Remove trailing whitespace.

This commit is contained in:
Bartosz Taudul 2020-10-29 23:06:28 +01:00
parent e2515c6a99
commit 8b4e03486d

View File

@ -123,7 +123,7 @@ struct ConcurrentQueueDefaultTraits
{
// General-purpose size type. std::size_t is strongly recommended.
typedef std::size_t size_t;
// The type used for the enqueue and dequeue indices. Must be at least as
// large as size_t. Should be significantly larger than the number of elements
// you expect to hold at once, especially if you have a high turnover rate;
@ -135,37 +135,37 @@ struct ConcurrentQueueDefaultTraits
// whether the queue is lock-free with a 64-int type depends on the whether
// std::atomic<std::uint64_t> is lock-free, which is platform-specific.
typedef std::size_t index_t;
// Internally, all elements are enqueued and dequeued from multi-element
// blocks; this is the smallest controllable unit. If you expect few elements
// but many producers, a smaller block size should be favoured. For few producers
// and/or many elements, a larger block size is preferred. A sane default
// is provided. Must be a power of 2.
static const size_t BLOCK_SIZE = 64*1024;
// For explicit producers (i.e. when using a producer token), the block is
// checked for being empty by iterating through a list of flags, one per element.
// For large block sizes, this is too inefficient, and switching to an atomic
// counter-based approach is faster. The switch is made for block sizes strictly
// larger than this threshold.
static const size_t EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = 32;
// How many full blocks can be expected for a single explicit producer? This should
// reflect that number's maximum for optimal performance. Must be a power of 2.
static const size_t EXPLICIT_INITIAL_INDEX_SIZE = 32;
// Controls the number of items that an explicit consumer (i.e. one with a token)
// must consume before it causes all consumers to rotate and move on to the next
// internal queue.
static const std::uint32_t EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE = 256;
// The maximum number of elements (inclusive) that can be enqueued to a sub-queue.
// Enqueue operations that would cause this limit to be surpassed will fail. Note
// that this limit is enforced at the block level (for performance reasons), i.e.
// it's rounded up to the nearest block size.
static const size_t MAX_SUBQUEUE_SIZE = details::const_numeric_max<size_t>::value;
// Memory allocation can be customized if needed.
// malloc should return nullptr on failure, and handle alignment like std::malloc.
#if defined(malloc) || defined(free)
@ -203,13 +203,13 @@ namespace details
std::atomic<bool> inactive;
ProducerToken* token;
uint64_t threadId;
ConcurrentQueueProducerTypelessBase()
: next(nullptr), inactive(false), token(nullptr), threadId(0)
{
}
};
template<typename T>
static inline bool circular_less_than(T a, T b)
{
@ -223,7 +223,7 @@ namespace details
#pragma warning(pop)
#endif
}
template<typename U>
static inline char* align_for(char* ptr)
{
@ -247,7 +247,7 @@ namespace details
++x;
return x;
}
template<typename T>
static inline void swap_relaxed(std::atomic<T>& left, std::atomic<T>& right)
{
@ -255,13 +255,13 @@ namespace details
left.store(std::move(right.load(std::memory_order_relaxed)), std::memory_order_relaxed);
right.store(std::move(temp), std::memory_order_relaxed);
}
template<typename T>
static inline T const& nomove(T const& x)
{
return x;
}
template<bool Enable>
struct nomove_if
{
@ -271,7 +271,7 @@ namespace details
return x;
}
};
template<>
struct nomove_if<false>
{
@ -282,19 +282,19 @@ namespace details
return std::forward<U>(x);
}
};
template<typename It>
static inline auto deref_noexcept(It& it) noexcept -> decltype(*it)
{
return *it;
}
#if defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)
template<typename T> struct is_trivially_destructible : std::is_trivially_destructible<T> { };
#else
template<typename T> struct is_trivially_destructible : std::has_trivial_destructor<T> { };
#endif
template<typename T> struct static_is_lock_free_num { enum { value = 0 }; };
template<> struct static_is_lock_free_num<signed char> { enum { value = ATOMIC_CHAR_LOCK_FREE }; };
template<> struct static_is_lock_free_num<short> { enum { value = ATOMIC_SHORT_LOCK_FREE }; };
@ -337,7 +337,7 @@ struct ProducerToken
other.producer->token = &other;
}
}
// A token is always valid unless:
// 1) Memory allocation failed during construction
// 2) It was moved via the move constructor
@ -347,7 +347,7 @@ struct ProducerToken
// that the token is valid for use with a specific queue,
// but not which one; that's up to the user to track.
inline bool valid() const { return producer != nullptr; }
~ProducerToken()
{
if (producer != nullptr) {
@ -355,14 +355,14 @@ struct ProducerToken
producer->inactive.store(true, std::memory_order_release);
}
}
// Disable copying and assignment
ProducerToken(ProducerToken const&) = delete;
ProducerToken& operator=(ProducerToken const&) = delete;
private:
template<typename T, typename Traits> friend class ConcurrentQueue;
protected:
details::ConcurrentQueueProducerTypelessBase* producer;
};
@ -392,14 +392,14 @@ struct ConsumerToken
std::swap(currentProducer, other.currentProducer);
std::swap(desiredProducer, other.desiredProducer);
}
// Disable copying and assignment
ConsumerToken(ConsumerToken const&) = delete;
ConsumerToken& operator=(ConsumerToken const&) = delete;
private:
template<typename T, typename Traits> friend class ConcurrentQueue;
private: // but shared with ConcurrentQueue
std::uint32_t initialOffset;
std::uint32_t lastKnownGlobalOffset;
@ -417,10 +417,10 @@ public:
typedef moodycamel::ProducerToken producer_token_t;
typedef moodycamel::ConsumerToken consumer_token_t;
typedef typename Traits::index_t index_t;
typedef typename Traits::size_t size_t;
static const size_t BLOCK_SIZE = static_cast<size_t>(Traits::BLOCK_SIZE);
static const size_t EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = static_cast<size_t>(Traits::EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD);
static const size_t EXPLICIT_INITIAL_INDEX_SIZE = static_cast<size_t>(Traits::EXPLICIT_INITIAL_INDEX_SIZE);
@ -462,7 +462,7 @@ public:
{
populate_initial_block_list(capacity / BLOCK_SIZE + ((capacity & (BLOCK_SIZE - 1)) == 0 ? 0 : 1));
}
// Computes the correct amount of pre-allocated blocks for you based
// on the minimum number of elements you want available at any given
// time, and the maximum concurrent number of each type of producer.
@ -476,7 +476,7 @@ public:
size_t blocks = (((minCapacity + BLOCK_SIZE - 1) / BLOCK_SIZE) - 1) * (maxExplicitProducers + 1) + 2 * (maxExplicitProducers);
populate_initial_block_list(blocks);
}
// Note: The queue should not be accessed concurrently while it's
// being deleted. It's up to the user to synchronize this.
// This method is not thread safe.
@ -492,7 +492,7 @@ public:
destroy(ptr);
ptr = next;
}
// Destroy global free list
auto block = freeList.head_unsafe();
while (block != nullptr) {
@ -502,7 +502,7 @@ public:
}
block = next;
}
// Destroy initial free list
destroy_array(initialBlockPool, initialBlockPoolSize);
}
@ -559,8 +559,8 @@ public:
return count;
}
}
// Returns an estimate of the total number of elements currently in the queue. This
// estimate is only accurate if the queue has completely stabilized before it is called
// (i.e. all enqueue and dequeue operations have completed and their memory effects are
@ -575,8 +575,8 @@ public:
}
return size;
}
// Returns true if the underlying atomic variables used by
// the queue are lock-free (they should be on most platforms).
// Thread-safe.
@ -595,12 +595,12 @@ private:
friend struct ProducerToken;
friend struct ConsumerToken;
friend struct ExplicitProducer;
///////////////////////////////
// Queue methods
///////////////////////////////
inline bool update_current_producer_after_rotation(consumer_token_t& token)
{
// Ah, there's been a rotation, figure out where we should be!
@ -623,7 +623,7 @@ private:
}
}
}
std::uint32_t delta = globalOffset - token.lastKnownGlobalOffset;
if (delta >= prodCount) {
delta = delta % prodCount;
@ -634,27 +634,27 @@ private:
token.desiredProducer = tail;
}
}
token.lastKnownGlobalOffset = globalOffset;
token.currentProducer = token.desiredProducer;
token.itemsConsumedFromCurrent = 0;
return true;
}
///////////////////////////
// Free list
///////////////////////////
template <typename N>
struct FreeListNode
{
FreeListNode() : freeListRefs(0), freeListNext(nullptr) { }
std::atomic<std::uint32_t> freeListRefs;
std::atomic<N*> freeListNext;
};
// A simple CAS-based lock-free free list. Not the fastest thing in the world under heavy contention, but
// simple and correct (assuming nodes are never freed until after the free list is destroyed), and fairly
// speedy under low contention.
@ -678,7 +678,7 @@ private:
add_knowing_refcount_is_zero(node);
}
}
inline N* try_get()
{
auto head = freeListHead.load(std::memory_order_acquire);
@ -689,7 +689,7 @@ private:
head = freeListHead.load(std::memory_order_acquire);
continue;
}
// Good, reference count has been incremented (it wasn't at zero), which means we can read the
// next and not worry about it changing between now and the time we do the CAS
auto next = head->freeListNext.load(std::memory_order_relaxed);
@ -697,12 +697,12 @@ private:
// Yay, got the node. This means it was on the list, which means shouldBeOnFreeList must be false no
// matter the refcount (because nobody else knows it's been taken off yet, it can't have been put back on).
assert((head->freeListRefs.load(std::memory_order_relaxed) & SHOULD_BE_ON_FREELIST) == 0);
// Decrease refcount twice, once for our ref, and once for the list's ref
head->freeListRefs.fetch_sub(2, std::memory_order_release);
return head;
}
// OK, the head must have changed on us, but we still need to decrease the refcount we increased.
// Note that we don't need to release any memory effects, but we do need to ensure that the reference
// count decrement happens-after the CAS on the head.
@ -711,13 +711,13 @@ private:
add_knowing_refcount_is_zero(prevHead);
}
}
return nullptr;
}
// Useful for traversing the list when there's no contention (e.g. to destroy remaining nodes)
N* head_unsafe() const { return freeListHead.load(std::memory_order_relaxed); }
private:
inline void add_knowing_refcount_is_zero(N* node)
{
@ -742,27 +742,27 @@ private:
return;
}
}
private:
// Implemented like a stack, but where node order doesn't matter (nodes are inserted out of order under contention)
std::atomic<N*> freeListHead;
static const std::uint32_t REFS_MASK = 0x7FFFFFFF;
static const std::uint32_t SHOULD_BE_ON_FREELIST = 0x80000000;
};
///////////////////////////
// Block
///////////////////////////
struct Block
{
Block()
: next(nullptr), elementsCompletelyDequeued(0), freeListRefs(0), freeListNext(nullptr), shouldBeOnFreeList(false), dynamicallyAllocated(true)
{
}
inline bool is_empty() const
{
if (compile_time_condition<BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD>::value) {
@ -772,7 +772,7 @@ private:
return false;
}
}
// Aha, empty; make sure we have all other memory effects that happened before the empty flags were set
std::atomic_thread_fence(std::memory_order_acquire);
return true;
@ -787,7 +787,7 @@ private:
return false;
}
}
// Returns true if the block is now empty (does not apply in explicit context)
inline bool set_empty(index_t i)
{
@ -804,7 +804,7 @@ private:
return prevVal == BLOCK_SIZE - 1;
}
}
// Sets multiple contiguous item statuses to 'empty' (assumes no wrapping and count > 0).
// Returns true if the block is now empty (does not apply in explicit context).
inline bool set_many_empty(index_t i, size_t count)
@ -826,7 +826,7 @@ private:
return prevVal + count == BLOCK_SIZE;
}
}
inline void set_all_empty()
{
if (BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
@ -840,7 +840,7 @@ private:
elementsCompletelyDequeued.store(BLOCK_SIZE, std::memory_order_relaxed);
}
}
inline void reset_empty()
{
if (compile_time_condition<BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD>::value) {
@ -889,7 +889,7 @@ private:
///////////////////////////
// Producer base
///////////////////////////
struct ProducerBase : public details::ConcurrentQueueProducerTypelessBase
{
ProducerBase(ConcurrentQueue* parent_) :
@ -901,39 +901,39 @@ private:
parent(parent_)
{
}
virtual ~ProducerBase() { };
template<class NotifyThread, class ProcessData>
inline size_t dequeue_bulk(NotifyThread notifyThread, ProcessData processData)
{
return static_cast<ExplicitProducer*>(this)->dequeue_bulk(notifyThread, processData);
}
inline ProducerBase* next_prod() const { return static_cast<ProducerBase*>(next); }
inline size_t size_approx() const
{
auto tail = tailIndex.load(std::memory_order_relaxed);
auto head = headIndex.load(std::memory_order_relaxed);
return details::circular_less_than(head, tail) ? static_cast<size_t>(tail - head) : 0;
}
inline index_t getTail() const { return tailIndex.load(std::memory_order_relaxed); }
protected:
std::atomic<index_t> tailIndex; // Where to enqueue to next
std::atomic<index_t> headIndex; // Where to dequeue from next
std::atomic<index_t> dequeueOptimisticCount;
std::atomic<index_t> dequeueOvercommit;
Block* tailBlock;
public:
ConcurrentQueue* parent;
};
public:
///////////////////////////
// Explicit queue
@ -953,10 +953,10 @@ private:
if (poolBasedIndexSize > pr_blockIndexSize) {
pr_blockIndexSize = poolBasedIndexSize;
}
new_block_index(0); // This creates an index with double the number of current entries, i.e. EXPLICIT_INITIAL_INDEX_SIZE
}
~ExplicitProducer()
{
// Destruct any elements not yet dequeued.
@ -975,7 +975,7 @@ private:
assert(details::circular_less_than<index_t>(pr_blockIndexEntries[i].base, this->headIndex.load(std::memory_order_relaxed)));
halfDequeuedBlock = pr_blockIndexEntries[i].block;
}
// Start at the head block (note the first line in the loop gives us the head from the tail on the first iteration)
auto block = this->tailBlock;
do {
@ -983,12 +983,12 @@ private:
if (block->ConcurrentQueue::Block::is_empty()) {
continue;
}
size_t i = 0; // Offset into block
if (block == halfDequeuedBlock) {
i = static_cast<size_t>(this->headIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1));
}
// Walk through all the items in the block; if this is the tail block, we need to stop when we reach the tail index
auto lastValidIndex = (this->tailIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 ? BLOCK_SIZE : static_cast<size_t>(this->tailIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1));
while (i != BLOCK_SIZE && (block != this->tailBlock || i != lastValidIndex)) {
@ -996,7 +996,7 @@ private:
}
} while (block != this->tailBlock);
}
// Destroy all blocks that we own
if (this->tailBlock != nullptr) {
auto block = this->tailBlock;
@ -1011,7 +1011,7 @@ private:
block = nextBlock;
} while (block != this->tailBlock);
}
// Destroy the block indices
auto header = static_cast<BlockIndexHeader*>(pr_blockIndexRaw);
while (header != nullptr) {
@ -1021,12 +1021,12 @@ private:
header = prev;
}
}
inline void enqueue_begin_alloc(index_t currentTailIndex)
{
// We reached the end of a block, start a new one
if (this->tailBlock != nullptr && this->tailBlock->next->ConcurrentQueue::Block::is_empty()) {
// We can re-use the block ahead of us, it's empty!
// We can re-use the block ahead of us, it's empty!
this->tailBlock = this->tailBlock->next;
this->tailBlock->ConcurrentQueue::Block::reset_empty();
@ -1080,7 +1080,7 @@ private:
{
return this->tailIndex;
}
template<class NotifyThread, class ProcessData>
size_t dequeue_bulk(NotifyThread notifyThread, ProcessData processData)
{
@ -1090,10 +1090,10 @@ private:
if (details::circular_less_than<size_t>(0, desiredCount)) {
desiredCount = desiredCount < 8192 ? desiredCount : 8192;
std::atomic_thread_fence(std::memory_order_acquire);
auto myDequeueCount = this->dequeueOptimisticCount.fetch_add(desiredCount, std::memory_order_relaxed);
assert(overcommit <= myDequeueCount);
tail = this->tailIndex.load(std::memory_order_acquire);
auto actualCount = static_cast<size_t>(tail - (myDequeueCount - overcommit));
if (details::circular_less_than<size_t>(0, actualCount)) {
@ -1101,15 +1101,15 @@ private:
if (actualCount < desiredCount) {
this->dequeueOvercommit.fetch_add(desiredCount - actualCount, std::memory_order_release);
}
// Get the first index. Note that since there's guaranteed to be at least actualCount elements, this
// will never exceed tail.
auto firstIndex = this->headIndex.fetch_add(actualCount, std::memory_order_acq_rel);
// Determine which block the first element is in
auto localBlockIndex = blockIndex.load(std::memory_order_acquire);
auto localBlockIndexHead = localBlockIndex->front.load(std::memory_order_acquire);
auto headBase = localBlockIndex->entries[localBlockIndexHead].base;
auto firstBlockBaseIndex = firstIndex & ~static_cast<index_t>(BLOCK_SIZE - 1);
auto offset = static_cast<size_t>(static_cast<typename std::make_signed<index_t>::type>(firstBlockBaseIndex - headBase) / BLOCK_SIZE);
@ -1132,7 +1132,7 @@ private:
block->ConcurrentQueue::Block::set_many_empty(firstIndexInBlock, static_cast<size_t>(endIndex - firstIndexInBlock));
indexIndex = (indexIndex + 1) & (localBlockIndex->size - 1);
} while (index != firstIndex + actualCount);
return actualCount;
}
else {
@ -1140,7 +1140,7 @@ private:
this->dequeueOvercommit.fetch_add(desiredCount, std::memory_order_release);
}
}
return 0;
}
@ -1150,7 +1150,7 @@ private:
index_t base;
Block* block;
};
struct BlockIndexHeader
{
size_t size;
@ -1158,12 +1158,12 @@ private:
BlockIndexEntry* entries;
void* prev;
};
bool new_block_index(size_t numberOfFilledSlotsToExpose)
{
auto prevBlockSizeMask = pr_blockIndexSize - 1;
// Create the new block
pr_blockIndexSize <<= 1;
auto newRawPtr = static_cast<char*>((Traits::malloc)(sizeof(BlockIndexHeader) + std::alignment_of<BlockIndexEntry>::value - 1 + sizeof(BlockIndexEntry) * pr_blockIndexSize));
@ -1171,9 +1171,9 @@ private:
pr_blockIndexSize >>= 1; // Reset to allow graceful retry
return false;
}
auto newBlockIndexEntries = reinterpret_cast<BlockIndexEntry*>(details::align_for<BlockIndexEntry>(newRawPtr + sizeof(BlockIndexHeader)));
// Copy in all the old indices, if any
size_t j = 0;
if (pr_blockIndexSlotsUsed != 0) {
@ -1183,25 +1183,25 @@ private:
i = (i + 1) & prevBlockSizeMask;
} while (i != pr_blockIndexFront);
}
// Update everything
auto header = new (newRawPtr) BlockIndexHeader;
header->size = pr_blockIndexSize;
header->front.store(numberOfFilledSlotsToExpose - 1, std::memory_order_relaxed);
header->entries = newBlockIndexEntries;
header->prev = pr_blockIndexRaw; // we link the new block to the old one so we can free it later
pr_blockIndexFront = j;
pr_blockIndexEntries = newBlockIndexEntries;
pr_blockIndexRaw = newRawPtr;
blockIndex.store(header, std::memory_order_release);
return true;
}
private:
std::atomic<BlockIndexHeader*> blockIndex;
// To be used by producer only -- consumer must use the ones in referenced by blockIndex
size_t pr_blockIndexSlotsUsed;
size_t pr_blockIndexSize;
@ -1209,18 +1209,18 @@ private:
BlockIndexEntry* pr_blockIndexEntries;
void* pr_blockIndexRaw;
};
ExplicitProducer* get_explicit_producer(producer_token_t const& token)
{
return static_cast<ExplicitProducer*>(token.producer);
}
private:
//////////////////////////////////
// Block pool manipulation
//////////////////////////////////
void populate_initial_block_list(size_t blockCount)
{
initialBlockPoolSize = blockCount;
@ -1228,7 +1228,7 @@ private:
initialBlockPool = nullptr;
return;
}
initialBlockPool = create_array<Block>(blockCount);
if (initialBlockPool == nullptr) {
initialBlockPoolSize = 0;
@ -1237,23 +1237,23 @@ private:
initialBlockPool[i].dynamicallyAllocated = false;
}
}
inline Block* try_get_block_from_initial_pool()
{
if (initialBlockPoolIndex.load(std::memory_order_relaxed) >= initialBlockPoolSize) {
return nullptr;
}
auto index = initialBlockPoolIndex.fetch_add(1, std::memory_order_relaxed);
return index < initialBlockPoolSize ? (initialBlockPool + index) : nullptr;
}
inline void add_block_to_free_list(Block* block)
{
freeList.add(block);
}
inline void add_blocks_to_free_list(Block* block)
{
while (block != nullptr) {
@ -1262,12 +1262,12 @@ private:
block = next;
}
}
inline Block* try_get_block_from_free_list()
{
return freeList.try_get();
}
// Gets a free block from one of the memory pools, or allocates a new one (if applicable)
Block* requisition_block()
{
@ -1275,26 +1275,26 @@ private:
if (block != nullptr) {
return block;
}
block = try_get_block_from_free_list();
if (block != nullptr) {
return block;
}
return create<Block>();
}
//////////////////////////////////
// Producer list manipulation
//////////////////////////////////
//////////////////////////////////
ProducerBase* recycle_or_create_producer()
{
bool recycled;
return recycle_or_create_producer(recycled);
}
ProducerBase* recycle_or_create_producer(bool& recycled)
{
// Try to re-use one first
@ -1315,25 +1315,25 @@ private:
recycled = false;
return add_producer(static_cast<ProducerBase*>(create<ExplicitProducer>(this)));
}
ProducerBase* add_producer(ProducerBase* producer)
{
// Handle failed memory allocation
if (producer == nullptr) {
return nullptr;
}
producerCount.fetch_add(1, std::memory_order_relaxed);
// Add it to the lock-free list
auto prevTail = producerListTail.load(std::memory_order_relaxed);
do {
producer->next = prevTail;
} while (!producerListTail.compare_exchange_weak(prevTail, producer, std::memory_order_release, std::memory_order_relaxed));
return producer;
}
void reown_producers()
{
// After another instance is moved-into/swapped-with this one, all the
@ -1343,18 +1343,18 @@ private:
ptr->parent = this;
}
}
//////////////////////////////////
// Utility functions
//////////////////////////////////
template<typename U>
static inline U* create_array(size_t count)
{
assert(count > 0);
return static_cast<U*>((Traits::malloc)(sizeof(U) * count));
}
template<typename U>
static inline void destroy_array(U* p, size_t count)
{
@ -1364,21 +1364,21 @@ private:
(Traits::free)(p);
}
}
template<typename U>
static inline U* create()
{
auto p = (Traits::malloc)(sizeof(U));
return new (p) U;
}
template<typename U, typename A1>
static inline U* create(A1&& a1)
{
auto p = (Traits::malloc)(sizeof(U));
return new (p) U(std::forward<A1>(a1));
}
template<typename U>
static inline void destroy(U* p)
{
@ -1391,13 +1391,13 @@ private:
private:
std::atomic<ProducerBase*> producerListTail;
std::atomic<std::uint32_t> producerCount;
std::atomic<size_t> initialBlockPoolIndex;
Block* initialBlockPool;
size_t initialBlockPoolSize;
FreeList<Block> freeList;
std::atomic<std::uint32_t> nextExplicitConsumerId;
std::atomic<std::uint32_t> globalExplicitConsumerOffset;
};