << std::endl
    << "    {" << std::endl
    << "      return *reinterpret_cast<Vk" << dependencyData.name << "*>(this);" << std::endl
    << "    }" << std::endl
    << std::endl;

  // operator==() and operator!=()
  // only structs without a union as a member can have a meaningfull == and != operation; we filter them out
  if (!containsUnion(dependencyData.name, m_structs))
  {
    // two structs are compared by comparing each of the elements
    os << "    bool operator==( " << dependencyData.name << " const& rhs ) const" << std::endl
      << "    {" << std::endl
      << "      return ";
    for (size_t i = 0; i < it->second.members.size(); i++)
    {
      if (i != 0)
      {
        os << std::endl << "          && ";
      }
      if (!it->second.members[i].arraySize.empty())
      {
        os << "( memcmp( " << it->second.members[i].name << ", rhs." << it->second.members[i].name << ", " << it->second.members[i].arraySize << " * sizeof( " << it->second.members[i].type << " ) ) == 0 )";
      }
      else
      {
        os << "( " << it->second.members[i].name << " == rhs." << it->second.members[i].name << " )";
      }
    }
    os << ";" << std::endl
      << "    }" << std::endl
      << std::endl
      << "    bool operator!=( " << dependencyData.name << " const& rhs ) const" << std::endl
      << "    {" << std::endl
      << "      return !operator==( rhs );" << std::endl
      << "    }" << std::endl
      << std::endl;
  }

  // the member variables
  for (size_t i = 0; i < it->second.members.size(); i++)
  {
    if (it->second.members[i].type == "StructureType")
    {
      assert((i == 0) && (it->second.members[i].name == "sType"));
      if (!it->second.members[i].values.empty())
      {
        assert(!it->second.members[i].values.empty());
        auto nameIt = m_nameMap.find(it->second.members[i].values);
        assert(nameIt != m_nameMap.end());
        os << "  private:" << std::endl
          << "    StructureType sType = " << nameIt->second << ";" << std::endl
          << std::endl
          << "  public:" << std::endl;
      }
      else
      {
        os << "    StructureType sType;" << std::endl;
      }
    }
    else
    {
      os << "    " << it->second.members[i].type << " " << it->second.members[i].name;
      if (it->second.members[i].name == "pNext")
      {
        os << " = nullptr";
      }
      else if (!it->second.members[i].arraySize.empty())
      {
        os << "[" << it->second.members[i].arraySize << "]";
      }
      os << ";" << std::endl;
    }
  }
  os << "  };" << std::endl
    << "  static_assert( sizeof( " << dependencyData.name << " ) == sizeof( Vk" << dependencyData.name << " ), \"struct and wrapper have different size!\" );" << std::endl;

  if (!it->second.alias.empty())
  {
    os << std::endl
      << "  using " << it->second.alias << " = " << dependencyData.name << ";" << std::endl;
  }

  leaveProtect(os, it->second.protect);
  os << std::endl;
}

void VulkanHppGenerator::writeUniqueTypes(std::ostream &os, std::pair<std::string, std::set<std::string>> const& deleterTypes)
{
  os << "#ifndef VULKAN_HPP_NO_SMART_HANDLE" << std::endl;
  if (!deleterTypes.first.empty())
  {
    os << "  class " << deleterTypes.first << ";" << std::endl;
  }
  os << std::endl;

  for (auto const& dt : deleterTypes.second)
  {
    auto ddit = m_deleters.find(dt);
    assert(ddit != m_deleters.end());

    std::string deleterType = (deleterTypes.first.empty() ? "NoParent" : deleterTypes.first);

    os << "  template <typename Dispatch> class UniqueHandleTraits<" << dt << ",Dispatch> {public: " <<  "using owner = " << deleterType << "; " << "using deleter = " << (ddit->second.pool.empty() ? "Object" : "Pool") << ((ddit->second.call.substr(0, 4) == "free") ? "Free<" : "Destroy<") << (deleterTypes.first.empty() ? "NoParent" : deleterTypes.first) << (ddit->second.pool.empty() ? "" : ", " + ddit->second.pool) << ",Dispatch>; };\n";
    os << "  using Unique" << dt << " = UniqueHandle<" << dt << ",DispatchLoaderStatic>;" << std::endl;
  }
  os << "#endif /*VULKAN_HPP_NO_SMART_HANDLE*/" << std::endl
    << std::endl;
}

void VulkanHppGenerator::writeTypeUnion(std::ostream & os, DependencyData const& dependencyData, std::map<std::string, std::string> const& defaultValues)
{
  std::map<std::string, StructData>::const_iterator it = m_structs.find(dependencyData.name);
  assert(it != m_structs.end());

  std::ostringstream oss;
  os << "  union " << dependencyData.name << std::endl
    << "  {" << std::endl;

  for (size_t i = 0; i<it->second.members.size(); i++)
  {
    // one constructor per union element
    os << "    " << dependencyData.name << "( ";
    if (it->second.members[i].arraySize.empty())
    {
      os << it->second.members[i].type << " ";
    }
    else
    {
      os << "const std::array<" << it->second.members[i].type << "," << it->second.members[i].arraySize << ">& ";
    }
    os << it->second.members[i].name << "_";

    // just the very first constructor gets default arguments
    if (i == 0)
    {
      std::map<std::string, std::string>::const_iterator defaultIt = defaultValues.find(it->second.members[i].pureType);
      assert(defaultIt != defaultValues.end());
      if (it->second.members[i].arraySize.empty())
      {
        os << " = " << defaultIt->second;
      }
      else
      {
        os << " = { {" << defaultIt->second << "} }";
      }
    }
    os << " )" << std::endl
      << "    {" << std::endl
      << "      ";
    if (it->second.members[i].arraySize.empty())
    {
      os << it->second.members[i].name << " = " << it->second.members[i].name << "_";
    }
    else
    {
      os << "memcpy( &" << it->second.members[i].name << ", " << it->second.members[i].name << "_.data(), " << it->second.members[i].arraySize << " * sizeof( " << it->second.members[i].type << " ) )";
    }
    os << ";" << std::endl
      << "    }" << std::endl
      << std::endl;
  }

  for (size_t i = 0; i<it->second.members.size(); i++)
  {
    // one setter per union element
    assert(!it->second.returnedOnly);
    writeStructSetter(os, dependencyData.name, it->second.members[i]);
  }

  // the implicit cast operators to the native type
  os << "    operator Vk" << dependencyData.name << " const&() const" << std::endl
    << "    {" << std::endl
    << "      return *reinterpret_cast<const Vk" << dependencyData.name << "*>(this);" << std::endl
    << "    }" << std::endl
    << std::endl
    << "    operator Vk" << dependencyData.name << " &()" << std::endl
    << "    {" << std::endl
    << "      return *reinterpret_cast<Vk" << dependencyData.name << "*>(this);" << std::endl
    << "    }" << std::endl
    << std::endl;

  // the union member variables
  // if there's at least one Vk... type in this union, check for unrestricted unions support
  bool needsUnrestrictedUnions = false;
  for (size_t i = 0; i < it->second.members.size() && !needsUnrestrictedUnions; i++)
  {
    needsUnrestrictedUnions = (m_vkTypes.find(it->second.members[i].type) != m_vkTypes.end());
  }
  if (needsUnrestrictedUnions)
  {
    os << "#ifdef VULKAN_HPP_HAS_UNRESTRICTED_UNIONS" << std::endl;
    for (size_t i = 0; i < it->second.members.size(); i++)
    {
      os << "    " << it->second.members[i].type << " " << it->second.members[i].name;
      if (!it->second.members[i].arraySize.empty())
      {
        os << "[" << it->second.members[i].arraySize << "]";
      }
      os << ";" << std::endl;
    }
    os << "#else" << std::endl;
  }
  for (size_t i = 0; i < it->second.members.size(); i++)
  {
    os << "    ";
    if (m_vkTypes.find(it->second.members[i].type) != m_vkTypes.end())
    {
      os << "Vk";
    }
    os << it->second.members[i].type << " " << it->second.members[i].name;
    if (!it->second.members[i].arraySize.empty())
    {
      os << "[" << it->second.members[i].arraySize << "]";
    }
    os << ";" << std::endl;
  }
  if (needsUnrestrictedUnions)
  {
    os << "#endif  // VULKAN_HPP_HAS_UNRESTRICTED_UNIONS" << std::endl;
  }
  os << "  };" << std::endl
    << std::endl;
}

#if !defined(NDEBUG)
void VulkanHppGenerator::checkExtensionRequirements()
{
  for (auto const& ext : m_extensions)
  {
    for (auto const& req : ext.second.requires)
    {
      auto reqExt = m_extensions.find(req);
      assert(reqExt != m_extensions.end());
      assert(reqExt->second.protect.empty() || (reqExt->second.protect == ext.second.protect));
    }
  }
}

void VulkanHppGenerator::skipVendorID(tinyxml2::XMLElement const* element)
{
  std::map<std::string, std::string> attributes = getAttributes(element);
  checkAttributes(attributes, element->GetLineNum(), { { "comment",{} },{ "id",{} },{ "name",{} } }, {});
  checkElements(getChildElements(element), {});

  VendorIDData vendorID;
  for (auto const& attribute : attributes)
  {
    std::string name = attribute.first;
    if (name == "comment")
    {
      vendorID.comment = attribute.second;
    }
    else if (name == "id")
    {
      vendorID.id = attribute.second;
    }
    else
    {
      assert(name == "name");
      vendorID.name = attribute.second;
    }
  }
  m_vendorIDs.push_back(vendorID);
}

void VulkanHppGenerator::skipVendorIDs(tinyxml2::XMLElement const* element)
{
  checkAttributes(getAttributes(element), element->GetLineNum(), { { "comment",{} } }, {});
  std::vector<tinyxml2::XMLElement const*> children = getChildElements(element);
  checkElements(children, { "vendorid" });

  for (auto child : children)
  {
    skipVendorID(child);
  }
}
#endif

void VulkanHppGenerator::EnumData::addEnumValue(std::string const &enumName, std::string const& tag, std::map<std::string, std::string> & nameMap)
{
  EnumValueData evd;
  evd.name = createEnumValueName(enumName, prefix, postfix, bitmask, tag);
  evd.value = enumName;

  auto it = std::find_if(values.begin(), values.end(), [&evd](EnumValueData const& _evd) { return _evd.name == evd.name; });
  if (it == values.end())
  {
    values.push_back(evd);
    assert(nameMap.find(enumName) == nameMap.end());
    nameMap[enumName] = this->name + "::" + evd.name;
  }
  else
  {
    assert(it->value == evd.value);
  }
}

void VulkanHppGenerator::writeDelegationClassStatic(std::ostream &os)
{
  os << "class DispatchLoaderStatic" << std::endl
     << "{"                    << std::endl
     << "public:\n";

  for (auto command : m_commands)
  {
    enterProtect(os, command.second.protect);
    os << "  " << command.second.unchangedReturnType << " vk" << startUpperCase(command.second.fullName) << "( ";
    bool first = true;
    for (auto param : command.second.params)
    {
      if (!first) {
        os << ", ";
      }
      os << param.unchangedType << " " << param.name;
      if (!param.arraySize.empty())
      {
        os << "[" << param.arraySize << "]";
      }
      first = false;
    }
    os << "  ) const\n"
      << "  {\n"
      << "    return ::vk" << startUpperCase(command.second.fullName) << "( ";
    first = true;
    for (auto param : command.second.params)
    {
      if (!first) {
        os << ", ";
      }
      os << param.name;
      first = false;
    }
    os << ");\n";
    os << "  }\n";
    leaveProtect(os, command.second.protect);
  }
  os << "};\n";
}

void VulkanHppGenerator::writeDelegationClassDynamic(std::ostream &os)
{
  os << "  class DispatchLoaderDynamic" << std::endl
     << "  {" << std::endl
     << "  public:" << std::endl;

  for (auto command : m_commands)
  {
    enterProtect(os, command.second.protect);
    os << "    PFN_vk" << startUpperCase(command.second.fullName) << " vk" << startUpperCase(command.second.fullName) << " = 0;" << std::endl;
    leaveProtect(os, command.second.protect);
  }

  // write initialization function to fetch function pointers
  os << "  public:" << std::endl
     << "    DispatchLoaderDynamic(Instance instance = Instance(), Device device = Device())" << std::endl
     << "    {" << std::endl
     << "      if (instance)" << std::endl
     << "      {" << std::endl
     << "        init(instance, device);" << std::endl
     << "      }" << std::endl
     << "    }" << std::endl << std::endl
     << "    void init(Instance instance, Device device = Device())" << std::endl
     << "    {" << std::endl;

  for (auto command : m_commands)
  {
    enterProtect(os, command.second.protect);
    if (!command.second.params.empty() 
      && m_handles.find(command.second.params[0].type) != m_handles.end()
      && command.second.params[0].type != "Instance"
      && command.second.params[0].type != "PhysicalDevice")
    {
      os << "      vk" << startUpperCase(command.second.fullName) << " = PFN_vk" << startUpperCase(command.second.fullName) 
        << "(device ? device.getProcAddr( \"vk" << startUpperCase(command.second.fullName) << "\") : instance.getProcAddr( \"vk" << startUpperCase(command.second.fullName) << "\"));" << std::endl;
    }
    else {
      os << "      vk" << startUpperCase(command.second.fullName) << " = PFN_vk" << startUpperCase(command.second.fullName) << "(instance.getProcAddr( \"vk" << startUpperCase(command.second.fullName) << "\"));" << std::endl;
    }
    leaveProtect(os, command.second.protect);
  }
  os << "    }" << std::endl;
  os << "  };\n";
}

int main( int argc, char **argv )
{
  try {
    tinyxml2::XMLDocument doc;

    std::string filename = (argc == 1) ? VK_SPEC : argv[1];
    std::cout << "Loading vk.xml from " << filename << std::endl;
    std::cout << "Writing vulkan.hpp to " << VULKAN_HPP_FILE << std::endl;

    tinyxml2::XMLError error = doc.LoadFile(filename.c_str());
    if (error != tinyxml2::XML_SUCCESS)
    {
      std::cout << "VkGenerate: failed to load file " << filename << " . Error code: " << error << std::endl;
      return -1;
    }

    VulkanHppGenerator generator;

    bool foundLicense = false;

    tinyxml2::XMLElement const* registryElement = doc.FirstChildElement();
    checkAttributes(getAttributes(registryElement), registryElement->GetLineNum(), {}, {});
    assert(strcmp(registryElement->Value(), "registry") == 0);
    assert(!registryElement->NextSiblingElement());

    std::vector<tinyxml2::XMLElement const*> children = getChildElements(registryElement);
    checkElements(children, { "commands", "comment", "enums", "extensions", "feature", "tags", "types", "vendorids", "platforms" });
    for (auto child : children)
    {
      const std::string value = child->Value();
      if (value == "commands")
      {
        generator.readCommands(child);
      }
      else if (value == "comment")
      {
        if (!foundLicense)
        {
          // get the vulkan license header and skip any leading spaces
          generator.readComment(child);
          foundLicense = true;
        }
      }
      else if (value == "enums")
      {
        generator.readEnums(child);
      }
      else if (value == "extensions")
      {
        generator.readExtensions(child);
      }
      else if (value == "feature")
      {
        generator.readFeature(child);
      }
      else if (value == "tags")
      {
        generator.readTags(child);
      }
      else if (value == "types")
      {
        generator.readTypes(child);
      }
      else if (value == "vendorids")
      {
#if !defined(NDEBUG)
        generator.skipVendorIDs(child);
#endif
      }
      else if (value == "platforms")
      {
        // skip this tag
      }
      else
      {
        std::stringstream lineNumber;
        lineNumber << child->GetLineNum();
        std::cerr << "warning: Unhandled tag " << value << " at line number: " << lineNumber.str() << "!" << std::endl;
      }
    }

    generator.sortDependencies();

#if !defined(NDEBUG)
    generator.checkExtensionRequirements();
#endif

    std::map<std::string, std::string> defaultValues = generator.createDefaults();

    std::ofstream ofs(VULKAN_HPP_FILE);
    ofs << generator.getVulkanLicenseHeader() << std::endl
      << R"(
#ifndef VULKAN_HPP
#define VULKAN_HPP

#include <algorithm>
#include <array>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <initializer_list>
#include <string>
#include <system_error>
#include <tuple>
#include <type_traits>
#include <vulkan/vulkan.h>
#ifndef VULKAN_HPP_DISABLE_ENHANCED_MODE
# include <memory>
# include <vector>
#endif /*VULKAN_HPP_DISABLE_ENHANCED_MODE*/
#if !defined(VULKAN_HPP_ASSERT)
# include <cassert>
# define VULKAN_HPP_ASSERT   assert
#endif

// <tuple> includes <sys/sysmacros.h> through some other header
// this results in major(x) being resolved to gnu_dev_major(x)
// which is an expression in a constructor initializer list.
#if defined(major)
  #undef major
#endif
#if defined(minor)
  #undef minor
#endif

// Windows defines MemoryBarrier which is deprecated and collides
// with the vk::MemoryBarrier struct.
#ifdef MemoryBarrier
  #undef MemoryBarrier
#endif

)";

    writeVersionCheck(ofs, generator.getVersion());
    writeTypesafeCheck(ofs, generator.getTypesafeCheck());
    ofs << versionCheckHeader
      << inlineHeader
      << explicitHeader
      << constExprHeader
      << std::endl
      << vkNamespace
      << flagsHeader
      << optionalClassHeader
      << arrayProxyHeader
      << uniqueHandleHeader
      << structureChainHeader;

    // first of all, write out vk::Result and the exception handling stuff
    generator.writeResultEnum(ofs);

    ofs << "} // namespace VULKAN_HPP_NAMESPACE" << std::endl
      << std::endl
      << "namespace std" << std::endl
      << "{" << std::endl
      << "  template <>" << std::endl
      << "  struct is_error_code_enum<VULKAN_HPP_NAMESPACE::Result> : public true_type" << std::endl
      << "  {};" << std::endl
      << "}" << std::endl
      << std::endl
      << "namespace VULKAN_HPP_NAMESPACE" << std::endl
      << "{" << std::endl
      << resultValueHeader
      << createResultValueHeader;
    generator.writeDelegationClassStatic(ofs);
    ofs << deleterClassString;

    generator.writeTypes(ofs, defaultValues);
    generator.writeStructureChainValidation(ofs);
    generator.writeToStringFunctions(ofs);

    generator.writeDelegationClassDynamic(ofs);

    ofs << "} // namespace VULKAN_HPP_NAMESPACE" << std::endl
      << std::endl
      << "#endif" << std::endl;
  }
  catch (std::exception const& e)
  {
    std::cout << "caught exception: " << e.what() << std::endl;
    return -1;
  }
  catch (...)
  {
    std::cout << "caught unknown exception" << std::endl;
    return -1;
  }
}