/usr/include/isc/refcount.h is in libbind-dev 1:9.9.5.dfsg-9+deb8u15.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 | /*
* Copyright (C) 2004-2007, 2009 Internet Systems Consortium, Inc. ("ISC")
* Copyright (C) 2001, 2003 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: refcount.h,v 1.17 2009/09/29 23:48:04 tbox Exp $ */
#ifndef ISC_REFCOUNT_H
#define ISC_REFCOUNT_H 1
#include <isc/atomic.h>
#include <isc/lang.h>
#include <isc/mutex.h>
#include <isc/platform.h>
#include <isc/types.h>
#include <isc/util.h>
/*! \file isc/refcount.h
* \brief Implements a locked reference counter.
*
* These functions may actually be
* implemented using macros, and implementations of these macros are below.
* The isc_refcount_t type should not be accessed directly, as its contents
* depend on the implementation.
*/
ISC_LANG_BEGINDECLS
/*
* Function prototypes
*/
/*
* isc_result_t
* isc_refcount_init(isc_refcount_t *ref, unsigned int n);
*
* Initialize the reference counter. There will be 'n' initial references.
*
* Requires:
* ref != NULL
*/
/*
* void
* isc_refcount_destroy(isc_refcount_t *ref);
*
* Destroys a reference counter.
*
* Requires:
* ref != NULL
* The number of references is 0.
*/
/*
* void
* isc_refcount_increment(isc_refcount_t *ref, unsigned int *targetp);
* isc_refcount_increment0(isc_refcount_t *ref, unsigned int *targetp);
*
* Increments the reference count, returning the new value in targetp if it's
* not NULL. The reference counter typically begins with the initial counter
* of 1, and will be destroyed once the counter reaches 0. Thus,
* isc_refcount_increment() additionally requires the previous counter be
* larger than 0 so that an error which violates the usage can be easily
* caught. isc_refcount_increment0() does not have this restriction.
*
* Requires:
* ref != NULL.
*/
/*
* void
* isc_refcount_decrement(isc_refcount_t *ref, unsigned int *targetp);
*
* Decrements the reference count, returning the new value in targetp if it's
* not NULL.
*
* Requires:
* ref != NULL.
*/
/*
* Sample implementations
*/
#ifdef ISC_PLATFORM_USETHREADS
#ifdef ISC_PLATFORM_HAVEXADD
#define ISC_REFCOUNT_HAVEATOMIC 1
typedef struct isc_refcount {
isc_int32_t refs;
} isc_refcount_t;
#define isc_refcount_destroy(rp) REQUIRE((rp)->refs == 0)
#define isc_refcount_current(rp) ((unsigned int)((rp)->refs))
#define isc_refcount_increment0(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
isc_int32_t prev; \
prev = isc_atomic_xadd(&(rp)->refs, 1); \
if (_tmp != NULL) \
*_tmp = prev + 1; \
} while (0)
#define isc_refcount_increment(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
isc_int32_t prev; \
prev = isc_atomic_xadd(&(rp)->refs, 1); \
REQUIRE(prev > 0); \
if (_tmp != NULL) \
*_tmp = prev + 1; \
} while (0)
#define isc_refcount_decrement(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
isc_int32_t prev; \
prev = isc_atomic_xadd(&(rp)->refs, -1); \
REQUIRE(prev > 0); \
if (_tmp != NULL) \
*_tmp = prev - 1; \
} while (0)
#else /* ISC_PLATFORM_HAVEXADD */
typedef struct isc_refcount {
int refs;
isc_mutex_t lock;
} isc_refcount_t;
/*% Destroys a reference counter. */
#define isc_refcount_destroy(rp) \
do { \
REQUIRE((rp)->refs == 0); \
DESTROYLOCK(&(rp)->lock); \
} while (0)
#define isc_refcount_current(rp) ((unsigned int)((rp)->refs))
/*% Increments the reference count, returning the new value in targetp if it's not NULL. */
#define isc_refcount_increment0(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
LOCK(&(rp)->lock); \
++((rp)->refs); \
if (_tmp != NULL) \
*_tmp = ((rp)->refs); \
UNLOCK(&(rp)->lock); \
} while (0)
#define isc_refcount_increment(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
LOCK(&(rp)->lock); \
REQUIRE((rp)->refs > 0); \
++((rp)->refs); \
if (_tmp != NULL) \
*_tmp = ((rp)->refs); \
UNLOCK(&(rp)->lock); \
} while (0)
/*% Decrements the reference count, returning the new value in targetp if it's not NULL. */
#define isc_refcount_decrement(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
LOCK(&(rp)->lock); \
REQUIRE((rp)->refs > 0); \
--((rp)->refs); \
if (_tmp != NULL) \
*_tmp = ((rp)->refs); \
UNLOCK(&(rp)->lock); \
} while (0)
#endif /* ISC_PLATFORM_HAVEXADD */
#else /* ISC_PLATFORM_USETHREADS */
typedef struct isc_refcount {
int refs;
} isc_refcount_t;
#define isc_refcount_destroy(rp) REQUIRE((rp)->refs == 0)
#define isc_refcount_current(rp) ((unsigned int)((rp)->refs))
#define isc_refcount_increment0(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
int _n = ++(rp)->refs; \
if (_tmp != NULL) \
*_tmp = _n; \
} while (0)
#define isc_refcount_increment(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
int _n; \
REQUIRE((rp)->refs > 0); \
_n = ++(rp)->refs; \
if (_tmp != NULL) \
*_tmp = _n; \
} while (0)
#define isc_refcount_decrement(rp, tp) \
do { \
unsigned int *_tmp = (unsigned int *)(tp); \
int _n; \
REQUIRE((rp)->refs > 0); \
_n = --(rp)->refs; \
if (_tmp != NULL) \
*_tmp = _n; \
} while (0)
#endif /* ISC_PLATFORM_USETHREADS */
isc_result_t
isc_refcount_init(isc_refcount_t *ref, unsigned int n);
ISC_LANG_ENDDECLS
#endif /* ISC_REFCOUNT_H */
|