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4fde2b273d
Programmer needs to ensure that initializations happens before other operations on gatomicrefcount as otherwise they could access uninitialized memory, so there is no practical use case for making initialization atomic.
124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
/* grefcount.h: Reference counting
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*
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* Copyright 2018 Emmanuele Bassi
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __GREFCOUNT_H__
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#define __GREFCOUNT_H__
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#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
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#error "Only <glib.h> can be included directly."
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#endif
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#include <glib/gatomic.h>
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#include <glib/gtypes.h>
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G_BEGIN_DECLS
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GLIB_AVAILABLE_IN_2_58
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void g_ref_count_init (grefcount *rc);
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GLIB_AVAILABLE_IN_2_58
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void g_ref_count_inc (grefcount *rc);
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GLIB_AVAILABLE_IN_2_58
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gboolean g_ref_count_dec (grefcount *rc);
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GLIB_AVAILABLE_IN_2_58
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gboolean g_ref_count_compare (grefcount *rc,
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gint val);
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GLIB_AVAILABLE_IN_2_58
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void g_atomic_ref_count_init (gatomicrefcount *arc);
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GLIB_AVAILABLE_IN_2_58
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void g_atomic_ref_count_inc (gatomicrefcount *arc);
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GLIB_AVAILABLE_IN_2_58
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gboolean g_atomic_ref_count_dec (gatomicrefcount *arc);
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GLIB_AVAILABLE_IN_2_58
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gboolean g_atomic_ref_count_compare (gatomicrefcount *arc,
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gint val);
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/* On GCC we can use __extension__ to inline the API without using
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* ancillary functions; we only do this when disabling checks, as
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* it disables warnings when saturating the reference counters
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*/
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#if defined(__GNUC__) && defined(G_DISABLE_CHECKS)
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# define g_ref_count_init(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
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(void) (0 ? *(rc) ^ *(rc) : 1); \
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*(rc) = -1; \
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}))
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# define g_ref_count_inc(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
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(void) (0 ? *(rc) ^ *(rc) : 1); \
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if (*(rc) == G_MININT) ; else { \
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*(rc) -= 1; \
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} \
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}))
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# define g_ref_count_dec(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
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grefcount __rc = *(rc); \
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__rc += 1; \
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if (__rc == 0) ; else { \
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*(rc) = __rc; \
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} \
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(gboolean) (__rc == 0); \
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}))
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# define g_ref_count_compare(rc,val) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (grefcount)); \
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(void) (0 ? *(rc) ^ (val) : 1); \
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(gboolean) (*(rc) == -(val)); \
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}))
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# define g_atomic_ref_count_init(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
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(void) (0 ? *(rc) ^ *(rc) : 1); \
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*(rc) = 1; \
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}))
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# define g_atomic_ref_count_inc(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
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(void) (0 ? *(rc) ^ *(rc) : 1); \
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(void) (g_atomic_int_get (rc) == G_MAXINT ? 0 : g_atomic_int_inc ((rc))); \
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}))
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# define g_atomic_ref_count_dec(rc) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
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(void) (0 ? *(rc) ^ *(rc) : 1); \
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g_atomic_int_dec_and_test ((rc)); \
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}))
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# define g_atomic_ref_count_compare(rc,val) \
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(G_GNUC_EXTENSION ({ \
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G_STATIC_ASSERT (sizeof *(rc) == sizeof (gatomicrefcount)); \
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(void) (0 ? *(rc) ^ (val) : 1); \
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(gboolean) (g_atomic_int_get (rc) == (val)); \
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}))
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#endif /* __GNUC__ && G_DISABLE_CHECKS */
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G_END_DECLS
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#endif /* __GREFCOUNT_H__ */
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