206 lines
6.3 KiB
C
206 lines
6.3 KiB
C
/* Declarations for `malloc' and friends.
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Copyright 1990, 1991 Free Software Foundation
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Written May 1989 by Mike Haertel.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA.
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The author may be reached (Email) at the address mike@ai.mit.edu,
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or (US mail) as Mike Haertel c/o Free Software Foundation. */
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#ifndef _MALLOC_H
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#define _MALLOC_H 1
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/* IGNORE(@ */
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#include <features.h>
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#define __need_NULL
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#define __need_size_t
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#define __need_ptrdiff_t
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#include <stddef.h>
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/* @) */
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#ifndef NULL
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#define NULL 0
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#endif
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#ifdef __STDC__
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#include <stddef.h>
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#else
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#undef size_t
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#define size_t unsigned int
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#endif
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/* Allocate SIZE bytes of memory. */
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extern PTR EXFUN(malloc, (size_t __size));
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/* Re-allocate the previously allocated block
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in PTR, making the new block SIZE bytes long. */
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extern PTR EXFUN(realloc, (PTR __ptr, size_t __size));
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/* Allocate NMEMB elements of SIZE bytes each, all initialized to 0. */
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extern PTR EXFUN(calloc, (size_t __nmemb, size_t __size));
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/* Free a block allocated by `malloc', `realloc' or `calloc'. */
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extern void EXFUN(free, (PTR __ptr));
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/* Allocate SIZE bytes allocated to ALIGNMENT bytes. */
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extern PTR EXFUN(memalign, (size_t __alignment, size_t __size));
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/* Allocate SIZE bytes on a page boundary. */
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extern PTR EXFUN(valloc, (size_t __size));
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#ifdef _MALLOC_INTERNAL
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#if defined(__GNU_LIBRARY__) || defined(__STDC__)
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#include <limits.h>
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#else
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#define CHAR_BIT 8
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#endif
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/* The allocator divides the heap into blocks of fixed size; large
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requests receive one or more whole blocks, and small requests
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receive a fragment of a block. Fragment sizes are powers of two,
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and all fragments of a block are the same size. When all the
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fragments in a block have been freed, the block itself is freed. */
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#define INT_BIT (CHAR_BIT * sizeof(int))
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#define BLOCKLOG (INT_BIT > 16 ? 12 : 9)
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#define BLOCKSIZE (1 << BLOCKLOG)
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#define BLOCKIFY(SIZE) (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE)
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/* Determine the amount of memory spanned by the initial heap table
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(not an absolute limit). */
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#define HEAP (INT_BIT > 16 ? 4194304 : 65536)
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/* Number of contiguous free blocks allowed to build up at the end of
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memory before they will be returned to the system. */
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#define FINAL_FREE_BLOCKS 8
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/* Where to start searching the free list when looking for new memory.
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The two possible values are 0 and _heapindex. Starting at 0 seems
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to reduce total memory usage, while starting at _heapindex seems to
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run faster. */
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#define MALLOC_SEARCH_START _heapindex
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/* Data structure giving per-block information. */
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typedef union
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{
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/* Heap information for a busy block. */
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struct
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{
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/* Zero for a large block, or positive giving the
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logarithm to the base two of the fragment size. */
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int type;
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union
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{
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struct
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{
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size_t nfree; /* Free fragments in a fragmented block. */
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size_t first; /* First free fragment of the block. */
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} frag;
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/* Size (in blocks) of a large cluster. */
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size_t size;
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} info;
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} busy;
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/* Heap information for a free block (that may be the first of
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a free cluster). */
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struct
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{
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size_t size; /* Size (in blocks) of a free cluster. */
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size_t next; /* Index of next free cluster. */
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size_t prev; /* Index of previous free cluster. */
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} free;
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} malloc_info;
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/* Pointer to first block of the heap. */
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extern char *_heapbase;
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/* Table indexed by block number giving per-block information. */
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extern malloc_info *_heapinfo;
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/* Address to block number and vice versa. */
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#define BLOCK(A) (((char *) (A) - _heapbase) / BLOCKSIZE + 1)
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/* The following line MUST be split! m4 will not process it otherwise. */
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#define ADDRESS(B) \
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((PTR) (((B) - 1) * BLOCKSIZE + _heapbase))
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/* Current search index for the heap table. */
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extern size_t _heapindex;
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/* Limit of valid info table indices. */
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extern size_t _heaplimit;
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/* Doubly linked lists of free fragments. */
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struct list
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{
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struct list *next;
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struct list *prev;
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};
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/* Free list headers for each fragment size. */
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extern struct list _fraghead[];
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/* List of blocks allocated with `memalign' (or `valloc'). */
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struct alignlist
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{
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struct alignlist *next;
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PTR aligned; /* The address that memaligned returned. */
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PTR exact; /* The address that malloc returned. */
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};
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extern struct alignlist *_aligned_blocks;
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/* Instrumentation. */
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extern size_t _chunks_used;
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extern size_t _bytes_used;
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extern size_t _chunks_free;
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extern size_t _bytes_free;
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/* Internal version of `free' used in `morecore'. */
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extern void EXFUN(__free, (PTR __ptr));
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#endif /* _MALLOC_INTERNAL. */
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/* Underlying allocation function; successive calls should
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return contiguous pieces of memory. */
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extern PTR EXFUN((*__morecore), (ptrdiff_t __size));
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/* Default value of `__morecore'. */
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extern PTR EXFUN(__default_morecore, (ptrdiff_t __size));
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/* Nonzero if `malloc' has been called and done its initialization. */
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extern int __malloc_initialized;
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/* Hooks for debugging versions. */
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extern void EXFUN((*__free_hook), (PTR __ptr));
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extern PTR EXFUN((*__malloc_hook), (size_t __size));
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extern PTR EXFUN((*__realloc_hook), (PTR __ptr, size_t __size));
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/* Activate a standard collection of debugging hooks. */
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extern void EXFUN(mcheck, (void EXFUN((*__func), (void))));
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/* Statistics available to the user. */
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struct mstats
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{
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size_t bytes_total; /* Total size of the heap. */
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size_t chunks_used; /* Chunks allocated by the user. */
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size_t bytes_used; /* Byte total of user-allocated chunks. */
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size_t chunks_free; /* Chunks in the free list. */
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size_t bytes_free; /* Byte total of chunks in the free list. */
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};
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/* Pick up the current statistics. */
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extern struct mstats EXFUN(mstats, (NOARGS));
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#endif /* malloc.h */
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