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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* The Original Code is Mozilla Communicator client code, released
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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* ***** END LICENSE BLOCK ***** */
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* Lifetime-based fast allocation, inspired by much prior art, including
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* "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
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* David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
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* Also supports LIFO allocation (JS_ARENA_MARK/JS_ARENA_RELEASE).
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typedef struct JSArena JSArena;
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typedef struct JSArenaPool JSArenaPool;
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JSArena *next; /* next arena for this lifetime */
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jsuword base; /* aligned base address, follows this header */
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jsuword limit; /* one beyond last byte in arena */
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jsuword avail; /* points to next available byte */
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typedef struct JSArenaStats JSArenaStats;
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JSArenaStats *next; /* next in arenaStats list */
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char *name; /* name for debugging */
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uint32 narenas; /* number of arenas in pool */
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uint32 nallocs; /* number of JS_ARENA_ALLOCATE() calls */
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uint32 nmallocs; /* number of malloc() calls */
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uint32 ndeallocs; /* number of lifetime deallocations */
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uint32 ngrows; /* number of JS_ARENA_GROW() calls */
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uint32 ninplace; /* number of in-place growths */
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uint32 nreallocs; /* number of arena grow extending reallocs */
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uint32 nreleases; /* number of JS_ARENA_RELEASE() calls */
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uint32 nfastrels; /* number of "fast path" releases */
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size_t nbytes; /* total bytes allocated */
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size_t maxalloc; /* maximum allocation size in bytes */
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double variance; /* size variance accumulator */
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JSArena first; /* first arena in pool list */
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JSArena *current; /* arena from which to allocate space */
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size_t arenasize; /* net exact size of a new arena */
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jsuword mask; /* alignment mask (power-of-2 - 1) */
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* If the including .c file uses only one power-of-2 alignment, it may define
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* JS_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
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* per ALLOCATE and GROW.
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#ifdef JS_ARENA_CONST_ALIGN_MASK
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#define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + JS_ARENA_CONST_ALIGN_MASK) \
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& ~(jsuword)JS_ARENA_CONST_ALIGN_MASK)
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#define JS_INIT_ARENA_POOL(pool, name, size) \
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JS_InitArenaPool(pool, name, size, JS_ARENA_CONST_ALIGN_MASK + 1)
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#define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + (pool)->mask) & ~(pool)->mask)
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#define JS_ARENA_ALLOCATE(p, pool, nb) \
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JS_ARENA_ALLOCATE_CAST(p, void *, pool, nb)
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#define JS_ARENA_ALLOCATE_TYPE(p, type, pool) \
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JS_ARENA_ALLOCATE_COMMON(p, type *, pool, sizeof(type), 0)
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#define JS_ARENA_ALLOCATE_CAST(p, type, pool, nb) \
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JS_ARENA_ALLOCATE_COMMON(p, type, pool, nb, _nb > _a->limit)
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* NB: In JS_ARENA_ALLOCATE_CAST and JS_ARENA_GROW_CAST, always subtract _nb
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* from a->limit rather than adding _nb to _p, to avoid overflowing a 32-bit
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* address space (possible when running a 32-bit program on a 64-bit system
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* where the kernel maps the heap up against the top of the 32-bit address
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* Thanks to Juergen Kreileder <jk@blackdown.de>, who brought this up in
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* https://bugzilla.mozilla.org/show_bug.cgi?id=279273.
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#define JS_ARENA_ALLOCATE_COMMON(p, type, pool, nb, guard) \
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JSArena *_a = (pool)->current; \
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size_t _nb = JS_ARENA_ALIGN(pool, nb); \
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jsuword _p = _a->avail; \
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if ((guard) || _p > _a->limit - _nb) \
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_p = (jsuword)JS_ArenaAllocate(pool, _nb); \
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_a->avail = _p + _nb; \
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JS_ArenaCountAllocation(pool, nb); \
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#define JS_ARENA_GROW(p, pool, size, incr) \
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JS_ARENA_GROW_CAST(p, void *, pool, size, incr)
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#define JS_ARENA_GROW_CAST(p, type, pool, size, incr) \
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JSArena *_a = (pool)->current; \
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if (_a->avail == (jsuword)(p) + JS_ARENA_ALIGN(pool, size)) { \
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size_t _nb = (size) + (incr); \
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_nb = JS_ARENA_ALIGN(pool, _nb); \
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if (_a->limit >= _nb && (jsuword)(p) <= _a->limit - _nb) { \
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_a->avail = (jsuword)(p) + _nb; \
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JS_ArenaCountInplaceGrowth(pool, size, incr); \
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} else if ((jsuword)(p) == _a->base) { \
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p = (type) JS_ArenaRealloc(pool, p, size, incr); \
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p = (type) JS_ArenaGrow(pool, p, size, incr); \
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p = (type) JS_ArenaGrow(pool, p, size, incr); \
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JS_ArenaCountGrowth(pool, size, incr); \
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#define JS_ARENA_MARK(pool) ((void *) (pool)->current->avail)
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#define JS_UPTRDIFF(p,q) ((jsuword)(p) - (jsuword)(q))
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#define JS_FREE_PATTERN 0xDA
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#define JS_CLEAR_UNUSED(a) (JS_ASSERT((a)->avail <= (a)->limit), \
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memset((void*)(a)->avail, JS_FREE_PATTERN, \
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(a)->limit - (a)->avail))
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#define JS_CLEAR_ARENA(a) memset((void*)(a), JS_FREE_PATTERN, \
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(a)->limit - (jsuword)(a))
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#define JS_CLEAR_UNUSED(a) /* nothing */
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#define JS_CLEAR_ARENA(a) /* nothing */
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#define JS_ARENA_RELEASE(pool, mark) \
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char *_m = (char *)(mark); \
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JSArena *_a = (pool)->current; \
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if (_a != &(pool)->first && \
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JS_UPTRDIFF(_m, _a->base) <= JS_UPTRDIFF(_a->avail, _a->base)) { \
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_a->avail = (jsuword)JS_ARENA_ALIGN(pool, _m); \
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JS_ASSERT(_a->avail <= _a->limit); \
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JS_CLEAR_UNUSED(_a); \
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JS_ArenaCountRetract(pool, _m); \
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JS_ArenaRelease(pool, _m); \
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JS_ArenaCountRelease(pool, _m); \
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#define JS_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
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#define JS_COUNT_ARENA(pool,op)
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#define JS_ARENA_DESTROY(pool, a, pnext) \
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JS_COUNT_ARENA(pool,--); \
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if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
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*(pnext) = (a)->next; \
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* Initialize an arena pool with the given name for debugging and metering,
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* with a minimum size per arena of size bytes.
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extern JS_PUBLIC_API(void)
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JS_InitArenaPool(JSArenaPool *pool, const char *name, size_t size,
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* Free the arenas in pool. The user may continue to allocate from pool
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* after calling this function. There is no need to call JS_InitArenaPool()
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* again unless JS_FinishArenaPool(pool) has been called.
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extern JS_PUBLIC_API(void)
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JS_FreeArenaPool(JSArenaPool *pool);
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* Free the arenas in pool and finish using it altogether.
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extern JS_PUBLIC_API(void)
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JS_FinishArenaPool(JSArenaPool *pool);
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* Deprecated do-nothing function.
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extern JS_PUBLIC_API(void)
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JS_ArenaFinish(void);
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* Deprecated do-nothing function.
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extern JS_PUBLIC_API(void)
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JS_ArenaShutDown(void);
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* Friend functions used by the JS_ARENA_*() macros.
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extern JS_PUBLIC_API(void *)
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JS_ArenaAllocate(JSArenaPool *pool, size_t nb);
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extern JS_PUBLIC_API(void *)
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JS_ArenaRealloc(JSArenaPool *pool, void *p, size_t size, size_t incr);
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extern JS_PUBLIC_API(void *)
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JS_ArenaGrow(JSArenaPool *pool, void *p, size_t size, size_t incr);
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extern JS_PUBLIC_API(void)
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JS_ArenaRelease(JSArenaPool *pool, char *mark);
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* Function to be used directly when an allocation has likely grown to consume
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* an entire JSArena, in which case the arena is returned to the malloc heap.
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extern JS_PUBLIC_API(void)
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JS_ArenaFreeAllocation(JSArenaPool *pool, void *p, size_t size);
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extern JS_PUBLIC_API(void)
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JS_ArenaCountAllocation(JSArenaPool *pool, size_t nb);
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extern JS_PUBLIC_API(void)
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JS_ArenaCountInplaceGrowth(JSArenaPool *pool, size_t size, size_t incr);
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extern JS_PUBLIC_API(void)
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JS_ArenaCountGrowth(JSArenaPool *pool, size_t size, size_t incr);
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extern JS_PUBLIC_API(void)
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JS_ArenaCountRelease(JSArenaPool *pool, char *mark);
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extern JS_PUBLIC_API(void)
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JS_ArenaCountRetract(JSArenaPool *pool, char *mark);
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extern JS_PUBLIC_API(void)
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JS_DumpArenaStats(FILE *fp);
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#else /* !JS_ARENAMETER */
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#define JS_ArenaCountAllocation(ap, nb) /* nothing */
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#define JS_ArenaCountInplaceGrowth(ap, size, incr) /* nothing */
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#define JS_ArenaCountGrowth(ap, size, incr) /* nothing */
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#define JS_ArenaCountRelease(ap, mark) /* nothing */
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#define JS_ArenaCountRetract(ap, mark) /* nothing */
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#endif /* !JS_ARENAMETER */
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#endif /* jsarena_h___ */
added
removed
src/js/jsarena.h
