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38 lines
1.4 KiB
PHP
38 lines
1.4 KiB
PHP
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/* ------------------- Chunks sizes and alignments ----------------------- */
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#define MCHUNK_SIZE (sizeof(mchunk))
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#if FOOTERS
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#define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
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#else /* FOOTERS */
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#define CHUNK_OVERHEAD (SIZE_T_SIZE)
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#endif /* FOOTERS */
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/* MMapped chunks need a second word of overhead ... */
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#define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
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/* ... and additional padding for fake next-chunk at foot */
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#define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES)
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/* The smallest size we can malloc is an aligned minimal chunk */
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#define MIN_CHUNK_SIZE\
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((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
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/* conversion from malloc headers to user pointers, and back */
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#define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES))
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#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
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/* chunk associated with aligned address A */
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#define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A)))
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/* Bounds on request (not chunk) sizes. */
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#define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2)
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#define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
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/* pad request bytes into a usable size */
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#define pad_request(req) \
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(((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
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/* pad request, checking for minimum (but not maximum) */
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#define request2size(req) \
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(((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
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