161 lines
5 KiB
C
Executable file
161 lines
5 KiB
C
Executable file
/* Declarations for `malloc' and friends.
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Copyright 1990 Free Software Foundation
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Written May 1989 by Mike Haertel.
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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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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#ifndef _MALLOC_H
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#define _MALLOC_H 1
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#ifndef __ONEFILE
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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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#endif
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#ifdef _MALLOC_INTERNAL
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#ifndef __ONEFILE
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#include <limits.h>
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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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#define ADDRESS(B) ((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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/* 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 previous. */
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extern PTR EXFUN(__default_morecore, (ptrdiff_t __size));
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/* Flag whether malloc has been called. */
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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), (NOARGS))));
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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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