libsecurity_asn1/lib/plarena.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /*
   3  * The contents of this file are subject to the Mozilla Public
   4  * License Version 1.1 (the "License"); you may not use this file
   5  * except in compliance with the License. You may obtain a copy of
   6  * the License at http://www.mozilla.org/MPL/
   7  *
   8  * Software distributed under the License is distributed on an "AS
   9  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  10  * implied. See the License for the specific language governing
  11  * rights and limitations under the License.
  12  *
  13  * The Original Code is the Netscape Portable Runtime (NSPR).
  14  *
  15  * The Initial Developer of the Original Code is Netscape
  16  * Communications Corporation.  Portions created by Netscape are
  17  * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
  18  * Rights Reserved.
  19  *
  20  * Contributor(s):
  21  *
  22  * Alternatively, the contents of this file may be used under the
  23  * terms of the GNU General Public License Version 2 or later (the
  24  * "GPL"), in which case the provisions of the GPL are applicable
  25  * instead of those above.  If you wish to allow use of your
  26  * version of this file only under the terms of the GPL and not to
  27  * allow others to use your version of this file under the MPL,
  28  * indicate your decision by deleting the provisions above and
  29  * replace them with the notice and other provisions required by
  30  * the GPL.  If you do not delete the provisions above, a recipient
  31  * may use your version of this file under either the MPL or the
  32  * GPL.
  33  */
  34
  35 #ifndef plarena_h___
  36 #define plarena_h___
  37 /*
  38  * Lifetime-based fast allocation, inspired by much prior art, including
  39  * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
  40  * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
  41  *
  42  * Also supports LIFO allocation (PL_ARENA_MARK/PL_ARENA_RELEASE).
  43  */
  44 #include "prtypes.h"
  45 #include "plarenas.h"
  46
  47 PR_BEGIN_EXTERN_C
  48
  49 typedef struct PLArena          PLArena;
  50
  51 struct PLArena {
  52     PLArena     *next;          /* next arena for this lifetime */
  53     PRUword     base;           /* aligned base address, follows this header */
  54     PRUword     limit;          /* one beyond last byte in arena */
  55     PRUword     avail;          /* points to next available byte */
  56 };
  57
  58 #ifdef PL_ARENAMETER
  59 typedef struct PLArenaStats PLArenaStats;
  60
  61 struct PLArenaStats {
  62     PLArenaStats  *next;        /* next in arenaStats list */
  63     char          *name;        /* name for debugging */
  64     PRUint32      narenas;      /* number of arenas in pool */
  65     PRUint32      nallocs;      /* number of PL_ARENA_ALLOCATE() calls */
  66     PRUint32      nreclaims;    /* number of reclaims from freeArenas */
  67     PRUint32      nmallocs;     /* number of malloc() calls */
  68     PRUint32      ndeallocs;    /* number of lifetime deallocations */
  69     PRUint32      ngrows;       /* number of PL_ARENA_GROW() calls */
  70     PRUint32      ninplace;     /* number of in-place growths */
  71     PRUint32      nreleases;    /* number of PL_ARENA_RELEASE() calls */
  72     PRUint32      nfastrels;    /* number of "fast path" releases */
  73     PRUint32      nbytes;       /* total bytes allocated */
  74     PRUint32      maxalloc;     /* maximum allocation size in bytes */
  75     PRFloat64     variance;     /* size variance accumulator */
  76 };
  77 #endif
  78
  79 struct PLArenaPool {
  80     PLArena     first;          /* first arena in pool list */
  81     PLArena     *current;       /* arena from which to allocate space */
  82     PRSize      arenasize;      /* net exact size of a new arena */
  83     PRUword     mask;           /* alignment mask (power-of-2 - 1) */
  84 #ifdef PL_ARENAMETER
  85     PLArenaStats stats;
  86 #endif
  87 };
  88
  89 /*
  90  * If the including .c file uses only one power-of-2 alignment, it may define
  91  * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
  92  * per ALLOCATE and GROW.
  93  */
  94 #ifdef PL_ARENA_CONST_ALIGN_MASK
  95 #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
  96                                 & ~PL_ARENA_CONST_ALIGN_MASK)
  97
  98 #define PL_INIT_ARENA_POOL(pool, name, size) \
  99         PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
 100 #else
 101 #define PL_ARENA_ALIGN(pool, n) (typeof(n))(((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
 102 #endif
 103
 104 #define PL_ARENA_ALLOCATE(p, pool, nb) \
 105     PR_BEGIN_MACRO \
 106         PLArena *_a = (pool)->current; \
 107         PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \
 108         PRUword _p = _a->avail; \
 109         PRUword _q = _p + _nb; \
 110         if (_q > _a->limit) \
 111             _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
 112         else \
 113             _a->avail = _q; \
 114         p = (void *)_p; \
 115         PL_ArenaCountAllocation(pool, nb); \
 116     PR_END_MACRO
 117
 118 #define PL_ARENA_GROW(p, pool, size, incr) \
 119     PR_BEGIN_MACRO \
 120         PLArena *_a = (pool)->current; \
 121         PRUword _p = _a->avail; \
 122         PRUword _q = (PRUword)p + size + incr; \
 123         if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
 124             _q <= _a->limit) { \
 125             _a->avail = PL_ARENA_ALIGN(pool, _q); \
 126             PL_ArenaCountInplaceGrowth(pool, size, incr); \
 127         } else { \
 128             p = PL_ArenaGrow(pool, p, size, incr); \
 129         } \
 130         PL_ArenaCountGrowth(pool, size, incr); \
 131     PR_END_MACRO
 132
 133 #define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
 134 #define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
 135
 136 #ifdef DEBUG
 137 #define PL_FREE_PATTERN 0xDA
 138 #define PL_CLEAR_UNUSED(a) (PR_ASSERT((a)->avail <= (a)->limit), \
 139                            memset((void*)(a)->avail, PL_FREE_PATTERN, \
 140                            (a)->limit - (a)->avail))
 141 #define PL_CLEAR_ARENA(a)  memset((void*)(a), PL_FREE_PATTERN, \
 142                            (a)->limit - (PRUword)(a))
 143 #else
 144 #define PL_CLEAR_UNUSED(a)
 145 #define PL_CLEAR_ARENA(a)
 146 #endif
 147
 148 #if ARENA_MARK_ENABLE
 149
 150 #define PL_ARENA_RELEASE(pool, mark) \
 151     PR_BEGIN_MACRO \
 152         char *_m = (char *)(mark); \
 153         PLArena *_a = (pool)->current; \
 154         if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
 155             _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
 156             PL_CLEAR_UNUSED(_a); \
 157             PL_ArenaCountRetract(pool, _m); \
 158         } else { \
 159             PL_ArenaRelease(pool, _m); \
 160         } \
 161         PL_ArenaCountRelease(pool, _m); \
 162     PR_END_MACRO
 163
 164 #else   /* !ARENA_MARK_ENABLE */
 165
 166 #define PL_ARENA_RELEASE(pool, mark)
 167
 168 #endif  /* ARENA_MARK_ENABLE */
 169
 170 #ifdef PL_ARENAMETER
 171 #define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
 172 #else
 173 #define PL_COUNT_ARENA(pool,op)
 174 #endif
 175
 176 #define PL_ARENA_DESTROY(pool, a, pnext) \
 177     PR_BEGIN_MACRO \
 178         PL_COUNT_ARENA(pool,--); \
 179         if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
 180         *(pnext) = (a)->next; \
 181         PL_CLEAR_ARENA(a); \
 182         free(a); \
 183         (a) = 0; \
 184     PR_END_MACRO
 185
 186 #ifdef PL_ARENAMETER
 187
 188 #include <stdio.h>
 189
 190 PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);
 191
 192 PR_EXTERN(void) PL_ArenaCountInplaceGrowth(
 193     PLArenaPool *pool, PRUint32 size, PRUint32 incr);
 194
 195 PR_EXTERN(void) PL_ArenaCountGrowth(
 196     PLArenaPool *pool, PRUint32 size, PRUint32 incr);
 197
 198 PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);
 199
 200 PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);
 201
 202 PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);
 203
 204 #else  /* !PL_ARENAMETER */
 205
 206 #define PL_ArenaCountAllocation(ap, nb)                 /* nothing */
 207 #define PL_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */
 208 #define PL_ArenaCountGrowth(ap, size, incr)             /* nothing */
 209 #define PL_ArenaCountRelease(ap, mark)                  /* nothing */
 210 #define PL_ArenaCountRetract(ap, mark)                  /* nothing */
 211
 212 #endif /* !PL_ARENAMETER */
 213
 214 PR_END_EXTERN_C
 215
 216 #endif /* plarena_h___ */