зеркало из https://github.com/mozilla/pjs.git
354 строки
9.6 KiB
C
354 строки
9.6 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.1 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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/*
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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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*/
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#include <stdlib.h>
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#include <string.h>
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#include "plarena.h"
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#include "prmem.h"
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#include "prbit.h"
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#include "prlog.h"
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#include "prmon.h"
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#include "prinit.h"
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static PLArena *arena_freelist;
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#ifdef PL_ARENAMETER
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static PLArenaStats *arena_stats_list;
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#define COUNT(pool,what) (pool)->stats.what++
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#else
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#define COUNT(pool,what) /* nothing */
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#endif
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#define PL_ARENA_DEFAULT_ALIGN sizeof(double)
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static PRMonitor *arenaLock;
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static PRCallOnceType once;
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/*
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** InitializeArenas() -- Initialize arena operations.
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**
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** InitializeArenas() is called exactly once and only once from
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** LockArena(). This function creates the arena protection
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** monitor: arenaLock.
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**
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** Note: If the arenaLock cannot be created, InitializeArenas()
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** fails quietly, returning only PR_FAILURE. This percolates up
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** to the application using the Arena API. He gets no arena
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** from PL_ArenaAllocate(). It's up to him to fail gracefully
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** or recover.
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**
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*/
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static PRStatus InitializeArenas( void )
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{
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PR_ASSERT( arenaLock == NULL );
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arenaLock = PR_NewMonitor();
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if ( arenaLock == NULL )
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return PR_FAILURE;
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else
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return PR_SUCCESS;
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} /* end ArenaInitialize() */
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static PRStatus LockArena( void )
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{
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PRStatus rc = PR_CallOnce( &once, InitializeArenas );
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if ( PR_FAILURE != rc )
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PR_EnterMonitor( arenaLock );
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return(rc);
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} /* end LockArena() */
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static void UnlockArena( void )
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{
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PR_ExitMonitor( arenaLock );
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return;
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} /* end UnlockArena() */
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PR_IMPLEMENT(void) PL_InitArenaPool(
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PLArenaPool *pool, const char *name, PRUint32 size, PRUint32 align)
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{
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#if defined(XP_MAC)
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#pragma unused (name)
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#endif
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if (align == 0)
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align = PL_ARENA_DEFAULT_ALIGN;
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pool->mask = PR_BITMASK(PR_CeilingLog2(align));
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pool->first.next = NULL;
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pool->first.base = pool->first.avail = pool->first.limit =
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(PRUword)PL_ARENA_ALIGN(pool, &pool->first + 1);
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pool->current = &pool->first;
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pool->arenasize = size;
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#ifdef PL_ARENAMETER
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memset(&pool->stats, 0, sizeof pool->stats);
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pool->stats.name = strdup(name);
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pool->stats.next = arena_stats_list;
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arena_stats_list = &pool->stats;
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#endif
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}
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PR_IMPLEMENT(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb)
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{
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PLArena **ap, *a, *b;
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PRUint32 sz;
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void *p;
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PR_ASSERT((nb & pool->mask) == 0);
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#if defined(WIN16)
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if (nb >= 60000U)
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return 0;
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#endif /* WIN16 */
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if ( PR_FAILURE == LockArena())
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return(0);
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ap = &arena_freelist;
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for (a = pool->current; a->avail + nb > a->limit; pool->current = a) {
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if (a->next) { /* move to next arena */
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a = a->next;
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continue;
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}
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while ((b = *ap) != 0) { /* reclaim a free arena */
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if (b->limit - b->base == pool->arenasize) {
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*ap = b->next;
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b->next = 0;
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a = a->next = b;
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COUNT(pool, nreclaims);
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goto claim;
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}
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ap = &b->next;
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}
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sz = PR_MAX(pool->arenasize, nb); /* allocate a new arena */
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sz += sizeof *a + pool->mask; /* header and alignment slop */
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b = (PLArena*)PR_MALLOC(sz);
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if (!b)
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{
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UnlockArena();
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return 0;
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}
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a = a->next = b;
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a->next = 0;
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a->limit = (PRUword)a + sz;
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PL_COUNT_ARENA(pool,++);
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COUNT(pool, nmallocs);
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claim:
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a->base = a->avail = (PRUword)PL_ARENA_ALIGN(pool, a + 1);
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}
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UnlockArena();
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p = (void *)a->avail;
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a->avail += nb;
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return p;
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}
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PR_IMPLEMENT(void *) PL_ArenaGrow(
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PLArenaPool *pool, void *p, PRUint32 size, PRUint32 incr)
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{
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void *newp;
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PL_ARENA_ALLOCATE(newp, pool, size + incr);
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if (newp)
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memcpy(newp, p, size);
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return newp;
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}
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/*
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* Free tail arenas linked after head, which may not be the true list head.
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* Reset pool->current to point to head in case it pointed at a tail arena.
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*/
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static void FreeArenaList(PLArenaPool *pool, PLArena *head, PRBool reallyFree)
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{
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PLArena **ap, *a;
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ap = &head->next;
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a = *ap;
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if (!a)
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return;
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#ifdef DEBUG
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do {
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PR_ASSERT(a->base <= a->avail && a->avail <= a->limit);
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a->avail = a->base;
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PL_CLEAR_UNUSED(a);
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} while ((a = a->next) != 0);
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a = *ap;
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#endif
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if (reallyFree) {
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do {
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*ap = a->next;
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PL_CLEAR_ARENA(a);
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PL_COUNT_ARENA(pool,--);
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PR_DELETE(a);
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} while ((a = *ap) != 0);
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} else {
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/* Insert the whole arena chain at the front of the freelist. */
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do {
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ap = &(*ap)->next;
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} while (*ap);
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LockArena();
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*ap = arena_freelist;
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arena_freelist = a;
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head->next = 0;
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UnlockArena();
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}
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pool->current = head;
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}
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PR_IMPLEMENT(void) PL_ArenaRelease(PLArenaPool *pool, char *mark)
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{
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PLArena *a;
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for (a = pool->first.next; a; a = a->next) {
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if (PR_UPTRDIFF(mark, a->base) < PR_UPTRDIFF(a->avail, a->base)) {
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a->avail = (PRUword)PL_ARENA_ALIGN(pool, mark);
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FreeArenaList(pool, a, PR_TRUE);
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return;
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}
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}
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}
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PR_IMPLEMENT(void) PL_FreeArenaPool(PLArenaPool *pool)
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{
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FreeArenaList(pool, &pool->first, PR_FALSE);
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COUNT(pool, ndeallocs);
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}
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PR_IMPLEMENT(void) PL_FinishArenaPool(PLArenaPool *pool)
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{
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FreeArenaList(pool, &pool->first, PR_TRUE);
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#ifdef PL_ARENAMETER
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{
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PLArenaStats *stats, **statsp;
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if (pool->stats.name)
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PR_DELETE(pool->stats.name);
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for (statsp = &arena_stats_list; (stats = *statsp) != 0;
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statsp = &stats->next) {
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if (stats == &pool->stats) {
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*statsp = stats->next;
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return;
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}
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}
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}
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#endif
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}
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PR_IMPLEMENT(void) PL_CompactArenaPool(PLArenaPool *ap)
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{
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#if XP_MAC
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#pragma unused (ap)
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#if 0
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PRArena *curr = &(ap->first);
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while (curr) {
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reallocSmaller(curr, curr->avail - (uprword_t)curr);
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curr->limit = curr->avail;
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curr = curr->next;
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}
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#endif
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#endif
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}
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PR_IMPLEMENT(void) PL_ArenaFinish()
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{
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PLArena *a, *next;
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LockArena();
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for (a = arena_freelist; a; a = next) {
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next = a->next;
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PR_DELETE(a);
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}
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arena_freelist = NULL;
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UnlockArena();
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}
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#ifdef PL_ARENAMETER
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PR_IMPLEMENT(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb)
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{
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pool->stats.nallocs++;
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pool->stats.nbytes += nb;
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if (nb > pool->stats.maxalloc)
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pool->stats.maxalloc = nb;
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pool->stats.variance += nb * nb;
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}
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PR_IMPLEMENT(void) PL_ArenaCountInplaceGrowth(
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PLArenaPool *pool, PRUint32 size, PRUint32 incr)
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{
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pool->stats.ninplace++;
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}
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PR_IMPLEMENT(void) PL_ArenaCountGrowth(
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PLArenaPool *pool, PRUint32 size, PRUint32 incr)
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{
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pool->stats.ngrows++;
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pool->stats.nbytes += incr;
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pool->stats.variance -= size * size;
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size += incr;
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if (size > pool->stats.maxalloc)
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pool->stats.maxalloc = size;
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pool->stats.variance += size * size;
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}
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PR_IMPLEMENT(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark)
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{
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pool->stats.nreleases++;
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}
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PR_IMPLEMENT(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark)
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{
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pool->stats.nfastrels++;
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}
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#include <math.h>
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#include <stdio.h>
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PR_IMPLEMENT(void) PL_DumpArenaStats(FILE *fp)
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{
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PLArenaStats *stats;
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double mean, variance;
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for (stats = arena_stats_list; stats; stats = stats->next) {
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if (stats->nallocs != 0) {
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mean = (double)stats->nbytes / stats->nallocs;
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variance = fabs(stats->variance / stats->nallocs - mean * mean);
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} else {
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mean = variance = 0;
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}
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fprintf(fp, "\n%s allocation statistics:\n", stats->name);
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fprintf(fp, " number of arenas: %u\n", stats->narenas);
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fprintf(fp, " number of allocations: %u\n", stats->nallocs);
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fprintf(fp, " number of free arena reclaims: %u\n", stats->nreclaims);
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fprintf(fp, " number of malloc calls: %u\n", stats->nmallocs);
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fprintf(fp, " number of deallocations: %u\n", stats->ndeallocs);
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fprintf(fp, " number of allocation growths: %u\n", stats->ngrows);
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fprintf(fp, " number of in-place growths: %u\n", stats->ninplace);
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fprintf(fp, "number of released allocations: %u\n", stats->nreleases);
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fprintf(fp, " number of fast releases: %u\n", stats->nfastrels);
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fprintf(fp, " total bytes allocated: %u\n", stats->nbytes);
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fprintf(fp, " mean allocation size: %g\n", mean);
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fprintf(fp, " standard deviation: %g\n", sqrt(variance));
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fprintf(fp, " maximum allocation size: %u\n", stats->maxalloc);
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}
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}
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#endif /* PL_ARENAMETER */
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