/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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*
* The contents of this file are subject to the Mozilla Public License Version
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*
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* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Netscape Portable Runtime (NSPR).
*
* The Initial Developer of the Original Code is Netscape
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* Rights Reserved.
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*
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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*/
#ifndef plarena_h___
#define plarena_h___
/*
* Lifetime-based fast allocation, inspired by much prior art, including
* "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
* David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
*
* Also supports LIFO allocation (PL_ARENA_MARK/PL_ARENA_RELEASE).
*/
#include "prtypes.h"
#include "plarenas.h"
PR_BEGIN_EXTERN_C
typedef struct PLArena PLArena;
struct PLArena {
PLArena *next; /* next arena for this lifetime */
PRUword base; /* aligned base address, follows this header */
PRUword limit; /* one beyond last byte in arena */
PRUword avail; /* points to next available byte */
};
#ifdef PL_ARENAMETER
typedef struct PLArenaStats PLArenaStats;
struct PLArenaStats {
PLArenaStats *next; /* next in arenaStats list */
char *name; /* name for debugging */
PRUint32 narenas; /* number of arenas in pool */
PRUint32 nallocs; /* number of PL_ARENA_ALLOCATE() calls */
PRUint32 nreclaims; /* number of reclaims from freeArenas */
PRUint32 nmallocs; /* number of malloc() calls */
PRUint32 ndeallocs; /* number of lifetime deallocations */
PRUint32 ngrows; /* number of PL_ARENA_GROW() calls */
PRUint32 ninplace; /* number of in-place growths */
PRUint32 nreleases; /* number of PL_ARENA_RELEASE() calls */
PRUint32 nfastrels; /* number of "fast path" releases */
PRUint32 nbytes; /* total bytes allocated */
PRUint32 maxalloc; /* maximum allocation size in bytes */
PRFloat64 variance; /* size variance accumulator */
};
#endif
struct PLArenaPool {
PLArena first; /* first arena in pool list */
PLArena *current; /* arena from which to allocate space */
PRUint32 arenasize; /* net exact size of a new arena */
PRUword mask; /* alignment mask (power-of-2 - 1) */
#ifdef PL_ARENAMETER
PLArenaStats stats;
#endif
};
/*
* If the including .c file uses only one power-of-2 alignment, it may define
* PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
* per ALLOCATE and GROW.
*/
#ifdef PL_ARENA_CONST_ALIGN_MASK
#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
& ~PL_ARENA_CONST_ALIGN_MASK)
#define PL_INIT_ARENA_POOL(pool, name, size) \
PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
#else
#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
#endif
#define PL_ARENA_ALLOCATE(p, pool, nb) \
PR_BEGIN_MACRO \
PLArena *_a = (pool)->current; \
PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \
PRUword _p = _a->avail; \
PRUword _q = _p + _nb; \
if (_q > _a->limit) \
_p = (PRUword)PL_ArenaAllocate(pool, _nb); \
else \
_a->avail = _q; \
p = (void *)_p; \
PL_ArenaCountAllocation(pool, nb); \
PR_END_MACRO
#define PL_ARENA_GROW(p, pool, size, incr) \
PR_BEGIN_MACRO \
PLArena *_a = (pool)->current; \
PRUint32 _incr = PL_ARENA_ALIGN(pool, incr); \
PRUword _p = _a->avail; \
PRUword _q = _p + _incr; \
if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
_q <= _a->limit) { \
_a->avail = _q; \
PL_ArenaCountInplaceGrowth(pool, size, incr); \
} else { \
p = PL_ArenaGrow(pool, p, size, incr); \
} \
PL_ArenaCountGrowth(pool, size, incr); \
PR_END_MACRO
#define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
#define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
#ifdef DEBUG
#define PL_FREE_PATTERN 0xDA
#define PL_CLEAR_UNUSED(a) (PR_ASSERT((a)->avail <= (a)->limit), \
memset((void*)(a)->avail, PL_FREE_PATTERN, \
(a)->limit - (a)->avail))
#define PL_CLEAR_ARENA(a) memset((void*)(a), PL_FREE_PATTERN, \
(a)->limit - (PRUword)(a))
#else
#define PL_CLEAR_UNUSED(a)
#define PL_CLEAR_ARENA(a)
#endif
#define PL_ARENA_RELEASE(pool, mark) \
PR_BEGIN_MACRO \
char *_m = (char *)(mark); \
PLArena *_a = (pool)->current; \
if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
_a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
PL_CLEAR_UNUSED(_a); \
PL_ArenaCountRetract(pool, _m); \
} else { \
PL_ArenaRelease(pool, _m); \
} \
PL_ArenaCountRelease(pool, _m); \
PR_END_MACRO
#ifdef PL_ARENAMETER
#define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
#else
#define PL_COUNT_ARENA(pool,op)
#endif
#define PL_ARENA_DESTROY(pool, a, pnext) \
PR_BEGIN_MACRO \
PL_COUNT_ARENA(pool,--); \
if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
*(pnext) = (a)->next; \
PL_CLEAR_ARENA(a); \
free(a); \
(a) = 0; \
PR_END_MACRO
#ifdef PL_ARENAMETER
#include <stdio.h>
PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);
PR_EXTERN(void) PL_ArenaCountInplaceGrowth(
PLArenaPool *pool, PRUint32 size, PRUint32 incr);
PR_EXTERN(void) PL_ArenaCountGrowth(
PLArenaPool *pool, PRUint32 size, PRUint32 incr);
PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);
PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);
PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);
#else /* !PL_ARENAMETER */
#define PL_ArenaCountAllocation(ap, nb) /* nothing */
#define PL_ArenaCountInplaceGrowth(ap, size, incr) /* nothing */
#define PL_ArenaCountGrowth(ap, size, incr) /* nothing */
#define PL_ArenaCountRelease(ap, mark) /* nothing */
#define PL_ArenaCountRetract(ap, mark) /* nothing */
#endif /* !PL_ARENAMETER */
PR_END_EXTERN_C
#endif /* plarena_h___ */