lib/malloclib/malloc.h

   1 /* Declarations for `malloc' and friends.
   2    Copyright 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
   3                   Written May 1989 by Mike Haertel.
   4
   5 This library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 This library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with this library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.
  19
  20    The author may be reached (Email) at the address mike@ai.mit.edu,
  21    or (US mail) as Mike Haertel c/o Free Software Foundation.  */
  22
  23 #ifndef _MALLOC_H
  24
  25 #define _MALLOC_H       1
  26
  27 #ifdef _MALLOC_INTERNAL
  28 /* Harmless, gets __GNU_LIBRARY__ defined.
  29    We must do this before #defining size_t and ptrdiff_t
  30    because <stdio.h> tries to typedef them on some systems.  */
  31 #include <stdio.h>
  32 #endif
  33
  34 #ifdef  __cplusplus
  35 extern "C"
  36 {
  37 #endif
  38
  39 #if defined (__cplusplus) || (defined (__STDC__) && __STDC__)
  40 #undef  __P
  41 #define __P(args)       args
  42 #undef  __ptr_t
  43 #define __ptr_t         void *
  44 #else /* Not C++ or ANSI C.  */
  45 #undef  __P
  46 #define __P(args)       ()
  47 #undef  const
  48 #define const
  49 #undef  __ptr_t
  50 #define __ptr_t         char *
  51 #endif /* C++ or ANSI C.  */
  52
  53 #ifndef NULL
  54 #define NULL    0
  55 #endif
  56
  57 #ifdef  __STDC__
  58 #include <stddef.h>
  59 #else
  60 #undef  size_t
  61 #define size_t          unsigned int
  62 #undef  ptrdiff_t
  63 #define ptrdiff_t       int
  64 #endif
  65
  66
  67 /* Allocate SIZE bytes of memory.  */
  68 extern __ptr_t malloc __P ((size_t __size));
  69 /* Re-allocate the previously allocated block
  70    in __ptr_t, making the new block SIZE bytes long.  */
  71 extern __ptr_t realloc __P ((__ptr_t __ptr, size_t __size));
  72 /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
  73 extern __ptr_t calloc __P ((size_t __nmemb, size_t __size));
  74 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
  75 extern void free __P ((__ptr_t __ptr));
  76
  77 /* Allocate SIZE bytes allocated to ALIGNMENT bytes.  */
  78 extern __ptr_t memalign __P ((size_t __alignment, size_t __size));
  79
  80 /* Allocate SIZE bytes on a page boundary.  */
  81 extern __ptr_t valloc __P ((size_t __size));
  82
  83
  84 #ifdef _MALLOC_INTERNAL
  85
  86 #ifdef  HAVE_CONFIG_H
  87 #include "config.h"
  88 #endif
  89
  90 #if     defined(__GNU_LIBRARY__) || defined(STDC_HEADERS) || defined(USG)
  91 #include <string.h>
  92 #else
  93 #ifndef memset
  94 #define memset(s, zero, n)      bzero ((s), (n))
  95 #endif
  96 #ifndef memcpy
  97 #define memcpy(d, s, n)         bcopy ((s), (d), (n))
  98 #endif
  99 #ifndef memmove
 100 #define memmove(d, s, n)        bcopy ((s), (d), (n))
 101 #endif
 102 #endif
 103
 104
 105 #if     defined(__GNU_LIBRARY__) || defined(__STDC__)
 106 #include <limits.h>
 107 #else
 108 #define CHAR_BIT        8
 109 #endif
 110
 111 /* The allocator divides the heap into blocks of fixed size; large
 112    requests receive one or more whole blocks, and small requests
 113    receive a fragment of a block.  Fragment sizes are powers of two,
 114    and all fragments of a block are the same size.  When all the
 115    fragments in a block have been freed, the block itself is freed.  */
 116 #define INT_BIT         (CHAR_BIT * sizeof(int))
 117 #define BLOCKLOG        (INT_BIT > 16 ? 12 : 9)
 118 #define BLOCKSIZE       (1 << BLOCKLOG)
 119 #define BLOCKIFY(SIZE)  (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE)
 120
 121 /* Determine the amount of memory spanned by the initial heap table
 122    (not an absolute limit).  */
 123 #define HEAP            (INT_BIT > 16 ? 4194304 : 65536)
 124
 125 /* Number of contiguous free blocks allowed to build up at the end of
 126    memory before they will be returned to the system.  */
 127 #define FINAL_FREE_BLOCKS       8
 128
 129 /* Data structure giving per-block information.  */
 130 typedef union
 131   {
 132     /* Heap information for a busy block.  */
 133     struct
 134       {
 135         /* Zero for a large block, or positive giving the
 136            logarithm to the base two of the fragment size.  */
 137         int type;
 138         union
 139           {
 140             struct
 141               {
 142                 size_t nfree;   /* Free fragments in a fragmented block.  */
 143                 size_t first;   /* First free fragment of the block.  */
 144               } frag;
 145             /* Size (in blocks) of a large cluster.  */
 146             size_t size;
 147           } info;
 148       } busy;
 149     /* Heap information for a free block
 150        (that may be the first of a free cluster).  */
 151     struct
 152       {
 153         size_t size;            /* Size (in blocks) of a free cluster.  */
 154         size_t next;            /* Index of next free cluster.  */
 155         size_t prev;            /* Index of previous free cluster.  */
 156       } free;
 157   } malloc_info;
 158
 159 /* Pointer to first block of the heap.  */
 160 extern char *_heapbase;
 161
 162 /* Table indexed by block number giving per-block information.  */
 163 extern malloc_info *_heapinfo;
 164
 165 /* Address to block number and vice versa.  */
 166 #define BLOCK(A)        (((char *) (A) - _heapbase) / BLOCKSIZE + 1)
 167 #define ADDRESS(B)      ((__ptr_t) (((B) - 1) * BLOCKSIZE + _heapbase))
 168
 169 /* Current search index for the heap table.  */
 170 extern size_t _heapindex;
 171
 172 /* Limit of valid info table indices.  */
 173 extern size_t _heaplimit;
 174
 175 /* Doubly linked lists of free fragments.  */
 176 struct list
 177   {
 178     struct list *next;
 179     struct list *prev;
 180   };
 181
 182 /* Count of blocks for each fragment size. */
 183 extern int _fragblocks[];
 184
 185 /* Free list headers for each fragment size.  */
 186 extern struct list _fraghead[];
 187
 188 /* List of blocks allocated with `memalign' (or `valloc').  */
 189 struct alignlist
 190   {
 191     struct alignlist *next;
 192     __ptr_t aligned;            /* The address that memaligned returned.  */
 193     __ptr_t exact;              /* The address that malloc returned.  */
 194   };
 195 extern struct alignlist *_aligned_blocks;
 196
 197 /* Instrumentation.  */
 198 extern size_t _chunks_used;
 199 extern size_t _bytes_used;
 200 extern size_t _chunks_free;
 201 extern size_t _bytes_free;
 202
 203 /* Internal version of `free' used in `morecore' (malloc.c). */
 204 extern void _free_internal __P ((__ptr_t __ptr));
 205
 206 #endif /* _MALLOC_INTERNAL.  */
 207
 208 /* Underlying allocation function; successive calls should
 209    return contiguous pieces of memory.  */
 210 extern __ptr_t (*__morecore) __P ((ptrdiff_t __size));
 211
 212 /* Default value of `__morecore'.  */
 213 extern __ptr_t __default_morecore __P ((ptrdiff_t __size));
 214
 215 /* If not NULL, this function is called after each time
 216    `__morecore' is called to increase the data size.  */
 217 extern void (*__after_morecore_hook) __P ((void));
 218
 219 /* Nonzero if `malloc' has been called and done its initialization.  */
 220 extern int __malloc_initialized;
 221
 222 /* Hooks for debugging versions.  */
 223 extern void (*__free_hook) __P ((__ptr_t __ptr));
 224 extern __ptr_t (*__malloc_hook) __P ((size_t __size));
 225 extern __ptr_t (*__realloc_hook) __P ((__ptr_t __ptr, size_t __size));
 226
 227 /* Activate a standard collection of debugging hooks.  */
 228 extern int mcheck __P ((void (*__bfunc) __P ((char *)),
 229                         void (*__afunc) __P ((void))));
 230
 231 /* Activate a standard collection of tracing hooks.  */
 232 extern void mtrace __P ((void));
 233
 234 /* Statistics available to the user.  */
 235 struct mstats
 236   {
 237     size_t bytes_total;         /* Total size of the heap. */
 238     size_t chunks_used;         /* Chunks allocated by the user. */
 239     size_t bytes_used;          /* Byte total of user-allocated chunks. */
 240     size_t chunks_free;         /* Chunks in the free list. */
 241     size_t bytes_free;          /* Byte total of chunks in the free list. */
 242   };
 243
 244 /* Pick up the current statistics. */
 245 extern struct mstats mstats __P ((void));
 246
 247 /* Call WARNFUN with a warning message when memory usage is high.  */
 248 extern void memory_warnings __P ((__ptr_t __start,
 249                                   void (*__warnfun) __P ((__const char *))));
 250
 251
 252 /* Relocating allocator.  */
 253
 254 /* Allocate SIZE bytes, and store the address in *HANDLEPTR.  */
 255 extern __ptr_t r_alloc __P ((__ptr_t *__handleptr, size_t __size));
 256
 257 /* Free the storage allocated in HANDLEPTR.  */
 258 extern void r_alloc_free __P ((__ptr_t *__handleptr));
 259
 260 /* Adjust the block at HANDLEPTR to be SIZE bytes long.  */
 261 extern __ptr_t r_re_alloc __P ((__ptr_t *__handleptr, size_t __size));
 262
 263
 264 #ifdef  __cplusplus
 265 }
 266 #endif
 267
 268 #endif /* malloc.h  */