| 1 | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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| 2 | /* ***** BEGIN LICENSE BLOCK *****
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| 3 | * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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| 4 | *
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| 5 | * The contents of this file are subject to the Mozilla Public License Version
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| 6 | * 1.1 (the "License"); you may not use this file except in compliance with
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| 7 | * the License. You may obtain a copy of the License at
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| 8 | * http://www.mozilla.org/MPL/
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| 9 | *
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| 10 | * Software distributed under the License is distributed on an "AS IS" basis,
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| 11 | * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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| 12 | * for the specific language governing rights and limitations under the
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| 13 | * License.
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| 14 | *
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| 15 | * The Original Code is the Netscape Portable Runtime (NSPR).
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| 16 | *
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| 17 | * The Initial Developer of the Original Code is Netscape
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| 18 | * Communications Corporation. Portions created by Netscape are
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| 19 | * Copyright (C) 1998-2000 Netscape Communications Corporation. All
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| 20 | * Rights Reserved.
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| 21 | *
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| 22 | * Contributor(s):
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| 23 | *
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| 24 | * Alternatively, the contents of this file may be used under the terms of
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| 25 | * either the GNU General Public License Version 2 or later (the "GPL"), or
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| 26 | * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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| 27 | * in which case the provisions of the GPL or the LGPL are applicable instead
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| 28 | * of those above. If you wish to allow use of your version of this file only
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| 29 | * under the terms of either the GPL or the LGPL, and not to allow others to
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| 30 | * use your version of this file under the terms of the MPL, indicate your
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| 31 | * decision by deleting the provisions above and replace them with the notice
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| 32 | * and other provisions required by the GPL or the LGPL. If you do not delete
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| 33 | * the provisions above, a recipient may use your version of this file under
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| 34 | * the terms of any one of the MPL, the GPL or the LGPL.
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| 35 | *
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| 36 | * ***** END LICENSE BLOCK *****
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| 37 | */
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| 38 |
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| 39 | #ifndef plarena_h___
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| 40 | #define plarena_h___
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| 41 | /*
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| 42 | * Lifetime-based fast allocation, inspired by much prior art, including
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| 43 | * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
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| 44 | * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
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| 45 | *
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| 46 | * Also supports LIFO allocation (PL_ARENA_MARK/PL_ARENA_RELEASE).
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| 47 | */
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| 48 | #include "prtypes.h"
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| 49 | #include "plarenas.h"
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| 50 |
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| 51 | PR_BEGIN_EXTERN_C
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| 52 |
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| 53 | typedef struct PLArena PLArena;
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| 54 |
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| 55 | struct PLArena {
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| 56 | PLArena *next; /* next arena for this lifetime */
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| 57 | PRUword base; /* aligned base address, follows this header */
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| 58 | PRUword limit; /* one beyond last byte in arena */
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| 59 | PRUword avail; /* points to next available byte */
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| 60 | };
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| 61 |
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| 62 | struct PLArenaPool {
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| 63 | PLArena first; /* first arena in pool list */
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| 64 | PLArena *current; /* arena from which to allocate space */
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| 65 | PRUint32 arenasize; /* net exact size of a new arena */
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| 66 | PRUword mask; /* alignment mask (power-of-2 - 1) */
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| 67 | };
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| 68 |
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| 69 | /*
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| 70 | * If the including .c file uses only one power-of-2 alignment, it may define
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| 71 | * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
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| 72 | * per ALLOCATE and GROW.
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| 73 | */
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| 74 | #ifdef PL_ARENA_CONST_ALIGN_MASK
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| 75 | #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
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| 76 | & ~PL_ARENA_CONST_ALIGN_MASK)
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| 77 |
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| 78 | #define PL_INIT_ARENA_POOL(pool, name, size) \
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| 79 | PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
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| 80 | #else
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| 81 | #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
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| 82 | #endif
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| 83 |
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| 84 | #define PL_ARENA_ALLOCATE(p, pool, nb) \
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| 85 | PR_BEGIN_MACRO \
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| 86 | PLArena *_a = (pool)->current; \
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| 87 | PRUint32 _nb = PL_ARENA_ALIGN(pool, (PRUint32)nb); \
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| 88 | PRUword _p = _a->avail; \
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| 89 | if (_nb < (PRUint32)nb) { \
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| 90 | _p = 0; \
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| 91 | } else if (_nb > (_a->limit - _a->avail)) { \
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| 92 | _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
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| 93 | } else { \
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| 94 | _a->avail += _nb; \
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| 95 | } \
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| 96 | p = (void *)_p; \
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| 97 | if (p) { \
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| 98 | PL_ArenaCountAllocation(pool, nb); \
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| 99 | } \
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| 100 | PR_END_MACRO
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| 101 |
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| 102 | #define PL_ARENA_GROW(p, pool, size, incr) \
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| 103 | PR_BEGIN_MACRO \
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| 104 | PLArena *_a = (pool)->current; \
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| 105 | PRUint32 _incr = PL_ARENA_ALIGN(pool, (PRUint32)incr); \
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| 106 | if (_incr < (PRUint32)incr) { \
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| 107 | p = NULL; \
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| 108 | } else if (_a->avail == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
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| 109 | _incr <= (_a->limit - _a->avail)) { \
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| 110 | _a->avail = _incr; \
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| 111 | PL_ArenaCountInplaceGrowth(pool, size, (RTUint32)incr); \
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| 112 | } else { \
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| 113 | p = PL_ArenaGrow(pool, p, size, (PRUint32)incr); \
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| 114 | } \
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| 115 | if (p) { \
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| 116 | PL_ArenaCountGrowth(pool, size, (PRUint32)incr); \
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| 117 | } \
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| 118 | PR_END_MACRO
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| 119 |
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| 120 | #define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
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| 121 | #define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
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| 122 |
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| 123 | #ifdef DEBUG
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| 124 | #define PL_FREE_PATTERN 0xDA
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| 125 | #define PL_CLEAR_UNUSED(a) Assert((a)->avail <= (a)->limit); \
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| 126 | memset((void*)(a)->avail, PL_FREE_PATTERN, \
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| 127 | (a)->limit - (a)->avail)
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| 128 | #define PL_CLEAR_ARENA(a) memset((void*)(a), PL_FREE_PATTERN, \
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| 129 | (a)->limit - (PRUword)(a))
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| 130 | #else
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| 131 | #define PL_CLEAR_UNUSED(a)
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| 132 | #define PL_CLEAR_ARENA(a)
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| 133 | #endif
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| 134 |
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| 135 | #define PL_ARENA_RELEASE(pool, mark) \
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| 136 | PR_BEGIN_MACRO \
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| 137 | char *_m = (char *)(mark); \
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| 138 | PLArena *_a = (pool)->current; \
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| 139 | if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
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| 140 | _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
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| 141 | PL_CLEAR_UNUSED(_a); \
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| 142 | PL_ArenaCountRetract(pool, _m); \
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| 143 | } else { \
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| 144 | PL_ArenaRelease(pool, _m); \
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| 145 | } \
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| 146 | PL_ArenaCountRelease(pool, _m); \
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| 147 | PR_END_MACRO
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| 148 |
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| 149 | #define PL_COUNT_ARENA(pool,op)
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| 150 |
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| 151 | #define PL_ARENA_DESTROY(pool, a, pnext) \
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| 152 | PR_BEGIN_MACRO \
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| 153 | PL_COUNT_ARENA(pool,--); \
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| 154 | if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
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| 155 | *(pnext) = (a)->next; \
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| 156 | PL_CLEAR_ARENA(a); \
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| 157 | free(a); \
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| 158 | (a) = 0; \
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| 159 | PR_END_MACRO
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| 160 |
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| 161 | #define PL_ArenaCountAllocation(ap, nb) /* nothing */
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| 162 | #define PL_ArenaCountInplaceGrowth(ap, size, incr) /* nothing */
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| 163 | #define PL_ArenaCountGrowth(ap, size, incr) /* nothing */
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| 164 | #define PL_ArenaCountRelease(ap, mark) /* nothing */
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| 165 | #define PL_ArenaCountRetract(ap, mark) /* nothing */
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| 166 |
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| 167 | PR_END_EXTERN_C
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| 168 |
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| 169 | #endif /* plarena_h___ */
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