malloc/obstack.c

   1 /* obstack.c - subroutines used implicitly by object stack macros
   2    Copyright (C) 1988,89,90,91,92,93,94,96 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU C Library.  Its master source is NOT part of
   5    the C library, however.  The master source lives in /gd/gnu/lib.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Library General Public License as
   9    published by the Free Software Foundation; either version 2 of the
  10    License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Library General Public License for more details.
  16
  17    You should have received a copy of the GNU Library General Public
  18    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  19    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "obstack.h"
  23
  24 /* NOTE BEFORE MODIFYING THIS FILE: This version number must be
  25    incremented whenever callers compiled using an old obstack.h can no
  26    longer properly call the functions in this obstack.c.  */
  27 #define OBSTACK_INTERFACE_VERSION 1
  28
  29 /* Comment out all this code if we are using the GNU C Library, and are not
  30    actually compiling the library itself, and the installed library
  31    supports the same library interface we do.  This code is part of the GNU
  32    C Library, but also included in many other GNU distributions.  Compiling
  33    and linking in this code is a waste when using the GNU C library
  34    (especially if it is a shared library).  Rather than having every GNU
  35    program understand `configure --with-gnu-libc' and omit the object
  36    files, it is simpler to just do this in the source for each such file.  */
  37
  38 #include <stdio.h>              /* Random thing to get __GNU_LIBRARY__.  */
  39 #if !defined (_LIBC) && defined (__GNU_LIBRARY__) && __GNU_LIBRARY__ > 1
  40 #include <gnu-versions.h>
  41 #if _GNU_OBSTACK_INTERFACE_VERSION == OBSTACK_INTERFACE_VERSION
  42 #define ELIDE_CODE
  43 #endif
  44 #endif
  45
  46
  47 #ifndef ELIDE_CODE
  48
  49
  50 #if defined (__STDC__) && __STDC__
  51 #define POINTER void *
  52 #else
  53 #define POINTER char *
  54 #endif
  55
  56 /* Determine default alignment.  */
  57 struct fooalign {char x; double d;};
  58 #define DEFAULT_ALIGNMENT  \
  59   ((PTR_INT_TYPE) ((char *) &((struct fooalign *) 0)->d - (char *) 0))
  60 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
  61    But in fact it might be less smart and round addresses to as much as
  62    DEFAULT_ROUNDING.  So we prepare for it to do that.  */
  63 union fooround {long x; double d;};
  64 #define DEFAULT_ROUNDING (sizeof (union fooround))
  65
  66 /* When we copy a long block of data, this is the unit to do it with.
  67    On some machines, copying successive ints does not work;
  68    in such a case, redefine COPYING_UNIT to `long' (if that works)
  69    or `char' as a last resort.  */
  70 #ifndef COPYING_UNIT
  71 #define COPYING_UNIT int
  72 #endif
  73
  74
  75 /* The functions allocating more room by calling `obstack_chunk_alloc'
  76    jump to the handler pointed to by `obstack_alloc_failed_handler'.
  77    This variable by default points to the internal function
  78    `print_and_abort'.  */
  79 #if defined (__STDC__) && __STDC__
  80 static void print_and_abort (void);
  81 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
  82 #else
  83 static void print_and_abort ();
  84 void (*obstack_alloc_failed_handler) () = print_and_abort;
  85 #endif
  86
  87 /* Exit value used when `print_and_abort' is used.  */
  88 #if defined (__STDC__) && __STDC__
  89 #include <stdlib.h>
  90 #endif
  91 #ifndef EXIT_FAILURE
  92 #define EXIT_FAILURE 1
  93 #endif
  94 int obstack_exit_failure = EXIT_FAILURE;
  95
  96 /* The non-GNU-C macros copy the obstack into this global variable
  97    to avoid multiple evaluation.  */
  98
  99 struct obstack *_obstack;
 100
 101 /* Define a macro that either calls functions with the traditional malloc/free
 102    calling interface, or calls functions with the mmalloc/mfree interface
 103    (that adds an extra first argument), based on the state of use_extra_arg.
 104    For free, do not use ?:, since some compilers, like the MIPS compilers,
 105    do not allow (expr) ? void : void.  */
 106
 107 #define CALL_CHUNKFUN(h, size) \
 108   (((h) -> use_extra_arg) \
 109    ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
 110    : (*(struct _obstack_chunk *(*) ()) (h)->chunkfun) ((size)))
 111
 112 #define CALL_FREEFUN(h, old_chunk) \
 113   do { \
 114     if ((h) -> use_extra_arg) \
 115       (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
 116     else \
 117       (*(void (*) ()) (h)->freefun) ((old_chunk)); \
 118   } while (0)
 119
 120 \f
 121 /* Initialize an obstack H for use.  Specify chunk size SIZE (0 means default).
 122    Objects start on multiples of ALIGNMENT (0 means use default).
 123    CHUNKFUN is the function to use to allocate chunks,
 124    and FREEFUN the function to free them.
 125
 126    Return nonzero if successful, zero if out of memory.
 127    To recover from an out of memory error,
 128    free up some memory, then call this again.  */
 129
 130 int
 131 _obstack_begin (h, size, alignment, chunkfun, freefun)
 132      struct obstack *h;
 133      int size;
 134      int alignment;
 135      POINTER (*chunkfun) ();
 136      void (*freefun) ();
 137 {
 138   register struct _obstack_chunk *chunk; /* points to new chunk */
 139
 140   if (alignment == 0)
 141     alignment = DEFAULT_ALIGNMENT;
 142   if (size == 0)
 143     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 144     {
 145       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 146          Use the values for range checking, because if range checking is off,
 147          the extra bytes won't be missed terribly, but if range checking is on
 148          and we used a larger request, a whole extra 4096 bytes would be
 149          allocated.
 150
 151          These number are irrelevant to the new GNU malloc.  I suspect it is
 152          less sensitive to the size of the request.  */
 153       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 154                     + 4 + DEFAULT_ROUNDING - 1)
 155                    & ~(DEFAULT_ROUNDING - 1));
 156       size = 4096 - extra;
 157     }
 158
 159   h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun;
 160   h->freefun = freefun;
 161   h->chunk_size = size;
 162   h->alignment_mask = alignment - 1;
 163   h->use_extra_arg = 0;
 164
 165   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 166   if (!chunk)
 167     (*obstack_alloc_failed_handler) ();
 168   h->next_free = h->object_base = chunk->contents;
 169   h->chunk_limit = chunk->limit
 170     = (char *) chunk + h->chunk_size;
 171   chunk->prev = 0;
 172   /* The initial chunk now contains no empty object.  */
 173   h->maybe_empty_object = 0;
 174   h->alloc_failed = 0;
 175   return 1;
 176 }
 177
 178 int
 179 _obstack_begin_1 (h, size, alignment, chunkfun, freefun, arg)
 180      struct obstack *h;
 181      int size;
 182      int alignment;
 183      POINTER (*chunkfun) ();
 184      void (*freefun) ();
 185      POINTER arg;
 186 {
 187   register struct _obstack_chunk *chunk; /* points to new chunk */
 188
 189   if (alignment == 0)
 190     alignment = DEFAULT_ALIGNMENT;
 191   if (size == 0)
 192     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 193     {
 194       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 195          Use the values for range checking, because if range checking is off,
 196          the extra bytes won't be missed terribly, but if range checking is on
 197          and we used a larger request, a whole extra 4096 bytes would be
 198          allocated.
 199
 200          These number are irrelevant to the new GNU malloc.  I suspect it is
 201          less sensitive to the size of the request.  */
 202       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 203                     + 4 + DEFAULT_ROUNDING - 1)
 204                    & ~(DEFAULT_ROUNDING - 1));
 205       size = 4096 - extra;
 206     }
 207
 208   h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun;
 209   h->freefun = freefun;
 210   h->chunk_size = size;
 211   h->alignment_mask = alignment - 1;
 212   h->extra_arg = arg;
 213   h->use_extra_arg = 1;
 214
 215   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 216   if (!chunk)
 217     (*obstack_alloc_failed_handler) ();
 218   h->next_free = h->object_base = chunk->contents;
 219   h->chunk_limit = chunk->limit
 220     = (char *) chunk + h->chunk_size;
 221   chunk->prev = 0;
 222   /* The initial chunk now contains no empty object.  */
 223   h->maybe_empty_object = 0;
 224   h->alloc_failed = 0;
 225   return 1;
 226 }
 227
 228 /* Allocate a new current chunk for the obstack *H
 229    on the assumption that LENGTH bytes need to be added
 230    to the current object, or a new object of length LENGTH allocated.
 231    Copies any partial object from the end of the old chunk
 232    to the beginning of the new one.  */
 233
 234 void
 235 _obstack_newchunk (h, length)
 236      struct obstack *h;
 237      int length;
 238 {
 239   register struct _obstack_chunk *old_chunk = h->chunk;
 240   register struct _obstack_chunk *new_chunk;
 241   register long new_size;
 242   register int obj_size = h->next_free - h->object_base;
 243   register int i;
 244   int already;
 245
 246   /* Compute size for new chunk.  */
 247   new_size = (obj_size + length) + (obj_size >> 3) + 100;
 248   if (new_size < h->chunk_size)
 249     new_size = h->chunk_size;
 250
 251   /* Allocate and initialize the new chunk.  */
 252   new_chunk = CALL_CHUNKFUN (h, new_size);
 253   if (!new_chunk)
 254     (*obstack_alloc_failed_handler) ();
 255   h->chunk = new_chunk;
 256   new_chunk->prev = old_chunk;
 257   new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
 258
 259   /* Move the existing object to the new chunk.
 260      Word at a time is fast and is safe if the object
 261      is sufficiently aligned.  */
 262   if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
 263     {
 264       for (i = obj_size / sizeof (COPYING_UNIT) - 1;
 265            i >= 0; i--)
 266         ((COPYING_UNIT *)new_chunk->contents)[i]
 267           = ((COPYING_UNIT *)h->object_base)[i];
 268       /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
 269          but that can cross a page boundary on a machine
 270          which does not do strict alignment for COPYING_UNITS.  */
 271       already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
 272     }
 273   else
 274     already = 0;
 275   /* Copy remaining bytes one by one.  */
 276   for (i = already; i < obj_size; i++)
 277     new_chunk->contents[i] = h->object_base[i];
 278
 279   /* If the object just copied was the only data in OLD_CHUNK,
 280      free that chunk and remove it from the chain.
 281      But not if that chunk might contain an empty object.  */
 282   if (h->object_base == old_chunk->contents && ! h->maybe_empty_object)
 283     {
 284       new_chunk->prev = old_chunk->prev;
 285       CALL_FREEFUN (h, old_chunk);
 286     }
 287
 288   h->object_base = new_chunk->contents;
 289   h->next_free = h->object_base + obj_size;
 290   /* The new chunk certainly contains no empty object yet.  */
 291   h->maybe_empty_object = 0;
 292 }
 293
 294 /* Return nonzero if object OBJ has been allocated from obstack H.
 295    This is here for debugging.
 296    If you use it in a program, you are probably losing.  */
 297
 298 #if defined (__STDC__) && __STDC__
 299 /* Suppress -Wmissing-prototypes warning.  We don't want to declare this in
 300    obstack.h because it is just for debugging.  */
 301 int _obstack_allocated_p (struct obstack *h, POINTER obj);
 302 #endif
 303
 304 int
 305 _obstack_allocated_p (h, obj)
 306      struct obstack *h;
 307      POINTER obj;
 308 {
 309   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 310   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 311
 312   lp = (h)->chunk;
 313   /* We use >= rather than > since the object cannot be exactly at
 314      the beginning of the chunk but might be an empty object exactly
 315      at the end of an adjacent chunk.  */
 316   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 317     {
 318       plp = lp->prev;
 319       lp = plp;
 320     }
 321   return lp != 0;
 322 }
 323 \f
 324 /* Free objects in obstack H, including OBJ and everything allocate
 325    more recently than OBJ.  If OBJ is zero, free everything in H.  */
 326
 327 #undef obstack_free
 328
 329 /* This function has two names with identical definitions.
 330    This is the first one, called from non-ANSI code.  */
 331
 332 void
 333 _obstack_free (h, obj)
 334      struct obstack *h;
 335      POINTER obj;
 336 {
 337   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 338   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 339
 340   lp = h->chunk;
 341   /* We use >= because there cannot be an object at the beginning of a chunk.
 342      But there can be an empty object at that address
 343      at the end of another chunk.  */
 344   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 345     {
 346       plp = lp->prev;
 347       CALL_FREEFUN (h, lp);
 348       lp = plp;
 349       /* If we switch chunks, we can't tell whether the new current
 350          chunk contains an empty object, so assume that it may.  */
 351       h->maybe_empty_object = 1;
 352     }
 353   if (lp)
 354     {
 355       h->object_base = h->next_free = (char *) (obj);
 356       h->chunk_limit = lp->limit;
 357       h->chunk = lp;
 358     }
 359   else if (obj != 0)
 360     /* obj is not in any of the chunks! */
 361     abort ();
 362 }
 363
 364 /* This function is used from ANSI code.  */
 365
 366 void
 367 obstack_free (h, obj)
 368      struct obstack *h;
 369      POINTER obj;
 370 {
 371   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 372   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 373
 374   lp = h->chunk;
 375   /* We use >= because there cannot be an object at the beginning of a chunk.
 376      But there can be an empty object at that address
 377      at the end of another chunk.  */
 378   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 379     {
 380       plp = lp->prev;
 381       CALL_FREEFUN (h, lp);
 382       lp = plp;
 383       /* If we switch chunks, we can't tell whether the new current
 384          chunk contains an empty object, so assume that it may.  */
 385       h->maybe_empty_object = 1;
 386     }
 387   if (lp)
 388     {
 389       h->object_base = h->next_free = (char *) (obj);
 390       h->chunk_limit = lp->limit;
 391       h->chunk = lp;
 392     }
 393   else if (obj != 0)
 394     /* obj is not in any of the chunks! */
 395     abort ();
 396 }
 397 \f
 398 int
 399 _obstack_memory_used (h)
 400      struct obstack *h;
 401 {
 402   register struct _obstack_chunk* lp;
 403   register int nbytes = 0;
 404
 405   for (lp = h->chunk; lp != 0; lp = lp->prev)
 406     {
 407       nbytes += lp->limit - (char *) lp;
 408     }
 409   return nbytes;
 410 }
 411 \f
 412 /* Define the error handler.  */
 413 #ifndef _
 414 # ifdef HAVE_LIBINTL_H
 415 #  include <libintl.h>
 416 #  ifndef _
 417 #   define _(Str) gettext (Str)
 418 #  endif
 419 # else
 420 #  define _(Str) (Str)
 421 # endif
 422 #endif
 423
 424 static void
 425 print_and_abort ()
 426 {
 427   fputs (_("memory exhausted\n"), stderr);
 428   exit (obstack_exit_failure);
 429 }
 430 \f
 431 #if 0
 432 /* These are now turned off because the applications do not use it
 433    and it uses bcopy via obstack_grow, which causes trouble on sysV.  */
 434
 435 /* Now define the functional versions of the obstack macros.
 436    Define them to simply use the corresponding macros to do the job.  */
 437
 438 #if defined (__STDC__) && __STDC__
 439 /* These function definitions do not work with non-ANSI preprocessors;
 440    they won't pass through the macro names in parentheses.  */
 441
 442 /* The function names appear in parentheses in order to prevent
 443    the macro-definitions of the names from being expanded there.  */
 444
 445 POINTER (obstack_base) (obstack)
 446      struct obstack *obstack;
 447 {
 448   return obstack_base (obstack);
 449 }
 450
 451 POINTER (obstack_next_free) (obstack)
 452      struct obstack *obstack;
 453 {
 454   return obstack_next_free (obstack);
 455 }
 456
 457 int (obstack_object_size) (obstack)
 458      struct obstack *obstack;
 459 {
 460   return obstack_object_size (obstack);
 461 }
 462
 463 int (obstack_room) (obstack)
 464      struct obstack *obstack;
 465 {
 466   return obstack_room (obstack);
 467 }
 468
 469 int (obstack_make_room) (obstack, length)
 470      struct obstack *obstack;
 471      int length;
 472 {
 473   return obstack_make_room (obstack, length);
 474 }
 475
 476 void (obstack_grow) (obstack, pointer, length)
 477      struct obstack *obstack;
 478      POINTER pointer;
 479      int length;
 480 {
 481   obstack_grow (obstack, pointer, length);
 482 }
 483
 484 void (obstack_grow0) (obstack, pointer, length)
 485      struct obstack *obstack;
 486      POINTER pointer;
 487      int length;
 488 {
 489   obstack_grow0 (obstack, pointer, length);
 490 }
 491
 492 void (obstack_1grow) (obstack, character)
 493      struct obstack *obstack;
 494      int character;
 495 {
 496   obstack_1grow (obstack, character);
 497 }
 498
 499 void (obstack_blank) (obstack, length)
 500      struct obstack *obstack;
 501      int length;
 502 {
 503   obstack_blank (obstack, length);
 504 }
 505
 506 void (obstack_1grow_fast) (obstack, character)
 507      struct obstack *obstack;
 508      int character;
 509 {
 510   obstack_1grow_fast (obstack, character);
 511 }
 512
 513 void (obstack_blank_fast) (obstack, length)
 514      struct obstack *obstack;
 515      int length;
 516 {
 517   obstack_blank_fast (obstack, length);
 518 }
 519
 520 POINTER (obstack_finish) (obstack)
 521      struct obstack *obstack;
 522 {
 523   return obstack_finish (obstack);
 524 }
 525
 526 POINTER (obstack_alloc) (obstack, length)
 527      struct obstack *obstack;
 528      int length;
 529 {
 530   return obstack_alloc (obstack, length);
 531 }
 532
 533 POINTER (obstack_copy) (obstack, pointer, length)
 534      struct obstack *obstack;
 535      POINTER pointer;
 536      int length;
 537 {
 538   return obstack_copy (obstack, pointer, length);
 539 }
 540
 541 POINTER (obstack_copy0) (obstack, pointer, length)
 542      struct obstack *obstack;
 543      POINTER pointer;
 544      int length;
 545 {
 546   return obstack_copy0 (obstack, pointer, length);
 547 }
 548
 549 #endif /* __STDC__ */
 550
 551 #endif /* 0 */
 552
 553 #endif  /* !ELIDE_CODE */