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Annotation of sbbs/javascript/include/mozilla/js/jsarena.h, revision 1.1

1.1     ! root        1: /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
        !             2:  *
        !             3:  * The contents of this file are subject to the Netscape 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/NPL/
        !             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 Mozilla Communicator client code, released
        !            14:  * March 31, 1998.
        !            15:  *
        !            16:  * The Initial Developer of the Original Code is Netscape
        !            17:  * Communications Corporation.  Portions created by Netscape are
        !            18:  * Copyright (C) 1998 Netscape Communications Corporation. All
        !            19:  * Rights Reserved.
        !            20:  *
        !            21:  * Contributor(s): 
        !            22:  *
        !            23:  * Alternatively, the contents of this file may be used under the
        !            24:  * terms of the GNU Public License (the "GPL"), in which case the
        !            25:  * provisions of the GPL are applicable instead of those above.
        !            26:  * If you wish to allow use of your version of this file only
        !            27:  * under the terms of the GPL and not to allow others to use your
        !            28:  * version of this file under the NPL, indicate your decision by
        !            29:  * deleting the provisions above and replace them with the notice
        !            30:  * and other provisions required by the GPL.  If you do not delete
        !            31:  * the provisions above, a recipient may use your version of this
        !            32:  * file under either the NPL or the GPL.
        !            33:  */
        !            34: 
        !            35: #ifndef jsarena_h___
        !            36: #define jsarena_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 (JS_ARENA_MARK/JS_ARENA_RELEASE).
        !            43:  */
        !            44: #include <stdlib.h>
        !            45: #include "jstypes.h"
        !            46: #include "jscompat.h"
        !            47: 
        !            48: JS_BEGIN_EXTERN_C
        !            49: 
        !            50: typedef struct JSArena JSArena;
        !            51: typedef struct JSArenaPool JSArenaPool;
        !            52: 
        !            53: struct JSArena {
        !            54:     JSArena     *next;          /* next arena for this lifetime */
        !            55:     jsuword     base;           /* aligned base address, follows this header */
        !            56:     jsuword     limit;          /* one beyond last byte in arena */
        !            57:     jsuword     avail;          /* points to next available byte */
        !            58: };
        !            59: 
        !            60: #ifdef JS_ARENAMETER
        !            61: typedef struct JSArenaStats JSArenaStats;
        !            62: 
        !            63: struct JSArenaStats {
        !            64:     JSArenaStats *next;         /* next in arenaStats list */
        !            65:     char        *name;          /* name for debugging */
        !            66:     uint32      narenas;        /* number of arenas in pool */
        !            67:     uint32      nallocs;        /* number of JS_ARENA_ALLOCATE() calls */
        !            68:     uint32      nreclaims;      /* number of reclaims from freeArenas */
        !            69:     uint32      nmallocs;       /* number of malloc() calls */
        !            70:     uint32      ndeallocs;      /* number of lifetime deallocations */
        !            71:     uint32      ngrows;         /* number of JS_ARENA_GROW() calls */
        !            72:     uint32      ninplace;       /* number of in-place growths */
        !            73:     uint32      nreallocs;      /* number of arena grow extending reallocs */
        !            74:     uint32      nreleases;      /* number of JS_ARENA_RELEASE() calls */
        !            75:     uint32      nfastrels;      /* number of "fast path" releases */
        !            76:     size_t      nbytes;         /* total bytes allocated */
        !            77:     size_t      maxalloc;       /* maximum allocation size in bytes */
        !            78:     double      variance;       /* size variance accumulator */
        !            79: };
        !            80: #endif
        !            81: 
        !            82: struct JSArenaPool {
        !            83:     JSArena     first;          /* first arena in pool list */
        !            84:     JSArena     *current;       /* arena from which to allocate space */
        !            85:     size_t      arenasize;      /* net exact size of a new arena */
        !            86:     jsuword     mask;           /* alignment mask (power-of-2 - 1) */
        !            87: #ifdef JS_ARENAMETER
        !            88:     JSArenaStats stats;
        !            89: #endif
        !            90: };
        !            91: 
        !            92: /*
        !            93:  * If the including .c file uses only one power-of-2 alignment, it may define
        !            94:  * JS_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
        !            95:  * per ALLOCATE and GROW.
        !            96:  */
        !            97: #ifdef JS_ARENA_CONST_ALIGN_MASK
        !            98: #define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + JS_ARENA_CONST_ALIGN_MASK)   \
        !            99:                                 & ~(jsuword)JS_ARENA_CONST_ALIGN_MASK)
        !           100: 
        !           101: #define JS_INIT_ARENA_POOL(pool, name, size) \
        !           102:        JS_InitArenaPool(pool, name, size, JS_ARENA_CONST_ALIGN_MASK + 1)
        !           103: #else
        !           104: #define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + (pool)->mask) & ~(pool)->mask)
        !           105: #endif
        !           106: 
        !           107: #define JS_ARENA_ALLOCATE(p, pool, nb)                                        \
        !           108:     JS_ARENA_ALLOCATE_CAST(p, void *, pool, nb)
        !           109: 
        !           110: #define JS_ARENA_ALLOCATE_TYPE(p, type, pool)                                 \
        !           111:     JS_ARENA_ALLOCATE_CAST(p, type *, pool, sizeof(type))
        !           112: 
        !           113: #define JS_ARENA_ALLOCATE_CAST(p, type, pool, nb)                             \
        !           114:     JS_BEGIN_MACRO                                                            \
        !           115:        JSArena *_a = (pool)->current;                                        \
        !           116:        size_t _nb = JS_ARENA_ALIGN(pool, nb);                                \
        !           117:        jsuword _p = _a->avail;                                               \
        !           118:        jsuword _q = _p + _nb;                                                \
        !           119:        if (_q > _a->limit)                                                   \
        !           120:            _p = (jsuword)JS_ArenaAllocate(pool, _nb);                        \
        !           121:        else                                                                  \
        !           122:            _a->avail = _q;                                                   \
        !           123:        p = (type) _p;                                                        \
        !           124:        JS_ArenaCountAllocation(pool, nb);                                    \
        !           125:     JS_END_MACRO
        !           126: 
        !           127: #define JS_ARENA_GROW(p, pool, size, incr)                                    \
        !           128:     JS_ARENA_GROW_CAST(p, void *, pool, size, incr)
        !           129: 
        !           130: #define JS_ARENA_GROW_CAST(p, type, pool, size, incr)                         \
        !           131:     JS_BEGIN_MACRO                                                            \
        !           132:         JSArena *_a = (pool)->current;                                        \
        !           133:         if (_a->avail == (jsuword)(p) + JS_ARENA_ALIGN(pool, size)) {         \
        !           134:             size_t _nb = (size) + (incr);                                     \
        !           135:             jsuword _q = (jsuword)(p) + JS_ARENA_ALIGN(pool, _nb);            \
        !           136:             if (_q <= _a->limit) {                                            \
        !           137:                 _a->avail = _q;                                               \
        !           138:                 JS_ArenaCountInplaceGrowth(pool, size, incr);                 \
        !           139:             } else if ((jsuword)(p) == _a->base) {                            \
        !           140:                 p = (type) JS_ArenaRealloc(pool, p, size, incr);              \
        !           141:             } else {                                                          \
        !           142:                 p = (type) JS_ArenaGrow(pool, p, size, incr);                 \
        !           143:             }                                                                 \
        !           144:         } else {                                                              \
        !           145:             p = (type) JS_ArenaGrow(pool, p, size, incr);                     \
        !           146:         }                                                                     \
        !           147:         JS_ArenaCountGrowth(pool, size, incr);                                \
        !           148:     JS_END_MACRO
        !           149: 
        !           150: #define JS_ARENA_MARK(pool)     ((void *) (pool)->current->avail)
        !           151: #define JS_UPTRDIFF(p,q)        ((jsuword)(p) - (jsuword)(q))
        !           152: 
        !           153: #ifdef DEBUG
        !           154: #define JS_FREE_PATTERN         0xDA
        !           155: #define JS_CLEAR_UNUSED(a)      (JS_ASSERT((a)->avail <= (a)->limit),         \
        !           156:                                  memset((void*)(a)->avail, JS_FREE_PATTERN,   \
        !           157:                                         (a)->limit - (a)->avail))
        !           158: #define JS_CLEAR_ARENA(a)       memset((void*)(a), JS_FREE_PATTERN,           \
        !           159:                                        (a)->limit - (jsuword)(a))
        !           160: #else
        !           161: #define JS_CLEAR_UNUSED(a)      /* nothing */
        !           162: #define JS_CLEAR_ARENA(a)       /* nothing */
        !           163: #endif
        !           164: 
        !           165: #define JS_ARENA_RELEASE(pool, mark)                                          \
        !           166:     JS_BEGIN_MACRO                                                            \
        !           167:         char *_m = (char *)(mark);                                            \
        !           168:         JSArena *_a = (pool)->current;                                        \
        !           169:         if (_a != &(pool)->first &&                                           \
        !           170:             JS_UPTRDIFF(_m, _a->base) <= JS_UPTRDIFF(_a->avail, _a->base)) {  \
        !           171:             _a->avail = (jsuword)JS_ARENA_ALIGN(pool, _m);                    \
        !           172:             JS_ASSERT(_a->avail <= _a->limit);                                \
        !           173:             JS_CLEAR_UNUSED(_a);                                              \
        !           174:             JS_ArenaCountRetract(pool, _m);                                   \
        !           175:         } else {                                                              \
        !           176:             JS_ArenaRelease(pool, _m);                                        \
        !           177:         }                                                                     \
        !           178:         JS_ArenaCountRelease(pool, _m);                                       \
        !           179:     JS_END_MACRO
        !           180: 
        !           181: #ifdef JS_ARENAMETER
        !           182: #define JS_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
        !           183: #else
        !           184: #define JS_COUNT_ARENA(pool,op)
        !           185: #endif
        !           186: 
        !           187: #define JS_ARENA_DESTROY(pool, a, pnext)                                      \
        !           188:     JS_BEGIN_MACRO                                                            \
        !           189:         JS_COUNT_ARENA(pool,--);                                              \
        !           190:         if ((pool)->current == (a)) (pool)->current = &(pool)->first;         \
        !           191:         *(pnext) = (a)->next;                                                 \
        !           192:         JS_CLEAR_ARENA(a);                                                    \
        !           193:         free(a);                                                              \
        !           194:         (a) = NULL;                                                           \
        !           195:     JS_END_MACRO
        !           196: 
        !           197: /*
        !           198:  * Initialize an arena pool with the given name for debugging and metering,
        !           199:  * with a minimum size per arena of size bytes.
        !           200:  */
        !           201: extern JS_PUBLIC_API(void)
        !           202: JS_InitArenaPool(JSArenaPool *pool, const char *name, size_t size,
        !           203:                  size_t align);
        !           204: 
        !           205: /*
        !           206:  * Free the arenas in pool.  The user may continue to allocate from pool
        !           207:  * after calling this function.  There is no need to call JS_InitArenaPool()
        !           208:  * again unless JS_FinishArenaPool(pool) has been called.
        !           209:  */
        !           210: extern JS_PUBLIC_API(void)
        !           211: JS_FreeArenaPool(JSArenaPool *pool);
        !           212: 
        !           213: /*
        !           214:  * Free the arenas in pool and finish using it altogether.
        !           215:  */
        !           216: extern JS_PUBLIC_API(void)
        !           217: JS_FinishArenaPool(JSArenaPool *pool);
        !           218: 
        !           219: /*
        !           220:  * Finish using arenas, freeing all memory associated with them except for
        !           221:  * any locks needed for thread safety.
        !           222:  */
        !           223: extern JS_PUBLIC_API(void)
        !           224: JS_ArenaFinish(void);
        !           225: 
        !           226: /*
        !           227:  * Free any locks or other memory needed for thread safety, just before
        !           228:  * shutting down.  At that point, we must be called by a single thread.
        !           229:  *
        !           230:  * After shutting down, the next thread to call JS_InitArenaPool must not
        !           231:  * race with any other thread.  Once a pool has been initialized, threads
        !           232:  * may safely call jsarena.c functions on thread-local pools.  The upshot
        !           233:  * is that pools are per-thread, but the underlying global freelist is
        !           234:  * thread-safe, provided that both the first pool initialization and the
        !           235:  * shut-down call are single-threaded.
        !           236:  */
        !           237: extern JS_PUBLIC_API(void)
        !           238: JS_ArenaShutDown(void);
        !           239: 
        !           240: /*
        !           241:  * Friend functions used by the JS_ARENA_*() macros.
        !           242:  */
        !           243: extern JS_PUBLIC_API(void *)
        !           244: JS_ArenaAllocate(JSArenaPool *pool, size_t nb);
        !           245: 
        !           246: extern JS_PUBLIC_API(void *)
        !           247: JS_ArenaRealloc(JSArenaPool *pool, void *p, size_t size, size_t incr);
        !           248: 
        !           249: extern JS_PUBLIC_API(void *)
        !           250: JS_ArenaGrow(JSArenaPool *pool, void *p, size_t size, size_t incr);
        !           251: 
        !           252: extern JS_PUBLIC_API(void)
        !           253: JS_ArenaRelease(JSArenaPool *pool, char *mark);
        !           254: 
        !           255: /*
        !           256:  * Function to be used directly when an allocation has likely grown to consume
        !           257:  * an entire JSArena, in which case the arena is returned to the malloc heap.
        !           258:  */
        !           259: extern JS_PUBLIC_API(void)
        !           260: JS_ArenaFreeAllocation(JSArenaPool *pool, void *p, size_t size);
        !           261: 
        !           262: #ifdef JS_ARENAMETER
        !           263: 
        !           264: #include <stdio.h>
        !           265: 
        !           266: extern JS_PUBLIC_API(void)
        !           267: JS_ArenaCountAllocation(JSArenaPool *pool, size_t nb);
        !           268: 
        !           269: extern JS_PUBLIC_API(void)
        !           270: JS_ArenaCountInplaceGrowth(JSArenaPool *pool, size_t size, size_t incr);
        !           271: 
        !           272: extern JS_PUBLIC_API(void)
        !           273: JS_ArenaCountGrowth(JSArenaPool *pool, size_t size, size_t incr);
        !           274: 
        !           275: extern JS_PUBLIC_API(void)
        !           276: JS_ArenaCountRelease(JSArenaPool *pool, char *mark);
        !           277: 
        !           278: extern JS_PUBLIC_API(void)
        !           279: JS_ArenaCountRetract(JSArenaPool *pool, char *mark);
        !           280: 
        !           281: extern JS_PUBLIC_API(void)
        !           282: JS_DumpArenaStats(FILE *fp);
        !           283: 
        !           284: #else  /* !JS_ARENAMETER */
        !           285: 
        !           286: #define JS_ArenaCountAllocation(ap, nb)                 /* nothing */
        !           287: #define JS_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */
        !           288: #define JS_ArenaCountGrowth(ap, size, incr)             /* nothing */
        !           289: #define JS_ArenaCountRelease(ap, mark)                  /* nothing */
        !           290: #define JS_ArenaCountRetract(ap, mark)                  /* nothing */
        !           291: 
        !           292: #endif /* !JS_ARENAMETER */
        !           293: 
        !           294: JS_END_EXTERN_C
        !           295: 
        !           296: #endif /* jsarena_h___ */

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