plarena.h
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- /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
- /* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * 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
- * Communications Corporation. Portions created by Netscape are
- * Copyright (C) 1998-2000 Netscape Communications Corporation. All
- * Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK *****
- */
- #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___ */