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#ifndef _ALLOCATOR_FIXEDSIZE_ALLOCATOR
#define _ALLOCATOR_FIXEDSIZE_ALLOCATOR
#include "Runtime/Allocator/MemoryMacros.h"
#include "Runtime/Misc/AllocatorLabels.h"
template <unsigned BlockSize>
class
FixedSizeAllocator
{
public:
FixedSizeAllocator(MemLabelId memLabel);
~FixedSizeAllocator();
void* alloc();
void free( void* mem );
void reset();
void free_memory();
unsigned total_allocated() const;
unsigned total_free() const;
unsigned capacity() const;
private:
// we can do this template parameter
static const UInt8 BlocksInChunk = 255;
struct
Chunk
{
UInt8 data[BlocksInChunk*BlockSize];
Chunk* next;
UInt8 first_available;
UInt8 total_available;
};
Chunk* m_Chunk;
// we can store pointers -- they will be updated anyway should the new chunk be added
Chunk* m_AllocChunk;
Chunk* m_DeallocChunk;
MemLabelId m_MemLabel;
void create_chunk();
void reset_chunk( Chunk* chunk );
void* alloc_from( Chunk* chunk );
void dealloc_from( void* mem, Chunk* chunk );
bool mem_from( void* mem, Chunk* chunk );
};
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::reset_chunk( Chunk* chunk )
{
AssertBreak(chunk);
chunk->first_available = 0;
chunk->total_available = BlocksInChunk;
// store index of next available block in-place, as first byte of the block
UInt8 next_available_i = 1;
UInt8* next_available_mem = (UInt8*)chunk->data;
while( next_available_i != BlocksInChunk )
{
*next_available_mem = next_available_i;
++next_available_i;
next_available_mem += BlockSize;
}
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::create_chunk()
{
Chunk* newChunk = (Chunk*)UNITY_MALLOC(m_MemLabel, sizeof(Chunk));
reset_chunk(newChunk);
newChunk->next = 0;
if( m_Chunk )
{
Chunk* tail_chunk = m_Chunk;
while( tail_chunk->next )
tail_chunk = tail_chunk->next;
tail_chunk->next = newChunk;
}
else
{
m_Chunk = newChunk;
}
m_AllocChunk = m_DeallocChunk = newChunk;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline
FixedSizeAllocator<BlockSize>::FixedSizeAllocator(MemLabelId memLabel)
: m_Chunk(0),
m_AllocChunk(0),
m_DeallocChunk(0),
m_MemLabel(memLabel)
{
// TODO: create chunk right away?
//create_chunk()
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline
FixedSizeAllocator<BlockSize>::~FixedSizeAllocator()
{
free_memory();
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline bool
FixedSizeAllocator<BlockSize>::mem_from( void* mem, Chunk* chunk )
{
return ( (UInt8*)mem >= (UInt8*)chunk->data
// TODO: align into account
&& (UInt8*)mem < (UInt8*)chunk->data + BlocksInChunk*BlockSize );
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void*
FixedSizeAllocator<BlockSize>::alloc_from( Chunk* chunk )
{
AssertBreak( chunk );
AssertBreak( chunk->total_available );
UInt8* ret = (UInt8*)chunk->data + chunk->first_available*BlockSize;
chunk->first_available = *ret;
--chunk->total_available;
return ret;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::dealloc_from( void* mem, Chunk* chunk )
{
AssertBreak( chunk );
AssertBreak( mem_from(mem, chunk) );
UInt8* release_ptr = (UInt8*)mem;
AssertBreak( (release_ptr - (UInt8*)chunk->data) % BlockSize == 0 );
*release_ptr = chunk->first_available;
chunk->first_available = (release_ptr - (UInt8*)chunk->data) / BlockSize;
++chunk->total_available;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void*
FixedSizeAllocator<BlockSize>::alloc()
{
if( m_AllocChunk == 0 || m_AllocChunk->total_available == 0 )
{
// fallback to linear search
m_AllocChunk = m_Chunk;
while( m_AllocChunk )
{
if( m_AllocChunk->total_available )
break;
m_AllocChunk = m_AllocChunk->next;
}
if( !m_AllocChunk )
create_chunk();
}
return alloc_from(m_AllocChunk);
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::free( void* mem )
{
AssertBreak(m_DeallocChunk);
if( !mem )
return;
if( !mem_from(mem, m_DeallocChunk) )
{
// we want to exploit possible locality
// but for now we store chunks in single-linked list
// fallback to simple linear search;
m_DeallocChunk = m_Chunk;
while( m_DeallocChunk )
{
if( mem_from(mem, m_DeallocChunk) )
break;
m_DeallocChunk = m_DeallocChunk->next;
}
}
AssertBreak(m_DeallocChunk);
dealloc_from( mem, m_DeallocChunk );
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::reset()
{
Chunk* target_chunk = m_Chunk;
while( target_chunk )
{
reset_chunk(target_chunk);
target_chunk = target_chunk->next;
}
m_AllocChunk = m_DeallocChunk = m_Chunk;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline void
FixedSizeAllocator<BlockSize>::free_memory()
{
Chunk* target_chunk = m_Chunk;
while( target_chunk )
{
Chunk* nextChunk = target_chunk->next;
UNITY_FREE(m_MemLabel, target_chunk);
target_chunk = nextChunk;
}
m_AllocChunk = m_DeallocChunk = m_Chunk = 0;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline unsigned
FixedSizeAllocator<BlockSize>::capacity() const
{
unsigned ret = 0;
Chunk* target_chunk = m_Chunk;
while( target_chunk )
{
ret += BlocksInChunk*BlockSize;
target_chunk = target_chunk->next;
}
return ret;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline unsigned
FixedSizeAllocator<BlockSize>::total_free() const
{
unsigned ret = 0;
Chunk* target_chunk = m_Chunk;
while( target_chunk )
{
ret += target_chunk->total_available * BlockSize;
target_chunk = target_chunk->next;
}
return ret;
}
//------------------------------------------------------------------------------
template <unsigned BlockSize>
inline unsigned
FixedSizeAllocator<BlockSize>::total_allocated() const
{
return capacity() - total_free();
}
//==============================================================================
#endif // _ALLOCATOR_FIXEDSIZE_ALLOCATOR
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