static void *AcquireBlock(size_t size)
{
register size_t
i;
register void
*block;
/*
Find free block.
*/
size=(size_t) (size+sizeof(size_t)+6*sizeof(size_t)-1) & -(4U*sizeof(size_t));
i=AllocationPolicy(size);
block=memory_pool.blocks[i];
while ((block != (void *) NULL) && (SizeOfBlock(block) < size))
block=NextBlockInList(block);
if (block == (void *) NULL)
{
i++;
while (memory_pool.blocks[i] == (void *) NULL)
i++;
block=memory_pool.blocks[i];
if (i >= MaxBlocks)
return((void *) NULL);
}
assert((*BlockHeader(NextBlock(block)) & PreviousBlockBit) == 0);
assert(SizeOfBlock(block) >= size);
RemoveFreeBlock(block,AllocationPolicy(SizeOfBlock(block)));
if (SizeOfBlock(block) > size)
{
size_t
blocksize;
void
*next;
/*
Split block.
*/
next=(char *) block+size;
blocksize=SizeOfBlock(block)-size;
*BlockHeader(next)=blocksize;
*BlockFooter(next,blocksize)=blocksize;
InsertFreeBlock(next,AllocationPolicy(blocksize));
*BlockHeader(block)=size | (*BlockHeader(block) & ~SizeMask);
}
assert(size == SizeOfBlock(block));
*BlockHeader(NextBlock(block))|=PreviousBlockBit;
memory_pool.allocation+=size;
return(block);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ E x p a n d H e a p %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ExpandHeap() get more memory from the system. It returns MagickTrue on
% success otherwise MagickFalse.
%
% The format of the ExpandHeap method is:
%
% MagickBooleanType ExpandHeap(size_t size)
%
% A description of each parameter follows:
%
% o size: the size of the memory in bytes we require.
%
*/
static MagickBooleanType ExpandHeap(size_t size)
{
DataSegmentInfo
*segment_info;
MagickBooleanType
mapped;
register ssize_t
i;
register void
*block;
size_t
blocksize;
void
*segment;
blocksize=((size+12*sizeof(size_t))+SegmentSize-1) & -SegmentSize;
assert(memory_pool.number_segments < MaxSegments);
segment=MapBlob(-1,IOMode,0,blocksize);
mapped=segment != (void *) NULL ? MagickTrue : MagickFalse;
if (segment == (void *) NULL)
segment=(void *) memory_methods.acquire_memory_handler(blocksize);
if (segment == (void *) NULL)
return(MagickFalse);
segment_info=(DataSegmentInfo *) free_segments;
free_segments=segment_info->next;
segment_info->mapped=mapped;
segment_info->length=blocksize;
segment_info->allocation=segment;
segment_info->bound=(char *) segment+blocksize;
i=(ssize_t) memory_pool.number_segments-1;
for ( ; (i >= 0) && (memory_pool.segments[i]->allocation > segment); i--)
memory_pool.segments[i+1]=memory_pool.segments[i];
memory_pool.segments[i+1]=segment_info;
memory_pool.number_segments++;
size=blocksize-12*sizeof(size_t);
block=(char *) segment_info->allocation+4*sizeof(size_t);
*BlockHeader(block)=size | PreviousBlockBit;
*BlockFooter(block,size)=size;
InsertFreeBlock(block,AllocationPolicy(size));
block=NextBlock(block);
assert(block < segment_info->bound);
*BlockHeader(block)=2*sizeof(size_t);
*BlockHeader(NextBlock(block))=PreviousBlockBit;
return(MagickTrue);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% R e l i n q u i s h M a g i c k M e m o r y %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% RelinquishMagickMemory() frees memory acquired with AcquireMagickMemory()
% or AcquireQuantumMemory() for reuse.
%
% The format of the RelinquishMagickMemory method is:
%
% void *RelinquishMagickMemory(void *memory)
%
% A description of each parameter follows:
%
% o memory: A pointer to a block of memory to free for reuse.
%
*/
MagickExport void *RelinquishMagickMemory(void *memory)
{
if (memory == (void *) NULL)
return((void *) NULL);
#if !defined(MAGICKCORE_ZERO_CONFIGURATION_SUPPORT)
memory_methods.destroy_memory_handler(memory);
#else
LockSemaphoreInfo(memory_semaphore);
assert((SizeOfBlock(memory) % (4*sizeof(size_t))) == 0);
assert((*BlockHeader(NextBlock(memory)) & PreviousBlockBit) != 0);
if ((*BlockHeader(memory) & PreviousBlockBit) == 0)
{
void
*previous;
/*
Coalesce with previous adjacent block.
*/
previous=PreviousBlock(memory);
RemoveFreeBlock(previous,AllocationPolicy(SizeOfBlock(previous)));
*BlockHeader(previous)=(SizeOfBlock(previous)+SizeOfBlock(memory)) |
(*BlockHeader(previous) & ~SizeMask);
memory=previous;
}
if ((*BlockHeader(NextBlock(NextBlock(memory))) & PreviousBlockBit) == 0)
{
void
*next;
/*
Coalesce with next adjacent block.
*/
next=NextBlock(memory);
RemoveFreeBlock(next,AllocationPolicy(SizeOfBlock(next)));
*BlockHeader(memory)=(SizeOfBlock(memory)+SizeOfBlock(next)) |
(*BlockHeader(memory) & ~SizeMask);
}
*BlockFooter(memory,SizeOfBlock(memory))=SizeOfBlock(memory);
*BlockHeader(NextBlock(memory))&=(~PreviousBlockBit);
InsertFreeBlock(memory,AllocationPolicy(SizeOfBlock(memory)));
UnlockSemaphoreInfo(memory_semaphore);
#endif
return((void *) NULL);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% R e l i n q u i s h M a g i c k M e m o r y %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% RelinquishMagickMemory() zeros memory that has been allocated, frees it for
% reuse.
%
% The format of the RelinquishMagickMemory method is:
%
% void *RelinquishMagickMemory(void *memory)
%
% A description of each parameter follows:
%
% o memory: A pointer to a block of memory to free for reuse.
%
*/
MagickExport void *RelinquishMagickMemory(void *memory)
{
if (memory == (void *) NULL)
return((void *) NULL);
#if !defined(UseEmbeddableMagick)
free(memory);
#else
assert((SizeOfBlock(memory) % (4*sizeof(size_t))) == 0);
assert((*BlockHeader(NextBlock(memory)) & PreviousBlockBit) != 0);
AcquireSemaphoreInfo(&memory_semaphore);
if ((*BlockHeader(memory) & PreviousBlockBit) == 0)
{
void
*previous;
/*
Coalesce with previous adjacent block.
*/
previous=PreviousBlock(memory);
RemoveFreeBlock(previous,AllocationPolicy(SizeOfBlock(previous)));
*BlockHeader(previous)=(SizeOfBlock(previous)+SizeOfBlock(memory)) |
(*BlockHeader(previous) & ~SizeMask);
memory=previous;
}
if ((*BlockHeader(NextBlock(NextBlock(memory))) & PreviousBlockBit) == 0)
{
void
*next;
/*
Coalesce with next adjacent block.
*/
next=NextBlock(memory);
RemoveFreeBlock(next,AllocationPolicy(SizeOfBlock(next)));
*BlockHeader(memory)=(SizeOfBlock(memory)+SizeOfBlock(next)) |
(*BlockHeader(memory) & ~SizeMask);
}
*BlockFooter(memory,SizeOfBlock(memory))=SizeOfBlock(memory);
*BlockHeader(NextBlock(memory))&=(~PreviousBlockBit);
InsertFreeBlock(memory,AllocationPolicy(SizeOfBlock(memory)));
RelinquishSemaphoreInfo(memory_semaphore);
#endif
return((void *) NULL);
}
