//
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#ifndef AMD_VULKAN_MEMORY_ALLOCATOR_H
#define AMD_VULKAN_MEMORY_ALLOCATOR_H

/** \mainpage Vulkan Memory Allocator

Version 2.0.0-alpha.1 (2017-07-04)

Members grouped: see <a href="modules.html"><b>Modules</b></a>.

All members: see vk_mem_alloc.h.

\section problem Problem Statement

Memory allocation and resource (buffer and image) creation in Vulkan is
difficult (comparing to older graphics API-s, like D3D11 or OpenGL) for several
reasons:

- It requires a lot of boilerplate code, just like everything else in Vulkan,
  because it is a low-level and high-performance API.
- There is additional level of indirection: VkDeviceMemory is allocated
  separately from creating VkBuffer/VkImage and they must be bound together. The
  binding cannot be changed later - resource must be recreated.
- Driver must be queried for supported memory heaps and memory types. Different
  IHV-s provide different types of it.
- It is recommended practice to allocate bigger chunks of memory and assign
  parts of them to particular resources.

\section features Features

This library is helps game developers to manage memory allocations and resource
creation by offering some higher-level functions. Features of the library could
be divided into several layers, low level to high level:

-# Functions that help to choose correct and optimal memory type based on
   intended usage of the memory.
   - Required or preferred traits of the memory are expressed using higher-level
     description comparing to Vulkan flags.
-# Functions that allocate memory blocks, reserve and return parts of them
   (VkDeviceMemory + offset + size) to the user.
   - Library keeps track of allocated memory blocks, used and unused ranges
     inside them, finds best matching unused ranges for new allocations, takes
     all the rules of alignment into consideration.
-# Functions that can create an image/buffer, allocate memory for it and bind
   them together - all in one call.

\section prequisites Prequisites

- Self-contained C++ library in single header file. No external dependencies
  other than standard C and C++ library and of course Vulkan.
- Public interface in C, in same convention as Vulkan API. Implementation in
  C++.
- Interface documented using Doxygen-style comments.
- Platform-independent, but developed and tested on Windows using Visual Studio.
- Error handling implemented by returning VkResult error codes - same way as in
  Vulkan.

\section quick_start Quick Start

In your project code:

-# Include "vk_mem_alloc.h" file wherever you want to use the library.
-# In exacly one C++ file define following macro before include to build library
   implementation.


    #define VMA_IMPLEMENTATION
    #include "vk_mem_alloc.h"

At program startup:

-# Initialize Vulkan to have VkPhysicalDevice and VkDevice object.
-# Fill VmaAllocatorCreateInfo structure and create VmaAllocator object by
   calling vmaCreateAllocator().


    VmaAllocatorCreateInfo allocatorInfo = {};
    allocatorInfo.physicalDevice = physicalDevice;
    allocatorInfo.device = device;

    VmaAllocator allocator;
    vmaCreateAllocator(&allocatorInfo, &allocator);

When you want to create a buffer or image:

-# Fill VkBufferCreateInfo / VkImageCreateInfo structure.
-# Fill VmaMemoryRequirements structure.
-# Call vmaCreateBuffer() / vmaCreateImage() to get VkBuffer/VkImage with memory
   already allocated and bound to it.


    VkBufferCreateInfo bufferInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
    bufferInfo.size = myBufferSize;
    bufferInfo.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;

    VmaMemoryRequirements memReq = {};
    memReq.usage = VMA_MEMORY_USAGE_GPU_ONLY;

    VkBuffer buffer;
    VmaAllocation allocation;
    vmaCreateBuffer(allocator, &bufferInfo, &memReq, &buffer, &allocation, nullptr);

Don't forget to destroy your objects:


    vmaDestroyBuffer(allocator, buffer, allocation);
    vmaDestroyAllocator(allocator);

\section configuration Configuration

Please check "CONFIGURATION SECTION" in the code to find macros that you can define
before each #include of this file or change directly in this file to provide
your own implementation of basic facilities like assert, min and max functions,
mutex etc. C++ STL is used by default, but changing these allows you to get rid
of any STL usage if you want, as many game developers tend to do.

\section custom_memory_allocator Custom memory allocator

You can use custom memory allocator by filling optional member
VmaAllocatorCreateInfo::pAllocationCallbacks. These functions will be passed to
Vulkan, as well as used by the library itself to make any CPU-side allocations.

\section thread_safety Thread safety

All calls to functions that take VmaAllocator as first parameter are safe to
call from multiple threads simultaneously, synchronized internally when needed.
*/

#include <vulkan/vulkan.h>

////////////////////////////////////////////////////////////////////////////////
/** \defgroup general General
@{
*/

VK_DEFINE_HANDLE(VmaAllocator)

/// Callback function called after successful vkAllocateMemory.
typedef void (VKAPI_PTR *PFN_vmaAllocateDeviceMemoryFunction)(
    VmaAllocator      allocator,
    uint32_t          memoryType,
    VkDeviceMemory    memory,
    VkDeviceSize      size);
/// Callback function called before vkFreeMemory.
typedef void (VKAPI_PTR *PFN_vmaFreeDeviceMemoryFunction)(
    VmaAllocator      allocator,
    uint32_t          memoryType,
    VkDeviceMemory    memory,
    VkDeviceSize      size);

/** \brief Set of callbacks that the library will call for vkAllocateMemory and vkFreeMemory.

Provided for informative purpose, e.g. to gather statistics about number of
allocations or total amount of memory allocated in Vulkan.
*/
typedef struct VmaDeviceMemoryCallbacks {
    /// Optional, can be null.
    PFN_vmaAllocateDeviceMemoryFunction pfnAllocate;
    /// Optional, can be null.
    PFN_vmaFreeDeviceMemoryFunction pfnFree;
} VmaDeviceMemoryCallbacks;

/// Description of a Allocator to be created.
typedef struct VmaAllocatorCreateInfo
{
    /// Vulkan physical device.
    /** It must be valid throughout whole lifetime of created Allocator. */
    VkPhysicalDevice physicalDevice;
    /// Vulkan device.
    /** It must be valid throughout whole lifetime of created Allocator. */
    VkDevice device;
    /// Size of a single memory block to allocate for resources.
    /** Set to 0 to use default, which is currently 256 MB. */
    VkDeviceSize preferredLargeHeapBlockSize;
    /// Size of a single memory block to allocate for resources from a small heap <= 512 MB.
    /** Set to 0 to use default, which is currently 64 MB. */
    VkDeviceSize preferredSmallHeapBlockSize;
    /// Custom allocation callbacks.
    /** Optional, can be null. When specified, will also be used for all CPU-side memory allocations. */
    const VkAllocationCallbacks* pAllocationCallbacks;
    /// Informative callbacks for vkAllocateMemory, vkFreeMemory.
    /** Optional, can be null. */
    const VmaDeviceMemoryCallbacks* pDeviceMemoryCallbacks;
} VmaAllocatorCreateInfo;

/// Creates Allocator object.
VkResult vmaCreateAllocator(
    const VmaAllocatorCreateInfo* pCreateInfo,
    VmaAllocator* pAllocator);

/// Destroys allocator object.
void vmaDestroyAllocator(
    VmaAllocator allocator);

/**
PhysicalDeviceProperties are fetched from physicalDevice by the allocator.
You can access it here, without fetching it again on your own.
*/
void vmaGetPhysicalDeviceProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceProperties** ppPhysicalDeviceProperties);

/**
PhysicalDeviceMemoryProperties are fetched from physicalDevice by the allocator.
You can access it here, without fetching it again on your own.
*/
void vmaGetMemoryProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceMemoryProperties** ppPhysicalDeviceMemoryProperties);

/**
\brief Given Memory Type Index, returns Property Flags of this memory type.

This is just a convenience function. Same information can be obtained using
vmaGetMemoryProperties().
*/
void vmaGetMemoryTypeProperties(
    VmaAllocator allocator,
    uint32_t memoryTypeIndex,
    VkMemoryPropertyFlags* pFlags);

typedef struct VmaStatInfo
{
    uint32_t AllocationCount;
    uint32_t SuballocationCount;
    uint32_t UnusedRangeCount;
    VkDeviceSize UsedBytes;
    VkDeviceSize UnusedBytes;
    VkDeviceSize SuballocationSizeMin, SuballocationSizeAvg, SuballocationSizeMax;
    VkDeviceSize UnusedRangeSizeMin, UnusedRangeSizeAvg, UnusedRangeSizeMax;
} VmaStatInfo;

/// General statistics from current state of Allocator.
struct VmaStats
{
    VmaStatInfo memoryType[VK_MAX_MEMORY_TYPES];
    VmaStatInfo memoryHeap[VK_MAX_MEMORY_HEAPS];
    VmaStatInfo total;
};

/// Retrieves statistics from current state of the Allocator.
void vmaCalculateStats(
    VmaAllocator allocator,
    VmaStats* pStats);

#define VMA_STATS_STRING_ENABLED 1

#if VMA_STATS_STRING_ENABLED

/// Builds and returns statistics as string in JSON format.
/** @param[out] ppStatsString Must be freed using vmaFreeStatsString() function.
*/
void vmaBuildStatsString(
    VmaAllocator allocator,
    char** ppStatsString,
    VkBool32 detailedMap);

void vmaFreeStatsString(
    VmaAllocator allocator,
    char* pStatsString);

#endif // #if VMA_STATS_STRING_ENABLED

/** @} */

////////////////////////////////////////////////////////////////////////////////
/** \defgroup layer1 Layer 1 Choosing Memory Type
@{
*/

typedef enum VmaMemoryUsage
{
    /// No intended memory usage specified.
    VMA_MEMORY_USAGE_UNKNOWN = 0,
    /// Memory will be used on device only, no need to be mapped on host.
    VMA_MEMORY_USAGE_GPU_ONLY = 1,
    /// Memory will be mapped on host. Could be used for transfer to device.
    /** Guarantees to be HOST_VISIBLE and HOST_COHERENT. */
    VMA_MEMORY_USAGE_CPU_ONLY = 2,
    /// Memory will be used for frequent (dynamic) updates from host and reads on device.
    /** Guarantees to be HOST_VISIBLE. */
    VMA_MEMORY_USAGE_CPU_TO_GPU = 3,
    /// Memory will be used for writing on device and readback on host.
    /** Guarantees to be HOST_VISIBLE. */
    VMA_MEMORY_USAGE_GPU_TO_CPU = 4,
    VMA_MEMORY_USAGE_MAX_ENUM = 0x7FFFFFFF
} VmaMemoryUsage;

/// Flags to be passed as VmaMemoryRequirements::flags.
typedef enum VmaMemoryRequirementFlagBits {
    /** \brief Set this flag if the allocation should have its own memory block.
    
    Use it for special, big resources, like fullscreen images used as attachments.
   
    This flag must also be used for host visible resources that you want to map
    simultaneously because otherwise they might end up as regions of the same
    VkDeviceMemory, while mapping same VkDeviceMemory multiple times is illegal.
    */
    VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT = 0x00000001,

    /** \brief Set this flag to only try to allocate from existing VkDeviceMemory blocks and never create new such block.
    
    If new allocation cannot be placed in any of the existing blocks, allocation
    fails with VK_ERROR_OUT_OF_DEVICE_MEMORY error.
    
    It makes no sense to set VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT and
    VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT at the same time. */
    VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT = 0x00000002,
    /** \brief Set to use a memory that will be persistently mapped and retrieve pointer to it.
    
    Pointer to mapped memory will be returned through ppMappedData. You cannot
    map the memory on your own as multiple maps of a single VkDeviceMemory are
    illegal.
    */
    VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT = 0x00000004,

    VMA_MEMORY_REQUIREMENT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
} VmaMemoryRequirementFlagBits;
typedef VkFlags VmaMemoryRequirementFlags;

typedef struct VmaMemoryRequirements
{
    VmaMemoryRequirementFlags flags;
    /** \brief Intended usage of memory.
    
    Leave VMA_MEMORY_USAGE_UNKNOWN if you specify requiredFlags. You can also use both.
    */
    VmaMemoryUsage usage;
    /** \brief Flags that must be set in a Memory Type chosen for an allocation.
    
    Leave 0 if you specify requirement via usage. */
    VkMemoryPropertyFlags requiredFlags;
    /** \brief Flags that preferably should be set in a Memory Type chosen for an allocation.
    
    Set to 0 if no additional flags are prefered and only requiredFlags should be used.
    If not 0, it must be a superset or equal to requiredFlags. */
    VkMemoryPropertyFlags preferredFlags;
    /** \brief Custom general-purpose pointer that will be stored in VmaAllocation, can be read as VmaAllocationInfo::pUserData and changed using vmaSetAllocationUserData(). */
    void* pUserData;
} VmaMemoryRequirements;

/**
This algorithm tries to find a memory type that:

- Is allowed by memoryTypeBits.
- Contains all the flags from pMemoryRequirements->requiredFlags.
- Matches intended usage.
- Has as many flags from pMemoryRequirements->preferredFlags as possible.

\return Returns VK_ERROR_FEATURE_NOT_PRESENT if not found. Receiving such result
from this function or any other allocating function probably means that your
device doesn't support any memory type with requested features for the specific
type of resource you want to use it for. Please check parameters of your
resource, like image layout (OPTIMAL versus LINEAR) or mip level count.
*/
VkResult vmaFindMemoryTypeIndex(
    VmaAllocator allocator,
    uint32_t memoryTypeBits,
    const VmaMemoryRequirements* pMemoryRequirements,
    uint32_t* pMemoryTypeIndex);

/** @} */

////////////////////////////////////////////////////////////////////////////////
/** \defgroup layer2 Layer 2 Allocating Memory
@{
*/

VK_DEFINE_HANDLE(VmaAllocation)

/** \brief Parameters of VmaAllocation objects, that can be retrieved using function vmaGetAllocationInfo().
*/
typedef struct VmaAllocationInfo {
    /** \brief Memory type index that this allocation was allocated from.
    
    It never changes.
    */
    uint32_t memoryType;
    /** \brief Handle to Vulkan memory object.

    Same memory object can be shared by multiple allocations.
    
    It can change after call to vmaDefragment() if this allocation is passed to the function.
    */
    VkDeviceMemory deviceMemory;
    /** \brief Offset into deviceMemory object to the beginning of this allocation, in bytes. (deviceMemory, offset) pair is unique to this allocation.

    It can change after call to vmaDefragment() if this allocation is passed to the function.
    */
    VkDeviceSize offset;
    /** \brief Size of this allocation, in bytes.

    It never changes.
    */
    VkDeviceSize size;
    /** \brief Pointer to the beginning of this allocation as mapped data. Null if this alloaction is not persistently mapped.

    It can change after call to vmaUnmapPersistentlyMappedMemory(), vmaMapPersistentlyMappedMemory().
    It can also change after call to vmaDefragment() if this allocation is passed to the function.
    */
    void* pMappedData;
    /** \brief Custom general-purpose pointer that was passed as VmaMemoryRequirements::pUserData or set using vmaSetAllocationUserData().

    It can change after call to vmaSetAllocationUserData() for this allocation.
    */
    void* pUserData;
} VmaAllocationInfo;

/** \brief General purpose memory allocation.

@param[out] pAllocation Handle to allocated memory.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function VmaGetAllocationInfo().

You should free the memory using vmaFreeMemory().

It is recommended to use vmaAllocateMemoryForBuffer(), vmaAllocateMemoryForImage(),
vmaCreateBuffer(), vmaCreateImage() instead whenever possible.
*/
VkResult vmaAllocateMemory(
    VmaAllocator allocator,
    const VkMemoryRequirements* pVkMemoryRequirements,
    const VmaMemoryRequirements* pVmaMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/**
@param[out] pAllocation Handle to allocated memory.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function VmaGetAllocationInfo().

You should free the memory using vmaFreeMemory().
*/
VkResult vmaAllocateMemoryForBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    const VmaMemoryRequirements* pMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/// Function similar to vmaAllocateMemoryForBuffer().
VkResult vmaAllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaMemoryRequirements* pMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

/// Frees memory previously allocated using vmaAllocateMemory(), vmaAllocateMemoryForBuffer(), or vmaAllocateMemoryForImage().
void vmaFreeMemory(
    VmaAllocator allocator,
    VmaAllocation allocation);

/// Returns current information about specified allocation.
void vmaGetAllocationInfo(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VmaAllocationInfo* pAllocationInfo);

/// Sets pUserData in given allocation to new value.
void vmaSetAllocationUserData(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void* pUserData);

/**
Feel free to use vkMapMemory on these memory blocks on you own if you want, but
just for convenience and to make sure correct offset and size is always
specified, usage of vmaMapMemory() / vmaUnmapMemory() is recommended.

Do not use it on memory allocated with VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT
as multiple maps to same VkDeviceMemory is illegal.
*/
VkResult vmaMapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void** ppData);

void vmaUnmapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation);

/** \brief Unmaps persistently mapped memory of types that is HOST_COHERENT and DEVICE_LOCAL.

This is optional performance optimization. You should call it on Windows for
time of call to vkQueueSubmit and vkQueuePresent, for performance reasons,
because of the internal behavior of WDDM.

After this call VmaAllocationInfo::pMappedData of some allocations may become null.

This call is reference-counted. Memory is mapped again after you call
vmaMapPersistentlyMappedMemory() same number of times that you called
vmaUnmapPersistentlyMappedMemory().
*/
void vmaUnmapPersistentlyMappedMemory(VmaAllocator allocator);

/** \brief Maps back persistently mapped memory of types that is HOST_COHERENT and DEVICE_LOCAL.

See vmaUnmapPersistentlyMappedMemory().

After this call VmaAllocationInfo::pMappedData of some allocation may have value
different than before calling vmaUnmapPersistentlyMappedMemory().
*/
VkResult vmaMapPersistentlyMappedMemory(VmaAllocator allocator);

/** \brief Optional configuration parameters to be passed to function vmaDefragment(). */
typedef struct VmaDefragmentationInfo {
    /** \brief Maximum total numbers of bytes that can be copied while moving allocations to different places.
    
    Default is VK_WHOLE_SIZE, which means no limit.
    */
    VkDeviceSize maxBytesToMove;
    /** \brief Maximum number of allocations that can be moved to different place.

    Default is UINT32_MAX, which means no limit.
    */
    uint32_t maxAllocationsToMove;
} VmaDefragmentationInfo;

/** \brief Statistics returned by function vmaDefragment(). */
typedef struct VmaDefragmentationStats {
    /// Total number of bytes that have been copied while moving allocations to different places.
    VkDeviceSize bytesMoved;
    /// Total number of bytes that have been released to the system by freeing empty VkDeviceMemory objects.
    VkDeviceSize bytesFreed;
    /// Number of allocations that have been moved to different places.
    uint32_t allocationsMoved;
    /// Number of empty VkDeviceMemory objects that have been released to the system.
    uint32_t deviceMemoryBlocksFreed;
} VmaDefragmentationStats;

/** \brief Compacts memory by moving allocations.

@param pAllocations Array of allocations that can be moved during this compation.
@param allocationCount Number of elements in pAllocations and pAllocationsChanged arrays.
@param[out] pAllocationsChanged Array of boolean values that will indicate whether matching allocation in pAllocations array has been moved. This parameter is optional. Pass null if you don't need this information.
@param pDefragmentationInfo Configuration parameters. Optional - pass null to use default values.
@param[out] pDefragmentationStats Statistics returned by the function. Optional - pass null if you don't need this information.
@return VK_SUCCESS if completed, VK_INCOMPLETE if succeeded but didn't make all possible optimizations because limits specified in pDefragmentationInfo have been reached, negative error code in case of error.

This function works by moving allocations to different places (different
VkDeviceMemory objects and/or different offsets) in order to optimize memory
usage. Only allocations that are in pAllocations array can be moved. All other
allocations are considered nonmovable in this call. Basic rules:

- Only allocations made in memory types that have
  VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT flag can be compacted. You may pass other
  allocations but it makes no sense - these will never be moved.
- You may pass allocations made with VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT but
  it makes no sense - they will never be moved.
- Both allocations made with or without VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT
  flag can be compacted. If not persistently mapped, memory will be mapped
  temporarily inside this function if needed, so it shouldn't be mapped by you for
  the time of this call.
- You must not pass same VmaAllocation object multiple times in pAllocations array.

The function also frees empty VkDeviceMemory blocks.

After allocation has been moved, its VmaAllocationInfo::deviceMemory and/or
VmaAllocationInfo::offset changes. You must query them again using
vmaGetAllocationInfo() if you need them.

If an allocation has been moved, data in memory is copied to new place
automatically, but if it was bound to a buffer or an image, you must destroy
that object yourself, create new one and bind it to the new memory pointed by
the allocation. You must use vkDestroyBuffer(), vkDestroyImage(),
vkCreateBuffer(), vkCreateImage() for that purpose and NOT vmaDestroyBuffer(),
vmaDestroyImage(), vmaCreateBuffer(), vmaCreateImage()! Example:


    VkDevice device = ...;
    VmaAllocator allocator = ...;
    std::vector<VkBuffer> buffers = ...;
    std::vector<VmaAllocation> allocations = ...;

    std::vector<VkBool32> allocationsChanged(allocations.size());
    vmaDefragment(allocator, allocations.data(), allocations.size(), allocationsChanged.data(), nullptr, nullptr);

    for(size_t i = 0; i < allocations.size(); ++i)
    {
        if(allocationsChanged[i])
        {
            VmaAllocationInfo allocInfo;
            vmaGetAllocationInfo(allocator, allocations[i], &allocInfo);

            vkDestroyBuffer(device, buffers[i], nullptr);

            VkBufferCreateInfo bufferInfo = ...;
            vkCreateBuffer(device, &bufferInfo, nullptr, &buffers[i]);
            
            .// You can make dummy call to vkGetBufferMemoryRequirements here to silence validation layer warning.
            
            vkBindBufferMemory(device, buffers[i], allocInfo.deviceMemory, allocInfo.offset);
        }
    }

This function may be time-consuming, so you shouldn't call it too often (like
every frame or after every resource creation/destruction), but rater you can
call it on special occasions (like when reloading a game level, when you just
destroyed a lot of objects).
*/
VkResult vmaDefragment(
    VmaAllocator allocator,
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo *pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats);

/** @} */

////////////////////////////////////////////////////////////////////////////////
/** \defgroup layer3 Layer 3 Creating Buffers and Images
@{
*/

/**
@param[out] pBuffer Buffer that was created.
@param[out] pAllocation Allocation that was created.
@param[out] pAllocationInfo Optional. Information about allocated memory. It can be later fetched using function VmaGetAllocationInfo().

This function automatically:

-# Creates buffer/image.
-# Allocates appropriate memory for it.
-# Binds the buffer/image with the memory.

You do not (and should not) pass returned pMemory to vmaFreeMemory. Only calling
vmaDestroyBuffer() / vmaDestroyImage() is required for objects created using
vmaCreateBuffer() / vmaCreateImage().
*/
VkResult vmaCreateBuffer(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pCreateInfo,
    const VmaMemoryRequirements* pMemoryRequirements,
    VkBuffer* pBuffer,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

void vmaDestroyBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    VmaAllocation allocation);

/// Function similar to vmaCreateBuffer().
VkResult vmaCreateImage(
    VmaAllocator allocator,
    const VkImageCreateInfo* pCreateInfo,
    const VmaMemoryRequirements* pMemoryRequirements,
    VkImage* pImage,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo);

void vmaDestroyImage(
    VmaAllocator allocator,
    VkImage image,
    VmaAllocation allocation);

/** @} */

#endif // AMD_VULKAN_MEMORY_ALLOCATOR_H

#ifdef VMA_IMPLEMENTATION
#undef VMA_IMPLEMENTATION

#include <cstdint>
#include <cstdlib>

/*******************************************************************************
CONFIGURATION SECTION

Define some of these macros before each #include of this header or change them
here if you need other then default behavior depending on your environment.
*/

// Define this macro to 1 to make the library use STL containers instead of its own implementation.
//#define VMA_USE_STL_CONTAINERS 1

/* Set this macro to 1 to make the library including and using STL containers:
std::pair, std::vector, std::list, std::unordered_map.

Set it to 0 or undefined to make the library using its own implementation of
the containers.
*/
#if VMA_USE_STL_CONTAINERS
   #define VMA_USE_STL_VECTOR 1
   #define VMA_USE_STL_UNORDERED_MAP 1
   #define VMA_USE_STL_LIST 1
#endif

#if VMA_USE_STL_VECTOR
   #include <vector>
#endif

#if VMA_USE_STL_UNORDERED_MAP
   #include <unordered_map>
#endif

#if VMA_USE_STL_LIST
   #include <list>
#endif

/*
Following headers are used in this CONFIGURATION section only, so feel free to
remove them if not needed.
*/
#include <cassert> // for assert
#include <algorithm> // for min, max
#include <mutex> // for std::mutex

#if !defined(_WIN32)
    #include <malloc.h> // for aligned_alloc()
#endif

// Normal assert to check for programmer's errors, especially in Debug configuration.
#ifndef VMA_ASSERT
   #ifdef _DEBUG
       #define VMA_ASSERT(expr)         assert(expr)
   #else
       #define VMA_ASSERT(expr)
   #endif
#endif

// Assert that will be called very often, like inside data structures e.g. operator[].
// Making it non-empty can make program slow.
#ifndef VMA_HEAVY_ASSERT
   #ifdef _DEBUG
       #define VMA_HEAVY_ASSERT(expr)   //VMA_ASSERT(expr)
   #else
       #define VMA_HEAVY_ASSERT(expr)
   #endif
#endif

#ifndef VMA_NULL
   // Value used as null pointer. Define it to e.g.: nullptr, NULL, 0, (void*)0.
   #define VMA_NULL   nullptr
#endif

#ifndef VMA_ALIGN_OF
   #define VMA_ALIGN_OF(type)       (__alignof(type))
#endif

#ifndef VMA_SYSTEM_ALIGNED_MALLOC
   #if defined(_WIN32)
       #define VMA_SYSTEM_ALIGNED_MALLOC(size, alignment)   (_aligned_malloc((size), (alignment)))
   #else
       #define VMA_SYSTEM_ALIGNED_MALLOC(size, alignment)   (aligned_alloc((alignment), (size) ))
   #endif
#endif

#ifndef VMA_SYSTEM_FREE
   #if defined(_WIN32)
       #define VMA_SYSTEM_FREE(ptr)   _aligned_free(ptr)
   #else
       #define VMA_SYSTEM_FREE(ptr)   free(ptr)
   #endif
#endif

#ifndef VMA_MIN
   #define VMA_MIN(v1, v2)    (std::min((v1), (v2)))
#endif

#ifndef VMA_MAX
   #define VMA_MAX(v1, v2)    (std::max((v1), (v2)))
#endif

#ifndef VMA_SWAP
   #define VMA_SWAP(v1, v2)   std::swap((v1), (v2))
#endif

#ifndef VMA_SORT
   #define VMA_SORT(beg, end, cmp)  std::sort(beg, end, cmp)
#endif

#ifndef VMA_DEBUG_LOG
   #define VMA_DEBUG_LOG(format, ...)
   /*
   #define VMA_DEBUG_LOG(format, ...) do { \
       printf(format, __VA_ARGS__); \
       printf("\n"); \
   } while(false)
   */
#endif

// Define this macro to 1 to enable functions: vmaBuildStatsString, vmaFreeStatsString.
#if VMA_STATS_STRING_ENABLED
   static inline void VmaUint32ToStr(char* outStr, size_t strLen, uint32_t num)
   {
       _ultoa_s(num, outStr, strLen, 10);
   }
   static inline void VmaUint64ToStr(char* outStr, size_t strLen, uint64_t num)
   {
       _ui64toa_s(num, outStr, strLen, 10);
   }
#endif

#ifndef VMA_MUTEX
   class VmaMutex
   {
   public:
       VmaMutex() { }
       ~VmaMutex() { }
       void Lock() { m_Mutex.lock(); }
       void Unlock() { m_Mutex.unlock(); }
   private:
       std::mutex m_Mutex;
   };
   #define VMA_MUTEX VmaMutex
#endif

#ifndef VMA_BEST_FIT
   /**
   Main parameter for function assessing how good is a free suballocation for a new
   allocation request.

   - Set to 1 to use Best-Fit algorithm - prefer smaller blocks, as close to the
     size of requested allocations as possible.
   - Set to 0 to use Worst-Fit algorithm - prefer larger blocks, as large as
     possible.

   Experiments in special testing environment showed that Best-Fit algorithm is
   better.
   */
   #define VMA_BEST_FIT (1)
#endif

#ifndef VMA_DEBUG_ALWAYS_OWN_MEMORY
   /**
   Every object will have its own allocation.
   Define to 1 for debugging purposes only.
   */
   #define VMA_DEBUG_ALWAYS_OWN_MEMORY (0)
#endif

#ifndef VMA_DEBUG_ALIGNMENT
   /**
   Minimum alignment of all suballocations, in bytes.
   Set to more than 1 for debugging purposes only. Must be power of two.
   */
   #define VMA_DEBUG_ALIGNMENT (1)
#endif

#ifndef VMA_DEBUG_MARGIN
   /**
   Minimum margin between suballocations, in bytes.
   Set nonzero for debugging purposes only.
   */
   #define VMA_DEBUG_MARGIN (0)
#endif

#ifndef VMA_DEBUG_GLOBAL_MUTEX
   /**
   Set this to 1 for debugging purposes only, to enable single mutex protecting all
   entry calls to the library. Can be useful for debugging multithreading issues.
   */
   #define VMA_DEBUG_GLOBAL_MUTEX (0)
#endif

#ifndef VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY
   /**
   Minimum value for VkPhysicalDeviceLimits::bufferImageGranularity.
   Set to more than 1 for debugging purposes only. Must be power of two.
   */
   #define VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY (1)
#endif

#ifndef VMA_SMALL_HEAP_MAX_SIZE
   /// Maximum size of a memory heap in Vulkan to consider it "small".
   #define VMA_SMALL_HEAP_MAX_SIZE (512 * 1024 * 1024)
#endif

#ifndef VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE
   /// Default size of a block allocated as single VkDeviceMemory from a "large" heap.
   #define VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE (256 * 1024 * 1024)
#endif

#ifndef VMA_DEFAULT_SMALL_HEAP_BLOCK_SIZE
   /// Default size of a block allocated as single VkDeviceMemory from a "small" heap.
   #define VMA_DEFAULT_SMALL_HEAP_BLOCK_SIZE (64 * 1024 * 1024)
#endif

/*******************************************************************************
END OF CONFIGURATION
*/

static VkAllocationCallbacks VmaEmptyAllocationCallbacks = {
    VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL, VMA_NULL };

// Returns number of bits set to 1 in (v).
static inline uint32_t CountBitsSet(uint32_t v)
{
	uint32_t c = v - ((v >> 1) & 0x55555555);
	c = ((c >>  2) & 0x33333333) + (c & 0x33333333);
	c = ((c >>  4) + c) & 0x0F0F0F0F;
	c = ((c >>  8) + c) & 0x00FF00FF;
	c = ((c >> 16) + c) & 0x0000FFFF;
	return c;
}

// Aligns given value up to nearest multiply of align value. For example: VmaAlignUp(11, 8) = 16.
// Use types like uint32_t, uint64_t as T.
template <typename T>
static inline T VmaAlignUp(T val, T align)
{
	return (val + align - 1) / align * align;
}

// Division with mathematical rounding to nearest number.
template <typename T>
inline T VmaRoundDiv(T x, T y)
{
	return (x + (y / (T)2)) / y;
}

#ifndef VMA_SORT

template<typename Iterator, typename Compare>
Iterator VmaQuickSortPartition(Iterator beg, Iterator end, Compare cmp)
{
    Iterator centerValue = end; --centerValue;
    Iterator insertIndex = beg;
    for(Iterator i = beg; i < centerValue; ++i)
    {
        if(cmp(*i, *centerValue))
        {
            if(insertIndex != i)
            {
                VMA_SWAP(*i, *insertIndex);
            }
            ++insertIndex;
        }
    }
    if(insertIndex != centerValue)
    {
        VMA_SWAP(*insertIndex, *centerValue);
    }
    return insertIndex;
}

template<typename Iterator, typename Compare>
void VmaQuickSort(Iterator beg, Iterator end, Compare cmp)
{
	if(beg < end)
    {
        Iterator it = VmaQuickSortPartition<Iterator, Compare>(beg, end, cmp);
        VmaQuickSort<Iterator, Compare>(beg, it, cmp);
        VmaQuickSort<Iterator, Compare>(it + 1, end, cmp);
    }
}

#define VMA_SORT(beg, end, cmp) VmaQuickSort(beg, end, cmp)

#endif // #ifndef VMA_SORT

/*
Returns true if two memory blocks occupy overlapping pages.
ResourceA must be in less memory offset than ResourceB.

Algorithm is based on "Vulkan 1.0.39 - A Specification (with all registered Vulkan extensions)"
chapter 11.6 "Resource Memory Association", paragraph "Buffer-Image Granularity".
*/
static inline bool VmaBlocksOnSamePage(
    VkDeviceSize resourceAOffset,
    VkDeviceSize resourceASize,
    VkDeviceSize resourceBOffset,
    VkDeviceSize pageSize)
{
    VMA_ASSERT(resourceAOffset + resourceASize <= resourceBOffset && resourceASize > 0 && pageSize > 0);
    VkDeviceSize resourceAEnd = resourceAOffset + resourceASize - 1;
    VkDeviceSize resourceAEndPage = resourceAEnd & ~(pageSize - 1);
    VkDeviceSize resourceBStart = resourceBOffset;
    VkDeviceSize resourceBStartPage = resourceBStart & ~(pageSize - 1);
    return resourceAEndPage == resourceBStartPage;
}

enum VmaSuballocationType
{
    VMA_SUBALLOCATION_TYPE_FREE = 0,
    VMA_SUBALLOCATION_TYPE_UNKNOWN = 1,
    VMA_SUBALLOCATION_TYPE_BUFFER = 2,
    VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN = 3,
    VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR = 4,
    VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL = 5,
    VMA_SUBALLOCATION_TYPE_MAX_ENUM = 0x7FFFFFFF
};

/*
Returns true if given suballocation types could conflict and must respect
VkPhysicalDeviceLimits::bufferImageGranularity. They conflict if one is buffer
or linear image and another one is optimal image. If type is unknown, behave
conservatively.
*/
static inline bool VmaIsBufferImageGranularityConflict(
    VmaSuballocationType suballocType1,
    VmaSuballocationType suballocType2)
{
    if(suballocType1 > suballocType2)
        VMA_SWAP(suballocType1, suballocType2);
    
    switch(suballocType1)
    {
    case VMA_SUBALLOCATION_TYPE_FREE:
        return false;
    case VMA_SUBALLOCATION_TYPE_UNKNOWN:
        return true;
    case VMA_SUBALLOCATION_TYPE_BUFFER:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR ||
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR:
        return
            suballocType2 == VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL;
    case VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL:
        return false;
    default:
        VMA_ASSERT(0);
        return true;
    }
}

// Helper RAII class to lock a mutex in constructor and unlock it in destructor (at the end of scope).
struct VmaMutexLock
{
public:
    VmaMutexLock(VMA_MUTEX& mutex) : m_Mutex(mutex) { mutex.Lock(); }
    ~VmaMutexLock() { m_Mutex.Unlock(); }

private:
    VMA_MUTEX& m_Mutex;
};

#if VMA_DEBUG_GLOBAL_MUTEX
    static VMA_MUTEX gDebugGlobalMutex;
    #define VMA_DEBUG_GLOBAL_MUTEX_LOCK VmaMutexLock debugGlobalMutexLock(gDebugGlobalMutex);
#else
    #define VMA_DEBUG_GLOBAL_MUTEX_LOCK
#endif

// Minimum size of a free suballocation to register it in the free suballocation collection.
static const VkDeviceSize VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER = 16;

/*
Performs binary search and returns iterator to first element that is greater or
equal to (key), according to comparison (cmp).

Cmp should return true if first argument is less than second argument.

Returned value is the found element, if present in the collection or place where
new element with value (key) should be inserted.
*/
template <typename IterT, typename KeyT, typename CmpT>
static IterT VmaBinaryFindFirstNotLess(IterT beg, IterT end, const KeyT &key, CmpT cmp)
{
	size_t down = 0, up = (end - beg);
	while(down < up)
	{
		const size_t mid = (down + up) / 2;
		if(cmp(*(beg+mid), key))
			down = mid + 1;
		else
			up = mid;
	}
	return beg + down;
}

////////////////////////////////////////////////////////////////////////////////
// Memory allocation

static void* VmaMalloc(const VkAllocationCallbacks* pAllocationCallbacks, size_t size, size_t alignment)
{
    if((pAllocationCallbacks != VMA_NULL) &&
        (pAllocationCallbacks->pfnAllocation != VMA_NULL))
    {
        return (*pAllocationCallbacks->pfnAllocation)(
            pAllocationCallbacks->pUserData,
            size,
            alignment,
            VK_SYSTEM_ALLOCATION_SCOPE_OBJECT);
    }
    else
    {
        return VMA_SYSTEM_ALIGNED_MALLOC(size, alignment);
    }
}

static void VmaFree(const VkAllocationCallbacks* pAllocationCallbacks, void* ptr)
{
    if((pAllocationCallbacks != VMA_NULL) &&
        (pAllocationCallbacks->pfnFree != VMA_NULL))
    {
        (*pAllocationCallbacks->pfnFree)(pAllocationCallbacks->pUserData, ptr);
    }
    else
    {
        VMA_SYSTEM_FREE(ptr);
    }
}

template<typename T>
static T* VmaAllocate(const VkAllocationCallbacks* pAllocationCallbacks)
{
    return (T*)VmaMalloc(pAllocationCallbacks, sizeof(T), VMA_ALIGN_OF(T));
}

template<typename T>
static T* VmaAllocateArray(const VkAllocationCallbacks* pAllocationCallbacks, size_t count)
{
    return (T*)VmaMalloc(pAllocationCallbacks, sizeof(T) * count, VMA_ALIGN_OF(T));
}

#define vma_new(allocator, type)   new(VmaAllocate<type>(allocator))(type)

#define vma_new_array(allocator, type, count)   new(VmaAllocateArray<type>((allocator), (count)))(type)

template<typename T>
static void vma_delete(const VkAllocationCallbacks* pAllocationCallbacks, T* ptr)
{
    ptr->~T();
    VmaFree(pAllocationCallbacks, ptr);
}

template<typename T>
static void vma_delete_array(const VkAllocationCallbacks* pAllocationCallbacks, T* ptr, size_t count)
{
    if(ptr != VMA_NULL)
    {
        for(size_t i = count; i--; )
            ptr[i].~T();
        VmaFree(pAllocationCallbacks, ptr);
    }
}

// STL-compatible allocator.
template<typename T>
class VmaStlAllocator
{
public:
    const VkAllocationCallbacks* const m_pCallbacks;
    typedef T value_type;
    
    VmaStlAllocator(const VkAllocationCallbacks* pCallbacks) : m_pCallbacks(pCallbacks) { }
    template<typename U> VmaStlAllocator(const VmaStlAllocator<U>& src) : m_pCallbacks(src.m_pCallbacks) { }

    T* allocate(size_t n) { return VmaAllocateArray<T>(m_pCallbacks, n); }
    void deallocate(T* p, size_t n) { VmaFree(m_pCallbacks, p); }

    template<typename U>
    bool operator==(const VmaStlAllocator<U>& rhs) const
    {
        return m_pCallbacks == rhs.m_pCallbacks;
    }
    template<typename U>
    bool operator!=(const VmaStlAllocator<U>& rhs) const
    {
        return m_pCallbacks != rhs.m_pCallbacks;
    }

    VmaStlAllocator& operator=(const VmaStlAllocator& x) = delete;
};

#if VMA_USE_STL_VECTOR

#define VmaVector std::vector

template<typename T, typename allocatorT>
static void VectorInsert(std::vector<T, allocatorT>& vec, size_t index, const T& item)
{
    vec.insert(vec.begin() + index, item);
}

template<typename T, typename allocatorT>
static void VectorRemove(std::vector<T, allocatorT>& vec, size_t index)
{
    vec.erase(vec.begin() + index);
}

#else // #if VMA_USE_STL_VECTOR

/* Class with interface compatible with subset of std::vector.
T must be POD because constructors and destructors are not called and memcpy is
used for these objects. */
template<typename T, typename AllocatorT>
class VmaVector
{
public:
    VmaVector(const AllocatorT& allocator) :
        m_Allocator(allocator),
        m_pArray(VMA_NULL),
        m_Count(0),
        m_Capacity(0)
    {
    }

    VmaVector(size_t count, const AllocatorT& allocator) :
        m_Allocator(allocator),
        m_pArray(count ? (T*)VmaAllocateArray<T>(allocator->m_pCallbacks, count) : VMA_NULL),
        m_Count(count),
        m_Capacity(count)
    {
    }
    
    VmaVector(const VmaVector<T, AllocatorT>& src) :
        m_Allocator(src.m_Allocator),
        m_pArray(src.m_Count ? (T*)VmaAllocateArray<T>(src->m_pCallbacks, src.m_Count) : VMA_NULL),
        m_Count(src.m_Count),
        m_Capacity(src.m_Count)
    {
        if(m_Count != 0)
            memcpy(m_pArray, src.m_pArray, m_Count * sizeof(T));
    }
    
    ~VmaVector()
    {
        VmaFree(m_Allocator.m_pCallbacks, m_pArray);
    }

    VmaVector& operator=(const VmaVector<T, AllocatorT>& rhs)
    {
        if(&rhs != this)
        {
            Resize(rhs.m_Count);
            if(m_Count != 0)
                memcpy(m_pArray, rhs.m_pArray, m_Count * sizeof(T));
        }
        return *this;
    }
    
    bool empty() const { return m_Count == 0; }
    size_t size() const { return m_Count; }
    T* data() { return m_pArray; }
    const T* data() const { return m_pArray; }
    
    T& operator[](size_t index)
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        return m_pArray[index];
    }
    const T& operator[](size_t index) const
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        return m_pArray[index];
    }

    T& front()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[0];
    }
    const T& front() const
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[0];
    }
    T& back()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[m_Count - 1];
    }
    const T& back() const
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        return m_pArray[m_Count - 1];
    }

    void reserve(size_t newCapacity, bool freeMemory = false)
    {
        newCapacity = VMA_MAX(newCapacity, m_Count);
        
        if((newCapacity < m_Capacity) && !freeMemory)
            newCapacity = m_Capacity;
        
        if(newCapacity != m_Capacity)
        {
            T* const newArray = newCapacity ? VmaAllocateArray<T>(m_Allocator, newCapacity) : VMA_NULL;
            if(m_Count != 0)
                memcpy(newArray, m_pArray, m_Count * sizeof(T));
            VmaFree(m_Allocator.m_pCallbacks, m_pArray);
            m_Capacity = newCapacity;
            m_pArray = newArray;
        }
    }

    void resize(size_t newCount, bool freeMemory = false)
    {
        size_t newCapacity = m_Capacity;
        if(newCount > m_Capacity)
            newCapacity = VMA_MAX(newCount, VMA_MAX(m_Capacity * 3 / 2, (size_t)8));
        else if(freeMemory)
            newCapacity = newCount;

        if(newCapacity != m_Capacity)
        {
            T* const newArray = newCapacity ? VmaAllocateArray<T>(m_Allocator.m_pCallbacks, newCapacity) : VMA_NULL;
            const size_t elementsToCopy = VMA_MIN(m_Count, newCount);
            if(elementsToCopy != 0)
                memcpy(newArray, m_pArray, elementsToCopy * sizeof(T));
            VmaFree(m_Allocator.m_pCallbacks, m_pArray);
            m_Capacity = newCapacity;
            m_pArray = newArray;
        }

        m_Count = newCount;
    }

    void clear(bool freeMemory = false)
    {
        resize(0, freeMemory);
    }

    void insert(size_t index, const T& src)
    {
        VMA_HEAVY_ASSERT(index <= m_Count);
        const size_t oldCount = size();
        resize(oldCount + 1);
        if(index < oldCount)
            memmove(m_pArray + (index + 1), m_pArray + index, (oldCount - index) * sizeof(T));
        m_pArray[index] = src;
    }

    void remove(size_t index)
    {
        VMA_HEAVY_ASSERT(index < m_Count);
        const size_t oldCount = size();
        if(index < oldCount - 1)
            memmove(m_pArray + index, m_pArray + (index + 1), (oldCount - index - 1) * sizeof(T));
        resize(oldCount - 1);
    }

    void push_back(const T& src)
    {
        const size_t newIndex = size();
        resize(newIndex + 1);
        m_pArray[newIndex] = src;
    }

    void pop_back()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        resize(size() - 1);
    }

    void push_front(const T& src)
    {
        insert(0, src);
    }

    void pop_front()
    {
        VMA_HEAVY_ASSERT(m_Count > 0);
        remove(0);
    }

    typedef T* iterator;

    iterator begin() { return m_pArray; }
    iterator end() { return m_pArray + m_Count; }

private:
    AllocatorT m_Allocator;
    T* m_pArray;
    size_t m_Count;
    size_t m_Capacity;
};

template<typename T, typename allocatorT>
static void VectorInsert(VmaVector<T, allocatorT>& vec, size_t index, const T& item)
{
    vec.insert(index, item);
}

template<typename T, typename allocatorT>
static void VectorRemove(VmaVector<T, allocatorT>& vec, size_t index)
{
    vec.remove(index);
}

#endif // #if VMA_USE_STL_VECTOR

////////////////////////////////////////////////////////////////////////////////
// class VmaPoolAllocator

/*
Allocator for objects of type T using a list of arrays (pools) to speed up
allocation. Number of elements that can be allocated is not bounded because
allocator can create multiple blocks.
*/
template<typename T>
class VmaPoolAllocator
{
public:
    VmaPoolAllocator(const VkAllocationCallbacks* pAllocationCallbacks, size_t itemsPerBlock);
    ~VmaPoolAllocator();
    void Clear();
    T* Alloc();
    void Free(T* ptr);

private:
    union Item
    {
        uint32_t NextFreeIndex;
        T Value;
    };

    struct ItemBlock
    {
        Item* pItems;
        uint32_t FirstFreeIndex;
    };
    
    const VkAllocationCallbacks* m_pAllocationCallbacks;
    size_t m_ItemsPerBlock;
    VmaVector< ItemBlock, VmaStlAllocator<ItemBlock> > m_ItemBlocks;

    ItemBlock& CreateNewBlock();
};

template<typename T>
VmaPoolAllocator<T>::VmaPoolAllocator(const VkAllocationCallbacks* pAllocationCallbacks, size_t itemsPerBlock) :
    m_pAllocationCallbacks(pAllocationCallbacks),
    m_ItemsPerBlock(itemsPerBlock),
    m_ItemBlocks(VmaStlAllocator<ItemBlock>(pAllocationCallbacks))
{
    VMA_ASSERT(itemsPerBlock > 0);
}

template<typename T>
VmaPoolAllocator<T>::~VmaPoolAllocator()
{
    Clear();
}

template<typename T>
void VmaPoolAllocator<T>::Clear()
{
    for(size_t i = m_ItemBlocks.size(); i--; )
        vma_delete_array(m_pAllocationCallbacks, m_ItemBlocks[i].pItems, m_ItemsPerBlock);
    m_ItemBlocks.clear();
}

template<typename T>
T* VmaPoolAllocator<T>::Alloc()
{
    for(size_t i = m_ItemBlocks.size(); i--; )
    {
        ItemBlock& block = m_ItemBlocks[i];
        // This block has some free items: Use first one.
        if(block.FirstFreeIndex != UINT32_MAX)
        {
            Item* const pItem = &block.pItems[block.FirstFreeIndex];
            block.FirstFreeIndex = pItem->NextFreeIndex;
            return &pItem->Value;
        }
    }

    // No block has free item: Create new one and use it.
    ItemBlock& newBlock = CreateNewBlock();
    Item* const pItem = &newBlock.pItems[0];
    newBlock.FirstFreeIndex = pItem->NextFreeIndex;
    return &pItem->Value;
}

template<typename T>
void VmaPoolAllocator<T>::Free(T* ptr)
{
    // Search all memory blocks to find ptr.
    for(size_t i = 0; i < m_ItemBlocks.size(); ++i)
    {
        ItemBlock& block = m_ItemBlocks[i];
        
        // Casting to union.
        Item* pItemPtr;
        memcpy(&pItemPtr, &ptr, sizeof(pItemPtr));
        
        // Check if pItemPtr is in address range of this block.
        if((pItemPtr >= block.pItems) && (pItemPtr < block.pItems + m_ItemsPerBlock))
        {
            const uint32_t index = static_cast<uint32_t>(pItemPtr - block.pItems);
            pItemPtr->NextFreeIndex = block.FirstFreeIndex;
            block.FirstFreeIndex = index;
            return;
        }
    }
    VMA_ASSERT(0 && "Pointer doesn't belong to this memory pool.");
}

template<typename T>
typename VmaPoolAllocator<T>::ItemBlock& VmaPoolAllocator<T>::CreateNewBlock()
{
    ItemBlock newBlock = {
        vma_new_array(m_pAllocationCallbacks, Item, m_ItemsPerBlock), 0 };

    m_ItemBlocks.push_back(newBlock);

    // Setup singly-linked list of all free items in this block.
    for(uint32_t i = 0; i < m_ItemsPerBlock - 1; ++i)
        newBlock.pItems[i].NextFreeIndex = i + 1;
    newBlock.pItems[m_ItemsPerBlock - 1].NextFreeIndex = UINT32_MAX;
    return m_ItemBlocks.back();
}

////////////////////////////////////////////////////////////////////////////////
// class VmaRawList, VmaList

#if VMA_USE_STL_LIST

#define VmaList std::list

#else // #if VMA_USE_STL_LIST

template<typename T>
struct VmaListItem
{
    VmaListItem* pPrev;
    VmaListItem* pNext;
    T Value;
};

// Doubly linked list.
template<typename T>
class VmaRawList
{
public:
    typedef VmaListItem<T> ItemType;

    VmaRawList(const VkAllocationCallbacks* pAllocationCallbacks);
    ~VmaRawList();
    void Clear();

    size_t GetCount() const { return m_Count; }
    bool IsEmpty() const { return m_Count == 0; }

    ItemType* Front() { return m_pFront; }
    const ItemType* Front() const { return m_pFront; }
    ItemType* Back() { return m_pBack; }
    const ItemType* Back() const { return m_pBack; }

    ItemType* PushBack();
    ItemType* PushFront();
    ItemType* PushBack(const T& value);
    ItemType* PushFront(const T& value);
    void PopBack();
    void PopFront();
    
    // Item can be null - it means PushBack.
    ItemType* InsertBefore(ItemType* pItem);
    // Item can be null - it means PushFront.
    ItemType* InsertAfter(ItemType* pItem);

    ItemType* InsertBefore(ItemType* pItem, const T& value);
    ItemType* InsertAfter(ItemType* pItem, const T& value);

    void Remove(ItemType* pItem);

private:
    const VkAllocationCallbacks* const m_pAllocationCallbacks;
    VmaPoolAllocator<ItemType> m_ItemAllocator;
    ItemType* m_pFront;
    ItemType* m_pBack;
    size_t m_Count;

    // Declared not defined, to block copy constructor and assignment operator.
    VmaRawList(const VmaRawList<T>& src);
    VmaRawList<T>& operator=(const VmaRawList<T>& rhs);
};

template<typename T>
VmaRawList<T>::VmaRawList(const VkAllocationCallbacks* pAllocationCallbacks) :
    m_pAllocationCallbacks(pAllocationCallbacks),
    m_ItemAllocator(pAllocationCallbacks, 128),
    m_pFront(VMA_NULL),
    m_pBack(VMA_NULL),
    m_Count(0)
{
}

template<typename T>
VmaRawList<T>::~VmaRawList()
{
    // Intentionally not calling Clear, because that would be unnecessary
    // computations to return all items to m_ItemAllocator as free.
}

template<typename T>
void VmaRawList<T>::Clear()
{
    if(IsEmpty() == false)
    {
        ItemType* pItem = m_pBack;
        while(pItem != VMA_NULL)
        {
            ItemType* const pPrevItem = pItem->pPrev;
            m_ItemAllocator.Free(pItem);
            pItem = pPrevItem;
        }
        m_pFront = VMA_NULL;
        m_pBack = VMA_NULL;
        m_Count = 0;
    }
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushBack()
{
    ItemType* const pNewItem = m_ItemAllocator.Alloc();
    pNewItem->pNext = VMA_NULL;
    if(IsEmpty())
    {
        pNewItem->pPrev = VMA_NULL;
        m_pFront = pNewItem;
        m_pBack = pNewItem;
        m_Count = 1;
    }
    else
    {
        pNewItem->pPrev = m_pBack;
        m_pBack->pNext = pNewItem;
        m_pBack = pNewItem;
        ++m_Count;
    }
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushFront()
{
    ItemType* const pNewItem = m_ItemAllocator.Alloc();
    pNewItem->pPrev = VMA_NULL;
    if(IsEmpty())
    {
        pNewItem->pNext = VMA_NULL;
        m_pFront = pNewItem;
        m_pBack = pNewItem;
        m_Count = 1;
    }
    else
    {
        pNewItem->pNext = m_pFront;
        m_pFront->pPrev = pNewItem;
        m_pFront = pNewItem;
        ++m_Count;
    }
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushBack(const T& value)
{
    ItemType* const pNewItem = PushBack();
    pNewItem->Value = value;
    return pNewItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::PushFront(const T& value)
{
    ItemType* const pNewItem = PushFront();
    pNewItem->Value = value;
    return pNewItem;
}

template<typename T>
void VmaRawList<T>::PopBack()
{
    VMA_HEAVY_ASSERT(m_Count > 0);
    ItemType* const pBackItem = m_pBack;
    ItemType* const pPrevItem = pBackItem->pPrev;
    if(pPrevItem != VMA_NULL)
        pPrevItem->pNext = VMA_NULL;
    m_pBack = pPrevItem;
    m_ItemAllocator.Free(pBackItem);
    --m_Count;
}

template<typename T>
void VmaRawList<T>::PopFront()
{
    VMA_HEAVY_ASSERT(m_Count > 0);
    ItemType* const pFrontItem = m_pFront;
    ItemType* const pNextItem = pFrontItem->pNext;
    if(pNextItem != VMA_NULL)
        pNextItem->pPrev = VMA_NULL;
    m_pFront = pNextItem;
    m_ItemAllocator.Free(pFrontItem);
    --m_Count;
}

template<typename T>
void VmaRawList<T>::Remove(ItemType* pItem)
{
    VMA_HEAVY_ASSERT(pItem != VMA_NULL);
    VMA_HEAVY_ASSERT(m_Count > 0);

    if(pItem->pPrev != VMA_NULL)
        pItem->pPrev->pNext = pItem->pNext;
    else
    {
        VMA_HEAVY_ASSERT(m_pFront == pItem);
        m_pFront = pItem->pNext;
    }

    if(pItem->pNext != VMA_NULL)
        pItem->pNext->pPrev = pItem->pPrev;
    else
    {
        VMA_HEAVY_ASSERT(m_pBack == pItem);
        m_pBack = pItem->pPrev;
    }

    m_ItemAllocator.Free(pItem);
    --m_Count;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertBefore(ItemType* pItem)
{
    if(pItem != VMA_NULL)
    {
        ItemType* const prevItem = pItem->pPrev;
        ItemType* const newItem = m_ItemAllocator.Alloc();
        newItem->pPrev = prevItem;
        newItem->pNext = pItem;
        pItem->pPrev = newItem;
        if(prevItem != VMA_NULL)
            prevItem->pNext = newItem;
        else
        {
            VMA_HEAVY_ASSERT(m_pFront = pItem);
            m_pFront = newItem;
        }
        ++m_Count;
        return newItem;
    }
    else
        return PushBack();
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertAfter(ItemType* pItem)
{
    if(pItem != VMA_NULL)
    {
        ItemType* const nextItem = pItem->pNext;
        ItemType* const newItem = m_ItemAllocator.Alloc();
        newItem->pNext = nextItem;
        newItem->pPrev = pItem;
        pItem->pNext = newItem;
        if(nextItem != VMA_NULL)
            nextItem->pPrev = newItem;
        else
        {
            VMA_HEAVY_ASSERT(m_pBack = pItem);
            m_pBack = newItem;
        }
        ++m_Count;
        return newItem;
    }
    else
        return PushFront();
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertBefore(ItemType* pItem, const T& value)
{
    ItemType* const newItem = InsertBefore(pItem);
    newItem->Value = value;
    return newItem;
}

template<typename T>
VmaListItem<T>* VmaRawList<T>::InsertAfter(ItemType* pItem, const T& value)
{
    ItemType* const newItem = InsertAfter(pItem);
    newItem->Value = value;
    return newItem;
}

template<typename T, typename AllocatorT>
class VmaList
{
public:
    class iterator
    {
    public:
        iterator() :
            m_pList(VMA_NULL),
            m_pItem(VMA_NULL)
        {
        }

        T& operator*() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return m_pItem->Value;
        }
        T* operator->() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return &m_pItem->Value;
        }

        iterator& operator++()
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            m_pItem = m_pItem->pNext;
            return *this;
        }
        iterator& operator--()
        {
            if(m_pItem != VMA_NULL)
                m_pItem = m_pItem->pPrev;
            else
            {
                VMA_HEAVY_ASSERT(!m_pList.IsEmpty());
                m_pItem = m_pList->Back();
            }
            return *this;
        }

        iterator operator++(int)
        {
            iterator result = *this;
            ++*this;
            return result;
        }
        iterator operator--(int)
        {
            iterator result = *this;
            --*this;
            return result;
        }

        bool operator==(const iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem == rhs.m_pItem;
        }
        bool operator!=(const iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem != rhs.m_pItem;
        }
        
    private:
        VmaRawList<T>* m_pList;
        VmaListItem<T>* m_pItem;

        iterator(VmaRawList<T>* pList, VmaListItem<T>* pItem) :
            m_pList(pList),
            m_pItem(pItem)
        {
        }

        friend class VmaList<T, AllocatorT>;
        friend class VmaList<T, AllocatorT>:: const_iterator;
    };

    class const_iterator
    {
    public:
        const_iterator() :
            m_pList(VMA_NULL),
            m_pItem(VMA_NULL)
        {
        }

        const_iterator(const iterator& src) :
            m_pList(src.m_pList),
            m_pItem(src.m_pItem)
        {
        }
        
        const T& operator*() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return m_pItem->Value;
        }
        const T* operator->() const
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            return &m_pItem->Value;
        }

        const_iterator& operator++()
        {
            VMA_HEAVY_ASSERT(m_pItem != VMA_NULL);
            m_pItem = m_pItem->pNext;
            return *this;
        }
        const_iterator& operator--()
        {
            if(m_pItem != VMA_NULL)
                m_pItem = m_pItem->pPrev;
            else
            {
                VMA_HEAVY_ASSERT(!m_pList->IsEmpty());
                m_pItem = m_pList->Back();
            }
            return *this;
        }

        const_iterator operator++(int)
        {
            const_iterator result = *this;
            ++*this;
            return result;
        }
        const_iterator operator--(int)
        {
            const_iterator result = *this;
            --*this;
            return result;
        }

        bool operator==(const const_iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem == rhs.m_pItem;
        }
        bool operator!=(const const_iterator& rhs) const
        {
            VMA_HEAVY_ASSERT(m_pList == rhs.m_pList);
            return m_pItem != rhs.m_pItem;
        }
        
    private:
        const_iterator(const VmaRawList<T>* pList, const VmaListItem<T>* pItem) :
            m_pList(pList),
            m_pItem(pItem)
        {
        }

        const VmaRawList<T>* m_pList;
        const VmaListItem<T>* m_pItem;

        friend class VmaList<T, AllocatorT>;
    };

    VmaList(const AllocatorT& allocator) : m_RawList(allocator.m_pCallbacks) { }

    bool empty() const { return m_RawList.IsEmpty(); }
    size_t size() const { return m_RawList.GetCount(); }

    iterator begin() { return iterator(&m_RawList, m_RawList.Front()); }
    iterator end() { return iterator(&m_RawList, VMA_NULL); }

    const_iterator cbegin() const { return const_iterator(&m_RawList, m_RawList.Front()); }
    const_iterator cend() const { return const_iterator(&m_RawList, VMA_NULL); }

    void clear() { m_RawList.Clear(); }
    void push_back(const T& value) { m_RawList.PushBack(value); }
    void erase(iterator it) { m_RawList.Remove(it.m_pItem); }
    iterator insert(iterator it, const T& value) { return iterator(&m_RawList, m_RawList.InsertBefore(it.m_pItem, value)); }

private:
    VmaRawList<T> m_RawList;
};

#endif // #if VMA_USE_STL_LIST

////////////////////////////////////////////////////////////////////////////////
// class VmaMap

#if VMA_USE_STL_UNORDERED_MAP

#define VmaPair std::pair

#define VMA_MAP_TYPE(KeyT, ValueT) \
    std::unordered_map< KeyT, ValueT, std::hash<KeyT>, std::equal_to<KeyT>, VmaStlAllocator< std::pair<KeyT, ValueT> > >

#else // #if VMA_USE_STL_UNORDERED_MAP

template<typename T1, typename T2>
struct VmaPair
{
    T1 first;
    T2 second;

    VmaPair() : first(), second() { }
    VmaPair(const T1& firstSrc, const T2& secondSrc) : first(firstSrc), second(secondSrc) { }
};

/* Class compatible with subset of interface of std::unordered_map.
KeyT, ValueT must be POD because they will be stored in VmaVector.
*/
template<typename KeyT, typename ValueT>
class VmaMap
{
public:
    typedef VmaPair<KeyT, ValueT> PairType;
    typedef PairType* iterator;

    VmaMap(const VmaStlAllocator<PairType>& allocator) : m_Vector(allocator) { }

    iterator begin() { return m_Vector.begin(); }
    iterator end() { return m_Vector.end(); }

    void insert(const PairType& pair);
    iterator find(const KeyT& key);
    void erase(iterator it);
    
private:
    VmaVector< PairType, VmaStlAllocator<PairType> > m_Vector;
};

#define VMA_MAP_TYPE(KeyT, ValueT) VmaMap<KeyT, ValueT>

template<typename FirstT, typename SecondT>
struct VmaPairFirstLess
{
    bool operator()(const VmaPair<FirstT, SecondT>& lhs, const VmaPair<FirstT, SecondT>& rhs) const
    {
        return lhs.first < rhs.first;
    }
    bool operator()(const VmaPair<FirstT, SecondT>& lhs, const FirstT& rhsFirst) const
    {
        return lhs.first < rhsFirst;
    }
};

template<typename KeyT, typename ValueT>
void VmaMap<KeyT, ValueT>::insert(const PairType& pair)
{
    const size_t indexToInsert = VmaBinaryFindFirstNotLess(
        m_Vector.data(),
        m_Vector.data() + m_Vector.size(),
        pair,
        VmaPairFirstLess<KeyT, ValueT>()) - m_Vector.data();
    VectorInsert(m_Vector, indexToInsert, pair);
}

template<typename KeyT, typename ValueT>
VmaPair<KeyT, ValueT>* VmaMap<KeyT, ValueT>::find(const KeyT& key)
{
    PairType* it = VmaBinaryFindFirstNotLess(
        m_Vector.data(),
        m_Vector.data() + m_Vector.size(),
        key,
        VmaPairFirstLess<KeyT, ValueT>());
    if((it != m_Vector.end()) && (it->first == key))
        return it;
    else
        return m_Vector.end();
}

template<typename KeyT, typename ValueT>
void VmaMap<KeyT, ValueT>::erase(iterator it)
{
    VectorRemove(m_Vector, it - m_Vector.begin());
}

#endif // #if VMA_USE_STL_UNORDERED_MAP

////////////////////////////////////////////////////////////////////////////////

class VmaBlock;

enum VMA_BLOCK_VECTOR_TYPE
{
    VMA_BLOCK_VECTOR_TYPE_UNMAPPED,
    VMA_BLOCK_VECTOR_TYPE_MAPPED,
    VMA_BLOCK_VECTOR_TYPE_COUNT
};

static VMA_BLOCK_VECTOR_TYPE VmaMemoryRequirementFlagsToBlockVectorType(VmaMemoryRequirementFlags flags)
{
    return (flags & VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT) != 0 ?
        VMA_BLOCK_VECTOR_TYPE_MAPPED :
        VMA_BLOCK_VECTOR_TYPE_UNMAPPED;
}

struct VmaAllocation_T
{
public:
    enum ALLOCATION_TYPE
    {
        ALLOCATION_TYPE_NONE,
        ALLOCATION_TYPE_BLOCK,
        ALLOCATION_TYPE_OWN,
    };

    VmaAllocation_T()
    {
        memset(this, 0, sizeof(VmaAllocation_T));
    }

    void InitBlockAllocation(
        VmaBlock* block,
        VkDeviceSize offset,
        VkDeviceSize alignment,
        VkDeviceSize size,
        VmaSuballocationType suballocationType,
        void* pUserData)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_NONE);
        VMA_ASSERT(block != VMA_NULL);
        m_Type = ALLOCATION_TYPE_BLOCK;
        m_Alignment = alignment;
        m_Size = size;
        m_pUserData = pUserData;
        m_SuballocationType = suballocationType;
        m_BlockAllocation.m_Block = block;
        m_BlockAllocation.m_Offset = offset;
    }

    void ChangeBlockAllocation(
        VmaBlock* block,
        VkDeviceSize offset)
    {
        VMA_ASSERT(block != VMA_NULL);
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_BLOCK);
        m_BlockAllocation.m_Block = block;
        m_BlockAllocation.m_Offset = offset;
    }

    void InitOwnAllocation(
        uint32_t memoryTypeIndex,
        VkDeviceMemory hMemory,
        VmaSuballocationType suballocationType,
        bool persistentMap,
        void* pMappedData,
        VkDeviceSize size,
        void* pUserData)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_NONE);
        VMA_ASSERT(hMemory != VK_NULL_HANDLE);
        m_Type = ALLOCATION_TYPE_OWN;
        m_Alignment = 0;
        m_Size = size;
        m_pUserData = pUserData;
        m_SuballocationType = suballocationType;
        m_OwnAllocation.m_MemoryTypeIndex = memoryTypeIndex;
        m_OwnAllocation.m_hMemory = hMemory;
        m_OwnAllocation.m_PersistentMap = persistentMap;
        m_OwnAllocation.m_pMappedData = pMappedData;
    }

    ALLOCATION_TYPE GetType() const { return m_Type; }
    VkDeviceSize GetAlignment() const { return m_Alignment; }
    VkDeviceSize GetSize() const { return m_Size; }
    void* GetUserData() const { return m_pUserData; }
    void SetUserData(void* pUserData) { m_pUserData = pUserData; }
    VmaSuballocationType GetSuballocationType() const { return m_SuballocationType; }

    VmaBlock* GetBlock() const
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_BLOCK);
        return m_BlockAllocation.m_Block;
    }
    VkDeviceSize GetOffset() const
    {
        return (m_Type == ALLOCATION_TYPE_BLOCK) ? m_BlockAllocation.m_Offset : 0;
    }
    VkDeviceMemory GetMemory() const;
    uint32_t GetMemoryTypeIndex() const;
    VMA_BLOCK_VECTOR_TYPE GetBlockVectorType() const;
    void* GetMappedData() const;

    VkResult OwnAllocMapPersistentlyMappedMemory(VkDevice hDevice)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_OWN);
        if(m_OwnAllocation.m_PersistentMap)
        {
            return vkMapMemory(hDevice, m_OwnAllocation.m_hMemory, 0, VK_WHOLE_SIZE, 0, &m_OwnAllocation.m_pMappedData);
        }
        return VK_SUCCESS;
    }
    void OwnAllocUnmapPersistentlyMappedMemory(VkDevice hDevice)
    {
        VMA_ASSERT(m_Type == ALLOCATION_TYPE_OWN);
        if(m_OwnAllocation.m_pMappedData)
        {
            VMA_ASSERT(m_OwnAllocation.m_PersistentMap);
            vkUnmapMemory(hDevice, m_OwnAllocation.m_hMemory);
            m_OwnAllocation.m_pMappedData = VMA_NULL;
        }
    }

private:
    VkDeviceSize m_Alignment;
    VkDeviceSize m_Size;
    void* m_pUserData;
    ALLOCATION_TYPE m_Type;
    VmaSuballocationType m_SuballocationType;

    union
    {
        // Allocation out of VmaBlock.
        struct BlockAllocation
        {
            VmaBlock* m_Block;
            VkDeviceSize m_Offset;
        } m_BlockAllocation;

        // Allocation for an object that has its own private VkDeviceMemory.
        struct OwnAllocation
        {
            uint32_t m_MemoryTypeIndex;
            VkDeviceMemory m_hMemory;
            bool m_PersistentMap;
            void* m_pMappedData;
        } m_OwnAllocation;
    };
};

/*
Represents a region of VmaBlock that is either assigned and returned as
allocated memory block or free.
*/
struct VmaSuballocation
{
    VkDeviceSize offset;
    VkDeviceSize size;
    VmaSuballocationType type;
};

typedef VmaList< VmaSuballocation, VmaStlAllocator<VmaSuballocation> > VmaSuballocationList;

// Parameters of an allocation.
struct VmaAllocationRequest
{
    VmaSuballocationList::iterator freeSuballocationItem;
    VkDeviceSize offset;
};

/* Single block of memory - VkDeviceMemory with all the data about its regions
assigned or free. */
class VmaBlock
{
public:
    uint32_t m_MemoryTypeIndex;
    VMA_BLOCK_VECTOR_TYPE m_BlockVectorType;
    VkDeviceMemory m_hMemory;
    VkDeviceSize m_Size;
    bool m_PersistentMap;
    void* m_pMappedData;
    uint32_t m_FreeCount;
    VkDeviceSize m_SumFreeSize;
    VmaSuballocationList m_Suballocations;
    // Suballocations that are free and have size greater than certain threshold.
    // Sorted by size, ascending.
    VmaVector< VmaSuballocationList::iterator, VmaStlAllocator< VmaSuballocationList::iterator > > m_FreeSuballocationsBySize;

    VmaBlock(VmaAllocator hAllocator);

    ~VmaBlock()
    {
        VMA_ASSERT(m_hMemory == VK_NULL_HANDLE);
    }

    // Always call after construction.
    void Init(
        uint32_t newMemoryTypeIndex,
        VMA_BLOCK_VECTOR_TYPE newBlockVectorType,
        VkDeviceMemory newMemory,
        VkDeviceSize newSize,
        bool persistentMap,
        void* pMappedData);
    // Always call before destruction.
    void Destroy(VmaAllocator allocator);
    
    // Validates all data structures inside this object. If not valid, returns false.
    bool Validate() const;
    
    // Tries to find a place for suballocation with given parameters inside this allocation.
    // If succeeded, fills pAllocationRequest and returns true.
    // If failed, returns false.
    bool CreateAllocationRequest(
        VkDeviceSize bufferImageGranularity,
        VkDeviceSize allocSize,
        VkDeviceSize allocAlignment,
        VmaSuballocationType allocType,
        VmaAllocationRequest* pAllocationRequest);

    // Checks if requested suballocation with given parameters can be placed in given pFreeSuballocItem.
    // If yes, fills pOffset and returns true. If no, returns false.
    bool CheckAllocation(
        VkDeviceSize bufferImageGranularity,
        VkDeviceSize allocSize,
        VkDeviceSize allocAlignment,
        VmaSuballocationType allocType,
        VmaSuballocationList::const_iterator freeSuballocItem,
        VkDeviceSize* pOffset) const;
    
    // Returns true if this allocation is empty - contains only single free suballocation.
    bool IsEmpty() const;

    // Makes actual allocation based on request. Request must already be checked
    // and valid.
    void Alloc(
        const VmaAllocationRequest& request,
        VmaSuballocationType type,
        VkDeviceSize allocSize);

    // Frees suballocation assigned to given memory region.
    void Free(const VmaAllocation allocation);

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaStringBuilder& sb) const;
#endif

private:
    // Given free suballocation, it merges it with following one, which must also be free.
    void MergeFreeWithNext(VmaSuballocationList::iterator item);
    // Releases given suballocation, making it free. Merges it with adjacent free
    // suballocations if applicable.
    void FreeSuballocation(VmaSuballocationList::iterator suballocItem);
    // Given free suballocation, it inserts it into sorted list of
    // m_FreeSuballocationsBySize if it's suitable.
    void RegisterFreeSuballocation(VmaSuballocationList::iterator item);
    // Given free suballocation, it removes it from sorted list of
    // m_FreeSuballocationsBySize if it's suitable.
    void UnregisterFreeSuballocation(VmaSuballocationList::iterator item);
};

struct VmaPointerLess
{
    bool operator()(const void* lhs, const void* rhs) const
    {
        return lhs < rhs;
    }
};

/* Sequence of VmaBlock. Represents memory blocks allocated for a specific
Vulkan memory type. */
struct VmaBlockVector
{
    // Incrementally sorted by sumFreeSize, ascending.
    VmaVector< VmaBlock*, VmaStlAllocator<VmaBlock*> > m_Blocks;

    VmaBlockVector(VmaAllocator hAllocator);
    ~VmaBlockVector();

    bool IsEmpty() const { return m_Blocks.empty(); }

    // Finds and removes given block from vector.
    void Remove(VmaBlock* pBlock);

    // Performs single step in sorting m_Blocks. They may not be fully sorted
    // after this call.
    void IncrementallySortBlocks();
    
    // Adds statistics of this BlockVector to pStats.
    void AddStats(VmaStats* pStats, uint32_t memTypeIndex, uint32_t memHeapIndex) const;

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaStringBuilder& sb) const;
#endif

    void UnmapPersistentlyMappedMemory();
    VkResult MapPersistentlyMappedMemory();

private:
    VmaAllocator m_hAllocator;
};

// Main allocator object.
struct VmaAllocator_T
{
    VkDevice m_hDevice;
    bool m_AllocationCallbacksSpecified;
    VkAllocationCallbacks m_AllocationCallbacks;
    VmaDeviceMemoryCallbacks m_DeviceMemoryCallbacks;
    VkDeviceSize m_PreferredLargeHeapBlockSize;
    VkDeviceSize m_PreferredSmallHeapBlockSize;
    // Non-zero when we are inside UnmapPersistentlyMappedMemory...MapPersistentlyMappedMemory.
    // Counter to allow nested calls to these functions.
    uint32_t m_UnmapPersistentlyMappedMemoryCounter;

    VkPhysicalDeviceProperties m_PhysicalDeviceProperties;
    VkPhysicalDeviceMemoryProperties m_MemProps;

    VmaBlockVector* m_pBlockVectors[VK_MAX_MEMORY_TYPES][VMA_BLOCK_VECTOR_TYPE_COUNT];
    /* There can be at most one allocation that is completely empty - a
    hysteresis to avoid pessimistic case of alternating creation and destruction
    of a VkDeviceMemory. */
    bool m_HasEmptyBlock[VK_MAX_MEMORY_TYPES];
    VMA_MUTEX m_BlocksMutex[VK_MAX_MEMORY_TYPES];

    // Each vector is sorted by memory (handle value).
    typedef VmaVector< VmaAllocation, VmaStlAllocator<VmaAllocation> > AllocationVectorType;
    AllocationVectorType* m_pOwnAllocations[VK_MAX_MEMORY_TYPES][VMA_BLOCK_VECTOR_TYPE_COUNT];
    VMA_MUTEX m_OwnAllocationsMutex[VK_MAX_MEMORY_TYPES];

    VmaAllocator_T(const VmaAllocatorCreateInfo* pCreateInfo);
    ~VmaAllocator_T();

    const VkAllocationCallbacks* GetAllocationCallbacks() const
    {
        return m_AllocationCallbacksSpecified ? &m_AllocationCallbacks : 0;
    }

    VkDeviceSize GetPreferredBlockSize(uint32_t memTypeIndex) const;

    VkDeviceSize GetBufferImageGranularity() const
    {
        return VMA_MAX(
            static_cast<VkDeviceSize>(VMA_DEBUG_MIN_BUFFER_IMAGE_GRANULARITY),
            m_PhysicalDeviceProperties.limits.bufferImageGranularity);
    }

    uint32_t GetMemoryHeapCount() const { return m_MemProps.memoryHeapCount; }
    uint32_t GetMemoryTypeCount() const { return m_MemProps.memoryTypeCount; }

    // Main allocation function.
    VkResult AllocateMemory(
        const VkMemoryRequirements& vkMemReq,
        const VmaMemoryRequirements& vmaMemReq,
        VmaSuballocationType suballocType,
        VmaAllocation* pAllocation);

    // Main deallocation function.
    void FreeMemory(const VmaAllocation allocation);

    void CalculateStats(VmaStats* pStats);

#if VMA_STATS_STRING_ENABLED
    void PrintDetailedMap(class VmaStringBuilder& sb);
#endif

    void UnmapPersistentlyMappedMemory();
    VkResult MapPersistentlyMappedMemory();

    VkResult Defragment(
        VmaAllocation* pAllocations,
        size_t allocationCount,
        VkBool32* pAllocationsChanged,
        const VmaDefragmentationInfo* pDefragmentationInfo,
        VmaDefragmentationStats* pDefragmentationStats);

    static void GetAllocationInfo(VmaAllocation hAllocation, VmaAllocationInfo* pAllocationInfo);

private:
    VkPhysicalDevice m_PhysicalDevice;

    VkResult AllocateMemoryOfType(
        const VkMemoryRequirements& vkMemReq,
        const VmaMemoryRequirements& vmaMemReq,
        uint32_t memTypeIndex,
        VmaSuballocationType suballocType,
        VmaAllocation* pAllocation);
    
    // Allocates and registers new VkDeviceMemory specifically for single allocation.
    VkResult AllocateOwnMemory(
        VkDeviceSize size,
        VmaSuballocationType suballocType,
        uint32_t memTypeIndex,
        bool map,
        void* pUserData,
        VmaAllocation* pAllocation);

    // Tries to free pMemory as Own Memory. Returns true if found and freed.
    void FreeOwnMemory(VmaAllocation allocation);
};

////////////////////////////////////////////////////////////////////////////////
// Memory allocation #2 after VmaAllocator_T definition

static void* VmaMalloc(VmaAllocator hAllocator, size_t size, size_t alignment)
{
    return VmaMalloc(&hAllocator->m_AllocationCallbacks, size, alignment);
}

static void VmaFree(VmaAllocator hAllocator, void* ptr)
{
    VmaFree(&hAllocator->m_AllocationCallbacks, ptr);
}

template<typename T>
static T* VmaAllocate(VmaAllocator hAllocator)
{
    return (T*)VmaMalloc(hAllocator, sizeof(T), VMA_ALIGN_OF(T));
}

template<typename T>
static T* VmaAllocateArray(VmaAllocator hAllocator, size_t count)
{
    return (T*)VmaMalloc(hAllocator, sizeof(T) * count, VMA_ALIGN_OF(T));
}

template<typename T>
static void vma_delete(VmaAllocator hAllocator, T* ptr)
{
    if(ptr != VMA_NULL)
    {
        ptr->~T();
        VmaFree(hAllocator, ptr);
    }
}

template<typename T>
static void vma_delete_array(VmaAllocator hAllocator, T* ptr, size_t count)
{
    if(ptr != VMA_NULL)
    {
        for(size_t i = count; i--; )
            ptr[i].~T();
        VmaFree(hAllocator, ptr);
    }
}

////////////////////////////////////////////////////////////////////////////////
// VmaStringBuilder

#if VMA_STATS_STRING_ENABLED

class VmaStringBuilder
{
public:
    VmaStringBuilder(VmaAllocator alloc) : m_Data(VmaStlAllocator<char>(alloc->GetAllocationCallbacks())) { }
    size_t GetLength() const { return m_Data.size(); }
    const char* GetData() const { return m_Data.data(); }

    void Add(char ch) { m_Data.push_back(ch); }
    void Add(const char* pStr);
    void AddNewLine() { Add('\n'); }
    void AddNumber(uint32_t num);
    void AddNumber(uint64_t num);
    void AddBool(bool b) { Add(b ? "true" : "false"); }
    void AddNull() { Add("null"); }
    void AddString(const char* pStr);

private:
    VmaVector< char, VmaStlAllocator<char> > m_Data;
};

void VmaStringBuilder::Add(const char* pStr)
{
    const size_t strLen = strlen(pStr);
    if(strLen > 0)
    {
        const size_t oldCount = m_Data.size();
        m_Data.resize(oldCount + strLen);
        memcpy(m_Data.data() + oldCount, pStr, strLen);
    }
}

void VmaStringBuilder::AddNumber(uint32_t num)
{
    char buf[11];
    VmaUint32ToStr(buf, sizeof(buf), num);
    Add(buf);
}

void VmaStringBuilder::AddNumber(uint64_t num)
{
    char buf[21];
    VmaUint64ToStr(buf, sizeof(buf), num);
    Add(buf);
}

void VmaStringBuilder::AddString(const char* pStr)
{
    Add('"');
    const size_t strLen = strlen(pStr);
    for(size_t i = 0; i < strLen; ++i)
    {
        char ch = pStr[i];
        if(ch == '\'')
            Add("\\\\");
        else if(ch == '"')
            Add("\\\"");
        else if(ch >= 32)
            Add(ch);
        else switch(ch)
        {
        case '\n':
            Add("\\n");
            break;
        case '\r':
            Add("\\r");
            break;
        case '\t':
            Add("\\t");
            break;
        default:
            VMA_ASSERT(0 && "Character not currently supported.");
            break;
        }
    }
    Add('"');
}

////////////////////////////////////////////////////////////////////////////////

VkDeviceMemory VmaAllocation_T::GetMemory() const
{
    return (m_Type == ALLOCATION_TYPE_BLOCK) ?
        m_BlockAllocation.m_Block->m_hMemory : m_OwnAllocation.m_hMemory;
}

uint32_t VmaAllocation_T::GetMemoryTypeIndex() const
{
    return (m_Type == ALLOCATION_TYPE_BLOCK) ?
        m_BlockAllocation.m_Block->m_MemoryTypeIndex : m_OwnAllocation.m_MemoryTypeIndex;
}

VMA_BLOCK_VECTOR_TYPE VmaAllocation_T::GetBlockVectorType() const
{
    return (m_Type == ALLOCATION_TYPE_BLOCK) ?
        m_BlockAllocation.m_Block->m_BlockVectorType :
        (m_OwnAllocation.m_PersistentMap ? VMA_BLOCK_VECTOR_TYPE_MAPPED : VMA_BLOCK_VECTOR_TYPE_UNMAPPED);
}

void* VmaAllocation_T::GetMappedData() const
{
    switch(m_Type)
    {
    case ALLOCATION_TYPE_BLOCK:
        if(m_BlockAllocation.m_Block->m_pMappedData != VMA_NULL)
        {
            return (char*)m_BlockAllocation.m_Block->m_pMappedData + m_BlockAllocation.m_Offset;
        }
        else
        {
            return VMA_NULL;
        }
        break;
    case ALLOCATION_TYPE_OWN:
        return m_OwnAllocation.m_pMappedData;
    default:
        VMA_ASSERT(0);
        return VMA_NULL;
    }
}

// Correspond to values of enum VmaSuballocationType.
static const char* VMA_SUBALLOCATION_TYPE_NAMES[] = {
    "FREE",
    "UNKNOWN",
    "BUFFER",
    "IMAGE_UNKNOWN",
    "IMAGE_LINEAR",
    "IMAGE_OPTIMAL",
};

static void VmaPrintStatInfo(VmaStringBuilder& sb, const VmaStatInfo& stat)
{
    sb.Add("{ \"Allocations\": ");
    sb.AddNumber(stat.AllocationCount);
    sb.Add(", \"Suballocations\": ");
    sb.AddNumber(stat.SuballocationCount);
    sb.Add(", \"UnusedRanges\": ");
    sb.AddNumber(stat.UnusedRangeCount);
    sb.Add(", \"UsedBytes\": ");
    sb.AddNumber(stat.UsedBytes);
    sb.Add(", \"UnusedBytes\": ");
    sb.AddNumber(stat.UnusedBytes);
    sb.Add(", \"SuballocationSize\": { \"Min\": ");
    sb.AddNumber(stat.SuballocationSizeMin);
    sb.Add(", \"Avg\": ");
    sb.AddNumber(stat.SuballocationSizeAvg);
    sb.Add(", \"Max\": ");
    sb.AddNumber(stat.SuballocationSizeMax);
    sb.Add(" }, \"UnusedRangeSize\": { \"Min\": ");
    sb.AddNumber(stat.UnusedRangeSizeMin);
    sb.Add(", \"Avg\": ");
    sb.AddNumber(stat.UnusedRangeSizeAvg);
    sb.Add(", \"Max\": ");
    sb.AddNumber(stat.UnusedRangeSizeMax);
    sb.Add(" } }");
}

#endif // #if VMA_STATS_STRING_ENABLED

struct VmaSuballocationItemSizeLess
{
    bool operator()(
        const VmaSuballocationList::iterator lhs,
        const VmaSuballocationList::iterator rhs) const
    {
        return lhs->size < rhs->size;
    }
    bool operator()(
        const VmaSuballocationList::iterator lhs,
        VkDeviceSize rhsSize) const
    {
        return lhs->size < rhsSize;
    }
};

VmaBlock::VmaBlock(VmaAllocator hAllocator) :
    m_MemoryTypeIndex(UINT32_MAX),
    m_BlockVectorType(VMA_BLOCK_VECTOR_TYPE_COUNT),
    m_hMemory(VK_NULL_HANDLE),
    m_Size(0),
    m_PersistentMap(false),
    m_pMappedData(VMA_NULL),
    m_FreeCount(0),
    m_SumFreeSize(0),
    m_Suballocations(VmaStlAllocator<VmaSuballocation>(hAllocator->GetAllocationCallbacks())),
    m_FreeSuballocationsBySize(VmaStlAllocator<VmaSuballocationList::iterator>(hAllocator->GetAllocationCallbacks()))
{
}

void VmaBlock::Init(
    uint32_t newMemoryTypeIndex,
    VMA_BLOCK_VECTOR_TYPE newBlockVectorType,
    VkDeviceMemory newMemory,
    VkDeviceSize newSize,
    bool persistentMap,
    void* pMappedData)
{
    VMA_ASSERT(m_hMemory == VK_NULL_HANDLE);

    m_MemoryTypeIndex = newMemoryTypeIndex;
    m_BlockVectorType = newBlockVectorType;
    m_hMemory = newMemory;
    m_Size = newSize;
    m_PersistentMap = persistentMap;
    m_pMappedData = pMappedData;
    m_FreeCount = 1;
    m_SumFreeSize = newSize;

    m_Suballocations.clear();
    m_FreeSuballocationsBySize.clear();

    VmaSuballocation suballoc = {};
    suballoc.offset = 0;
    suballoc.size = newSize;
    suballoc.type = VMA_SUBALLOCATION_TYPE_FREE;

    m_Suballocations.push_back(suballoc);
    VmaSuballocationList::iterator suballocItem = m_Suballocations.end();
    --suballocItem;
    m_FreeSuballocationsBySize.push_back(suballocItem);
}

void VmaBlock::Destroy(VmaAllocator allocator)
{
    VMA_ASSERT(m_hMemory != VK_NULL_HANDLE);
    if(m_pMappedData != VMA_NULL)
    {
        vkUnmapMemory(allocator->m_hDevice, m_hMemory);
        m_pMappedData = VMA_NULL;
    }

    // Callback.
    if(allocator->m_DeviceMemoryCallbacks.pfnFree != VMA_NULL)
    {
        (*allocator->m_DeviceMemoryCallbacks.pfnFree)(allocator, m_MemoryTypeIndex, m_hMemory, m_Size);
    }

    vkFreeMemory(allocator->m_hDevice, m_hMemory, allocator->GetAllocationCallbacks());
    m_hMemory = VK_NULL_HANDLE;
}

bool VmaBlock::Validate() const
{
    if((m_hMemory == VK_NULL_HANDLE) ||
        (m_Size == 0) ||
        m_Suballocations.empty())
    {
        return false;
    }
    
    // Expected offset of new suballocation as calculates from previous ones.
    VkDeviceSize calculatedOffset = 0;
    // Expected number of free suballocations as calculated from traversing their list.
    uint32_t calculatedFreeCount = 0;
    // Expected sum size of free suballocations as calculated from traversing their list.
    VkDeviceSize calculatedSumFreeSize = 0;
    // Expected number of free suballocations that should be registered in
    // m_FreeSuballocationsBySize calculated from traversing their list.
    size_t freeSuballocationsToRegister = 0;
    // True if previous visisted suballocation was free.
    bool prevFree = false;

    for(VmaSuballocationList::const_iterator suballocItem = m_Suballocations.cbegin();
        suballocItem != m_Suballocations.cend();
        ++suballocItem)
    {
        const VmaSuballocation& subAlloc = *suballocItem;
        
        // Actual offset of this suballocation doesn't match expected one.
        if(subAlloc.offset != calculatedOffset)
            return false;

        const bool currFree = (subAlloc.type == VMA_SUBALLOCATION_TYPE_FREE);
        // Two adjacent free suballocations are invalid. They should be merged.
        if(prevFree && currFree)
            return false;
        prevFree = currFree;

        if(currFree)
        {
            calculatedSumFreeSize += subAlloc.size;
            ++calculatedFreeCount;
            if(subAlloc.size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
                ++freeSuballocationsToRegister;
        }

        calculatedOffset += subAlloc.size;
    }

    // Number of free suballocations registered in m_FreeSuballocationsBySize doesn't
    // match expected one.
    if(m_FreeSuballocationsBySize.size() != freeSuballocationsToRegister)
        return false;

    VkDeviceSize lastSize = 0;
    for(size_t i = 0; i < m_FreeSuballocationsBySize.size(); ++i)
    {
        VmaSuballocationList::iterator suballocItem = m_FreeSuballocationsBySize[i];
        
        // Only free suballocations can be registered in m_FreeSuballocationsBySize.
        if(suballocItem->type != VMA_SUBALLOCATION_TYPE_FREE)
            return false;
        // They must be sorted by size ascending.
        if(suballocItem->size < lastSize)
            return false;

        lastSize = suballocItem->size;
    }

    // Check if totals match calculacted values.
    return
        (calculatedOffset == m_Size) &&
        (calculatedSumFreeSize == m_SumFreeSize) &&
        (calculatedFreeCount == m_FreeCount);
}

/*
How many suitable free suballocations to analyze before choosing best one.
- Set to 1 to use First-Fit algorithm - first suitable free suballocation will
  be chosen.
- Set to UINT32_MAX to use Best-Fit/Worst-Fit algorithm - all suitable free
  suballocations will be analized and best one will be chosen.
- Any other value is also acceptable.
*/
//static const uint32_t MAX_SUITABLE_SUBALLOCATIONS_TO_CHECK = 8;

bool VmaBlock::CreateAllocationRequest(
    VkDeviceSize bufferImageGranularity,
    VkDeviceSize allocSize,
    VkDeviceSize allocAlignment,
    VmaSuballocationType allocType,
    VmaAllocationRequest* pAllocationRequest)
{
    VMA_ASSERT(allocSize > 0);
    VMA_ASSERT(allocType != VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(pAllocationRequest != VMA_NULL);
    VMA_HEAVY_ASSERT(Validate());

    // There is not enough total free space in this allocation to fullfill the request: Early return.
    if(m_SumFreeSize < allocSize)
        return false;

    // Old brute-force algorithm, linearly searching suballocations.
    /*
    uint32_t suitableSuballocationsFound = 0;
    for(VmaSuballocationList::iterator suballocItem = suballocations.Front();
        suballocItem != VMA_NULL &&
            suitableSuballocationsFound < MAX_SUITABLE_SUBALLOCATIONS_TO_CHECK;
        suballocItem = suballocItem->Next)
    {
        if(suballocItem->Value.type == VMA_SUBALLOCATION_TYPE_FREE)
        {
            VkDeviceSize offset = 0, cost = 0;
            if(CheckAllocation(bufferImageGranularity, allocSize, allocAlignment, allocType, suballocItem, &offset, &cost))
            {
                ++suitableSuballocationsFound;
                if(cost < costLimit)
                {
                    pAllocationRequest->freeSuballocationItem = suballocItem;
                    pAllocationRequest->offset = offset;
                    pAllocationRequest->cost = cost;
                    if(cost == 0)
                        return true;
                    costLimit = cost;
                    betterSuballocationFound = true;
                }
            }
        }
    }
    */

    // New algorithm, efficiently searching freeSuballocationsBySize.
    const size_t freeSuballocCount = m_FreeSuballocationsBySize.size();
    if(freeSuballocCount > 0)
    {
        if(VMA_BEST_FIT)
        {
            // Find first free suballocation with size not less than allocSize.
            VmaSuballocationList::iterator* const it = VmaBinaryFindFirstNotLess(
                m_FreeSuballocationsBySize.data(),
                m_FreeSuballocationsBySize.data() + freeSuballocCount,
                allocSize,
                VmaSuballocationItemSizeLess());
            size_t index = it - m_FreeSuballocationsBySize.data();
            for(; index < freeSuballocCount; ++index)
            {
                VkDeviceSize offset = 0;
                const VmaSuballocationList::iterator suballocItem = m_FreeSuballocationsBySize[index];
                if(CheckAllocation(bufferImageGranularity, allocSize, allocAlignment, allocType, suballocItem, &offset))
                {
                    pAllocationRequest->freeSuballocationItem = suballocItem;
                    pAllocationRequest->offset = offset;
                    return true;
                }
            }
        }
        else
        {
            // Search staring from biggest suballocations.
            for(size_t index = freeSuballocCount; index--; )
            {
                VkDeviceSize offset = 0;
                const VmaSuballocationList::iterator suballocItem = m_FreeSuballocationsBySize[index];
                if(CheckAllocation(bufferImageGranularity, allocSize, allocAlignment, allocType, suballocItem, &offset))
                {
                    pAllocationRequest->freeSuballocationItem = suballocItem;
                    pAllocationRequest->offset = offset;
                    return true;
                }
            }
        }
    }

    return false;
}

bool VmaBlock::CheckAllocation(
    VkDeviceSize bufferImageGranularity,
    VkDeviceSize allocSize,
    VkDeviceSize allocAlignment,
    VmaSuballocationType allocType,
    VmaSuballocationList::const_iterator freeSuballocItem,
    VkDeviceSize* pOffset) const
{
    VMA_ASSERT(allocSize > 0);
    VMA_ASSERT(allocType != VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(freeSuballocItem != m_Suballocations.cend());
    VMA_ASSERT(pOffset != VMA_NULL);

    const VmaSuballocation& suballoc = *freeSuballocItem;
    VMA_ASSERT(suballoc.type == VMA_SUBALLOCATION_TYPE_FREE);

    // Size of this suballocation is too small for this request: Early return.
    if(suballoc.size < allocSize)
        return false;

    // Start from offset equal to beginning of this suballocation.
    *pOffset = suballoc.offset;
    
    // Apply VMA_DEBUG_MARGIN at the beginning.
    if((VMA_DEBUG_MARGIN > 0) && freeSuballocItem != m_Suballocations.cbegin())
        *pOffset += VMA_DEBUG_MARGIN;
    
    // Apply alignment.
    const VkDeviceSize alignment = VMA_MAX(allocAlignment, static_cast<VkDeviceSize>(VMA_DEBUG_ALIGNMENT));
    *pOffset = VmaAlignUp(*pOffset, alignment);
    
    // Check previous suballocations for BufferImageGranularity conflicts.
    // Make bigger alignment if necessary.
    if(bufferImageGranularity > 1)
    {
        bool bufferImageGranularityConflict = false;
        VmaSuballocationList::const_iterator prevSuballocItem = freeSuballocItem;
        while(prevSuballocItem != m_Suballocations.cbegin())
        {
            --prevSuballocItem;
            const VmaSuballocation& prevSuballoc = *prevSuballocItem;
            if(VmaBlocksOnSamePage(prevSuballoc.offset, prevSuballoc.size, *pOffset, bufferImageGranularity))
            {
                if(VmaIsBufferImageGranularityConflict(prevSuballoc.type, allocType))
                {
                    bufferImageGranularityConflict = true;
                    break;
                }
            }
            else
                // Already on previous page.
                break;
        }
        if(bufferImageGranularityConflict)
            *pOffset = VmaAlignUp(*pOffset, bufferImageGranularity);
    }
    
    // Calculate padding at the beginning based on current offset.
    const VkDeviceSize paddingBegin = *pOffset - suballoc.offset;

    // Calculate required margin at the end if this is not last suballocation.
    VmaSuballocationList::const_iterator next = freeSuballocItem;
    ++next;
    const VkDeviceSize requiredEndMargin =
        (next != m_Suballocations.cend()) ? VMA_DEBUG_MARGIN : 0;

    // Fail if requested size plus margin before and after is bigger than size of this suballocation.
    if(paddingBegin + allocSize + requiredEndMargin > suballoc.size)
        return false;

    // Check next suballocations for BufferImageGranularity conflicts.
    // If conflict exists, allocation cannot be made here.
    if(bufferImageGranularity > 1)
    {
        VmaSuballocationList::const_iterator nextSuballocItem = freeSuballocItem;
        ++nextSuballocItem;
        while(nextSuballocItem != m_Suballocations.cend())
        {
            const VmaSuballocation& nextSuballoc = *nextSuballocItem;
            if(VmaBlocksOnSamePage(*pOffset, allocSize, nextSuballoc.offset, bufferImageGranularity))
            {
                if(VmaIsBufferImageGranularityConflict(allocType, nextSuballoc.type))
                    return false;
            }
            else
                // Already on next page.
                break;
            ++nextSuballocItem;
        }
    }

    // All tests passed: Success. pOffset is already filled.
    return true;
}

bool VmaBlock::IsEmpty() const
{
    return (m_Suballocations.size() == 1) && (m_FreeCount == 1);
}

void VmaBlock::Alloc(
    const VmaAllocationRequest& request,
    VmaSuballocationType type,
    VkDeviceSize allocSize)
{
    VMA_ASSERT(request.freeSuballocationItem != m_Suballocations.end());
    VmaSuballocation& suballoc = *request.freeSuballocationItem;
    // Given suballocation is a free block.
    VMA_ASSERT(suballoc.type == VMA_SUBALLOCATION_TYPE_FREE);
    // Given offset is inside this suballocation.
    VMA_ASSERT(request.offset >= suballoc.offset);
    const VkDeviceSize paddingBegin = request.offset - suballoc.offset;
    VMA_ASSERT(suballoc.size >= paddingBegin + allocSize);
    const VkDeviceSize paddingEnd = suballoc.size - paddingBegin - allocSize;

    // Unregister this free suballocation from m_FreeSuballocationsBySize and update
    // it to become used.
    UnregisterFreeSuballocation(request.freeSuballocationItem);

    suballoc.offset = request.offset;
    suballoc.size = allocSize;
    suballoc.type = type;

    // If there are any free bytes remaining at the end, insert new free suballocation after current one.
    if(paddingEnd)
    {
        VmaSuballocation paddingSuballoc = {};
        paddingSuballoc.offset = request.offset + allocSize;
        paddingSuballoc.size = paddingEnd;
        paddingSuballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
        VmaSuballocationList::iterator next = request.freeSuballocationItem;
        ++next;
        const VmaSuballocationList::iterator paddingEndItem =
            m_Suballocations.insert(next, paddingSuballoc);
        RegisterFreeSuballocation(paddingEndItem);
    }

    // If there are any free bytes remaining at the beginning, insert new free suballocation before current one.
    if(paddingBegin)
    {
        VmaSuballocation paddingSuballoc = {};
        paddingSuballoc.offset = request.offset - paddingBegin;
        paddingSuballoc.size = paddingBegin;
        paddingSuballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
        const VmaSuballocationList::iterator paddingBeginItem =
            m_Suballocations.insert(request.freeSuballocationItem, paddingSuballoc);
        RegisterFreeSuballocation(paddingBeginItem);
    }

    // Update totals.
    m_FreeCount = m_FreeCount - 1;
    if(paddingBegin > 0)
        ++m_FreeCount;
    if(paddingEnd > 0)
        ++m_FreeCount;
    m_SumFreeSize -= allocSize;
}

void VmaBlock::FreeSuballocation(VmaSuballocationList::iterator suballocItem)
{
    // Change this suballocation to be marked as free.
    VmaSuballocation& suballoc = *suballocItem;
    suballoc.type = VMA_SUBALLOCATION_TYPE_FREE;
    
    // Update totals.
    ++m_FreeCount;
    m_SumFreeSize += suballoc.size;

    // Merge with previous and/or next suballocation if it's also free.
    bool mergeWithNext = false;
    bool mergeWithPrev = false;
    
    VmaSuballocationList::iterator nextItem = suballocItem;
    ++nextItem;
    if((nextItem != m_Suballocations.end()) && (nextItem->type == VMA_SUBALLOCATION_TYPE_FREE))
        mergeWithNext = true;

    VmaSuballocationList::iterator prevItem = suballocItem;
    if(suballocItem != m_Suballocations.begin())
    {
        --prevItem;
        if(prevItem->type == VMA_SUBALLOCATION_TYPE_FREE)
            mergeWithPrev = true;
    }

    if(mergeWithNext)
    {
        UnregisterFreeSuballocation(nextItem);
        MergeFreeWithNext(suballocItem);
    }

    if(mergeWithPrev)
    {
        UnregisterFreeSuballocation(prevItem);
        MergeFreeWithNext(prevItem);
        RegisterFreeSuballocation(prevItem);
    }
    else
        RegisterFreeSuballocation(suballocItem);
}

void VmaBlock::Free(const VmaAllocation allocation)
{
    // If suballocation to free has offset smaller than half of allocation size, search forward.
    // Otherwise search backward.
    const VkDeviceSize allocationOffset = allocation->GetOffset();
    const bool forwardDirection = allocationOffset < (m_Size / 2);
    if(forwardDirection)
    {
        for(VmaSuballocationList::iterator suballocItem = m_Suballocations.begin();
            suballocItem != m_Suballocations.end();
            ++suballocItem)
        {
            VmaSuballocation& suballoc = *suballocItem;
            if(suballoc.offset == allocationOffset)
            {
                FreeSuballocation(suballocItem);
                VMA_HEAVY_ASSERT(Validate());
                return;
            }
        }
        VMA_ASSERT(0 && "Not found!");
    }
    else
    {
        for(VmaSuballocationList::iterator suballocItem = m_Suballocations.begin();
            suballocItem != m_Suballocations.end();
            ++suballocItem)
        {
            VmaSuballocation& suballoc = *suballocItem;
            if(suballoc.offset == allocationOffset)
            {
                FreeSuballocation(suballocItem);
                VMA_HEAVY_ASSERT(Validate());
                return;
            }
        }
        VMA_ASSERT(0 && "Not found!");
    }
}

#if VMA_STATS_STRING_ENABLED

void VmaBlock::PrintDetailedMap(class VmaStringBuilder& sb) const
{
    sb.Add("{\n\t\t\t\"Bytes\": ");
    sb.AddNumber(m_Size);
    sb.Add(",\n\t\t\t\"FreeBytes\": ");
    sb.AddNumber(m_SumFreeSize);
    sb.Add(",\n\t\t\t\"Suballocations\": ");
    sb.AddNumber(m_Suballocations.size());
    sb.Add(",\n\t\t\t\"FreeSuballocations\": ");
    sb.AddNumber(m_FreeCount);
    sb.Add(",\n\t\t\t\"SuballocationList\": [");

    size_t i = 0;
    for(VmaSuballocationList::const_iterator suballocItem = m_Suballocations.cbegin();
        suballocItem != m_Suballocations.cend();
        ++suballocItem, ++i)
    {
        if(i > 0)
            sb.Add(",\n\t\t\t\t{ \"Type\": ");
        else
            sb.Add("\n\t\t\t\t{ \"Type\": ");
        sb.AddString(VMA_SUBALLOCATION_TYPE_NAMES[suballocItem->type]);
        sb.Add(", \"Size\": ");
        sb.AddNumber(suballocItem->size);
        sb.Add(", \"Offset\": ");
        sb.AddNumber(suballocItem->offset);
        sb.Add(" }");
    }

    sb.Add("\n\t\t\t]\n\t\t}");
}

#endif // #if VMA_STATS_STRING_ENABLED

void VmaBlock::MergeFreeWithNext(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item != m_Suballocations.end());
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    
    VmaSuballocationList::iterator nextItem = item;
    ++nextItem;
    VMA_ASSERT(nextItem != m_Suballocations.end());
    VMA_ASSERT(nextItem->type == VMA_SUBALLOCATION_TYPE_FREE);

    item->size += nextItem->size;
    --m_FreeCount;
    m_Suballocations.erase(nextItem);
}

void VmaBlock::RegisterFreeSuballocation(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(item->size > 0);

    if(item->size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
    {
        if(m_FreeSuballocationsBySize.empty())
            m_FreeSuballocationsBySize.push_back(item);
        else
        {
            VmaSuballocationList::iterator* const it = VmaBinaryFindFirstNotLess(
                m_FreeSuballocationsBySize.data(),
                m_FreeSuballocationsBySize.data() + m_FreeSuballocationsBySize.size(),
                item,
                VmaSuballocationItemSizeLess());
            size_t index = it - m_FreeSuballocationsBySize.data();
            VectorInsert(m_FreeSuballocationsBySize, index, item);
        }
    }
}

void VmaBlock::UnregisterFreeSuballocation(VmaSuballocationList::iterator item)
{
    VMA_ASSERT(item->type == VMA_SUBALLOCATION_TYPE_FREE);
    VMA_ASSERT(item->size > 0);

    if(item->size >= VMA_MIN_FREE_SUBALLOCATION_SIZE_TO_REGISTER)
    {
        VmaSuballocationList::iterator* const it = VmaBinaryFindFirstNotLess(
            m_FreeSuballocationsBySize.data(),
            m_FreeSuballocationsBySize.data() + m_FreeSuballocationsBySize.size(),
            item,
            VmaSuballocationItemSizeLess());
        for(size_t index = it - m_FreeSuballocationsBySize.data();
            index < m_FreeSuballocationsBySize.size();
            ++index)
        {
            if(m_FreeSuballocationsBySize[index] == item)
            {
                VectorRemove(m_FreeSuballocationsBySize, index);
                return;
            }
            VMA_ASSERT((m_FreeSuballocationsBySize[index]->size == item->size) && "Not found.");
        }
        VMA_ASSERT(0 && "Not found.");
    }
}

static void InitStatInfo(VmaStatInfo& outInfo)
{
    memset(&outInfo, 0, sizeof(outInfo));
    outInfo.SuballocationSizeMin = UINT64_MAX;
    outInfo.UnusedRangeSizeMin = UINT64_MAX;
}

static void CalcAllocationStatInfo(VmaStatInfo& outInfo, const VmaBlock& alloc)
{
    outInfo.AllocationCount = 1;

    const uint32_t rangeCount = (uint32_t)alloc.m_Suballocations.size();
    outInfo.SuballocationCount = rangeCount - alloc.m_FreeCount;
    outInfo.UnusedRangeCount = alloc.m_FreeCount;
    
    outInfo.UnusedBytes = alloc.m_SumFreeSize;
    outInfo.UsedBytes = alloc.m_Size - outInfo.UnusedBytes;

    outInfo.SuballocationSizeMin = UINT64_MAX;
    outInfo.SuballocationSizeMax = 0;
    outInfo.UnusedRangeSizeMin = UINT64_MAX;
    outInfo.UnusedRangeSizeMax = 0;

    for(VmaSuballocationList::const_iterator suballocItem = alloc.m_Suballocations.cbegin();
        suballocItem != alloc.m_Suballocations.cend();
        ++suballocItem)
    {
        const VmaSuballocation& suballoc = *suballocItem;
        if(suballoc.type != VMA_SUBALLOCATION_TYPE_FREE)
        {
            outInfo.SuballocationSizeMin = VMA_MIN(outInfo.SuballocationSizeMin, suballoc.size);
            outInfo.SuballocationSizeMax = VMA_MAX(outInfo.SuballocationSizeMax, suballoc.size);
        }
        else
        {
            outInfo.UnusedRangeSizeMin = VMA_MIN(outInfo.UnusedRangeSizeMin, suballoc.size);
            outInfo.UnusedRangeSizeMax = VMA_MAX(outInfo.UnusedRangeSizeMax, suballoc.size);
        }
    }
}

// Adds statistics srcInfo into inoutInfo, like: inoutInfo += srcInfo.
static void VmaAddStatInfo(VmaStatInfo& inoutInfo, const VmaStatInfo& srcInfo)
{
    inoutInfo.AllocationCount += srcInfo.AllocationCount;
    inoutInfo.SuballocationCount += srcInfo.SuballocationCount;
    inoutInfo.UnusedRangeCount += srcInfo.UnusedRangeCount;
    inoutInfo.UsedBytes += srcInfo.UsedBytes;
    inoutInfo.UnusedBytes += srcInfo.UnusedBytes;
    inoutInfo.SuballocationSizeMin = VMA_MIN(inoutInfo.SuballocationSizeMin, srcInfo.SuballocationSizeMin);
    inoutInfo.SuballocationSizeMax = VMA_MAX(inoutInfo.SuballocationSizeMax, srcInfo.SuballocationSizeMax);
    inoutInfo.UnusedRangeSizeMin = VMA_MIN(inoutInfo.UnusedRangeSizeMin, srcInfo.UnusedRangeSizeMin);
    inoutInfo.UnusedRangeSizeMax = VMA_MAX(inoutInfo.UnusedRangeSizeMax, srcInfo.UnusedRangeSizeMax);
}

static void VmaPostprocessCalcStatInfo(VmaStatInfo& inoutInfo)
{
    inoutInfo.SuballocationSizeAvg = (inoutInfo.SuballocationCount > 0) ?
        VmaRoundDiv<VkDeviceSize>(inoutInfo.UsedBytes, inoutInfo.SuballocationCount) : 0;
    inoutInfo.UnusedRangeSizeAvg = (inoutInfo.UnusedRangeCount > 0) ?
        VmaRoundDiv<VkDeviceSize>(inoutInfo.UnusedBytes, inoutInfo.UnusedRangeCount) : 0;
}

VmaBlockVector::VmaBlockVector(VmaAllocator hAllocator) :
    m_hAllocator(hAllocator),
    m_Blocks(VmaStlAllocator<VmaBlock*>(hAllocator->GetAllocationCallbacks()))
{
}

VmaBlockVector::~VmaBlockVector()
{
    for(size_t i = m_Blocks.size(); i--; )
    {
        m_Blocks[i]->Destroy(m_hAllocator);
        vma_delete(m_hAllocator, m_Blocks[i]);
    }
}

void VmaBlockVector::Remove(VmaBlock* pBlock)
{
    for(uint32_t blockIndex = 0; blockIndex < m_Blocks.size(); ++blockIndex)
    {
        if(m_Blocks[blockIndex] == pBlock)
        {
            VectorRemove(m_Blocks, blockIndex);
            return;
        }
    }
    VMA_ASSERT(0);
}

void VmaBlockVector::IncrementallySortBlocks()
{
    // Bubble sort only until first swap.
    for(size_t i = 1; i < m_Blocks.size(); ++i)
    {
        if(m_Blocks[i - 1]->m_SumFreeSize > m_Blocks[i]->m_SumFreeSize)
        {
            VMA_SWAP(m_Blocks[i - 1], m_Blocks[i]);
            return;
        }
    }
}

#if VMA_STATS_STRING_ENABLED

void VmaBlockVector::PrintDetailedMap(class VmaStringBuilder& sb) const
{
    for(size_t i = 0; i < m_Blocks.size(); ++i)
    {
        if(i > 0)
            sb.Add(",\n\t\t");
        else
            sb.Add("\n\t\t");
        m_Blocks[i]->PrintDetailedMap(sb);
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

void VmaBlockVector::UnmapPersistentlyMappedMemory()
{
    for(size_t i = m_Blocks.size(); i--; )
    {
        VmaBlock* pBlock = m_Blocks[i];
        if(pBlock->m_pMappedData != VMA_NULL)
        {
            VMA_ASSERT(pBlock->m_PersistentMap != false);
            vkUnmapMemory(m_hAllocator->m_hDevice, pBlock->m_hMemory);
            pBlock->m_pMappedData = VMA_NULL;
        }
    }
}

VkResult VmaBlockVector::MapPersistentlyMappedMemory()
{
    VkResult finalResult = VK_SUCCESS;
    for(size_t i = 0, count = m_Blocks.size(); i < count; ++i)
    {
        VmaBlock* pBlock = m_Blocks[i];
        if(pBlock->m_PersistentMap)
        {
            VMA_ASSERT(pBlock->m_pMappedData == nullptr);
            VkResult localResult = vkMapMemory(m_hAllocator->m_hDevice, pBlock->m_hMemory, 0, VK_WHOLE_SIZE, 0, &pBlock->m_pMappedData);
            if(localResult != VK_SUCCESS)
            {
                finalResult = localResult;
            }
        }
    }
    return finalResult;
}

void VmaBlockVector::AddStats(VmaStats* pStats, uint32_t memTypeIndex, uint32_t memHeapIndex) const
{
    for(uint32_t allocIndex = 0; allocIndex < m_Blocks.size(); ++allocIndex)
    {
        const VmaBlock* const pBlock = m_Blocks[allocIndex];
        VMA_ASSERT(pBlock);
        VMA_HEAVY_ASSERT(pBlock->Validate());
        VmaStatInfo allocationStatInfo;
        CalcAllocationStatInfo(allocationStatInfo, *pBlock);
        VmaAddStatInfo(pStats->total, allocationStatInfo);
        VmaAddStatInfo(pStats->memoryType[memTypeIndex], allocationStatInfo);
        VmaAddStatInfo(pStats->memoryHeap[memHeapIndex], allocationStatInfo);
    }
}

////////////////////////////////////////////////////////////////////////////////
// VmaDefragmentator

class VmaDefragmentator
{
    VkDevice m_hDevice;
    const VkAllocationCallbacks* m_pAllocationCallbacks;
    VkDeviceSize m_BufferImageGranularity;
    uint32_t m_MemTypeIndex;
    VMA_BLOCK_VECTOR_TYPE m_BlockVectorType;
    VkDeviceSize m_BytesMoved;
    uint32_t m_AllocationsMoved;

    struct AllocationInfo
    {
        VmaAllocation m_hAllocation;
        VkBool32* m_pChanged;

        AllocationInfo() :
            m_hAllocation(VK_NULL_HANDLE),
            m_pChanged(VMA_NULL)
        {
        }
    };

    struct AllocationInfoSizeGreater
    {
        bool operator()(const AllocationInfo& lhs, const AllocationInfo& rhs) const
        {
            return lhs.m_hAllocation->GetSize() > rhs.m_hAllocation->GetSize();
        }
    };

    // Used between AddAllocation and Defragment.
    VmaVector< AllocationInfo, VmaStlAllocator<AllocationInfo> > m_Allocations;

    struct BlockInfo
    {
        VmaBlock* m_pBlock;
        bool m_HasNonMovableAllocations;
        VmaVector< AllocationInfo, VmaStlAllocator<AllocationInfo> > m_Allocations;

        BlockInfo(const VkAllocationCallbacks* pAllocationCallbacks) :
            m_pBlock(VMA_NULL),
            m_HasNonMovableAllocations(true),
            m_Allocations(pAllocationCallbacks),
            m_pMappedDataForDefragmentation(VMA_NULL)
        {
        }

        void CalcHasNonMovableAllocations()
        {
            const size_t blockAllocCount =
                m_pBlock->m_Suballocations.size() - m_pBlock->m_FreeCount;
            const size_t defragmentAllocCount = m_Allocations.size();
            m_HasNonMovableAllocations = blockAllocCount != defragmentAllocCount;
        }

        void SortAllocationsBySizeDescecnding()
        {
            VMA_SORT(m_Allocations.begin(), m_Allocations.end(), AllocationInfoSizeGreater());
        }

        VkResult EnsureMapping(VkDevice hDevice, void** ppMappedData)
        {
            // It has already been mapped for defragmentation.
            if(m_pMappedDataForDefragmentation)
            {
                *ppMappedData = m_pMappedDataForDefragmentation;
                return VK_SUCCESS;
            }
            
            // It is persistently mapped.
            if(m_pBlock->m_PersistentMap)
            {
                VMA_ASSERT(m_pBlock->m_pMappedData != VMA_NULL);
                *ppMappedData = m_pBlock->m_pMappedData;
                return VK_SUCCESS;
            }
            
            // Map on first usage.
            VkResult res = vkMapMemory(hDevice, m_pBlock->m_hMemory, 0, VK_WHOLE_SIZE, 0, &m_pMappedDataForDefragmentation);
            *ppMappedData = m_pMappedDataForDefragmentation;
            return res;
        }

        void Unmap(VkDevice hDevice)
        {
            if(m_pMappedDataForDefragmentation != VMA_NULL)
            {
                vkUnmapMemory(hDevice, m_pBlock->m_hMemory);
            }
        }

    private:
        // Not null if mapped for defragmentation only, not persistently mapped.
        void* m_pMappedDataForDefragmentation;
    };

    struct BlockPointerLess
    {
        bool operator()(const BlockInfo* pLhsBlockInfo, const VmaBlock* pRhsBlock) const
        {
            return pLhsBlockInfo->m_pBlock < pRhsBlock;
        }
        bool operator()(const BlockInfo* pLhsBlockInfo, const BlockInfo* pRhsBlockInfo) const
        {
            return pLhsBlockInfo->m_pBlock < pRhsBlockInfo->m_pBlock;
        }
    };

    // 1. Blocks with some non-movable allocations go first.
    // 2. Blocks with smaller sumFreeSize go first.
    struct BlockInfoCompareMoveDestination
    {
        bool operator()(const BlockInfo* pLhsBlockInfo, const BlockInfo* pRhsBlockInfo) const
        {
            if(pLhsBlockInfo->m_HasNonMovableAllocations && !pRhsBlockInfo->m_HasNonMovableAllocations)
                return true;
            if(!pLhsBlockInfo->m_HasNonMovableAllocations && pRhsBlockInfo->m_HasNonMovableAllocations)
                return false;
            if(pLhsBlockInfo->m_pBlock->m_SumFreeSize < pRhsBlockInfo->m_pBlock->m_SumFreeSize)
                return true;
            return false;
        }
    };

    typedef VmaVector< BlockInfo*, VmaStlAllocator<BlockInfo*> > BlockInfoVector;
    BlockInfoVector m_Blocks;

    VkResult DefragmentRound(
        VkDeviceSize maxBytesToMove,
        uint32_t maxAllocationsToMove);

    static bool MoveMakesSense(
        size_t dstBlockIndex, VkDeviceSize dstOffset,
        size_t srcBlockIndex, VkDeviceSize srcOffset);

public:
    VmaDefragmentator(
        VkDevice hDevice,
        const VkAllocationCallbacks* pAllocationCallbacks,
        VkDeviceSize bufferImageGranularity,
        uint32_t memTypeIndex,
        VMA_BLOCK_VECTOR_TYPE blockVectorType);

    ~VmaDefragmentator();

    VkDeviceSize GetBytesMoved() const { return m_BytesMoved; }
    uint32_t GetAllocationsMoved() const { return m_AllocationsMoved; }

    void AddAllocation(VmaAllocation hAlloc, VkBool32* pChanged);

    VkResult Defragment(
        VmaBlockVector* pBlockVector,
        VkDeviceSize maxBytesToMove,
        uint32_t maxAllocationsToMove);
};

VmaDefragmentator::VmaDefragmentator(
    VkDevice hDevice,
    const VkAllocationCallbacks* pAllocationCallbacks,
    VkDeviceSize bufferImageGranularity,
    uint32_t memTypeIndex,
    VMA_BLOCK_VECTOR_TYPE blockVectorType) :
    m_hDevice(hDevice),
    m_pAllocationCallbacks(pAllocationCallbacks),
    m_BufferImageGranularity(bufferImageGranularity),
    m_MemTypeIndex(memTypeIndex),
    m_BlockVectorType(blockVectorType),
    m_BytesMoved(0),
    m_AllocationsMoved(0),
    m_Allocations(VmaStlAllocator<AllocationInfo>(pAllocationCallbacks)),
    m_Blocks(VmaStlAllocator<BlockInfo*>(pAllocationCallbacks))
{
}

VmaDefragmentator::~VmaDefragmentator()
{
    for(size_t i = m_Blocks.size(); i--; )
    {
        vma_delete(m_pAllocationCallbacks, m_Blocks[i]);
    }
}

void VmaDefragmentator::AddAllocation(VmaAllocation hAlloc, VkBool32* pChanged)
{
    AllocationInfo allocInfo;
    allocInfo.m_hAllocation = hAlloc;
    allocInfo.m_pChanged = pChanged;
    m_Allocations.push_back(allocInfo);
}

VkResult VmaDefragmentator::DefragmentRound(
    VkDeviceSize maxBytesToMove,
    uint32_t maxAllocationsToMove)
{
    if(m_Blocks.empty())
    {
        return VK_SUCCESS;
    }

    size_t srcBlockIndex = m_Blocks.size() - 1;
    size_t srcAllocIndex = SIZE_MAX;
    for(;;)
    {
        // 1. Find next allocation to move.
        // 1.1. Start from last to first m_Blocks - they are sorted from most "destination" to most "source".
        // 1.2. Then start from last to first m_Allocations - they are sorted from largest to smallest.
        while(srcAllocIndex >= m_Blocks[srcBlockIndex]->m_Allocations.size())
        {
            if(m_Blocks[srcBlockIndex]->m_Allocations.empty())
            {
                // Finished: no more allocations to process.
                if(srcBlockIndex == 0)
                {
                    return VK_SUCCESS;
                }
                else
                {
                    --srcBlockIndex;
                    srcAllocIndex = SIZE_MAX;
                }
            }
            else
            {
                srcAllocIndex = m_Blocks[srcBlockIndex]->m_Allocations.size() - 1;
            }
        }
        
        BlockInfo* pSrcBlockInfo = m_Blocks[srcBlockIndex];
        AllocationInfo& allocInfo = pSrcBlockInfo->m_Allocations[srcAllocIndex];

        const VkDeviceSize size = allocInfo.m_hAllocation->GetSize();
        const VkDeviceSize srcOffset = allocInfo.m_hAllocation->GetOffset();
        const VkDeviceSize alignment = allocInfo.m_hAllocation->GetAlignment();
        const VmaSuballocationType suballocType = allocInfo.m_hAllocation->GetSuballocationType();

        // 2. Try to find new place for this allocation in preceding or current block.
        for(size_t dstBlockIndex = 0; dstBlockIndex <= srcBlockIndex; ++dstBlockIndex)
        {
            BlockInfo* pDstBlockInfo = m_Blocks[dstBlockIndex];
            VmaAllocationRequest dstAllocRequest;
            if(pDstBlockInfo->m_pBlock->CreateAllocationRequest(
                m_BufferImageGranularity,
                size,
                alignment,
                suballocType,
                &dstAllocRequest) &&
            MoveMakesSense(
                dstBlockIndex, dstAllocRequest.offset, srcBlockIndex, srcOffset))
            {
                // Reached limit on number of allocations or bytes to move.
                if((m_AllocationsMoved + 1 > maxAllocationsToMove) ||
                    (m_BytesMoved + size > maxBytesToMove))
                {
                    return VK_INCOMPLETE;
                }

                void* pDstMappedData = VMA_NULL;
                VkResult res = pDstBlockInfo->EnsureMapping(m_hDevice, &pDstMappedData);
                if(res != VK_SUCCESS)
                {
                    return res;
                }

                void* pSrcMappedData = VMA_NULL;
                res = pSrcBlockInfo->EnsureMapping(m_hDevice, &pSrcMappedData);
                if(res != VK_SUCCESS)
                {
                    return res;
                }
                
                // THE PLACE WHERE ACTUAL DATA COPY HAPPENS.
                memcpy(
                    reinterpret_cast<char*>(pDstMappedData) + dstAllocRequest.offset,
                    reinterpret_cast<char*>(pSrcMappedData) + srcOffset,
                    size);
                
                pDstBlockInfo->m_pBlock->Alloc(dstAllocRequest, suballocType, size);
                pSrcBlockInfo->m_pBlock->Free(allocInfo.m_hAllocation);
                
                allocInfo.m_hAllocation->ChangeBlockAllocation(pDstBlockInfo->m_pBlock, dstAllocRequest.offset);
                
                if(allocInfo.m_pChanged != VMA_NULL)
                {
                    *allocInfo.m_pChanged = VK_TRUE;
                }

                ++m_AllocationsMoved;
                m_BytesMoved += size;

                VectorRemove(pSrcBlockInfo->m_Allocations, srcAllocIndex);

                break;
            }
        }

        // If not processed, this allocInfo remains in pBlockInfo->m_Allocations for next round.

        if(srcAllocIndex > 0)
        {
            --srcAllocIndex;
        }
        else
        {
            if(srcBlockIndex > 0)
            {
                --srcBlockIndex;
                srcAllocIndex = SIZE_MAX;
            }
            else
            {
                return VK_SUCCESS;
            }
        }
    }
}

VkResult VmaDefragmentator::Defragment(
    VmaBlockVector* pBlockVector,
    VkDeviceSize maxBytesToMove,
    uint32_t maxAllocationsToMove)
{
    if(m_Allocations.empty())
    {
        return VK_SUCCESS;
    }

    // Create block info for each block.
    const size_t blockCount = pBlockVector->m_Blocks.size();
    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        BlockInfo* pBlockInfo = vma_new(m_pAllocationCallbacks, BlockInfo)(m_pAllocationCallbacks);
        pBlockInfo->m_pBlock = pBlockVector->m_Blocks[blockIndex];
        m_Blocks.push_back(pBlockInfo);
    }

    // Sort them by m_pBlock pointer value.
    VMA_SORT(m_Blocks.begin(), m_Blocks.end(), BlockPointerLess());

    // Move allocation infos from m_Allocations to appropriate m_Blocks[i].m_Allocations.
    for(size_t allocIndex = 0, allocCount = m_Allocations.size(); allocIndex < allocCount; ++allocIndex)
    {
        AllocationInfo& allocInfo = m_Allocations[allocIndex];
        VmaBlock* pBlock = allocInfo.m_hAllocation->GetBlock();
        BlockInfoVector::iterator it = VmaBinaryFindFirstNotLess(m_Blocks.begin(), m_Blocks.end(), pBlock, BlockPointerLess());
        if(it != m_Blocks.end() && (*it)->m_pBlock == pBlock)
        {
            (*it)->m_Allocations.push_back(allocInfo);
        }
        else
        {
            VMA_ASSERT(0);
        }
    }
    m_Allocations.clear();

    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        BlockInfo* pBlockInfo = m_Blocks[blockIndex];
        pBlockInfo->CalcHasNonMovableAllocations();
        pBlockInfo->SortAllocationsBySizeDescecnding();
    }

    // Sort m_Blocks this time by the main criterium, from most "destination" to most "source" blocks.
    VMA_SORT(m_Blocks.begin(), m_Blocks.end(), BlockInfoCompareMoveDestination());

    // Execute defragmentation round (the main part).
    VkResult result = VK_SUCCESS;
    for(size_t round = 0; (round < 2) && (result == VK_SUCCESS); ++round)
    {
        result = DefragmentRound(maxBytesToMove, maxAllocationsToMove);
    }

    // Unmap blocks that were mapped for defragmentation.
    for(size_t blockIndex = 0; blockIndex < blockCount; ++blockIndex)
    {
        m_Blocks[blockIndex]->Unmap(m_hDevice);
    }

    return result;
}

bool VmaDefragmentator::MoveMakesSense(
        size_t dstBlockIndex, VkDeviceSize dstOffset,
        size_t srcBlockIndex, VkDeviceSize srcOffset)
{
    if(dstBlockIndex < srcBlockIndex)
    {
        return true;
    }
    if(dstBlockIndex > srcBlockIndex)
    {
        return false;
    }
    if(dstOffset < srcOffset)
    {
        return true;
    }
    return false;
}

////////////////////////////////////////////////////////////////////////////////
// VmaAllocator_T

VmaAllocator_T::VmaAllocator_T(const VmaAllocatorCreateInfo* pCreateInfo) :
    m_PhysicalDevice(pCreateInfo->physicalDevice),
    m_hDevice(pCreateInfo->device),
    m_AllocationCallbacksSpecified(pCreateInfo->pAllocationCallbacks != VMA_NULL),
    m_AllocationCallbacks(pCreateInfo->pAllocationCallbacks ?
        *pCreateInfo->pAllocationCallbacks : VmaEmptyAllocationCallbacks),
    m_PreferredLargeHeapBlockSize(0),
    m_PreferredSmallHeapBlockSize(0),
    m_UnmapPersistentlyMappedMemoryCounter(0)
{
    VMA_ASSERT(pCreateInfo->physicalDevice && pCreateInfo->device);    

    memset(&m_DeviceMemoryCallbacks, 0 ,sizeof(m_DeviceMemoryCallbacks));
    memset(&m_MemProps, 0, sizeof(m_MemProps));
    memset(&m_PhysicalDeviceProperties, 0, sizeof(m_PhysicalDeviceProperties));
        
    memset(&m_pBlockVectors, 0, sizeof(m_pBlockVectors));
    memset(&m_HasEmptyBlock, 0, sizeof(m_HasEmptyBlock));
    memset(&m_pOwnAllocations, 0, sizeof(m_pOwnAllocations));

    if(pCreateInfo->pDeviceMemoryCallbacks != VMA_NULL)
    {
        m_DeviceMemoryCallbacks.pfnAllocate = pCreateInfo->pDeviceMemoryCallbacks->pfnAllocate;
        m_DeviceMemoryCallbacks.pfnFree = pCreateInfo->pDeviceMemoryCallbacks->pfnFree;
    }

    m_PreferredLargeHeapBlockSize = (pCreateInfo->preferredLargeHeapBlockSize != 0) ?
        pCreateInfo->preferredLargeHeapBlockSize : static_cast<VkDeviceSize>(VMA_DEFAULT_LARGE_HEAP_BLOCK_SIZE);
    m_PreferredSmallHeapBlockSize = (pCreateInfo->preferredSmallHeapBlockSize != 0) ?
        pCreateInfo->preferredSmallHeapBlockSize : static_cast<VkDeviceSize>(VMA_DEFAULT_SMALL_HEAP_BLOCK_SIZE);

    vkGetPhysicalDeviceProperties(m_PhysicalDevice, &m_PhysicalDeviceProperties);
    vkGetPhysicalDeviceMemoryProperties(m_PhysicalDevice, &m_MemProps);

    for(size_t i = 0; i < GetMemoryTypeCount(); ++i)
    {
        for(size_t j = 0; j < VMA_BLOCK_VECTOR_TYPE_COUNT; ++j)
        {
            m_pBlockVectors[i][j] = vma_new(this, VmaBlockVector)(this);
            m_pOwnAllocations[i][j] = vma_new(this, AllocationVectorType)(VmaStlAllocator<VmaAllocation>(GetAllocationCallbacks()));
        }
    }
}

VmaAllocator_T::~VmaAllocator_T()
{
    for(uint32_t typeIndex = 0; typeIndex < GetMemoryTypeCount(); ++typeIndex)
    {
        for(size_t blockVectorType = VMA_BLOCK_VECTOR_TYPE_COUNT; blockVectorType--; )
        {
            AllocationVectorType* pOwnAllocations = m_pOwnAllocations[typeIndex][blockVectorType];
            VMA_ASSERT(pOwnAllocations != VMA_NULL && pOwnAllocations->size() == 0);
        }
    }

    for(size_t i = GetMemoryTypeCount(); i--; )
    {
        for(size_t j = VMA_BLOCK_VECTOR_TYPE_COUNT; j--; )
        {
            vma_delete(this, m_pOwnAllocations[i][j]);
            vma_delete(this, m_pBlockVectors[i][j]);
        }
    }
}

VkDeviceSize VmaAllocator_T::GetPreferredBlockSize(uint32_t memTypeIndex) const
{
    VkDeviceSize heapSize = m_MemProps.memoryHeaps[m_MemProps.memoryTypes[memTypeIndex].heapIndex].size;
    return (heapSize <= VMA_SMALL_HEAP_MAX_SIZE) ?
        m_PreferredSmallHeapBlockSize : m_PreferredLargeHeapBlockSize;
}

VkResult VmaAllocator_T::AllocateMemoryOfType(
    const VkMemoryRequirements& vkMemReq,
    const VmaMemoryRequirements& vmaMemReq,
    uint32_t memTypeIndex,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(pAllocation != VMA_NULL);
    VMA_DEBUG_LOG("  AllocateMemory: MemoryTypeIndex=%u, Size=%llu", memTypeIndex, vkMemReq.size);

    const VkDeviceSize preferredBlockSize = GetPreferredBlockSize(memTypeIndex);
    // Heuristics: Allocate own memory if requested size if greater than half of preferred block size.
    const bool ownMemory =
        (vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT) != 0 ||
        VMA_DEBUG_ALWAYS_OWN_MEMORY ||
        ((vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT) == 0 &&
            vkMemReq.size > preferredBlockSize / 2);

    if(ownMemory)
    {
        if((vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT) != 0)
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        else
        {
            return AllocateOwnMemory(
                vkMemReq.size,
                suballocType,
                memTypeIndex,
                (vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT) != 0,
                vmaMemReq.pUserData,
                pAllocation);
        }
    }
    else
    {
        uint32_t blockVectorType = VmaMemoryRequirementFlagsToBlockVectorType(vmaMemReq.flags);

        VmaMutexLock lock(m_BlocksMutex[memTypeIndex]);
        VmaBlockVector* const blockVector = m_pBlockVectors[memTypeIndex][blockVectorType];
        VMA_ASSERT(blockVector);

        // 1. Search existing allocations.
        // Forward order - prefer blocks with smallest amount of free space.
        for(size_t allocIndex = 0; allocIndex < blockVector->m_Blocks.size(); ++allocIndex )
        {
            VmaBlock* const pBlock = blockVector->m_Blocks[allocIndex];
            VMA_ASSERT(pBlock);
            VmaAllocationRequest allocRequest = {};
            // Check if can allocate from pBlock.
            if(pBlock->CreateAllocationRequest(
                GetBufferImageGranularity(),
                vkMemReq.size,
                vkMemReq.alignment,
                suballocType,
                &allocRequest))
            {
                // We no longer have an empty Allocation.
                if(pBlock->IsEmpty())
                    m_HasEmptyBlock[memTypeIndex] = false;
                // Allocate from this pBlock.
                pBlock->Alloc(allocRequest, suballocType, vkMemReq.size);
                *pAllocation = vma_new(this, VmaAllocation_T)();
                (*pAllocation)->InitBlockAllocation(
                    pBlock,
                    allocRequest.offset,
                    vkMemReq.alignment,
                    vkMemReq.size,
                    suballocType,
                    vmaMemReq.pUserData);
                VMA_HEAVY_ASSERT(pBlock->Validate());
                VMA_DEBUG_LOG("    Returned from existing allocation #%u", (uint32_t)allocIndex);
                return VK_SUCCESS;
            }
        }

        // 2. Create new Allocation.
        if((vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT) != 0)
        {
            VMA_DEBUG_LOG("    FAILED due to VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT");
            return VK_ERROR_OUT_OF_DEVICE_MEMORY;
        }
        else
        {
            // Start with full preferredBlockSize.
            VkMemoryAllocateInfo allocInfo = { VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
            allocInfo.memoryTypeIndex = memTypeIndex;
            allocInfo.allocationSize = preferredBlockSize;
            VkDeviceMemory mem = VK_NULL_HANDLE;
            VkResult res = vkAllocateMemory(m_hDevice, &allocInfo, GetAllocationCallbacks(), &mem);
            if(res < 0)
            {
                // 3. Try half the size.
                allocInfo.allocationSize /= 2;
                if(allocInfo.allocationSize >= vkMemReq.size)
                {
                    res = vkAllocateMemory(m_hDevice, &allocInfo, GetAllocationCallbacks(), &mem);
                    if(res < 0)
                    {
                        // 4. Try quarter the size.
                        allocInfo.allocationSize /= 2;
                        if(allocInfo.allocationSize >= vkMemReq.size)
                        {
                            res = vkAllocateMemory(m_hDevice, &allocInfo, GetAllocationCallbacks(), &mem);
                        }
                    }
                }
            }
            if(res < 0)
            {
                // 5. Try OwnAlloc.
                res = AllocateOwnMemory(
                    vkMemReq.size,
                    suballocType,
                    memTypeIndex,
                    (vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT) != 0,
                    vmaMemReq.pUserData,
                    pAllocation);
                if(res == VK_SUCCESS)
                {
                    // Succeeded: AllocateOwnMemory function already filld pMemory, nothing more to do here.
                    VMA_DEBUG_LOG("    Allocated as OwnMemory");
                    return VK_SUCCESS;
                }
                else
                {
                    // Everything failed: Return error code.
                    VMA_DEBUG_LOG("    vkAllocateMemory FAILED");
                    return res;
                }
            }

            // New VkDeviceMemory successfully created.

            // Map memory if needed.
            void* pMappedData = VMA_NULL;
            const bool persistentMap = (vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT) != 0;
            if(persistentMap && m_UnmapPersistentlyMappedMemoryCounter == 0)
            {
                res = vkMapMemory(m_hDevice, mem, 0, VK_WHOLE_SIZE, 0, &pMappedData);
                if(res < 0)
                {
                    VMA_DEBUG_LOG("    vkMapMemory FAILED");
                    vkFreeMemory(m_hDevice, mem, GetAllocationCallbacks());
                    return res;
                }
            }

            // Callback.
            if(m_DeviceMemoryCallbacks.pfnAllocate != VMA_NULL)
            {
                (*m_DeviceMemoryCallbacks.pfnAllocate)(this, memTypeIndex, mem, allocInfo.allocationSize);
            }

            // Create new Allocation for it.
            VmaBlock* const pBlock = vma_new(this, VmaBlock)(this);
            pBlock->Init(
                memTypeIndex,
                (VMA_BLOCK_VECTOR_TYPE)blockVectorType,
                mem,
                allocInfo.allocationSize,
                persistentMap,
                pMappedData);

            blockVector->m_Blocks.push_back(pBlock);

            // Allocate from pBlock. Because it is empty, dstAllocRequest can be trivially filled.
            VmaAllocationRequest allocRequest = {};
            allocRequest.freeSuballocationItem = pBlock->m_Suballocations.begin();
            allocRequest.offset = 0;
            pBlock->Alloc(allocRequest, suballocType, vkMemReq.size);
            *pAllocation = vma_new(this, VmaAllocation_T)();
            (*pAllocation)->InitBlockAllocation(
                pBlock,
                allocRequest.offset,
                vkMemReq.alignment,
                vkMemReq.size,
                suballocType,
                vmaMemReq.pUserData);
            VMA_HEAVY_ASSERT(pBlock->Validate());
            VMA_DEBUG_LOG("    Created new allocation Size=%llu", allocInfo.allocationSize);
            return VK_SUCCESS;
        }
    }
}

VkResult VmaAllocator_T::AllocateOwnMemory(
    VkDeviceSize size,
    VmaSuballocationType suballocType,
    uint32_t memTypeIndex,
    bool map,
    void* pUserData,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(pAllocation);

    VkMemoryAllocateInfo allocInfo = { VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO };
    allocInfo.memoryTypeIndex = memTypeIndex;
    allocInfo.allocationSize = size;

    // Allocate VkDeviceMemory.
    VkDeviceMemory hMemory = VK_NULL_HANDLE;
    VkResult res = vkAllocateMemory(m_hDevice, &allocInfo, GetAllocationCallbacks(), &hMemory);
    if(res < 0)
    {
        VMA_DEBUG_LOG("    vkAllocateMemory FAILED");
        return res;
    }

    void* pMappedData = nullptr;
    if(map)
    {
        if(m_UnmapPersistentlyMappedMemoryCounter == 0)
        {
            res = vkMapMemory(m_hDevice, hMemory, 0, VK_WHOLE_SIZE, 0, &pMappedData);
            if(res < 0)
            {
                VMA_DEBUG_LOG("    vkMapMemory FAILED");
                vkFreeMemory(m_hDevice, hMemory, GetAllocationCallbacks());
                return res;
            }
        }
    }

    // Callback.
    if(m_DeviceMemoryCallbacks.pfnAllocate != VMA_NULL)
    {
        (*m_DeviceMemoryCallbacks.pfnAllocate)(this, memTypeIndex, hMemory, size);
    }

    *pAllocation = vma_new(this, VmaAllocation_T)();
    (*pAllocation)->InitOwnAllocation(memTypeIndex, hMemory, suballocType, map, pMappedData, size, pUserData);

    // Register it in m_pOwnAllocations.
    {
        VmaMutexLock lock(m_OwnAllocationsMutex[memTypeIndex]);
        AllocationVectorType* pOwnAllocations = m_pOwnAllocations[memTypeIndex][map ? VMA_BLOCK_VECTOR_TYPE_MAPPED : VMA_BLOCK_VECTOR_TYPE_UNMAPPED];
        VMA_ASSERT(pOwnAllocations);
        VmaAllocation* const pOwnAllocationsBeg = pOwnAllocations->data();
        VmaAllocation* const pOwnAllocationsEnd = pOwnAllocationsBeg + pOwnAllocations->size();
        const size_t indexToInsert = VmaBinaryFindFirstNotLess(
            pOwnAllocationsBeg,
            pOwnAllocationsEnd,
            *pAllocation,
            VmaPointerLess()) - pOwnAllocationsBeg;
        VectorInsert(*pOwnAllocations, indexToInsert, *pAllocation);
    }

    VMA_DEBUG_LOG("    Allocated OwnMemory MemoryTypeIndex=#%u", memTypeIndex);

    return VK_SUCCESS;
}

VkResult VmaAllocator_T::AllocateMemory(
    const VkMemoryRequirements& vkMemReq,
    const VmaMemoryRequirements& vmaMemReq,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    if((vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT) != 0 &&
        (vmaMemReq.flags & VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT) != 0)
    {
        VMA_ASSERT(0 && "Specifying VMA_MEMORY_REQUIREMENT_OWN_MEMORY_BIT together with VMA_MEMORY_REQUIREMENT_NEVER_ALLOCATE_BIT makes no sense.");
        return VK_ERROR_OUT_OF_DEVICE_MEMORY;
    }

    // Bit mask of memory Vulkan types acceptable for this allocation.
    uint32_t memoryTypeBits = vkMemReq.memoryTypeBits;
    uint32_t memTypeIndex = UINT32_MAX;
    VkResult res = vmaFindMemoryTypeIndex(this, memoryTypeBits, &vmaMemReq, &memTypeIndex);
    if(res == VK_SUCCESS)
    {
        res = AllocateMemoryOfType(vkMemReq, vmaMemReq, memTypeIndex, suballocType, pAllocation);
        // Succeeded on first try.
        if(res == VK_SUCCESS)
        {
            return res;
        }
        // Allocation from this memory type failed. Try other compatible memory types.
        else
        {
            for(;;)
            {
                // Remove old memTypeIndex from list of possibilities.
                memoryTypeBits &= ~(1u << memTypeIndex);
                // Find alternative memTypeIndex.
                res = vmaFindMemoryTypeIndex(this, memoryTypeBits, &vmaMemReq, &memTypeIndex);
                if(res == VK_SUCCESS)
                {
                    res = AllocateMemoryOfType(vkMemReq, vmaMemReq, memTypeIndex, suballocType, pAllocation);
                    // Allocation from this alternative memory type succeeded.
                    if(res == VK_SUCCESS)
                    {
                        return res;
                    }
                    // else: Allocation from this memory type failed. Try next one - next loop iteration.
                }
                // No other matching memory type index could be found.
                else
                    // Not returning res, which is VK_ERROR_FEATURE_NOT_PRESENT, because we already failed to allocate once.
                    return VK_ERROR_OUT_OF_DEVICE_MEMORY;
            }
        }
    }
    // Can't find any single memory type maching requirements. res is VK_ERROR_FEATURE_NOT_PRESENT.
    else
        return res;
}

void VmaAllocator_T::FreeMemory(const VmaAllocation allocation)
{
    VMA_ASSERT(allocation);

    if(allocation->GetType() == VmaAllocation_T::ALLOCATION_TYPE_BLOCK)
    {
        VmaBlock* pBlockToDelete = VMA_NULL;

        const uint32_t memTypeIndex = allocation->GetMemoryTypeIndex();
        const VMA_BLOCK_VECTOR_TYPE blockVectorType = allocation->GetBlockVectorType();
        {
            VmaMutexLock lock(m_BlocksMutex[memTypeIndex]);

            VmaBlockVector* pBlockVector = m_pBlockVectors[memTypeIndex][blockVectorType];
            VmaBlock* pBlock = allocation->GetBlock();

            pBlock->Free(allocation);
            VMA_HEAVY_ASSERT(pBlock->Validate());

            VMA_DEBUG_LOG("  Freed from MemoryTypeIndex=%u", memTypeIndex);

            // pBlock became empty after this deallocation.
            if(pBlock->IsEmpty())
            {
                // Already has empty Allocation. We don't want to have two, so delete this one.
                if(m_HasEmptyBlock[memTypeIndex])
                {
                    pBlockToDelete = pBlock;
                    pBlockVector->Remove(pBlock);
                }
                // We now have first empty Allocation.
                else
                    m_HasEmptyBlock[memTypeIndex] = true;
            }
            // Must be called after srcBlockIndex is used, because later it may become invalid!
            pBlockVector->IncrementallySortBlocks();
        }
        // Destruction of a free Allocation. Deferred until this point, outside of mutex
        // lock, for performance reason.
        if(pBlockToDelete != VMA_NULL)
        {
            VMA_DEBUG_LOG("    Deleted empty allocation");
            pBlockToDelete->Destroy(this);
            vma_delete(this, pBlockToDelete);
        }

        vma_delete(this, allocation);
    }
    else // VmaAllocation_T::ALLOCATION_TYPE_OWN
    {
        FreeOwnMemory(allocation);
    }
}

void VmaAllocator_T::CalculateStats(VmaStats* pStats)
{
    InitStatInfo(pStats->total);
    for(size_t i = 0; i < VK_MAX_MEMORY_TYPES; ++i)
        InitStatInfo(pStats->memoryType[i]);
    for(size_t i = 0; i < VK_MAX_MEMORY_HEAPS; ++i)
        InitStatInfo(pStats->memoryHeap[i]);
    
    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        VmaMutexLock allocationsLock(m_BlocksMutex[memTypeIndex]);
        const uint32_t heapIndex = m_MemProps.memoryTypes[memTypeIndex].heapIndex;
        for(uint32_t blockVectorType = 0; blockVectorType < VMA_BLOCK_VECTOR_TYPE_COUNT; ++blockVectorType)
        {
            const VmaBlockVector* const pBlockVector = m_pBlockVectors[memTypeIndex][blockVectorType];
            VMA_ASSERT(pBlockVector);
            pBlockVector->AddStats(pStats, memTypeIndex, heapIndex);
        }
    }

    VmaPostprocessCalcStatInfo(pStats->total);
    for(size_t i = 0; i < GetMemoryTypeCount(); ++i)
        VmaPostprocessCalcStatInfo(pStats->memoryType[i]);
    for(size_t i = 0; i < GetMemoryHeapCount(); ++i)
        VmaPostprocessCalcStatInfo(pStats->memoryHeap[i]);
}

static const uint32_t VMA_VENDOR_ID_AMD = 4098;

void VmaAllocator_T::UnmapPersistentlyMappedMemory()
{
    if(m_UnmapPersistentlyMappedMemoryCounter++ == 0)
    {
        if(m_PhysicalDeviceProperties.vendorID == VMA_VENDOR_ID_AMD)
        {
            for(size_t memTypeIndex = m_MemProps.memoryTypeCount; memTypeIndex--; )
            {
                const VkMemoryPropertyFlags memFlags = m_MemProps.memoryTypes[memTypeIndex].propertyFlags;
                if((memFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0 &&
                    (memFlags & VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT) != 0)
                {
                    // Process OwnAllocations.
                    {
                        VmaMutexLock lock(m_OwnAllocationsMutex[memTypeIndex]);
                        AllocationVectorType* pOwnAllocationsVector = m_pOwnAllocations[memTypeIndex][VMA_BLOCK_VECTOR_TYPE_MAPPED];
                        for(size_t ownAllocIndex = pOwnAllocationsVector->size(); ownAllocIndex--; )
                        {
                            VmaAllocation hAlloc = (*pOwnAllocationsVector)[ownAllocIndex];
                            hAlloc->OwnAllocUnmapPersistentlyMappedMemory(m_hDevice);
                        }
                    }

                    // Process normal Allocations.
                    {
                        VmaMutexLock lock(m_BlocksMutex[memTypeIndex]);
                        VmaBlockVector* pBlockVector = m_pBlockVectors[memTypeIndex][VMA_BLOCK_VECTOR_TYPE_MAPPED];
                        pBlockVector->UnmapPersistentlyMappedMemory();
                    }
                }
            }
        }
    }
}

VkResult VmaAllocator_T::MapPersistentlyMappedMemory()
{
    VMA_ASSERT(m_UnmapPersistentlyMappedMemoryCounter > 0);
    if(--m_UnmapPersistentlyMappedMemoryCounter == 0)
    {
        VkResult finalResult = VK_SUCCESS;
        if(m_PhysicalDeviceProperties.vendorID == VMA_VENDOR_ID_AMD)
        {
            for(size_t memTypeIndex = 0; memTypeIndex < m_MemProps.memoryTypeCount; ++memTypeIndex)
            {
                const VkMemoryPropertyFlags memFlags = m_MemProps.memoryTypes[memTypeIndex].propertyFlags;
                if((memFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0 &&
                    (memFlags & VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT) != 0)
                {
                    // Process OwnAllocations.
                    {
                        VmaMutexLock lock(m_OwnAllocationsMutex[memTypeIndex]);
                        AllocationVectorType* pAllocationsVector = m_pOwnAllocations[memTypeIndex][VMA_BLOCK_VECTOR_TYPE_MAPPED];
                        for(size_t ownAllocIndex = 0, ownAllocCount = pAllocationsVector->size(); ownAllocIndex < ownAllocCount; ++ownAllocIndex)
                        {
                            VmaAllocation hAlloc = (*pAllocationsVector)[ownAllocIndex];
                            hAlloc->OwnAllocMapPersistentlyMappedMemory(m_hDevice);
                        }
                    }

                    // Process normal Allocations.
                    {
                        VmaMutexLock lock(m_BlocksMutex[memTypeIndex]);
                        VmaBlockVector* pBlockVector = m_pBlockVectors[memTypeIndex][VMA_BLOCK_VECTOR_TYPE_MAPPED];
                        VkResult localResult = pBlockVector->MapPersistentlyMappedMemory();
                        if(localResult != VK_SUCCESS)
                        {
                            finalResult = localResult;
                        }
                    }
                }
            }
        }
        return finalResult;
    }
    else
        return VK_SUCCESS;
}

VkResult VmaAllocator_T::Defragment(
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo* pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats)
{
    if(pAllocationsChanged != VMA_NULL)
    {
        memset(pAllocationsChanged, 0, sizeof(*pAllocationsChanged));
    }
    if(pDefragmentationStats != VMA_NULL)
    {
        memset(pDefragmentationStats, 0, sizeof(*pDefragmentationStats));
    }

    if(m_UnmapPersistentlyMappedMemoryCounter > 0)
    {
        VMA_DEBUG_LOG("ERROR: Cannot defragment when inside vmaUnmapPersistentlyMappedMemory.");
        return VK_ERROR_MEMORY_MAP_FAILED;
    }

    // Initialize defragmentators per memory type.
    const VkDeviceSize bufferImageGranularity = GetBufferImageGranularity();
    VmaDefragmentator* pDefragmentators[VK_MAX_MEMORY_TYPES][VMA_BLOCK_VECTOR_TYPE_COUNT];
    memset(pDefragmentators, 0, sizeof(pDefragmentators));
    for(uint32_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        // Only HOST_VISIBLE memory types can be defragmented.
        if((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
        {
            for(uint32_t blockVectorType = 0; blockVectorType < VMA_BLOCK_VECTOR_TYPE_COUNT; ++blockVectorType)
            {
                pDefragmentators[memTypeIndex][blockVectorType] = vma_new(this, VmaDefragmentator)(
                    m_hDevice,
                    GetAllocationCallbacks(),
                    bufferImageGranularity,
                    memTypeIndex,
                    (VMA_BLOCK_VECTOR_TYPE)blockVectorType);
            }
        }
    }

    // Dispatch pAllocations among defragmentators.
    for(size_t allocIndex = 0; allocIndex < allocationCount; ++allocIndex)
    {
        VmaAllocation hAlloc = pAllocations[allocIndex];
        VMA_ASSERT(hAlloc);
        if(hAlloc->GetType() == VmaAllocation_T::ALLOCATION_TYPE_BLOCK)
        {
            const uint32_t memTypeIndex = hAlloc->GetMemoryTypeIndex();
            // Only HOST_VISIBLE memory types can be defragmented.
            if((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
            {
                const VMA_BLOCK_VECTOR_TYPE blockVectorType = hAlloc->GetBlockVectorType();
                VkBool32* pChanged = (pAllocationsChanged != VMA_NULL) ?
                    &pAllocationsChanged[allocIndex] : VMA_NULL;
                pDefragmentators[memTypeIndex][blockVectorType]->AddAllocation(hAlloc, pChanged);
            }
            // else: skip this allocation, cannot move it.
        }
        // else ALLOCATION_TYPE_OWN: skip this allocation, nothing to defragment.
    }

    VkResult result = VK_SUCCESS;

    // Main processing.
    VkDeviceSize maxBytesToMove = SIZE_MAX;
    uint32_t maxAllocationsToMove = UINT32_MAX;
    if(pDefragmentationInfo != VMA_NULL)
    {
        maxBytesToMove = pDefragmentationInfo->maxBytesToMove;
        maxAllocationsToMove = pDefragmentationInfo->maxAllocationsToMove;
    }
    for(uint32_t memTypeIndex = 0;
        (memTypeIndex < GetMemoryTypeCount()) && (result == VK_SUCCESS);
        ++memTypeIndex)
    {
        // Only HOST_VISIBLE memory types can be defragmented.
        if((m_MemProps.memoryTypes[memTypeIndex].propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
        {
            VmaMutexLock lock(m_BlocksMutex[memTypeIndex]);

            for(uint32_t blockVectorType = 0;
                (blockVectorType < VMA_BLOCK_VECTOR_TYPE_COUNT) && (result == VK_SUCCESS);
                ++blockVectorType)
            {
                VmaBlockVector* pBlockVector = m_pBlockVectors[memTypeIndex][blockVectorType];

                // Defragment.
                result = pDefragmentators[memTypeIndex][blockVectorType]->Defragment(pBlockVector, maxBytesToMove, maxAllocationsToMove);

                // Accumulate statistics.
                if(pDefragmentationStats != VMA_NULL)
                {
                    const VkDeviceSize bytesMoved = pDefragmentators[memTypeIndex][blockVectorType]->GetBytesMoved();
                    const uint32_t allocationsMoved = pDefragmentators[memTypeIndex][blockVectorType]->GetAllocationsMoved();
                    pDefragmentationStats->bytesMoved += bytesMoved;
                    pDefragmentationStats->allocationsMoved += allocationsMoved;
                    VMA_ASSERT(bytesMoved <= maxBytesToMove);
                    VMA_ASSERT(allocationsMoved <= maxAllocationsToMove);
                    maxBytesToMove -= bytesMoved;
                    maxAllocationsToMove -= allocationsMoved;
                }

                // Free empty blocks.
                for(size_t blockIndex = pBlockVector->m_Blocks.size(); blockIndex--; )
                {
                    VmaBlock* pBlock = pBlockVector->m_Blocks[blockIndex];
                    if(pBlock->IsEmpty())
                    {
                        if(pDefragmentationStats != VMA_NULL)
                        {
                            ++pDefragmentationStats->deviceMemoryBlocksFreed;
                            pDefragmentationStats->bytesFreed += pBlock->m_Size;
                        }

                        VectorRemove(pBlockVector->m_Blocks, blockIndex);
                        pBlock->Destroy(this);
                        vma_delete(this, pBlock);
                    }
                }

                // All block vector types processed: we can be sure that all empty allocations have been freed.
                if(blockVectorType == VMA_BLOCK_VECTOR_TYPE_COUNT - 1)
                {
                    m_HasEmptyBlock[memTypeIndex] = false;
                }
            }
        }
    }

    // Destroy defragmentators.
    for(uint32_t memTypeIndex = GetMemoryTypeCount(); memTypeIndex--; )
    {
        for(size_t blockVectorType = VMA_BLOCK_VECTOR_TYPE_COUNT; blockVectorType--; )
        {
            vma_delete(this, pDefragmentators[memTypeIndex][blockVectorType]);
        }
    }

    return result;
}

void VmaAllocator_T::GetAllocationInfo(VmaAllocation hAllocation, VmaAllocationInfo* pAllocationInfo)
{
    pAllocationInfo->memoryType = hAllocation->GetMemoryTypeIndex();
    pAllocationInfo->deviceMemory = hAllocation->GetMemory();
    pAllocationInfo->offset = hAllocation->GetOffset();
    pAllocationInfo->size = hAllocation->GetSize();
    pAllocationInfo->pMappedData = hAllocation->GetMappedData();
    pAllocationInfo->pUserData = hAllocation->GetUserData();
}

void VmaAllocator_T::FreeOwnMemory(VmaAllocation allocation)
{
    VMA_ASSERT(allocation && allocation->GetType() == VmaAllocation_T::ALLOCATION_TYPE_OWN);

    const uint32_t memTypeIndex = allocation->GetMemoryTypeIndex();
    {
        VmaMutexLock lock(m_OwnAllocationsMutex[memTypeIndex]);
        AllocationVectorType* const pOwnAllocations = m_pOwnAllocations[memTypeIndex][allocation->GetBlockVectorType()];
        VMA_ASSERT(pOwnAllocations);
        VmaAllocation* const pOwnAllocationsBeg = pOwnAllocations->data();
        VmaAllocation* const pOwnAllocationsEnd = pOwnAllocationsBeg + pOwnAllocations->size();
        VmaAllocation* const pOwnAllocationIt = VmaBinaryFindFirstNotLess(
            pOwnAllocationsBeg,
            pOwnAllocationsEnd,
            allocation,
            VmaPointerLess());
        if(pOwnAllocationIt != pOwnAllocationsEnd)
        {
            const size_t ownAllocationIndex = pOwnAllocationIt - pOwnAllocationsBeg;
            VectorRemove(*pOwnAllocations, ownAllocationIndex);
        }
        else
        {
            VMA_ASSERT(0);
        }
    }

    VkDeviceMemory hMemory = allocation->GetMemory();
    
    // Callback.
    if(m_DeviceMemoryCallbacks.pfnFree != VMA_NULL)
    {
        (*m_DeviceMemoryCallbacks.pfnFree)(this, memTypeIndex, hMemory, allocation->GetSize());
    }

    if(allocation->GetMappedData() != VMA_NULL)
    {
        vkUnmapMemory(m_hDevice, hMemory);
    }
    
    vkFreeMemory(m_hDevice, hMemory, GetAllocationCallbacks());

    VMA_DEBUG_LOG("    Freed OwnMemory MemoryTypeIndex=%u", memTypeIndex);

    vma_delete(this, allocation);
}

#if VMA_STATS_STRING_ENABLED

void VmaAllocator_T::PrintDetailedMap(VmaStringBuilder& sb)
{
    bool ownAllocationsStarted = false;
    for(size_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
    {
        VmaMutexLock ownAllocationsLock(m_OwnAllocationsMutex[memTypeIndex]);
        for(uint32_t blockVectorType = 0; blockVectorType < VMA_BLOCK_VECTOR_TYPE_COUNT; ++blockVectorType)
        {
            AllocationVectorType* const pOwnAllocVector = m_pOwnAllocations[memTypeIndex][blockVectorType];
            VMA_ASSERT(pOwnAllocVector);
            if(pOwnAllocVector->empty() == false)
            {
                if(ownAllocationsStarted)
                    sb.Add(",\n\t\"Type ");
                else
                {
                    sb.Add(",\n\"OwnAllocations\": {\n\t\"Type ");
                    ownAllocationsStarted = true;
                }
                sb.AddNumber(memTypeIndex);
                if(blockVectorType == VMA_BLOCK_VECTOR_TYPE_MAPPED)
                {
                    sb.Add(" Mapped");
                }
                sb.Add("\": [");

                for(size_t i = 0; i < pOwnAllocVector->size(); ++i)
                {
                    const VmaAllocation hAlloc = (*pOwnAllocVector)[i];
                    if(i > 0)
                        sb.Add(",\n\t\t{ \"Size\": ");
                    else
                        sb.Add("\n\t\t{ \"Size\": ");
                    sb.AddNumber(hAlloc->GetSize());
                    sb.Add(", \"Type\": ");
                    sb.AddString(VMA_SUBALLOCATION_TYPE_NAMES[hAlloc->GetSuballocationType()]);
                    sb.Add(" }");
                }

                sb.Add("\n\t]");
            }
        }
    }
    if(ownAllocationsStarted)
        sb.Add("\n}");

    {
        bool allocationsStarted = false;
        for(size_t memTypeIndex = 0; memTypeIndex < GetMemoryTypeCount(); ++memTypeIndex)
        {
            VmaMutexLock globalAllocationsLock(m_BlocksMutex[memTypeIndex]);
            for(uint32_t blockVectorType = 0; blockVectorType < VMA_BLOCK_VECTOR_TYPE_COUNT; ++blockVectorType)
            {
                if(m_pBlockVectors[memTypeIndex][blockVectorType]->IsEmpty() == false)
                {
                    if(allocationsStarted)
                        sb.Add(",\n\t\"Type ");
                    else
                    {
                        sb.Add(",\n\"Allocations\": {\n\t\"Type ");
                        allocationsStarted = true;
                    }
                    sb.AddNumber(memTypeIndex);
                    if(blockVectorType == VMA_BLOCK_VECTOR_TYPE_MAPPED)
                    {
                        sb.Add(" Mapped");
                    }
                    sb.Add("\": [");

                    m_pBlockVectors[memTypeIndex][blockVectorType]->PrintDetailedMap(sb);

                    sb.Add("\n\t]");
                }
            }
        }
        if(allocationsStarted)
            sb.Add("\n}");
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

static VkResult AllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaMemoryRequirements* pMemoryRequirements,
    VmaSuballocationType suballocType,
    VmaAllocation* pAllocation)
{
    VMA_ASSERT(allocator && (image != VK_NULL_HANDLE) && pMemoryRequirements && pAllocation);
    
    VkMemoryRequirements vkMemReq = {};
    vkGetImageMemoryRequirements(allocator->m_hDevice, image, &vkMemReq);

    return allocator->AllocateMemory(
        vkMemReq,
        *pMemoryRequirements,
        suballocType,
        pAllocation);
}

////////////////////////////////////////////////////////////////////////////////
// Public interface

VkResult vmaCreateAllocator(
    const VmaAllocatorCreateInfo* pCreateInfo,
    VmaAllocator* pAllocator)
{
    VMA_ASSERT(pCreateInfo && pAllocator);
    VMA_DEBUG_LOG("vmaCreateAllocator");
    *pAllocator = vma_new(pCreateInfo->pAllocationCallbacks, VmaAllocator_T)(pCreateInfo);
    return VK_SUCCESS;
}

void vmaDestroyAllocator(
    VmaAllocator allocator)
{
    if(allocator != VK_NULL_HANDLE)
    {
        VMA_DEBUG_LOG("vmaDestroyAllocator");
        VkAllocationCallbacks allocationCallbacks = allocator->m_AllocationCallbacks;
        vma_delete(&allocationCallbacks, allocator);
    }
}

void vmaGetPhysicalDeviceProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceProperties **ppPhysicalDeviceProperties)
{
    VMA_ASSERT(allocator && ppPhysicalDeviceProperties);
    *ppPhysicalDeviceProperties = &allocator->m_PhysicalDeviceProperties;
}

void vmaGetMemoryProperties(
    VmaAllocator allocator,
    const VkPhysicalDeviceMemoryProperties** ppPhysicalDeviceMemoryProperties)
{
    VMA_ASSERT(allocator && ppPhysicalDeviceMemoryProperties);
    *ppPhysicalDeviceMemoryProperties = &allocator->m_MemProps;
}

void vmaGetMemoryTypeProperties(
    VmaAllocator allocator,
    uint32_t memoryTypeIndex,
    VkMemoryPropertyFlags* pFlags)
{
    VMA_ASSERT(allocator && pFlags);
    VMA_ASSERT(memoryTypeIndex < allocator->GetMemoryTypeCount());
    *pFlags = allocator->m_MemProps.memoryTypes[memoryTypeIndex].propertyFlags;
}

void vmaCalculateStats(
    VmaAllocator allocator,
    VmaStats* pStats)
{
    VMA_ASSERT(allocator && pStats);
    VMA_DEBUG_GLOBAL_MUTEX_LOCK
    allocator->CalculateStats(pStats);
}

#if VMA_STATS_STRING_ENABLED

void vmaBuildStatsString(
    VmaAllocator allocator,
    char** ppStatsString,
    VkBool32 detailedMap)
{
    VMA_ASSERT(allocator && ppStatsString);
    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    VmaStringBuilder sb(allocator);
    {
        VmaStats stats;
        allocator->CalculateStats(&stats);

        sb.Add("{\n\"Total\": ");
        VmaPrintStatInfo(sb, stats.total);
    
        for(uint32_t heapIndex = 0; heapIndex < allocator->GetMemoryHeapCount(); ++heapIndex)
        {
            sb.Add(",\n\"Heap ");
            sb.AddNumber(heapIndex);
            sb.Add("\": {\n\t\"Size\": ");
            sb.AddNumber(allocator->m_MemProps.memoryHeaps[heapIndex].size);
            sb.Add(",\n\t\"Flags\": ");
            if((allocator->m_MemProps.memoryHeaps[heapIndex].flags & VK_MEMORY_HEAP_DEVICE_LOCAL_BIT) != 0)
                sb.AddString("DEVICE_LOCAL");
            else
                sb.AddString("");
            if(stats.memoryHeap[heapIndex].AllocationCount > 0)
            {
                sb.Add(",\n\t\"Stats:\": ");
                VmaPrintStatInfo(sb, stats.memoryHeap[heapIndex]);
            }

            for(uint32_t typeIndex = 0; typeIndex < allocator->GetMemoryTypeCount(); ++typeIndex)
            {
                if(allocator->m_MemProps.memoryTypes[typeIndex].heapIndex == heapIndex)
                {
                    sb.Add(",\n\t\"Type ");
                    sb.AddNumber(typeIndex);
                    sb.Add("\": {\n\t\t\"Flags\": \"");
                    VkMemoryPropertyFlags flags = allocator->m_MemProps.memoryTypes[typeIndex].propertyFlags;
                    if((flags & VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT) != 0)
                        sb.Add(" DEVICE_LOCAL");
                    if((flags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) != 0)
                        sb.Add(" HOST_VISIBLE");
                    if((flags & VK_MEMORY_PROPERTY_HOST_COHERENT_BIT) != 0)
                        sb.Add(" HOST_COHERENT");
                    if((flags & VK_MEMORY_PROPERTY_HOST_CACHED_BIT) != 0)
                        sb.Add(" HOST_CACHED");
                    if((flags & VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT) != 0)
                        sb.Add(" LAZILY_ALLOCATED");
                    sb.Add("\"");
                    if(stats.memoryType[typeIndex].AllocationCount > 0)
                    {
                        sb.Add(",\n\t\t\"Stats\": ");
                        VmaPrintStatInfo(sb, stats.memoryType[typeIndex]);
                    }
                    sb.Add("\n\t}");
                }
            }
            sb.Add("\n}");
        }
        if(detailedMap == VK_TRUE)
            allocator->PrintDetailedMap(sb);
        sb.Add("\n}\n");
    }

    const size_t len = sb.GetLength();
    char* const pChars = vma_new_array(allocator, char, len + 1);
    if(len > 0)
        memcpy(pChars, sb.GetData(), len);
    pChars[len] = '\0';
    *ppStatsString = pChars;
}

void vmaFreeStatsString(
    VmaAllocator allocator,
    char* pStatsString)
{
    if(pStatsString != VMA_NULL)
    {
        VMA_ASSERT(allocator);
        size_t len = strlen(pStatsString);
        vma_delete_array(allocator, pStatsString, len + 1);
    }
}

#endif // #if VMA_STATS_STRING_ENABLED

/** This function is not protected by any mutex because it just reads immutable data.
*/
VkResult vmaFindMemoryTypeIndex(
    VmaAllocator allocator,
    uint32_t memoryTypeBits,
    const VmaMemoryRequirements* pMemoryRequirements,
    uint32_t* pMemoryTypeIndex)
{
    VMA_ASSERT(allocator != VK_NULL_HANDLE);
    VMA_ASSERT(pMemoryRequirements != VMA_NULL);
    VMA_ASSERT(pMemoryTypeIndex != VMA_NULL);
    
    uint32_t requiredFlags = pMemoryRequirements->requiredFlags;
    uint32_t preferredFlags = pMemoryRequirements->preferredFlags;
    if(preferredFlags == 0)
        preferredFlags = requiredFlags;
    // preferredFlags, if not 0, must be a superset of requiredFlags.
    VMA_ASSERT((requiredFlags & ~preferredFlags) == 0);

    // Convert usage to requiredFlags and preferredFlags.
    switch(pMemoryRequirements->usage)
    {
    case VMA_MEMORY_USAGE_UNKNOWN:
        break;
    case VMA_MEMORY_USAGE_GPU_ONLY:
        preferredFlags |= VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
        break;
    case VMA_MEMORY_USAGE_CPU_ONLY:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
        break;
    case VMA_MEMORY_USAGE_CPU_TO_GPU:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;
        preferredFlags |= VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT;
        break;
    case VMA_MEMORY_USAGE_GPU_TO_CPU:
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;
        preferredFlags |= VK_MEMORY_PROPERTY_HOST_COHERENT_BIT | VK_MEMORY_PROPERTY_HOST_CACHED_BIT;
        break;
    default:
        break;
    }

    if((pMemoryRequirements->flags & VMA_MEMORY_REQUIREMENT_PERSISTENT_MAP_BIT) != 0)
        requiredFlags |= VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT;

    *pMemoryTypeIndex = UINT32_MAX;
    uint32_t minCost = UINT32_MAX;
    for(uint32_t memTypeIndex = 0, memTypeBit = 1;
        memTypeIndex < allocator->GetMemoryTypeCount();
        ++memTypeIndex, memTypeBit <<= 1)
    {
        // This memory type is acceptable according to memoryTypeBits bitmask.
        if((memTypeBit & memoryTypeBits) != 0)
        {
            const VkMemoryPropertyFlags currFlags =
                allocator->m_MemProps.memoryTypes[memTypeIndex].propertyFlags;
            // This memory type contains requiredFlags.
            if((requiredFlags & ~currFlags) == 0)
            {
                // Calculate cost as number of bits from preferredFlags not present in this memory type.
                uint32_t currCost = CountBitsSet(preferredFlags & ~currFlags);
                // Remember memory type with lowest cost.
                if(currCost < minCost)
                {
                    *pMemoryTypeIndex = memTypeIndex;
                    if(currCost == 0)
                        return VK_SUCCESS;
                    minCost = currCost;
                }
            }
        }
    }
    return (*pMemoryTypeIndex != UINT32_MAX) ? VK_SUCCESS : VK_ERROR_FEATURE_NOT_PRESENT;
}

VkResult vmaAllocateMemory(
    VmaAllocator allocator,
    const VkMemoryRequirements* pVkMemoryRequirements,
    const VmaMemoryRequirements* pVmaMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pVkMemoryRequirements && pVmaMemoryRequirements && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->AllocateMemory(
        *pVkMemoryRequirements,
        *pVmaMemoryRequirements,
        VMA_SUBALLOCATION_TYPE_UNKNOWN,
        pAllocation);

    if(pAllocationInfo)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }
}

VkResult vmaAllocateMemoryForBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    const VmaMemoryRequirements* pMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && buffer != VK_NULL_HANDLE && pMemoryRequirements && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemoryForBuffer");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    VkMemoryRequirements vkMemReq = {};
    vkGetBufferMemoryRequirements(allocator->m_hDevice, buffer, &vkMemReq);

    return allocator->AllocateMemory(
        vkMemReq,
        *pMemoryRequirements,
        VMA_SUBALLOCATION_TYPE_BUFFER,
        pAllocation);

    if(pAllocationInfo)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }
}

VkResult vmaAllocateMemoryForImage(
    VmaAllocator allocator,
    VkImage image,
    const VmaMemoryRequirements* pMemoryRequirements,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && image != VK_NULL_HANDLE && pMemoryRequirements && pAllocation);

    VMA_DEBUG_LOG("vmaAllocateMemoryForImage");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return AllocateMemoryForImage(
        allocator,
        image,
        pMemoryRequirements,
        VMA_SUBALLOCATION_TYPE_IMAGE_UNKNOWN,
        pAllocation);

    if(pAllocationInfo)
    {
        allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
    }
}

void vmaFreeMemory(
    VmaAllocator allocator,
    VmaAllocation allocation)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_LOG("vmaFreeMemory");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->FreeMemory(allocation);
}

void vmaGetAllocationInfo(
    VmaAllocator allocator,
    VmaAllocation allocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && allocation && pAllocationInfo);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->GetAllocationInfo(allocation, pAllocationInfo);
}

void vmaSetAllocationUserData(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void* pUserData)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocation->SetUserData(pUserData);
}

VkResult vmaMapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation,
    void** ppData)
{
    VMA_ASSERT(allocator && allocation && ppData);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return vkMapMemory(allocator->m_hDevice, allocation->GetMemory(),
        allocation->GetOffset(), allocation->GetSize(), 0, ppData);
}

void vmaUnmapMemory(
    VmaAllocator allocator,
    VmaAllocation allocation)
{
    VMA_ASSERT(allocator && allocation);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    vkUnmapMemory(allocator->m_hDevice, allocation->GetMemory());
}

void vmaUnmapPersistentlyMappedMemory(VmaAllocator allocator)
{
    VMA_ASSERT(allocator);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    allocator->UnmapPersistentlyMappedMemory();
}

VkResult vmaMapPersistentlyMappedMemory(VmaAllocator allocator)
{
    VMA_ASSERT(allocator);

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->MapPersistentlyMappedMemory();
}

VkResult vmaDefragment(
    VmaAllocator allocator,
    VmaAllocation* pAllocations,
    size_t allocationCount,
    VkBool32* pAllocationsChanged,
    const VmaDefragmentationInfo *pDefragmentationInfo,
    VmaDefragmentationStats* pDefragmentationStats)
{
    VMA_ASSERT(allocator && pAllocations);

    VMA_DEBUG_LOG("vmaDefragment");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    return allocator->Defragment(pAllocations, allocationCount, pAllocationsChanged, pDefragmentationInfo, pDefragmentationStats);
}

VkResult vmaCreateBuffer(
    VmaAllocator allocator,
    const VkBufferCreateInfo* pCreateInfo,
    const VmaMemoryRequirements* pMemoryRequirements,
    VkBuffer* pBuffer,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pCreateInfo && pMemoryRequirements && pBuffer && pAllocation);
    
    VMA_DEBUG_LOG("vmaCreateBuffer");
    
    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    // 1. Create VkBuffer.
    VkResult res = vkCreateBuffer(allocator->m_hDevice, pCreateInfo, allocator->GetAllocationCallbacks(), pBuffer);
    if(res >= 0)
    {
        // 2. vkGetBufferMemoryRequirements.
        VkMemoryRequirements vkMemReq = {};
        vkGetBufferMemoryRequirements(allocator->m_hDevice, *pBuffer, &vkMemReq);

        // 3. Allocate memory using allocator.
        res = allocator->AllocateMemory(
            vkMemReq,
            *pMemoryRequirements,
            VMA_SUBALLOCATION_TYPE_BUFFER,
            pAllocation);
        if(res >= 0)
        {
            // 3. Bind buffer with memory.
            res = vkBindBufferMemory(allocator->m_hDevice, *pBuffer, (*pAllocation)->GetMemory(), (*pAllocation)->GetOffset());
            if(res >= 0)
            {
                // All steps succeeded.
                if(pAllocationInfo != VMA_NULL)
                {
                    allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
                }
                return VK_SUCCESS;
            }
            allocator->FreeMemory(*pAllocation);
            return res;
        }
        vkDestroyBuffer(allocator->m_hDevice, *pBuffer, allocator->GetAllocationCallbacks());
        return res;
    }
    return res;
}

void vmaDestroyBuffer(
    VmaAllocator allocator,
    VkBuffer buffer,
    VmaAllocation allocation)
{
    if(buffer != VK_NULL_HANDLE)
    {
        VMA_ASSERT(allocator);

        VMA_DEBUG_LOG("vmaDestroyBuffer");

        VMA_DEBUG_GLOBAL_MUTEX_LOCK

        vkDestroyBuffer(allocator->m_hDevice, buffer, allocator->GetAllocationCallbacks());
        
        allocator->FreeMemory(allocation);
    }
}

VkResult vmaCreateImage(
    VmaAllocator allocator,
    const VkImageCreateInfo* pCreateInfo,
    const VmaMemoryRequirements* pMemoryRequirements,
    VkImage* pImage,
    VmaAllocation* pAllocation,
    VmaAllocationInfo* pAllocationInfo)
{
    VMA_ASSERT(allocator && pCreateInfo && pMemoryRequirements && pImage && pAllocation);

    VMA_DEBUG_LOG("vmaCreateImage");

    VMA_DEBUG_GLOBAL_MUTEX_LOCK

    // 1. Create VkImage.
    VkResult res = vkCreateImage(allocator->m_hDevice, pCreateInfo, allocator->GetAllocationCallbacks(), pImage);
    if(res >= 0)
    {
        VkMappedMemoryRange mem = {};
        VmaSuballocationType suballocType = pCreateInfo->tiling == VK_IMAGE_TILING_OPTIMAL ?
            VMA_SUBALLOCATION_TYPE_IMAGE_OPTIMAL :
            VMA_SUBALLOCATION_TYPE_IMAGE_LINEAR;
        
        // 2. Allocate memory using allocator.
        res = AllocateMemoryForImage(allocator, *pImage, pMemoryRequirements, suballocType, pAllocation);
        if(res >= 0)
        {
            // 3. Bind image with memory.
            res = vkBindImageMemory(allocator->m_hDevice, *pImage, (*pAllocation)->GetMemory(), (*pAllocation)->GetOffset());
            if(res >= 0)
            {
                // All steps succeeded.
                if(pAllocationInfo != VMA_NULL)
                {
                    allocator->GetAllocationInfo(*pAllocation, pAllocationInfo);
                }
                return VK_SUCCESS;
            }
            allocator->FreeMemory(*pAllocation);
            return res;
        }
        vkDestroyImage(allocator->m_hDevice, *pImage, allocator->GetAllocationCallbacks());
        return res;
    }
    return res;
}

void vmaDestroyImage(
    VmaAllocator allocator,
    VkImage image,
    VmaAllocation allocation)
{
    if(image != VK_NULL_HANDLE)
    {
        VMA_ASSERT(allocator);

        VMA_DEBUG_LOG("vmaDestroyImage");

        VMA_DEBUG_GLOBAL_MUTEX_LOCK

        vkDestroyImage(allocator->m_hDevice, image, allocator->GetAllocationCallbacks());

        allocator->FreeMemory(allocation);
    }
}

#endif // #ifdef VMA_IMPLEMENTATION