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#pragma once
#include "ref.h"
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
struct TDefaultChunkedMemoryAllocatorTag
{ };
//! Mimics TChunkedMemoryPool but acts as an allocator returning shared refs.
class TChunkedMemoryAllocator
: private TNonCopyable
{
public:
static const i64 DefaultChunkSize;
static const double DefaultMaxSmallBlockSizeRatio;
explicit TChunkedMemoryAllocator(
i64 chunkSize = DefaultChunkSize,
double maxSmallBlockSizeRatio = DefaultMaxSmallBlockSizeRatio,
TRefCountedTypeCookie tagCookie = GetRefCountedTypeCookie<TDefaultChunkedMemoryAllocatorTag>());
template <class TTag>
explicit TChunkedMemoryAllocator(
TTag /*tag*/ = TTag(),
i64 chunkSize = DefaultChunkSize,
double maxSmallBlockSizeRatio = DefaultMaxSmallBlockSizeRatio)
: TChunkedMemoryAllocator(
chunkSize,
maxSmallBlockSizeRatio,
GetRefCountedTypeCookie<TTag>())
{ }
//! Allocates #sizes bytes without any alignment.
TSharedMutableRef AllocateUnaligned(i64 size);
//! Allocates #size bytes aligned with 8-byte granularity.
TSharedMutableRef AllocateAligned(i64 size, int align = 8);
private:
const i64 ChunkSize_;
const i64 MaxSmallBlockSize_;
const TRefCountedTypeCookie TagCookie_;
// Zero-sized arrays are prohibited by C++ standard
// Also even if supported they actually occupy some space (usually 1 byte)
char EmptyBuf_[1];
// Chunk memory layout:
// |AAAA|....|UUUU|
// Legend:
// A aligned allocations
// U unaligned allocations
// . free zone
char* FreeZoneBegin_ = EmptyBuf_;
char* FreeZoneEnd_ = EmptyBuf_;
TSharedMutableRef Chunk_;
TSharedMutableRef AllocateUnalignedSlow(i64 size);
TSharedMutableRef AllocateAlignedSlow(i64 size, int align);
TSharedMutableRef AllocateSlowCore(i64 size);
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
#define CHUNKED_MEMORY_ALLOCATOR_INL_H_
#include "chunked_memory_allocator-inl.h"
#undef CHUNKED_MEMORY_ALLOCATOR_INL_H_
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