gmem.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library 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 GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /*
  28  * MT safe
  29  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include <config.h>
  33 #endif
  34
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include "glib.h"
  38
  39 /* #define ENABLE_MEM_PROFILE */
  40 /* #define ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS */
  41 /* #define ENABLE_MEM_CHECK */
  42 #define MEM_PROFILE_TABLE_SIZE 8192
  43
  44 /*
  45  * This library can check for some attempts to do illegal things to
  46  * memory (ENABLE_MEM_CHECK), and can do profiling
  47  * (ENABLE_MEM_PROFILE).  Both features are implemented by storing
  48  * words before the start of the memory chunk.
  49  *
  50  * The first, at offset -2*SIZEOF_LONG, is used only if
  51  * ENABLE_MEM_CHECK is set, and stores 0 after the memory has been
  52  * allocated and 1 when it has been freed.  The second, at offset
  53  * -SIZEOF_LONG, is used if either flag is set and stores the size of
  54  * the block.
  55  *
  56  * The MEM_CHECK flag is checked when memory is realloc'd and free'd,
  57  * and it can be explicitly checked before using a block by calling
  58  * g_mem_check().
  59  */
  60
  61 #if defined(ENABLE_MEM_PROFILE) && defined(ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS)
  62 #define ENTER_MEM_CHUNK_ROUTINE() \
  63   g_private_set (allocating_for_mem_chunk, \
  64                 g_private_get (allocating_for_mem_chunk) + 1)
  65 #define LEAVE_MEM_CHUNK_ROUTINE() \
  66   g_private_set (allocating_for_mem_chunk, \
  67                 g_private_get (allocating_for_mem_chunk) - 1)
  68 #else
  69 #define ENTER_MEM_CHUNK_ROUTINE()
  70 #define LEAVE_MEM_CHUNK_ROUTINE()
  71 #endif
  72
  73
  74 #define MEM_AREA_SIZE 4L
  75
  76 #if SIZEOF_VOID_P > SIZEOF_LONG
  77 #define MEM_ALIGN     SIZEOF_VOID_P
  78 #else
  79 #define MEM_ALIGN     SIZEOF_LONG
  80 #endif
  81
  82
  83 typedef struct _GFreeAtom      GFreeAtom;
  84 typedef struct _GMemArea       GMemArea;
  85 typedef struct _GRealMemChunk  GRealMemChunk;
  86
  87 struct _GFreeAtom
  88 {
  89   GFreeAtom *next;
  90 };
  91
  92 struct _GMemArea
  93 {
  94   GMemArea *next;            /* the next mem area */
  95   GMemArea *prev;            /* the previous mem area */
  96   gulong index;              /* the current index into the "mem" array */
  97   gulong free;               /* the number of free bytes in this mem area */
  98   gulong allocated;          /* the number of atoms allocated from this area */
  99   gulong mark;               /* is this mem area marked for deletion */
 100   gchar mem[MEM_AREA_SIZE];  /* the mem array from which atoms get allocated
 101                               * the actual size of this array is determined by
 102                               *  the mem chunk "area_size". ANSI says that it
 103                               *  must be declared to be the maximum size it
 104                               *  can possibly be (even though the actual size
 105                               *  may be less).
 106                               */
 107 };
 108
 109 struct _GRealMemChunk
 110 {
 111   gchar *name;               /* name of this MemChunk...used for debugging output */
 112   gint type;                 /* the type of MemChunk: ALLOC_ONLY or ALLOC_AND_FREE */
 113   gint num_mem_areas;        /* the number of memory areas */
 114   gint num_marked_areas;     /* the number of areas marked for deletion */
 115   guint atom_size;           /* the size of an atom */
 116   gulong area_size;          /* the size of a memory area */
 117   GMemArea *mem_area;        /* the current memory area */
 118   GMemArea *mem_areas;       /* a list of all the mem areas owned by this chunk */
 119   GMemArea *free_mem_area;   /* the free area...which is about to be destroyed */
 120   GFreeAtom *free_atoms;     /* the free atoms list */
 121   GTree *mem_tree;           /* tree of mem areas sorted by memory address */
 122   GRealMemChunk *next;       /* pointer to the next chunk */
 123   GRealMemChunk *prev;       /* pointer to the previous chunk */
 124 };
 125
 126
 127 static gulong g_mem_chunk_compute_size (gulong    size,
 128                                         gulong    min_size);
 129 static gint   g_mem_chunk_area_compare (GMemArea *a,
 130                                         GMemArea *b);
 131 static gint   g_mem_chunk_area_search  (GMemArea *a,
 132                                         gchar    *addr);
 133
 134
 135 /* here we can't use StaticMutexes, as they depend upon a working
 136  * g_malloc, the same holds true for StaticPrivate */
 137 static GMutex* mem_chunks_lock = NULL;
 138 static GRealMemChunk *mem_chunks = NULL;
 139
 140 #ifdef ENABLE_MEM_PROFILE
 141 static GMutex* mem_profile_lock;
 142 static gulong allocations[MEM_PROFILE_TABLE_SIZE] = { 0 };
 143 static gulong allocated_mem = 0;
 144 static gulong freed_mem = 0;
 145 static GPrivate* allocating_for_mem_chunk = NULL;
 146 #define IS_IN_MEM_CHUNK_ROUTINE() \
 147   GPOINTER_TO_UINT (g_private_get (allocating_for_mem_chunk))
 148 #endif /* ENABLE_MEM_PROFILE */
 149
 150
 151 #ifndef USE_DMALLOC
 152
 153 gpointer
 154 g_malloc (gulong size)
 155 {
 156   gpointer p;
 157
 158
 159 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 160   gulong *t;
 161 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 162
 163
 164   if (size == 0)
 165     return NULL;
 166
 167
 168 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 169   size += SIZEOF_LONG;
 170 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 171
 172 #ifdef ENABLE_MEM_CHECK
 173   size += SIZEOF_LONG;
 174 #endif /* ENABLE_MEM_CHECK */
 175
 176
 177   p = (gpointer) malloc (size);
 178   if (!p)
 179     g_error ("could not allocate %ld bytes", size);
 180
 181
 182 #ifdef ENABLE_MEM_CHECK
 183   size -= SIZEOF_LONG;
 184
 185   t = p;
 186   p = ((guchar*) p + SIZEOF_LONG);
 187   *t = 0;
 188 #endif /* ENABLE_MEM_CHECK */
 189
 190 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 191   size -= SIZEOF_LONG;
 192
 193   t = p;
 194   p = ((guchar*) p + SIZEOF_LONG);
 195   *t = size;
 196
 197 #ifdef ENABLE_MEM_PROFILE
 198   g_mutex_lock (mem_profile_lock);
 199 #  ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 200   if(!IS_IN_MEM_CHUNK_ROUTINE()) {
 201 #  endif
 202     if (size <= MEM_PROFILE_TABLE_SIZE - 1)
 203       allocations[size-1] += 1;
 204     else
 205       allocations[MEM_PROFILE_TABLE_SIZE - 1] += 1;
 206     allocated_mem += size;
 207 #  ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 208   }
 209 #  endif
 210   g_mutex_unlock (mem_profile_lock);
 211 #endif /* ENABLE_MEM_PROFILE */
 212 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 213
 214
 215   return p;
 216 }
 217
 218 gpointer
 219 g_malloc0 (gulong size)
 220 {
 221   gpointer p;
 222
 223
 224 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 225   gulong *t;
 226 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 227
 228
 229   if (size == 0)
 230     return NULL;
 231
 232
 233 #if defined (ENABLE_MEM_PROFILE) || defined (ENABLE_MEM_CHECK)
 234   size += SIZEOF_LONG;
 235 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 236
 237 #ifdef ENABLE_MEM_CHECK
 238   size += SIZEOF_LONG;
 239 #endif /* ENABLE_MEM_CHECK */
 240
 241
 242   p = (gpointer) calloc (size, 1);
 243   if (!p)
 244     g_error ("could not allocate %ld bytes", size);
 245
 246
 247 #ifdef ENABLE_MEM_CHECK
 248   size -= SIZEOF_LONG;
 249
 250   t = p;
 251   p = ((guchar*) p + SIZEOF_LONG);
 252   *t = 0;
 253 #endif /* ENABLE_MEM_CHECK */
 254
 255 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 256   size -= SIZEOF_LONG;
 257
 258   t = p;
 259   p = ((guchar*) p + SIZEOF_LONG);
 260   *t = size;
 261
 262 #  ifdef ENABLE_MEM_PROFILE
 263   g_mutex_lock (mem_profile_lock);
 264 #    ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 265   if(!IS_IN_MEM_CHUNK_ROUTINE()) {
 266 #    endif
 267     if (size <= (MEM_PROFILE_TABLE_SIZE - 1))
 268       allocations[size-1] += 1;
 269     else
 270       allocations[MEM_PROFILE_TABLE_SIZE - 1] += 1;
 271     allocated_mem += size;
 272 #    ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 273   }
 274 #    endif
 275   g_mutex_unlock (mem_profile_lock);
 276 #  endif /* ENABLE_MEM_PROFILE */
 277 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 278
 279
 280   return p;
 281 }
 282
 283 gpointer
 284 g_realloc (gpointer mem,
 285            gulong   size)
 286 {
 287   gpointer p;
 288
 289 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 290   gulong *t;
 291 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 292
 293
 294   if (size == 0)
 295     {
 296       g_free (mem);
 297
 298       return NULL;
 299     }
 300
 301
 302 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 303   size += SIZEOF_LONG;
 304 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 305
 306 #ifdef ENABLE_MEM_CHECK
 307   size += SIZEOF_LONG;
 308 #endif /* ENABLE_MEM_CHECK */
 309
 310
 311   if (!mem)
 312     {
 313 #ifdef REALLOC_0_WORKS
 314       p = (gpointer) realloc (NULL, size);
 315 #else /* !REALLOC_0_WORKS */
 316       p = (gpointer) malloc (size);
 317 #endif /* !REALLOC_0_WORKS */
 318     }
 319   else
 320     {
 321 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 322       t = (gulong*) ((guchar*) mem - SIZEOF_LONG);
 323 #ifdef ENABLE_MEM_PROFILE
 324       g_mutex_lock (mem_profile_lock);
 325       freed_mem += *t;
 326       g_mutex_unlock (mem_profile_lock);
 327 #endif /* ENABLE_MEM_PROFILE */
 328       mem = t;
 329 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 330
 331 #ifdef ENABLE_MEM_CHECK
 332       t = (gulong*) ((guchar*) mem - SIZEOF_LONG);
 333       if (*t >= 1)
 334         g_warning ("trying to realloc freed memory\n");
 335       mem = t;
 336 #endif /* ENABLE_MEM_CHECK */
 337
 338       p = (gpointer) realloc (mem, size);
 339     }
 340
 341   if (!p)
 342     g_error ("could not reallocate %lu bytes", (gulong) size);
 343
 344
 345 #ifdef ENABLE_MEM_CHECK
 346   size -= SIZEOF_LONG;
 347
 348   t = p;
 349   p = ((guchar*) p + SIZEOF_LONG);
 350   *t = 0;
 351 #endif /* ENABLE_MEM_CHECK */
 352
 353 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 354   size -= SIZEOF_LONG;
 355
 356   t = p;
 357   p = ((guchar*) p + SIZEOF_LONG);
 358   *t = size;
 359
 360 #ifdef ENABLE_MEM_PROFILE
 361   g_mutex_lock (mem_profile_lock);
 362 #ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 363   if(!IS_IN_MEM_CHUNK_ROUTINE()) {
 364 #endif
 365     if (size <= (MEM_PROFILE_TABLE_SIZE - 1))
 366       allocations[size-1] += 1;
 367     else
 368       allocations[MEM_PROFILE_TABLE_SIZE - 1] += 1;
 369     allocated_mem += size;
 370 #ifdef ENABLE_MEM_PROFILE_EXCLUDES_MEM_CHUNKS
 371   }
 372 #endif
 373   g_mutex_unlock (mem_profile_lock);
 374 #endif /* ENABLE_MEM_PROFILE */
 375 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 376
 377
 378   return p;
 379 }
 380
 381 void
 382 g_free (gpointer mem)
 383 {
 384   if (mem)
 385     {
 386 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 387       gulong *t;
 388       gulong size;
 389 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 390
 391 #if defined(ENABLE_MEM_PROFILE) || defined(ENABLE_MEM_CHECK)
 392       t = (gulong*) ((guchar*) mem - SIZEOF_LONG);
 393       size = *t;
 394 #ifdef ENABLE_MEM_PROFILE
 395       g_mutex_lock (mem_profile_lock);
 396       freed_mem += size;
 397       g_mutex_unlock (mem_profile_lock);
 398 #endif /* ENABLE_MEM_PROFILE */
 399       mem = t;
 400 #endif /* ENABLE_MEM_PROFILE || ENABLE_MEM_CHECK */
 401
 402 #ifdef ENABLE_MEM_CHECK
 403       t = (gulong*) ((guchar*) mem - SIZEOF_LONG);
 404       if (*t >= 1)
 405         g_warning ("freeing previously freed (%lu times) memory\n", *t);
 406       *t += 1;
 407       mem = t;
 408
 409       memset ((guchar*) mem + 2 * SIZEOF_LONG, 0, size);
 410 #else /* ENABLE_MEM_CHECK */
 411       free (mem);
 412 #endif /* ENABLE_MEM_CHECK */
 413     }
 414 }
 415
 416 #endif /* ! USE_DMALLOC */
 417
 418
 419 void
 420 g_mem_profile (void)
 421 {
 422 #ifdef ENABLE_MEM_PROFILE
 423   gint i;
 424   gulong local_allocations[MEM_PROFILE_TABLE_SIZE];
 425   gulong local_allocated_mem;
 426   gulong local_freed_mem;
 427
 428   g_mutex_lock (mem_profile_lock);
 429   for (i = 0; i < MEM_PROFILE_TABLE_SIZE; i++)
 430     local_allocations[i] = allocations[i];
 431   local_allocated_mem = allocated_mem;
 432   local_freed_mem = freed_mem;
 433   g_mutex_unlock (mem_profile_lock);
 434
 435   for (i = 0; i < (MEM_PROFILE_TABLE_SIZE - 1); i++)
 436     if (local_allocations[i] > 0)
 437       g_log (g_log_domain_glib, G_LOG_LEVEL_INFO,
 438              "%lu allocations of %d bytes", local_allocations[i], i + 1);
 439
 440   if (local_allocations[MEM_PROFILE_TABLE_SIZE - 1] > 0)
 441     g_log (g_log_domain_glib, G_LOG_LEVEL_INFO,
 442            "%lu allocations of greater than %d bytes",
 443            local_allocations[MEM_PROFILE_TABLE_SIZE - 1], MEM_PROFILE_TABLE_SIZE - 1);
 444   g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "%lu bytes allocated", local_allocated_mem);
 445   g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "%lu bytes freed", local_freed_mem);
 446   g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "%lu bytes in use", local_allocated_mem - local_freed_mem);
 447 #endif /* ENABLE_MEM_PROFILE */
 448 }
 449
 450 void
 451 g_mem_check (gpointer mem)
 452 {
 453 #ifdef ENABLE_MEM_CHECK
 454   gulong *t;
 455
 456   t = (gulong*) ((guchar*) mem - SIZEOF_LONG - SIZEOF_LONG);
 457
 458   if (*t >= 1)
 459     g_warning ("mem: 0x%08lx has been freed %lu times\n", (gulong) mem, *t);
 460 #endif /* ENABLE_MEM_CHECK */
 461 }
 462
 463 GMemChunk*
 464 g_mem_chunk_new (gchar  *name,
 465                  gint    atom_size,
 466                  gulong  area_size,
 467                  gint    type)
 468 {
 469   GRealMemChunk *mem_chunk;
 470   gulong rarea_size;
 471
 472   g_return_val_if_fail (atom_size > 0, NULL);
 473   g_return_val_if_fail (area_size >= atom_size, NULL);
 474
 475   ENTER_MEM_CHUNK_ROUTINE();
 476
 477   area_size = (area_size + atom_size - 1) / atom_size;
 478   area_size *= atom_size;
 479
 480   mem_chunk = g_new (struct _GRealMemChunk, 1);
 481   mem_chunk->name = name;
 482   mem_chunk->type = type;
 483   mem_chunk->num_mem_areas = 0;
 484   mem_chunk->num_marked_areas = 0;
 485   mem_chunk->mem_area = NULL;
 486   mem_chunk->free_mem_area = NULL;
 487   mem_chunk->free_atoms = NULL;
 488   mem_chunk->mem_tree = NULL;
 489   mem_chunk->mem_areas = NULL;
 490   mem_chunk->atom_size = atom_size;
 491
 492   if (mem_chunk->type == G_ALLOC_AND_FREE)
 493     mem_chunk->mem_tree = g_tree_new ((GCompareFunc) g_mem_chunk_area_compare);
 494
 495   if (mem_chunk->atom_size % MEM_ALIGN)
 496     mem_chunk->atom_size += MEM_ALIGN - (mem_chunk->atom_size % MEM_ALIGN);
 497
 498   rarea_size = area_size + sizeof (GMemArea) - MEM_AREA_SIZE;
 499   rarea_size = g_mem_chunk_compute_size (rarea_size, atom_size + sizeof (GMemArea) - MEM_AREA_SIZE);
 500   mem_chunk->area_size = rarea_size - (sizeof (GMemArea) - MEM_AREA_SIZE);
 501
 502   g_mutex_lock (mem_chunks_lock);
 503   mem_chunk->next = mem_chunks;
 504   mem_chunk->prev = NULL;
 505   if (mem_chunks)
 506     mem_chunks->prev = mem_chunk;
 507   mem_chunks = mem_chunk;
 508   g_mutex_unlock (mem_chunks_lock);
 509
 510   LEAVE_MEM_CHUNK_ROUTINE();
 511
 512   return ((GMemChunk*) mem_chunk);
 513 }
 514
 515 void
 516 g_mem_chunk_destroy (GMemChunk *mem_chunk)
 517 {
 518   GRealMemChunk *rmem_chunk;
 519   GMemArea *mem_areas;
 520   GMemArea *temp_area;
 521
 522   g_return_if_fail (mem_chunk != NULL);
 523
 524   ENTER_MEM_CHUNK_ROUTINE();
 525
 526   rmem_chunk = (GRealMemChunk*) mem_chunk;
 527
 528   mem_areas = rmem_chunk->mem_areas;
 529   while (mem_areas)
 530     {
 531       temp_area = mem_areas;
 532       mem_areas = mem_areas->next;
 533       g_free (temp_area);
 534     }
 535
 536   if (rmem_chunk->next)
 537     rmem_chunk->next->prev = rmem_chunk->prev;
 538   if (rmem_chunk->prev)
 539     rmem_chunk->prev->next = rmem_chunk->next;
 540
 541   g_mutex_lock (mem_chunks_lock);
 542   if (rmem_chunk == mem_chunks)
 543     mem_chunks = mem_chunks->next;
 544   g_mutex_unlock (mem_chunks_lock);
 545
 546   if (rmem_chunk->type == G_ALLOC_AND_FREE)
 547     g_tree_destroy (rmem_chunk->mem_tree);
 548
 549   g_free (rmem_chunk);
 550
 551   LEAVE_MEM_CHUNK_ROUTINE();
 552 }
 553
 554 gpointer
 555 g_mem_chunk_alloc (GMemChunk *mem_chunk)
 556 {
 557   GRealMemChunk *rmem_chunk;
 558   GMemArea *temp_area;
 559   gpointer mem;
 560
 561   ENTER_MEM_CHUNK_ROUTINE();
 562
 563   g_return_val_if_fail (mem_chunk != NULL, NULL);
 564
 565   rmem_chunk = (GRealMemChunk*) mem_chunk;
 566
 567   while (rmem_chunk->free_atoms)
 568     {
 569       /* Get the first piece of memory on the "free_atoms" list.
 570        * We can go ahead and destroy the list node we used to keep
 571        *  track of it with and to update the "free_atoms" list to
 572        *  point to its next element.
 573        */
 574       mem = rmem_chunk->free_atoms;
 575       rmem_chunk->free_atoms = rmem_chunk->free_atoms->next;
 576
 577       /* Determine which area this piece of memory is allocated from */
 578       temp_area = g_tree_search (rmem_chunk->mem_tree,
 579                                  (GCompareFunc) g_mem_chunk_area_search,
 580                                  mem);
 581
 582       /* If the area has been marked, then it is being destroyed.
 583        *  (ie marked to be destroyed).
 584        * We check to see if all of the segments on the free list that
 585        *  reference this area have been removed. This occurs when
 586        *  the ammount of free memory is less than the allocatable size.
 587        * If the chunk should be freed, then we place it in the "free_mem_area".
 588        * This is so we make sure not to free the mem area here and then
 589        *  allocate it again a few lines down.
 590        * If we don't allocate a chunk a few lines down then the "free_mem_area"
 591        *  will be freed.
 592        * If there is already a "free_mem_area" then we'll just free this mem area.
 593        */
 594       if (temp_area->mark)
 595         {
 596           /* Update the "free" memory available in that area */
 597           temp_area->free += rmem_chunk->atom_size;
 598
 599           if (temp_area->free == rmem_chunk->area_size)
 600             {
 601               if (temp_area == rmem_chunk->mem_area)
 602                 rmem_chunk->mem_area = NULL;
 603
 604               if (rmem_chunk->free_mem_area)
 605                 {
 606                   rmem_chunk->num_mem_areas -= 1;
 607
 608                   if (temp_area->next)
 609                     temp_area->next->prev = temp_area->prev;
 610                   if (temp_area->prev)
 611                     temp_area->prev->next = temp_area->next;
 612                   if (temp_area == rmem_chunk->mem_areas)
 613                     rmem_chunk->mem_areas = rmem_chunk->mem_areas->next;
 614
 615                   if (rmem_chunk->type == G_ALLOC_AND_FREE)
 616                     g_tree_remove (rmem_chunk->mem_tree, temp_area);
 617                   g_free (temp_area);
 618                 }
 619               else
 620                 rmem_chunk->free_mem_area = temp_area;
 621
 622               rmem_chunk->num_marked_areas -= 1;
 623             }
 624         }
 625       else
 626         {
 627           /* Update the number of allocated atoms count.
 628            */
 629           temp_area->allocated += 1;
 630
 631           /* The area wasn't marked...return the memory
 632            */
 633           goto outa_here;
 634         }
 635     }
 636
 637   /* If there isn't a current mem area or the current mem area is out of space
 638    *  then allocate a new mem area. We'll first check and see if we can use
 639    *  the "free_mem_area". Otherwise we'll just malloc the mem area.
 640    */
 641   if ((!rmem_chunk->mem_area) ||
 642       ((rmem_chunk->mem_area->index + rmem_chunk->atom_size) > rmem_chunk->area_size))
 643     {
 644       if (rmem_chunk->free_mem_area)
 645         {
 646           rmem_chunk->mem_area = rmem_chunk->free_mem_area;
 647           rmem_chunk->free_mem_area = NULL;
 648         }
 649       else
 650         {
 651 #ifdef ENABLE_GC_FRIENDLY
 652           rmem_chunk->mem_area = (GMemArea*) g_malloc0 (sizeof (GMemArea) -
 653                                                         MEM_AREA_SIZE +
 654                                                         rmem_chunk->area_size);
 655 #else /* !ENABLE_GC_FRIENDLY */
 656           rmem_chunk->mem_area = (GMemArea*) g_malloc (sizeof (GMemArea) -
 657                                                        MEM_AREA_SIZE +
 658                                                        rmem_chunk->area_size);
 659 #endif /* ENABLE_GC_FRIENDLY */
 660
 661           rmem_chunk->num_mem_areas += 1;
 662           rmem_chunk->mem_area->next = rmem_chunk->mem_areas;
 663           rmem_chunk->mem_area->prev = NULL;
 664
 665           if (rmem_chunk->mem_areas)
 666             rmem_chunk->mem_areas->prev = rmem_chunk->mem_area;
 667           rmem_chunk->mem_areas = rmem_chunk->mem_area;
 668
 669           if (rmem_chunk->type == G_ALLOC_AND_FREE)
 670             g_tree_insert (rmem_chunk->mem_tree, rmem_chunk->mem_area, rmem_chunk->mem_area);
 671         }
 672
 673       rmem_chunk->mem_area->index = 0;
 674       rmem_chunk->mem_area->free = rmem_chunk->area_size;
 675       rmem_chunk->mem_area->allocated = 0;
 676       rmem_chunk->mem_area->mark = 0;
 677     }
 678
 679   /* Get the memory and modify the state variables appropriately.
 680    */
 681   mem = (gpointer) &rmem_chunk->mem_area->mem[rmem_chunk->mem_area->index];
 682   rmem_chunk->mem_area->index += rmem_chunk->atom_size;
 683   rmem_chunk->mem_area->free -= rmem_chunk->atom_size;
 684   rmem_chunk->mem_area->allocated += 1;
 685
 686 outa_here:
 687
 688   LEAVE_MEM_CHUNK_ROUTINE();
 689
 690   return mem;
 691 }
 692
 693 gpointer
 694 g_mem_chunk_alloc0 (GMemChunk *mem_chunk)
 695 {
 696   gpointer mem;
 697
 698   mem = g_mem_chunk_alloc (mem_chunk);
 699   if (mem)
 700     {
 701       GRealMemChunk *rmem_chunk = (GRealMemChunk*) mem_chunk;
 702
 703       memset (mem, 0, rmem_chunk->atom_size);
 704     }
 705
 706   return mem;
 707 }
 708
 709 void
 710 g_mem_chunk_free (GMemChunk *mem_chunk,
 711                   gpointer   mem)
 712 {
 713   GRealMemChunk *rmem_chunk;
 714   GMemArea *temp_area;
 715   GFreeAtom *free_atom;
 716
 717   g_return_if_fail (mem_chunk != NULL);
 718   g_return_if_fail (mem != NULL);
 719
 720   ENTER_MEM_CHUNK_ROUTINE();
 721
 722   rmem_chunk = (GRealMemChunk*) mem_chunk;
 723
 724 #ifdef ENABLE_GC_FRIENDLY
 725   memset (mem, 0, rmem_chunk->atom_size);
 726 #endif /* ENABLE_GC_FRIENDLY */
 727
 728   /* Don't do anything if this is an ALLOC_ONLY chunk
 729    */
 730   if (rmem_chunk->type == G_ALLOC_AND_FREE)
 731     {
 732       /* Place the memory on the "free_atoms" list
 733        */
 734       free_atom = (GFreeAtom*) mem;
 735       free_atom->next = rmem_chunk->free_atoms;
 736       rmem_chunk->free_atoms = free_atom;
 737
 738       temp_area = g_tree_search (rmem_chunk->mem_tree,
 739                                  (GCompareFunc) g_mem_chunk_area_search,
 740                                  mem);
 741
 742       temp_area->allocated -= 1;
 743
 744       if (temp_area->allocated == 0)
 745         {
 746           temp_area->mark = 1;
 747           rmem_chunk->num_marked_areas += 1;
 748         }
 749     }
 750
 751   LEAVE_MEM_CHUNK_ROUTINE();
 752 }
 753
 754 /* This doesn't free the free_area if there is one */
 755 void
 756 g_mem_chunk_clean (GMemChunk *mem_chunk)
 757 {
 758   GRealMemChunk *rmem_chunk;
 759   GMemArea *mem_area;
 760   GFreeAtom *prev_free_atom;
 761   GFreeAtom *temp_free_atom;
 762   gpointer mem;
 763
 764   g_return_if_fail (mem_chunk != NULL);
 765
 766   rmem_chunk = (GRealMemChunk*) mem_chunk;
 767
 768   if (rmem_chunk->type == G_ALLOC_AND_FREE)
 769     {
 770       prev_free_atom = NULL;
 771       temp_free_atom = rmem_chunk->free_atoms;
 772
 773       while (temp_free_atom)
 774         {
 775           mem = (gpointer) temp_free_atom;
 776
 777           mem_area = g_tree_search (rmem_chunk->mem_tree,
 778                                     (GCompareFunc) g_mem_chunk_area_search,
 779                                     mem);
 780
 781           /* If this mem area is marked for destruction then delete the
 782            *  area and list node and decrement the free mem.
 783            */
 784           if (mem_area->mark)
 785             {
 786               if (prev_free_atom)
 787                 prev_free_atom->next = temp_free_atom->next;
 788               else
 789                 rmem_chunk->free_atoms = temp_free_atom->next;
 790               temp_free_atom = temp_free_atom->next;
 791
 792               mem_area->free += rmem_chunk->atom_size;
 793               if (mem_area->free == rmem_chunk->area_size)
 794                 {
 795                   rmem_chunk->num_mem_areas -= 1;
 796                   rmem_chunk->num_marked_areas -= 1;
 797
 798                   if (mem_area->next)
 799                     mem_area->next->prev = mem_area->prev;
 800                   if (mem_area->prev)
 801                     mem_area->prev->next = mem_area->next;
 802                   if (mem_area == rmem_chunk->mem_areas)
 803                     rmem_chunk->mem_areas = rmem_chunk->mem_areas->next;
 804                   if (mem_area == rmem_chunk->mem_area)
 805                     rmem_chunk->mem_area = NULL;
 806
 807                   if (rmem_chunk->type == G_ALLOC_AND_FREE)
 808                     g_tree_remove (rmem_chunk->mem_tree, mem_area);
 809                   g_free (mem_area);
 810                 }
 811             }
 812           else
 813             {
 814               prev_free_atom = temp_free_atom;
 815               temp_free_atom = temp_free_atom->next;
 816             }
 817         }
 818     }
 819 }
 820
 821 void
 822 g_mem_chunk_reset (GMemChunk *mem_chunk)
 823 {
 824   GRealMemChunk *rmem_chunk;
 825   GMemArea *mem_areas;
 826   GMemArea *temp_area;
 827
 828   g_return_if_fail (mem_chunk != NULL);
 829
 830   rmem_chunk = (GRealMemChunk*) mem_chunk;
 831
 832   mem_areas = rmem_chunk->mem_areas;
 833   rmem_chunk->num_mem_areas = 0;
 834   rmem_chunk->mem_areas = NULL;
 835   rmem_chunk->mem_area = NULL;
 836
 837   while (mem_areas)
 838     {
 839       temp_area = mem_areas;
 840       mem_areas = mem_areas->next;
 841       g_free (temp_area);
 842     }
 843
 844   rmem_chunk->free_atoms = NULL;
 845
 846   if (rmem_chunk->mem_tree)
 847     g_tree_destroy (rmem_chunk->mem_tree);
 848   rmem_chunk->mem_tree = g_tree_new ((GCompareFunc) g_mem_chunk_area_compare);
 849 }
 850
 851 void
 852 g_mem_chunk_print (GMemChunk *mem_chunk)
 853 {
 854   GRealMemChunk *rmem_chunk;
 855   GMemArea *mem_areas;
 856   gulong mem;
 857
 858   g_return_if_fail (mem_chunk != NULL);
 859
 860   rmem_chunk = (GRealMemChunk*) mem_chunk;
 861   mem_areas = rmem_chunk->mem_areas;
 862   mem = 0;
 863
 864   while (mem_areas)
 865     {
 866       mem += rmem_chunk->area_size - mem_areas->free;
 867       mem_areas = mem_areas->next;
 868     }
 869
 870   g_log (g_log_domain_glib, G_LOG_LEVEL_INFO,
 871          "%s: %ld bytes using %d mem areas",
 872          rmem_chunk->name, mem, rmem_chunk->num_mem_areas);
 873 }
 874
 875 void
 876 g_mem_chunk_info (void)
 877 {
 878   GRealMemChunk *mem_chunk;
 879   gint count;
 880
 881   count = 0;
 882   g_mutex_lock (mem_chunks_lock);
 883   mem_chunk = mem_chunks;
 884   while (mem_chunk)
 885     {
 886       count += 1;
 887       mem_chunk = mem_chunk->next;
 888     }
 889   g_mutex_unlock (mem_chunks_lock);
 890
 891   g_log (g_log_domain_glib, G_LOG_LEVEL_INFO, "%d mem chunks", count);
 892
 893   g_mutex_lock (mem_chunks_lock);
 894   mem_chunk = mem_chunks;
 895   g_mutex_unlock (mem_chunks_lock);
 896
 897   while (mem_chunk)
 898     {
 899       g_mem_chunk_print ((GMemChunk*) mem_chunk);
 900       mem_chunk = mem_chunk->next;
 901     }
 902 }
 903
 904 void
 905 g_blow_chunks (void)
 906 {
 907   GRealMemChunk *mem_chunk;
 908
 909   g_mutex_lock (mem_chunks_lock);
 910   mem_chunk = mem_chunks;
 911   g_mutex_unlock (mem_chunks_lock);
 912   while (mem_chunk)
 913     {
 914       g_mem_chunk_clean ((GMemChunk*) mem_chunk);
 915       mem_chunk = mem_chunk->next;
 916     }
 917 }
 918
 919
 920 static gulong
 921 g_mem_chunk_compute_size (gulong size,
 922                           gulong min_size)
 923 {
 924   gulong power_of_2;
 925   gulong lower, upper;
 926
 927   power_of_2 = 16;
 928   while (power_of_2 < size)
 929     power_of_2 <<= 1;
 930
 931   lower = power_of_2 >> 1;
 932   upper = power_of_2;
 933
 934   if (size - lower < upper - size && lower >= min_size)
 935     return lower;
 936   else
 937     return upper;
 938 }
 939
 940 static gint
 941 g_mem_chunk_area_compare (GMemArea *a,
 942                           GMemArea *b)
 943 {
 944   if (a->mem > b->mem)
 945     return 1;
 946   else if (a->mem < b->mem)
 947     return -1;
 948   return 0;
 949 }
 950
 951 static gint
 952 g_mem_chunk_area_search (GMemArea *a,
 953                          gchar    *addr)
 954 {
 955   if (a->mem <= addr)
 956     {
 957       if (addr < &a->mem[a->index])
 958         return 0;
 959       return 1;
 960     }
 961   return -1;
 962 }
 963
 964 /* generic allocators
 965  */
 966 struct _GAllocator /* from gmem.c */
 967 {
 968   gchar         *name;
 969   guint16        n_preallocs;
 970   guint          is_unused : 1;
 971   guint          type : 4;
 972   GAllocator    *last;
 973   GMemChunk     *mem_chunk;
 974   gpointer       dummy; /* implementation specific */
 975 };
 976
 977 GAllocator*
 978 g_allocator_new (const gchar *name,
 979                  guint        n_preallocs)
 980 {
 981   GAllocator *allocator;
 982
 983   g_return_val_if_fail (name != NULL, NULL);
 984
 985   allocator = g_new0 (GAllocator, 1);
 986   allocator->name = g_strdup (name);
 987   allocator->n_preallocs = CLAMP (n_preallocs, 1, 65535);
 988   allocator->is_unused = TRUE;
 989   allocator->type = 0;
 990   allocator->last = NULL;
 991   allocator->mem_chunk = NULL;
 992   allocator->dummy = NULL;
 993
 994   return allocator;
 995 }
 996
 997 void
 998 g_allocator_free (GAllocator *allocator)
 999 {
1000   g_return_if_fail (allocator != NULL);
1001   g_return_if_fail (allocator->is_unused == TRUE);
1002
1003   g_free (allocator->name);
1004   if (allocator->mem_chunk)
1005     g_mem_chunk_destroy (allocator->mem_chunk);
1006
1007   g_free (allocator);
1008 }
1009
1010 void
1011 g_mem_init (void)
1012 {
1013   mem_chunks_lock = g_mutex_new();
1014 #ifdef ENABLE_MEM_PROFILE
1015   mem_profile_lock = g_mutex_new();
1016   allocating_for_mem_chunk = g_private_new(NULL);
1017 #endif
1018 }