Security/libsecurity_asn1/lib/plarena.c

   1 /*
   2  * Copyright (c) 2003-2006,2008,2010-2012 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * The contents of this file are subject to the Mozilla Public
  25  * License Version 1.1 (the "License"); you may not use this file
  26  * except in compliance with the License. You may obtain a copy of
  27  * the License at http://www.mozilla.org/MPL/
  28  *
  29  * Software distributed under the License is distributed on an "AS
  30  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  31  * implied. See the License for the specific language governing
  32  * rights and limitations under the License.
  33  *
  34  * The Original Code is the Netscape Portable Runtime (NSPR).
  35  *
  36  * The Initial Developer of the Original Code is Netscape
  37  * Communications Corporation.  Portions created by Netscape are
  38  * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
  39  * Rights Reserved.
  40  *
  41  * Contributor(s):
  42  *
  43  * Alternatively, the contents of this file may be used under the
  44  * terms of the GNU General Public License Version 2 or later (the
  45  * "GPL"), in which case the provisions of the GPL are applicable
  46  * instead of those above.  If you wish to allow use of your
  47  * version of this file only under the terms of the GPL and not to
  48  * allow others to use your version of this file under the MPL,
  49  * indicate your decision by deleting the provisions above and
  50  * replace them with the notice and other provisions required by
  51  * the GPL.  If you do not delete the provisions above, a recipient
  52  * may use your version of this file under either the MPL or the
  53  * GPL.
  54  */
  55
  56 /*
  57  * Lifetime-based fast allocation, inspired by much prior art, including
  58  * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
  59  * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
  60  */
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include "plarena.h"
  64 #include "prmem.h"
  65 #include "prbit.h"
  66 #include "prlog.h"
  67 #include "prinit.h"
  68
  69 #ifdef PL_ARENAMETER
  70 static PLArenaStats *arena_stats_list;
  71
  72 #define COUNT(pool,what)  (pool)->stats.what++
  73 #else
  74 #define COUNT(pool,what)  /* nothing */
  75 #endif
  76
  77 #define PL_ARENA_DEFAULT_ALIGN  sizeof(double)
  78
  79 PR_IMPLEMENT(void) PL_InitArenaPool(
  80     PLArenaPool *pool, const char *name, PRUint32 size, PRUint32 align)
  81 {
  82 #if !defined (__GNUC__)
  83 #pragma unused (name)
  84 #endif
  85
  86     if (align == 0)
  87         align = PL_ARENA_DEFAULT_ALIGN;
  88     pool->mask = PR_BITMASK(PR_CeilingLog2(align));
  89     pool->first.next = NULL;
  90     pool->first.base = pool->first.avail = pool->first.limit =
  91         (PRUword)PL_ARENA_ALIGN(pool, &pool->first + 1);
  92     pool->current = &pool->first;
  93     pool->arenasize = size;
  94 #ifdef PL_ARENAMETER
  95     memset(&pool->stats, 0, sizeof pool->stats);
  96     pool->stats.name = strdup(name);
  97     pool->stats.next = arena_stats_list;
  98     arena_stats_list = &pool->stats;
  99 #endif
 100 }
 101
 102
 103 /*
 104 ** PL_ArenaAllocate() -- allocate space from an arena pool
 105 **
 106 ** Description: PL_ArenaAllocate() allocates space from an arena
 107 ** pool.
 108 **
 109 ** First, try to satisfy the request from arenas starting at
 110 ** pool->current. Then try to allocate a new arena from the heap.
 111 **
 112 ** Returns: pointer to allocated space or NULL
 113 **
 114 ** Notes: The original implementation had some difficult to
 115 ** solve bugs; the code was difficult to read. Sometimes it's
 116 ** just easier to rewrite it. I did that. larryh.
 117 **
 118 ** See also: bugzilla: 45343.
 119 **
 120 */
 121
 122 PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
 123 {
 124     PLArena *a;
 125     char *rp;     /* returned pointer */
 126
 127     PR_ASSERT((nb & pool->mask) == 0);
 128
 129     nb = (PRUint32)PL_ARENA_ALIGN(pool, nb); /* force alignment */
 130
 131     /* attempt to allocate from arenas at pool->current */
 132     {
 133         a = pool->current;
 134         do {
 135             if ( a->avail +nb <= a->limit )  {
 136                 pool->current = a;
 137                 rp = (char *)a->avail;
 138                 a->avail += nb;
 139                 return rp;
 140             }
 141         } while( NULL != (a = a->next) );
 142     }
 143
 144     /* attempt to allocate from the heap */
 145     {
 146         PRSize sz = PR_MAX(pool->arenasize, nb);
 147         sz += sizeof(*a) + pool->mask;  /* header and alignment slop */
 148         a = (PLArena*)PR_MALLOC(sz);
 149         if ( NULL != a )  {
 150             a->limit = (PRUword)a + sz;
 151             a->base = a->avail = (PRUword)PL_ARENA_ALIGN(pool, a + 1);
 152             rp = (char *)a->avail;
 153             a->avail += nb;
 154             /* the newly allocated arena is linked after pool->current
 155             *  and becomes pool->current */
 156             a->next = pool->current->next;
 157             pool->current->next = a;
 158             pool->current = a;
 159             if ( NULL == pool->first.next )
 160                 pool->first.next = a;
 161             PL_COUNT_ARENA(pool,++);
 162             COUNT(pool, nmallocs);
 163             return(rp);
 164         }
 165     }
 166
 167     /* we got to here, and there's no memory to allocate */
 168     return(NULL);
 169 } /* --- end PL_ArenaAllocate() --- */
 170
 171 /*
 172  * Grow, a.k.a. realloc. The PL_ARENA_GROW macro has already handled
 173  * the possible grow-in-place action in which the current PLArena is the
 174  * source of the incoming pointer, and there is room in that arena for
 175  * the requested size.
 176  */
 177 PR_IMPLEMENT(void *) PL_ArenaGrow(
 178     PLArenaPool *pool, void *p, PRUint32 origSize, PRUint32 incr)
 179 {
 180     void *newp;
 181         PLArena *thisArena;
 182         PLArena *lastArena;
 183         PRUint32 origAlignSize;         // bytes currently reserved for caller
 184         PRUint32 newSize;                       // bytes actually mallocd here
 185
 186         /* expand at least by 2x */
 187         origAlignSize = PL_ARENA_ALIGN(pool, origSize);
 188         newSize = PR_MAX(origAlignSize+incr, 2*origAlignSize);
 189         newSize = PL_ARENA_ALIGN(pool, newSize);
 190     PL_ARENA_ALLOCATE(newp, pool, newSize);
 191     if (newp == NULL) {
 192                 return NULL;
 193         }
 194
 195         /*
 196          * Trim back the memory we just allocated to the amount our caller really
 197          * needs, leaving the remainder for grow-in-place on subsequent calls
 198          * to PL_ARENA_GROW.
 199          */
 200         PRUint32 newAlignSize = PL_ARENA_ALIGN(pool, origSize+incr);
 201         PR_ASSERT(pool->current->avail == ((PRUword)newp + newSize));
 202         pool->current->avail = (PRUword)newp + newAlignSize;
 203         PR_ASSERT(pool->current->avail <= pool->current->limit);
 204
 205         /* "realloc" */
 206         memcpy(newp, p, origSize);
 207
 208         /*
 209          * Free old memory only if it's the entire outstanding allocated
 210          * memory associated with one of our known PLArenas.
 211          */
 212         lastArena = &pool->first;                       /* pool->first always empty */
 213         thisArena = lastArena->next;            /* so, start here */
 214
 215         PRUword origPtr = (PRUword)p;
 216         while(thisArena != NULL) {
 217                 if(origPtr == thisArena->base) {
 218                         if((origPtr + origAlignSize) == thisArena->avail) {
 219                                 /* unlink */
 220                                 lastArena->next = thisArena->next;
 221
 222                                 /* and free */
 223                                 PL_CLEAR_ARENA(thisArena);
 224                                 PL_COUNT_ARENA(pool,--);
 225                                 PR_DELETE(thisArena);
 226                                 break;
 227                         }
 228                 }
 229                 lastArena = thisArena;
 230                 thisArena = thisArena->next;
 231         }
 232         /*
 233          * Note: inability to free is not an error; it just causes a temporary leak
 234          * of the old buffer (until the arena pool is freed, of course).
 235          */
 236     return newp;
 237 }
 238
 239 /*
 240  * Free tail arenas linked after head, which may not be the true list head.
 241  * Reset pool->current to point to head in case it pointed at a tail arena.
 242  */
 243 static void FreeArenaList(PLArenaPool *pool, PLArena *head, PRBool reallyFree)
 244 {
 245     PLArena **ap, *a;
 246
 247     ap = &head->next;
 248     a = *ap;
 249     if (!a)
 250         return;
 251
 252         do {
 253                 *ap = a->next;
 254                 PL_CLEAR_ARENA(a);
 255                 PL_COUNT_ARENA(pool,--);
 256                 PR_DELETE(a);
 257         } while ((a = *ap) != 0);
 258
 259     pool->current = head;
 260 }
 261
 262 PR_IMPLEMENT(void) PL_ArenaRelease(PLArenaPool *pool, char *mark)
 263 {
 264         #if ARENA_MARK_ENABLE
 265     PLArena *a;
 266
 267     for (a = pool->first.next; a; a = a->next) {
 268         if (PR_UPTRDIFF(mark, a->base) < PR_UPTRDIFF(a->avail, a->base)) {
 269             a->avail = (PRUword)PL_ARENA_ALIGN(pool, mark);
 270             FreeArenaList(pool, a, PR_FALSE);
 271             return;
 272         }
 273     }
 274         #endif  /* ARENA_MARK_ENABLE */
 275 }
 276
 277 PR_IMPLEMENT(void) PL_FreeArenaPool(PLArenaPool *pool)
 278 {
 279     FreeArenaList(pool, &pool->first, PR_FALSE);
 280     COUNT(pool, ndeallocs);
 281 }
 282
 283 PR_IMPLEMENT(void) PL_FinishArenaPool(PLArenaPool *pool)
 284 {
 285     FreeArenaList(pool, &pool->first, PR_TRUE);
 286 #ifdef PL_ARENAMETER
 287     {
 288         PLArenaStats *stats, **statsp;
 289
 290         if (pool->stats.name)
 291             PR_DELETE(pool->stats.name);
 292         for (statsp = &arena_stats_list; (stats = *statsp) != 0;
 293              statsp = &stats->next) {
 294             if (stats == &pool->stats) {
 295                 *statsp = stats->next;
 296                 return;
 297             }
 298         }
 299     }
 300 #endif
 301 }
 302
 303 PR_IMPLEMENT(void) PL_CompactArenaPool(PLArenaPool *ap)
 304 {
 305 }
 306
 307 PR_IMPLEMENT(void) PL_ArenaFinish(void)
 308 {
 309 }
 310
 311 #ifdef PL_ARENAMETER
 312 PR_IMPLEMENT(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb)
 313 {
 314     pool->stats.nallocs++;
 315     pool->stats.nbytes += nb;
 316     if (nb > pool->stats.maxalloc)
 317         pool->stats.maxalloc = nb;
 318     pool->stats.variance += nb * nb;
 319 }
 320
 321 PR_IMPLEMENT(void) PL_ArenaCountInplaceGrowth(
 322     PLArenaPool *pool, PRUint32 size, PRUint32 incr)
 323 {
 324     pool->stats.ninplace++;
 325 }
 326
 327 PR_IMPLEMENT(void) PL_ArenaCountGrowth(
 328     PLArenaPool *pool, PRUint32 size, PRUint32 incr)
 329 {
 330     pool->stats.ngrows++;
 331     pool->stats.nbytes += incr;
 332     pool->stats.variance -= size * size;
 333     size += incr;
 334     if (size > pool->stats.maxalloc)
 335         pool->stats.maxalloc = size;
 336     pool->stats.variance += size * size;
 337 }
 338
 339 PR_IMPLEMENT(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark)
 340 {
 341     pool->stats.nreleases++;
 342 }
 343
 344 PR_IMPLEMENT(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark)
 345 {
 346     pool->stats.nfastrels++;
 347 }
 348
 349 #include <math.h>
 350 #include <stdio.h>
 351
 352 PR_IMPLEMENT(void) PL_DumpArenaStats(FILE *fp)
 353 {
 354     PLArenaStats *stats;
 355     double mean, variance;
 356
 357     for (stats = arena_stats_list; stats; stats = stats->next) {
 358         if (stats->nallocs != 0) {
 359             mean = (double)stats->nbytes / stats->nallocs;
 360             variance = fabs(stats->variance / stats->nallocs - mean * mean);
 361         } else {
 362             mean = variance = 0;
 363         }
 364
 365         fprintf(fp, "\n%s allocation statistics:\n", stats->name);
 366         fprintf(fp, "              number of arenas: %u\n", stats->narenas);
 367         fprintf(fp, "         number of allocations: %u\n", stats->nallocs);
 368         fprintf(fp, " number of free arena reclaims: %u\n", stats->nreclaims);
 369         fprintf(fp, "        number of malloc calls: %u\n", stats->nmallocs);
 370         fprintf(fp, "       number of deallocations: %u\n", stats->ndeallocs);
 371         fprintf(fp, "  number of allocation growths: %u\n", stats->ngrows);
 372         fprintf(fp, "    number of in-place growths: %u\n", stats->ninplace);
 373         fprintf(fp, "number of released allocations: %u\n", stats->nreleases);
 374         fprintf(fp, "       number of fast releases: %u\n", stats->nfastrels);
 375         fprintf(fp, "         total bytes allocated: %u\n", stats->nbytes);
 376         fprintf(fp, "          mean allocation size: %g\n", mean);
 377         fprintf(fp, "            standard deviation: %g\n", sqrt(variance));
 378         fprintf(fp, "       maximum allocation size: %u\n", stats->maxalloc);
 379     }
 380 }
 381 #endif /* PL_ARENAMETER */