glib/grefcount.h

   1 /* grefcount.h: Reference counting
   2  *
   3  * Copyright 2018  Emmanuele Bassi
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #ifndef __GREFCOUNT_H__
  20 #define __GREFCOUNT_H__
  21
  22 #if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
  23 #error "Only <glib.h> can be included directly."
  24 #endif
  25
  26 #include <glib/gtypes.h>
  27
  28 G_BEGIN_DECLS
  29
  30 GLIB_AVAILABLE_IN_2_58
  31 void            g_ref_count_init                (grefcount       *rc);
  32 GLIB_AVAILABLE_IN_2_58
  33 void            g_ref_count_inc                 (grefcount       *rc);
  34 GLIB_AVAILABLE_IN_2_58
  35 gboolean        g_ref_count_dec                 (grefcount       *rc);
  36 GLIB_AVAILABLE_IN_2_58
  37 gboolean        g_ref_count_compare             (grefcount       *rc,
  38                                                  gint             val);
  39
  40 GLIB_AVAILABLE_IN_2_58
  41 void            g_atomic_ref_count_init         (gatomicrefcount *arc);
  42 GLIB_AVAILABLE_IN_2_58
  43 void            g_atomic_ref_count_inc          (gatomicrefcount *arc);
  44 GLIB_AVAILABLE_IN_2_58
  45 gboolean        g_atomic_ref_count_dec          (gatomicrefcount *arc);
  46 GLIB_AVAILABLE_IN_2_58
  47 gboolean        g_atomic_ref_count_compare      (gatomicrefcount *arc,
  48                                                  gint             val);
  49
  50 /* On GCC we can use __extension__ to inline the API without using
  51  * ancillary functions; we only do this when disabling checks, as
  52  * it disables warnings when saturating the reference counters
  53  */
  54 #if defined(__GNUC__) && defined(G_DISABLE_CHECKS)
  55
  56 # define g_ref_count_init(rc) \
  57   (G_GNUC_EXTENSION ({ \
  58     G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
  59     (void) (0 ? *(rc) ^ *(rc) : 1); \
  60     *(rc) = -1; \
  61   }))
  62
  63 # define g_ref_count_inc(rc) \
  64   (G_GNUC_EXTENSION ({ \
  65     G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
  66     (void) (0 ? *(rc) ^ *(rc) : 1); \
  67     if (*(rc) == G_MININT) ; else { \
  68       *(rc) -= 1; \
  69     } \
  70   }))
  71
  72 # define g_ref_count_dec(rc) \
  73   (G_GNUC_EXTENSION ({ \
  74     G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
  75     grefcount __rc = *(rc); \
  76     __rc += 1; \
  77     if (__rc == 0) ; else { \
  78       *(rc) = __rc; \
  79     } \
  80     (gboolean) (__rc == 0); \
  81   }))
  82
  83 # define g_ref_count_compare(rc,val) \
  84   (G_GNUC_EXTENSION ({ \
  85     G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
  86     (void) (0 ? *(rc) ^ (val) : 1); \
  87     (gboolean) (*(rc) == -(val)); \
  88   }))
  89
  90 # define g_atomic_ref_count_init(rc) \
  91   (G_GNUC_EXTENSION ({ \
  92     G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
  93     (void) (0 ? *(rc) ^ *(rc) : 1); \
  94     g_atomic_int_set ((rc), 1); \
  95   }))
  96
  97 # define g_atomic_ref_count_inc(rc) \
  98   (G_GNUC_EXTENSION ({ \
  99     G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
 100     (void) (0 ? *(rc) ^ *(rc) : 1); \
 101     (void) (g_atomic_int_get (rc) == G_MAXINT ? 0 : g_atomic_int_inc ((rc))); \
 102   }))
 103
 104 # define g_atomic_ref_count_dec(rc) \
 105   (G_GNUC_EXTENSION ({ \
 106     G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
 107     (void) (0 ? *(rc) ^ *(rc) : 1); \
 108     g_atomic_int_dec_and_test ((rc)); \
 109   }))
 110
 111 # define g_atomic_ref_count_compare(rc,val) \
 112   (G_GNUC_EXTENSION ({ \
 113     G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
 114     (void) (0 ? *(rc) ^ (val) : 1); \
 115     (gboolean) (g_atomic_int_get (rc) == (val)); \
 116   }))
 117
 118 #endif /* __GNUC__ && G_DISABLE_CHECKS */
 119
 120 G_END_DECLS
 121
 122 #endif /* __GREFCOUNT_H__ */