gnu/usr.bin/fgrep/obstack.c

   1 /* obstack.c - subroutines used implicitly by object stack macros
   2    Copyright (C) 1988 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify it
   5 under the terms of the GNU General Public License as published by the
   6 Free Software Foundation; either version 1, or (at your option) any
   7 later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18
  19 In other words, you are welcome to use, share and improve this program.
  20 You are forbidden to forbid anyone else to use, share and improve
  21 what you give them.   Help stamp out software-hoarding!  */
  22
  23
  24 #include "obstack.h"
  25
  26 #ifdef __STDC__
  27 #define POINTER void *
  28 #else
  29 #define POINTER char *
  30 #endif
  31
  32 /* Determine default alignment.  */
  33 struct fooalign {char x; double d;};
  34 #define DEFAULT_ALIGNMENT ((char *)&((struct fooalign *) 0)->d - (char *)0)
  35 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
  36    But in fact it might be less smart and round addresses to as much as
  37    DEFAULT_ROUNDING.  So we prepare for it to do that.  */
  38 union fooround {long x; double d;};
  39 #define DEFAULT_ROUNDING (sizeof (union fooround))
  40
  41 /* When we copy a long block of data, this is the unit to do it with.
  42    On some machines, copying successive ints does not work;
  43    in such a case, redefine COPYING_UNIT to `long' (if that works)
  44    or `char' as a last resort.  */
  45 #ifndef COPYING_UNIT
  46 #define COPYING_UNIT int
  47 #endif
  48
  49 /* The non-GNU-C macros copy the obstack into this global variable
  50    to avoid multiple evaluation.  */
  51
  52 struct obstack *_obstack;
  53 \f
  54 /* Initialize an obstack H for use.  Specify chunk size SIZE (0 means default).
  55    Objects start on multiples of ALIGNMENT (0 means use default).
  56    CHUNKFUN is the function to use to allocate chunks,
  57    and FREEFUN the function to free them.  */
  58
  59 void
  60 _obstack_begin (h, size, alignment, chunkfun, freefun)
  61      struct obstack *h;
  62      int size;
  63      int alignment;
  64      POINTER (*chunkfun) ();
  65      void (*freefun) ();
  66 {
  67   register struct _obstack_chunk* chunk; /* points to new chunk */
  68
  69   if (alignment == 0)
  70     alignment = DEFAULT_ALIGNMENT;
  71   if (size == 0)
  72     /* Default size is what GNU malloc can fit in a 4096-byte block.
  73        Pick a number small enough that when rounded up to DEFAULT_ROUNDING
  74        it is still smaller than 4096 - 4.  */
  75     {
  76       int extra = 4;
  77       if (extra < DEFAULT_ROUNDING)
  78         extra = DEFAULT_ROUNDING;
  79       size = 4096 - extra;
  80     }
  81
  82   h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun;
  83   h->freefun = freefun;
  84   h->chunk_size = size;
  85   h->alignment_mask = alignment - 1;
  86
  87   chunk = h->chunk = (*h->chunkfun) (h->chunk_size);
  88   h->next_free = h->object_base = chunk->contents;
  89   h->chunk_limit = chunk->limit
  90    = (char *) chunk + h->chunk_size;
  91   chunk->prev = 0;
  92 }
  93
  94 /* Allocate a new current chunk for the obstack *H
  95    on the assumption that LENGTH bytes need to be added
  96    to the current object, or a new object of length LENGTH allocated.
  97    Copies any partial object from the end of the old chunk
  98    to the beginning of the new one.  */
  99
 100 void
 101 _obstack_newchunk (h, length)
 102      struct obstack *h;
 103      int length;
 104 {
 105   register struct _obstack_chunk*       old_chunk = h->chunk;
 106   register struct _obstack_chunk*       new_chunk;
 107   register long new_size;
 108   register int obj_size = h->next_free - h->object_base;
 109   register int i;
 110   int already;
 111
 112   /* Compute size for new chunk.  */
 113   new_size = (obj_size + length) + (obj_size >> 3) + 100;
 114   if (new_size < h->chunk_size)
 115     new_size = h->chunk_size;
 116
 117   /* Allocate and initialize the new chunk.  */
 118   new_chunk = h->chunk = (*h->chunkfun) (new_size);
 119   new_chunk->prev = old_chunk;
 120   new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
 121
 122   /* Move the existing object to the new chunk.
 123      Word at a time is fast and is safe if the object
 124      is sufficiently aligned.  */
 125   if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
 126     {
 127       for (i = obj_size / sizeof (COPYING_UNIT) - 1;
 128            i >= 0; i--)
 129         ((COPYING_UNIT *)new_chunk->contents)[i]
 130           = ((COPYING_UNIT *)h->object_base)[i];
 131       /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
 132          but that can cross a page boundary on a machine
 133          which does not do strict alignment for COPYING_UNITS.  */
 134       already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
 135     }
 136   else
 137     already = 0;
 138   /* Copy remaining bytes one by one.  */
 139   for (i = already; i < obj_size; i++)
 140     new_chunk->contents[i] = h->object_base[i];
 141
 142   h->object_base = new_chunk->contents;
 143   h->next_free = h->object_base + obj_size;
 144 }
 145
 146 /* Return nonzero if object OBJ has been allocated from obstack H.
 147    This is here for debugging.
 148    If you use it in a program, you are probably losing.  */
 149
 150 int
 151 _obstack_allocated_p (h, obj)
 152      struct obstack *h;
 153      POINTER obj;
 154 {
 155   register struct _obstack_chunk*  lp;  /* below addr of any objects in this chunk */
 156   register struct _obstack_chunk*  plp; /* point to previous chunk if any */
 157
 158   lp = (h)->chunk;
 159   while (lp != 0 && ((POINTER)lp > obj || (POINTER)(lp)->limit < obj))
 160     {
 161       plp = lp -> prev;
 162       lp = plp;
 163     }
 164   return lp != 0;
 165 }
 166
 167 /* Free objects in obstack H, including OBJ and everything allocate
 168    more recently than OBJ.  If OBJ is zero, free everything in H.  */
 169
 170 void
 171 #ifdef __STDC__
 172 #undef obstack_free
 173 obstack_free (struct obstack *h, POINTER obj)
 174 #else
 175 _obstack_free (h, obj)
 176      struct obstack *h;
 177      POINTER obj;
 178 #endif
 179 {
 180   register struct _obstack_chunk*  lp;  /* below addr of any objects in this chunk */
 181   register struct _obstack_chunk*  plp; /* point to previous chunk if any */
 182
 183   lp = (h)->chunk;
 184   while (lp != 0 && ((POINTER)lp > obj || (POINTER)(lp)->limit < obj))
 185     {
 186       plp = lp -> prev;
 187       (*h->freefun) (lp);
 188       lp = plp;
 189     }
 190   if (lp)
 191     {
 192       (h)->object_base = (h)->next_free = (char *)(obj);
 193       (h)->chunk_limit = lp->limit;
 194       (h)->chunk = lp;
 195     }
 196   else if (obj != 0)
 197     /* obj is not in any of the chunks! */
 198     abort ();
 199 }
 200
 201 /* Let same .o link with output of gcc and other compilers.  */
 202
 203 #ifdef __STDC__
 204 void
 205 _obstack_free (h, obj)
 206      struct obstack *h;
 207      POINTER obj;
 208 {
 209   obstack_free (h, obj);
 210 }
 211 #endif
 212 \f
 213 #if 0
 214 /* These are now turned off because the applications do not use it
 215    and it uses bcopy via obstack_grow, which causes trouble on sysV.  */
 216
 217 /* Now define the functional versions of the obstack macros.
 218    Define them to simply use the corresponding macros to do the job.  */
 219
 220 #ifdef __STDC__
 221 /* These function definitions do not work with non-ANSI preprocessors;
 222    they won't pass through the macro names in parentheses.  */
 223
 224 /* The function names appear in parentheses in order to prevent
 225    the macro-definitions of the names from being expanded there.  */
 226
 227 POINTER (obstack_base) (obstack)
 228      struct obstack *obstack;
 229 {
 230   return obstack_base (obstack);
 231 }
 232
 233 POINTER (obstack_next_free) (obstack)
 234      struct obstack *obstack;
 235 {
 236   return obstack_next_free (obstack);
 237 }
 238
 239 int (obstack_object_size) (obstack)
 240      struct obstack *obstack;
 241 {
 242   return obstack_object_size (obstack);
 243 }
 244
 245 int (obstack_room) (obstack)
 246      struct obstack *obstack;
 247 {
 248   return obstack_room (obstack);
 249 }
 250
 251 void (obstack_grow) (obstack, pointer, length)
 252      struct obstack *obstack;
 253      POINTER pointer;
 254      int length;
 255 {
 256   obstack_grow (obstack, pointer, length);
 257 }
 258
 259 void (obstack_grow0) (obstack, pointer, length)
 260      struct obstack *obstack;
 261      POINTER pointer;
 262      int length;
 263 {
 264   obstack_grow0 (obstack, pointer, length);
 265 }
 266
 267 void (obstack_1grow) (obstack, character)
 268      struct obstack *obstack;
 269      int character;
 270 {
 271   obstack_1grow (obstack, character);
 272 }
 273
 274 void (obstack_blank) (obstack, length)
 275      struct obstack *obstack;
 276      int length;
 277 {
 278   obstack_blank (obstack, length);
 279 }
 280
 281 void (obstack_1grow_fast) (obstack, character)
 282      struct obstack *obstack;
 283      int character;
 284 {
 285   obstack_1grow_fast (obstack, character);
 286 }
 287
 288 void (obstack_blank_fast) (obstack, length)
 289      struct obstack *obstack;
 290      int length;
 291 {
 292   obstack_blank_fast (obstack, length);
 293 }
 294
 295 POINTER (obstack_finish) (obstack)
 296      struct obstack *obstack;
 297 {
 298   return obstack_finish (obstack);
 299 }
 300
 301 POINTER (obstack_alloc) (obstack, length)
 302      struct obstack *obstack;
 303      int length;
 304 {
 305   return obstack_alloc (obstack, length);
 306 }
 307
 308 POINTER (obstack_copy) (obstack, pointer, length)
 309      struct obstack *obstack;
 310      POINTER pointer;
 311      int length;
 312 {
 313   return obstack_copy (obstack, pointer, length);
 314 }
 315
 316 POINTER (obstack_copy0) (obstack, pointer, length)
 317      struct obstack *obstack;
 318      POINTER pointer;
 319      int length;
 320 {
 321   return obstack_copy0 (obstack, pointer, length);
 322 }
 323
 324 #endif /* __STDC__ */
 325
 326 #endif /* 0 */