include/yaz/shptr.h

   1 /* This file is part of the YAZ toolkit.
   2  * Copyright (C) 1995-2010 Index Data.
   3  * All rights reserved.
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  *
   7  *     * Redistributions of source code must retain the above copyright
   8  *       notice, this list of conditions and the following disclaimer.
   9  *     * Redistributions in binary form must reproduce the above copyright
  10  *       notice, this list of conditions and the following disclaimer in the
  11  *       documentation and/or other materials provided with the distribution.
  12  *     * Neither the name of Index Data nor the names of its contributors
  13  *       may be used to endorse or promote products derived from this
  14  *       software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
  17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /**
  29  * \file shptr.h
  30  * \brief Shared pointer macros
  31  */
  32
  33 #ifndef YAZ_SHARED_PTR_H
  34 #define YAZ_SHARED_PTR_H
  35
  36 #include <yaz/xmalloc.h>
  37 #include <yaz/mutex.h>
  38
  39 YAZ_BEGIN_CDECL
  40
  41 #define YAZ_SHPTR_TYPE(type) \
  42     struct type##_shptr \
  43     {                          \
  44     type ptr;                  \
  45     int ref;                   \
  46     YAZ_MUTEX mutex;           \
  47     };  \
  48     typedef struct type##_shptr *type##_shptr_t;
  49
  50 #define YAZ_SHPTR_INIT(p,n) {                   \
  51         p = xmalloc(sizeof(*p));                \
  52         p->ptr = n;                             \
  53         p->ref = 1;                             \
  54         p->mutex = 0;  \
  55         yaz_mutex_create(&p->mutex);            \
  56     }
  57
  58 #define YAZ_SHPTR_INC(p) {                      \
  59         yaz_mutex_enter(p->mutex);              \
  60         p->ref++;                               \
  61         yaz_mutex_leave(p->mutex);              \
  62     }
  63
  64 #define YAZ_SHPTR_DEC(p, destroy)  {             \
  65     yaz_mutex_enter(p->mutex);                   \
  66     if (--p->ref == 0) {                         \
  67         yaz_mutex_leave(p->mutex);               \
  68         destroy(p->ptr);                         \
  69         yaz_mutex_destroy(&p->mutex);            \
  70         xfree(p);                                \
  71         p = 0;                                   \
  72     } else { \
  73     yaz_mutex_leave(p->mutex); \
  74     } \
  75     }
  76
  77 YAZ_END_CDECL
  78
  79 #endif
  80 /*
  81  * Local variables:
  82  * c-basic-offset: 4
  83  * c-file-style: "Stroustrup"
  84  * indent-tabs-mode: nil
  85  * End:
  86  * vim: shiftwidth=4 tabstop=8 expandtab
  87  */
  88