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Diffstat (limited to 'lib/ds/plarena.h')
| -rw-r--r-- | lib/ds/plarena.h | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/lib/ds/plarena.h b/lib/ds/plarena.h new file mode 100644 index 0000000..d609404 --- /dev/null +++ b/lib/ds/plarena.h @@ -0,0 +1,214 @@ +/* -*- 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)) + +#define PL_CLEAR_UNUSED_PATTERN(a, pattern) \ + (PR_ASSERT((a)->avail <= (a)->limit), \ + memset((void*)(a)->avail, (pattern), (a)->limit - (a)->avail)) +#ifdef DEBUG +#define PL_FREE_PATTERN 0xDA +#define PL_CLEAR_UNUSED(a) PL_CLEAR_UNUSED_PATTERN((a), PL_FREE_PATTERN) +#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___ */ |