55 lines
2.4 KiB
C
55 lines
2.4 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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/* A type-safe atomic refcounter.
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*
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* DO NOT USE THIS UNLESS YOU ACTUALLY CARE ABOUT THREAD SAFETY! */
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typedef struct {
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volatile unsigned _value;
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} RefCount;
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#define REFCNT_GET(r) ((r)._value)
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#define REFCNT_INC(r) (__sync_add_and_fetch(&(r)._value, 1))
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#define REFCNT_DEC(r) (__sync_sub_and_fetch(&(r)._value, 1))
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#define REFCNT_INIT ((RefCount) { ._value = 1 })
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#define _DEFINE_ATOMIC_REF_FUNC(type, name, scope) \
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scope type *name##_ref(type *p) { \
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if (!p) \
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return NULL; \
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\
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assert_se(REFCNT_INC(p->n_ref) >= 2); \
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return p; \
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}
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#define _DEFINE_ATOMIC_UNREF_FUNC(type, name, free_func, scope) \
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scope type *name##_unref(type *p) { \
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if (!p) \
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return NULL; \
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\
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if (REFCNT_DEC(p->n_ref) > 0) \
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return NULL; \
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\
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return free_func(p); \
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}
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#define DEFINE_ATOMIC_REF_FUNC(type, name) \
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_DEFINE_ATOMIC_REF_FUNC(type, name,)
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#define DEFINE_PUBLIC_ATOMIC_REF_FUNC(type, name) \
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_DEFINE_ATOMIC_REF_FUNC(type, name, _public_)
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#define DEFINE_ATOMIC_UNREF_FUNC(type, name, free_func) \
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_DEFINE_ATOMIC_UNREF_FUNC(type, name, free_func,)
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#define DEFINE_PUBLIC_ATOMIC_UNREF_FUNC(type, name, free_func) \
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_DEFINE_ATOMIC_UNREF_FUNC(type, name, free_func, _public_)
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#define DEFINE_ATOMIC_REF_UNREF_FUNC(type, name, free_func) \
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DEFINE_ATOMIC_REF_FUNC(type, name); \
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DEFINE_ATOMIC_UNREF_FUNC(type, name, free_func);
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#define DEFINE_PUBLIC_ATOMIC_REF_UNREF_FUNC(type, name, free_func) \
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DEFINE_PUBLIC_ATOMIC_REF_FUNC(type, name); \
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DEFINE_PUBLIC_ATOMIC_UNREF_FUNC(type, name, free_func);
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