malloc/obstack.c

   1 /* obstack.c - subroutines used implicitly by object stack macros
   2    Copyright (C) 1988-1994,96,97,98,99,2000,2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.  Its master source is NOT part of
   4    the C library, however.  The master source lives in /gd/gnu/lib.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include <config.h>
  23 #endif
  24
  25 #include "obstack.h"
  26
  27 /* NOTE BEFORE MODIFYING THIS FILE: This version number must be
  28    incremented whenever callers compiled using an old obstack.h can no
  29    longer properly call the functions in this obstack.c.  */
  30 #define OBSTACK_INTERFACE_VERSION 1
  31
  32 /* Comment out all this code if we are using the GNU C Library, and are not
  33    actually compiling the library itself, and the installed library
  34    supports the same library interface we do.  This code is part of the GNU
  35    C Library, but also included in many other GNU distributions.  Compiling
  36    and linking in this code is a waste when using the GNU C library
  37    (especially if it is a shared library).  Rather than having every GNU
  38    program understand `configure --with-gnu-libc' and omit the object
  39    files, it is simpler to just do this in the source for each such file.  */
  40
  41 #include <stdio.h>              /* Random thing to get __GNU_LIBRARY__.  */
  42 #if !defined (_LIBC) && defined (__GNU_LIBRARY__) && __GNU_LIBRARY__ > 1
  43 #include <gnu-versions.h>
  44 #if _GNU_OBSTACK_INTERFACE_VERSION == OBSTACK_INTERFACE_VERSION
  45 #define ELIDE_CODE
  46 #endif
  47 #endif
  48
  49
  50 #ifndef ELIDE_CODE
  51
  52
  53 #if defined (__STDC__) && __STDC__
  54 #define POINTER void *
  55 #else
  56 #define POINTER char *
  57 #endif
  58
  59 /* Determine default alignment.  */
  60 struct fooalign {char x; double d;};
  61 #define DEFAULT_ALIGNMENT  \
  62   ((PTR_INT_TYPE) ((char *) &((struct fooalign *) 0)->d - (char *) 0))
  63 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
  64    But in fact it might be less smart and round addresses to as much as
  65    DEFAULT_ROUNDING.  So we prepare for it to do that.  */
  66 union fooround {long x; double d;};
  67 #define DEFAULT_ROUNDING (sizeof (union fooround))
  68
  69 /* When we copy a long block of data, this is the unit to do it with.
  70    On some machines, copying successive ints does not work;
  71    in such a case, redefine COPYING_UNIT to `long' (if that works)
  72    or `char' as a last resort.  */
  73 #ifndef COPYING_UNIT
  74 #define COPYING_UNIT int
  75 #endif
  76
  77
  78 /* The functions allocating more room by calling `obstack_chunk_alloc'
  79    jump to the handler pointed to by `obstack_alloc_failed_handler'.
  80    This can be set to a user defined function which should either
  81    abort gracefully or use longjump - but shouldn't return.  This
  82    variable by default points to the internal function
  83    `print_and_abort'.  */
  84 #if defined (__STDC__) && __STDC__
  85 static void print_and_abort (void);
  86 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
  87 #else
  88 static void print_and_abort ();
  89 void (*obstack_alloc_failed_handler) () = print_and_abort;
  90 #endif
  91
  92 /* Exit value used when `print_and_abort' is used.  */
  93 #if defined __GNU_LIBRARY__ || defined HAVE_STDLIB_H
  94 #include <stdlib.h>
  95 #endif
  96 #ifndef EXIT_FAILURE
  97 #define EXIT_FAILURE 1
  98 #endif
  99 int obstack_exit_failure = EXIT_FAILURE;
 100
 101 /* The non-GNU-C macros copy the obstack into this global variable
 102    to avoid multiple evaluation.  */
 103
 104 struct obstack *_obstack;
 105
 106 /* Define a macro that either calls functions with the traditional malloc/free
 107    calling interface, or calls functions with the mmalloc/mfree interface
 108    (that adds an extra first argument), based on the state of use_extra_arg.
 109    For free, do not use ?:, since some compilers, like the MIPS compilers,
 110    do not allow (expr) ? void : void.  */
 111
 112 #if defined (__STDC__) && __STDC__
 113 #define CALL_CHUNKFUN(h, size) \
 114   (((h) -> use_extra_arg) \
 115    ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
 116    : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
 117
 118 #define CALL_FREEFUN(h, old_chunk) \
 119   do { \
 120     if ((h) -> use_extra_arg) \
 121       (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
 122     else \
 123       (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
 124   } while (0)
 125 #else
 126 #define CALL_CHUNKFUN(h, size) \
 127   (((h) -> use_extra_arg) \
 128    ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
 129    : (*(struct _obstack_chunk *(*) ()) (h)->chunkfun) ((size)))
 130
 131 #define CALL_FREEFUN(h, old_chunk) \
 132   do { \
 133     if ((h) -> use_extra_arg) \
 134       (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
 135     else \
 136       (*(void (*) ()) (h)->freefun) ((old_chunk)); \
 137   } while (0)
 138 #endif
 139
 140 \f
 141 /* Initialize an obstack H for use.  Specify chunk size SIZE (0 means default).
 142    Objects start on multiples of ALIGNMENT (0 means use default).
 143    CHUNKFUN is the function to use to allocate chunks,
 144    and FREEFUN the function to free them.
 145
 146    Return nonzero if successful, calls obstack_alloc_failed_handler if
 147    allocation fails.  */
 148
 149 int
 150 _obstack_begin (h, size, alignment, chunkfun, freefun)
 151      struct obstack *h;
 152      int size;
 153      int alignment;
 154 #if defined (__STDC__) && __STDC__
 155      POINTER (*chunkfun) (long);
 156      void (*freefun) (void *);
 157 #else
 158      POINTER (*chunkfun) ();
 159      void (*freefun) ();
 160 #endif
 161 {
 162   register struct _obstack_chunk *chunk; /* points to new chunk */
 163
 164   if (alignment == 0)
 165     alignment = (int) DEFAULT_ALIGNMENT;
 166   if (size == 0)
 167     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 168     {
 169       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 170          Use the values for range checking, because if range checking is off,
 171          the extra bytes won't be missed terribly, but if range checking is on
 172          and we used a larger request, a whole extra 4096 bytes would be
 173          allocated.
 174
 175          These number are irrelevant to the new GNU malloc.  I suspect it is
 176          less sensitive to the size of the request.  */
 177       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 178                     + 4 + DEFAULT_ROUNDING - 1)
 179                    & ~(DEFAULT_ROUNDING - 1));
 180       size = 4096 - extra;
 181     }
 182
 183 #if defined (__STDC__) && __STDC__
 184   h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
 185   h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
 186 #else
 187   h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun;
 188   h->freefun = freefun;
 189 #endif
 190   h->chunk_size = size;
 191   h->alignment_mask = alignment - 1;
 192   h->use_extra_arg = 0;
 193
 194   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 195   if (!chunk)
 196     (*obstack_alloc_failed_handler) ();
 197   h->next_free = h->object_base = chunk->contents;
 198   h->chunk_limit = chunk->limit
 199     = (char *) chunk + h->chunk_size;
 200   chunk->prev = 0;
 201   /* The initial chunk now contains no empty object.  */
 202   h->maybe_empty_object = 0;
 203   h->alloc_failed = 0;
 204   return 1;
 205 }
 206
 207 int
 208 _obstack_begin_1 (h, size, alignment, chunkfun, freefun, arg)
 209      struct obstack *h;
 210      int size;
 211      int alignment;
 212 #if defined (__STDC__) && __STDC__
 213      POINTER (*chunkfun) (POINTER, long);
 214      void (*freefun) (POINTER, POINTER);
 215 #else
 216      POINTER (*chunkfun) ();
 217      void (*freefun) ();
 218 #endif
 219      POINTER arg;
 220 {
 221   register struct _obstack_chunk *chunk; /* points to new chunk */
 222
 223   if (alignment == 0)
 224     alignment = (int) DEFAULT_ALIGNMENT;
 225   if (size == 0)
 226     /* Default size is what GNU malloc can fit in a 4096-byte block.  */
 227     {
 228       /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
 229          Use the values for range checking, because if range checking is off,
 230          the extra bytes won't be missed terribly, but if range checking is on
 231          and we used a larger request, a whole extra 4096 bytes would be
 232          allocated.
 233
 234          These number are irrelevant to the new GNU malloc.  I suspect it is
 235          less sensitive to the size of the request.  */
 236       int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
 237                     + 4 + DEFAULT_ROUNDING - 1)
 238                    & ~(DEFAULT_ROUNDING - 1));
 239       size = 4096 - extra;
 240     }
 241
 242 #if defined(__STDC__) && __STDC__
 243   h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
 244   h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
 245 #else
 246   h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun;
 247   h->freefun = freefun;
 248 #endif
 249   h->chunk_size = size;
 250   h->alignment_mask = alignment - 1;
 251   h->extra_arg = arg;
 252   h->use_extra_arg = 1;
 253
 254   chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
 255   if (!chunk)
 256     (*obstack_alloc_failed_handler) ();
 257   h->next_free = h->object_base = chunk->contents;
 258   h->chunk_limit = chunk->limit
 259     = (char *) chunk + h->chunk_size;
 260   chunk->prev = 0;
 261   /* The initial chunk now contains no empty object.  */
 262   h->maybe_empty_object = 0;
 263   h->alloc_failed = 0;
 264   return 1;
 265 }
 266
 267 /* Allocate a new current chunk for the obstack *H
 268    on the assumption that LENGTH bytes need to be added
 269    to the current object, or a new object of length LENGTH allocated.
 270    Copies any partial object from the end of the old chunk
 271    to the beginning of the new one.  */
 272
 273 void
 274 _obstack_newchunk (h, length)
 275      struct obstack *h;
 276      int length;
 277 {
 278   register struct _obstack_chunk *old_chunk = h->chunk;
 279   register struct _obstack_chunk *new_chunk;
 280   register long new_size;
 281   register long obj_size = h->next_free - h->object_base;
 282   register long i;
 283   long already;
 284   char *object_base;
 285
 286   /* Compute size for new chunk.  */
 287   new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
 288   if (new_size < h->chunk_size)
 289     new_size = h->chunk_size;
 290
 291   /* Allocate and initialize the new chunk.  */
 292   new_chunk = CALL_CHUNKFUN (h, new_size);
 293   if (!new_chunk)
 294     (*obstack_alloc_failed_handler) ();
 295   h->chunk = new_chunk;
 296   new_chunk->prev = old_chunk;
 297   new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
 298
 299   /* Compute an aligned object_base in the new chunk */
 300   object_base =
 301     __INT_TO_PTR ((__PTR_TO_INT (new_chunk->contents) + h->alignment_mask)
 302                   & ~ (h->alignment_mask));
 303
 304   /* Move the existing object to the new chunk.
 305      Word at a time is fast and is safe if the object
 306      is sufficiently aligned.  */
 307   if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
 308     {
 309       for (i = obj_size / sizeof (COPYING_UNIT) - 1;
 310            i >= 0; i--)
 311         ((COPYING_UNIT *)object_base)[i]
 312           = ((COPYING_UNIT *)h->object_base)[i];
 313       /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
 314          but that can cross a page boundary on a machine
 315          which does not do strict alignment for COPYING_UNITS.  */
 316       already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
 317     }
 318   else
 319     already = 0;
 320   /* Copy remaining bytes one by one.  */
 321   for (i = already; i < obj_size; i++)
 322     object_base[i] = h->object_base[i];
 323
 324   /* If the object just copied was the only data in OLD_CHUNK,
 325      free that chunk and remove it from the chain.
 326      But not if that chunk might contain an empty object.  */
 327   if (h->object_base == old_chunk->contents && ! h->maybe_empty_object)
 328     {
 329       new_chunk->prev = old_chunk->prev;
 330       CALL_FREEFUN (h, old_chunk);
 331     }
 332
 333   h->object_base = object_base;
 334   h->next_free = h->object_base + obj_size;
 335   /* The new chunk certainly contains no empty object yet.  */
 336   h->maybe_empty_object = 0;
 337 }
 338
 339 /* Return nonzero if object OBJ has been allocated from obstack H.
 340    This is here for debugging.
 341    If you use it in a program, you are probably losing.  */
 342
 343 #if defined (__STDC__) && __STDC__
 344 /* Suppress -Wmissing-prototypes warning.  We don't want to declare this in
 345    obstack.h because it is just for debugging.  */
 346 int _obstack_allocated_p (struct obstack *h, POINTER obj);
 347 #endif
 348
 349 int
 350 _obstack_allocated_p (h, obj)
 351      struct obstack *h;
 352      POINTER obj;
 353 {
 354   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 355   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 356
 357   lp = (h)->chunk;
 358   /* We use >= rather than > since the object cannot be exactly at
 359      the beginning of the chunk but might be an empty object exactly
 360      at the end of an adjacent chunk.  */
 361   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 362     {
 363       plp = lp->prev;
 364       lp = plp;
 365     }
 366   return lp != 0;
 367 }
 368 \f
 369 /* Free objects in obstack H, including OBJ and everything allocate
 370    more recently than OBJ.  If OBJ is zero, free everything in H.  */
 371
 372 #undef obstack_free
 373
 374 /* This function has two names with identical definitions.
 375    This is the first one, called from non-ANSI code.  */
 376
 377 void
 378 _obstack_free (h, obj)
 379      struct obstack *h;
 380      POINTER obj;
 381 {
 382   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 383   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 384
 385   lp = h->chunk;
 386   /* We use >= because there cannot be an object at the beginning of a chunk.
 387      But there can be an empty object at that address
 388      at the end of another chunk.  */
 389   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 390     {
 391       plp = lp->prev;
 392       CALL_FREEFUN (h, lp);
 393       lp = plp;
 394       /* If we switch chunks, we can't tell whether the new current
 395          chunk contains an empty object, so assume that it may.  */
 396       h->maybe_empty_object = 1;
 397     }
 398   if (lp)
 399     {
 400       h->object_base = h->next_free = (char *) (obj);
 401       h->chunk_limit = lp->limit;
 402       h->chunk = lp;
 403     }
 404   else if (obj != 0)
 405     /* obj is not in any of the chunks! */
 406     abort ();
 407 }
 408
 409 /* This function is used from ANSI code.  */
 410
 411 void
 412 obstack_free (h, obj)
 413      struct obstack *h;
 414      POINTER obj;
 415 {
 416   register struct _obstack_chunk *lp;   /* below addr of any objects in this chunk */
 417   register struct _obstack_chunk *plp;  /* point to previous chunk if any */
 418
 419   lp = h->chunk;
 420   /* We use >= because there cannot be an object at the beginning of a chunk.
 421      But there can be an empty object at that address
 422      at the end of another chunk.  */
 423   while (lp != 0 && ((POINTER) lp >= obj || (POINTER) (lp)->limit < obj))
 424     {
 425       plp = lp->prev;
 426       CALL_FREEFUN (h, lp);
 427       lp = plp;
 428       /* If we switch chunks, we can't tell whether the new current
 429          chunk contains an empty object, so assume that it may.  */
 430       h->maybe_empty_object = 1;
 431     }
 432   if (lp)
 433     {
 434       h->object_base = h->next_free = (char *) (obj);
 435       h->chunk_limit = lp->limit;
 436       h->chunk = lp;
 437     }
 438   else if (obj != 0)
 439     /* obj is not in any of the chunks! */
 440     abort ();
 441 }
 442 \f
 443 int
 444 _obstack_memory_used (h)
 445      struct obstack *h;
 446 {
 447   register struct _obstack_chunk* lp;
 448   register int nbytes = 0;
 449
 450   for (lp = h->chunk; lp != 0; lp = lp->prev)
 451     {
 452       nbytes += lp->limit - (char *) lp;
 453     }
 454   return nbytes;
 455 }
 456 \f
 457 /* Define the error handler.  */
 458 #ifndef _
 459 # if defined HAVE_LIBINTL_H || defined _LIBC
 460 #  include <libintl.h>
 461 #  ifndef _
 462 #   define _(Str) gettext (Str)
 463 #  endif
 464 # else
 465 #  define _(Str) (Str)
 466 # endif
 467 #endif
 468 #if defined _LIBC && defined USE_IN_LIBIO
 469 # include <libio/iolibio.h>
 470 # define fputs(s, f) _IO_fputs (s, f)
 471 #endif
 472
 473 static void
 474 __attribute__ ((noreturn))
 475 print_and_abort ()
 476 {
 477   fputs (_("memory exhausted"), stderr);
 478   fputc ('\n', stderr);
 479   exit (obstack_exit_failure);
 480 }
 481 \f
 482 #if 0
 483 /* These are now turned off because the applications do not use it
 484    and it uses bcopy via obstack_grow, which causes trouble on sysV.  */
 485
 486 /* Now define the functional versions of the obstack macros.
 487    Define them to simply use the corresponding macros to do the job.  */
 488
 489 #if defined (__STDC__) && __STDC__
 490 /* These function definitions do not work with non-ANSI preprocessors;
 491    they won't pass through the macro names in parentheses.  */
 492
 493 /* The function names appear in parentheses in order to prevent
 494    the macro-definitions of the names from being expanded there.  */
 495
 496 POINTER (obstack_base) (obstack)
 497      struct obstack *obstack;
 498 {
 499   return obstack_base (obstack);
 500 }
 501
 502 POINTER (obstack_next_free) (obstack)
 503      struct obstack *obstack;
 504 {
 505   return obstack_next_free (obstack);
 506 }
 507
 508 int (obstack_object_size) (obstack)
 509      struct obstack *obstack;
 510 {
 511   return obstack_object_size (obstack);
 512 }
 513
 514 int (obstack_room) (obstack)
 515      struct obstack *obstack;
 516 {
 517   return obstack_room (obstack);
 518 }
 519
 520 int (obstack_make_room) (obstack, length)
 521      struct obstack *obstack;
 522      int length;
 523 {
 524   return obstack_make_room (obstack, length);
 525 }
 526
 527 void (obstack_grow) (obstack, data, length)
 528      struct obstack *obstack;
 529      const POINTER data;
 530      int length;
 531 {
 532   obstack_grow (obstack, data, length);
 533 }
 534
 535 void (obstack_grow0) (obstack, data, length)
 536      struct obstack *obstack;
 537      const POINTER data;
 538      int length;
 539 {
 540   obstack_grow0 (obstack, data, length);
 541 }
 542
 543 void (obstack_1grow) (obstack, character)
 544      struct obstack *obstack;
 545      int character;
 546 {
 547   obstack_1grow (obstack, character);
 548 }
 549
 550 void (obstack_blank) (obstack, length)
 551      struct obstack *obstack;
 552      int length;
 553 {
 554   obstack_blank (obstack, length);
 555 }
 556
 557 void (obstack_1grow_fast) (obstack, character)
 558      struct obstack *obstack;
 559      int character;
 560 {
 561   obstack_1grow_fast (obstack, character);
 562 }
 563
 564 void (obstack_blank_fast) (obstack, length)
 565      struct obstack *obstack;
 566      int length;
 567 {
 568   obstack_blank_fast (obstack, length);
 569 }
 570
 571 POINTER (obstack_finish) (obstack)
 572      struct obstack *obstack;
 573 {
 574   return obstack_finish (obstack);
 575 }
 576
 577 POINTER (obstack_alloc) (obstack, length)
 578      struct obstack *obstack;
 579      int length;
 580 {
 581   return obstack_alloc (obstack, length);
 582 }
 583
 584 POINTER (obstack_copy) (obstack, address, length)
 585      struct obstack *obstack;
 586      const POINTER address;
 587      int length;
 588 {
 589   return obstack_copy (obstack, address, length);
 590 }
 591
 592 POINTER (obstack_copy0) (obstack, address, length)
 593      struct obstack *obstack;
 594      const POINTER address;
 595      int length;
 596 {
 597   return obstack_copy0 (obstack, address, length);
 598 }
 599
 600 #endif /* __STDC__ */
 601
 602 #endif /* 0 */
 603
 604 #endif  /* !ELIDE_CODE */