mirror of
https://code.videolan.org/videolan/vlc
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488 lines
14 KiB
C
488 lines
14 KiB
C
/*****************************************************************************
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* vlc_atomic.h:
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*****************************************************************************
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* Copyright (C) 2010 Rémi Denis-Courmont
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* GNU 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 License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifndef VLC_ATOMIC_H
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# define VLC_ATOMIC_H
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/**
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* \file
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* Atomic operations do not require locking, but they are not very powerful.
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*/
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# if !defined (__cplusplus) && (__STDC_VERSION__ >= 201112L) \
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&& !defined (__STDC_NO_ATOMICS__)
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/*** Native C11 atomics ***/
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# include <stdatomic.h>
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# elif defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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/*** Intel/GCC atomics ***/
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# define ATOMIC_FLAG_INIT false
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# define ATOMIC_VAR_INIT(value) (value)
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# define atomic_init(obj, value) \
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do { *(obj) = (value); } while(0)
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# define kill_dependency(y) \
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((void)0)
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# define atomic_thread_fence(order) \
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__sync_synchronize()
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# define atomic_signal_fence(order) \
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((void)0)
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# define atomic_is_lock_free(obj) \
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false
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/* In principles, __sync_*() only supports int, long and long long and their
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* unsigned equivalents, i.e. 4-bytes and 8-bytes types, although GCC also
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* supports 1 and 2-bytes types. Some non-x86 architectures do not support
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* 8-byte atomic types (or not efficiently). So lets stick to (u)intptr_t. */
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typedef intptr_t atomic_flag;
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typedef intptr_t atomic_bool;
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typedef intptr_t atomic_char;
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typedef intptr_t atomic_schar;
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typedef uintptr_t atomic_uchar;
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typedef intptr_t atomic_short;
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typedef uintptr_t atomic_ushort;
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typedef intptr_t atomic_int;
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typedef uintptr_t atomic_uint;
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typedef intptr_t atomic_long;
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typedef uintptr_t atomic_ulong;
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//atomic_llong
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//atomic_ullong
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typedef uintptr_t atomic_char16_t;
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typedef uintptr_t atomic_char32_t;
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typedef uintptr_t atomic_wchar_t;
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typedef intptr_t atomic_int_least8_t;
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typedef uintptr_t atomic_uint_least8_t;
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typedef intptr_t atomic_int_least16_t;
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typedef uintptr_t atomic_uint_least16_t;
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typedef intptr_t atomic_int_least32_t;
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typedef uintptr_t atomic_uint_least32_t;
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//atomic_int_least64_t
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//atomic_uint_least64_t
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typedef intptr_t atomic_int_fast8_t;
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typedef uintptr_t atomic_uint_fast8_t;
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typedef intptr_t atomic_int_fast16_t;
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typedef uintptr_t atomic_uint_fast16_t;
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typedef intptr_t atomic_int_fast32_t;
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typedef uintptr_t atomic_uint_fast32_t;
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//atomic_int_fast64_t
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//atomic_uint_fast64_t
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typedef intptr_t atomic_intptr_t;
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typedef uintptr_t atomic_uintptr_t;
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typedef uintptr_t atomic_size_t;
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typedef intptr_t atomic_ptrdiff_t;
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//atomic_intmax_t
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//atomic_uintmax_t
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# define atomic_store(object,desired) \
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do { \
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*(object) = (desired); \
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__sync_synchronize(); \
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} while (0)
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# define atomic_store_explicit(object,desired,order) \
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atomic_store(object,desired)
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# define atomic_load(object) \
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(__sync_synchronize(), *(object))
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# define atomic_load_explicit(object,order) \
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atomic_load(object)
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static inline
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intptr_t vlc_atomic_exchange(volatile void *object, intptr_t desired)
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{
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volatile intptr_t *ptr = (volatile intptr_t *)object;
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intptr_t old;
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/* NOTE: while __sync_lock_test_and_set() is an atomic exchange, its memory
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* order is too weak (acquire instead of sequentially consistent).
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* Because of that, for lack of both C11 _Generic() and GNU C compound
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* statements, atomic exchange needs a helper function.
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* Thus all atomic types must have the same size. */
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do
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old = atomic_load(ptr);
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while (!__sync_bool_compare_and_swap(ptr, old, desired));
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return old;
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}
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# define atomic_exchange(object,desired) \
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vlc_atomic_exchange(object,desired)
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# define atomic_exchange_explicit(object,desired,order) \
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atomic_exchange(object,desired)
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static inline
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bool vlc_atomic_compare_exchange(volatile void *object, void *expected,
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intptr_t desired)
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{
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volatile intptr_t *ptr = (volatile intptr_t *)object;
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intptr_t old = *(intptr_t *)expected;
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intptr_t val = __sync_val_compare_and_swap(ptr, old, desired);
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if (old != val)
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{
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*(intptr_t *)expected = val;
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return false;
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}
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return true;
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}
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# define atomic_compare_exchange_strong(object,expected,desired) \
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vlc_atomic_compare_exchange(object, expected, desired)
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# define atomic_compare_exchange_strong_explicit(object,expected,desired,order) \
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atomic_compare_exchange_strong(object, expected, desired)
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# define atomic_compare_exchange_weak(object,expected,desired) \
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vlc_atomic_compare_exchange(object, expected, desired)
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# define atomic_compare_exchange_weak_explicit(object,expected,desired,order) \
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atomic_compare_exchange_weak(object, expected, desired)
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# define atomic_fetch_add(object,operand) \
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__sync_fetch_and_add(object, operand)
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# define atomic_fetch_add_explicit(object,operand,order) \
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atomic_fetch_add(object,operand)
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# define atomic_fetch_sub(object,operand) \
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__sync_fetch_and_sub(object, operand)
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# define atomic_fetch_sub_explicit(object,operand,order) \
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atomic_fetch_sub(object,operand)
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# define atomic_fetch_or(object,operand) \
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__sync_fetch_and_or(object, operand)
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# define atomic_fetch_or_explicit(object,operand,order) \
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atomic_fetch_or(object,operand)
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# define atomic_fetch_xor(object,operand) \
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__sync_fetch_and_sub(object, operand)
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# define atomic_fetch_xor_explicit(object,operand,order) \
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atomic_fetch_sub(object,operand)
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# define atomic_fetch_and(object,operand) \
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__sync_fetch_and_and(object, operand)
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# define atomic_fetch_and_explicit(object,operand,order) \
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atomic_fetch_and(object,operand)
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# define atomic_flag_test_and_set(object) \
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atomic_exchange(object, true)
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# define atomic_flag_test_and_set_explicit(object,order) \
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atomic_flag_test_and_set(object)
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# define atomic_flag_clear(object) \
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atomic_store(object, false)
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# define atomic_flag_clear_explicit(object,order) \
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atomic_flag_clear(object)
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# else
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/*** No atomics ***/
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# define ATOMIC_FLAG_INIT false
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# define ATOMIC_VAR_INIT(value) (value)
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# define atomic_init(obj, value) \
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do { *(obj) = (value); } while(0)
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# define kill_dependency(y) \
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((void)0)
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# define atomic_thread_fence(order) \
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__sync_synchronize()
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# define atomic_signal_fence(order) \
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((void)0)
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# define atomic_is_lock_free(obj) \
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false
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typedef uintptr_t atomic_generic_t;
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typedef atomic_generic_t atomic_flag;
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typedef atomic_generic_t atomic_bool;
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//typedef atomic_generic_t atomic_char;
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//typedef atomic_generic_t atomic_schar;
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typedef atomic_generic_t atomic_uchar;
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//typedef atomic_generic_t atomic_short;
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typedef atomic_generic_t atomic_ushort;
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//typedef atomic_generic_t atomic_int;
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typedef atomic_generic_t atomic_uint;
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//typedef atomic_generic_t atomic_long;
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typedef atomic_generic_t atomic_ulong;
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//typedef atomic_generic_t atomic_llong;
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//typedef atomic_generic_t atomic_ullong;
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//typedef atomic_generic_t atomic_char16_t;
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//typedef atomic_generic_t atomic_char32_t;
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//typedef atomic_generic_t atomic_wchar_t;
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//typedef atomic_generic_t atomic_int_least8_t;
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typedef atomic_generic_t atomic_uint_least8_t;
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//typedef atomic_generic_t atomic_int_least16_t;
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typedef atomic_generic_t atomic_uint_least16_t;
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//typedef atomic_generic_t atomic_int_least32_t;
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typedef atomic_generic_t atomic_uint_least32_t;
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//typedef atomic_generic_t atomic_int_least64_t;
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//typedef atomic_generic_t atomic_uint_least64_t;
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//typedef atomic_generic_t atomic_int_fast8_t;
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typedef atomic_generic_t atomic_uint_fast8_t;
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//typedef atomic_generic_t atomic_int_fast16_t;
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typedef atomic_generic_t atomic_uint_fast16_t;
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//typedef atomic_generic_t atomic_int_fast32_t;
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typedef atomic_generic_t atomic_uint_fast32_t;
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//typedef atomic_generic_t atomic_int_fast64_t
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//typedef atomic_generic_t atomic_uint_fast64_t;
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//typedef atomic_generic_t atomic_intptr_t;
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typedef atomic_generic_t atomic_uintptr_t;
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typedef atomic_generic_t atomic_size_t;
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//typedef atomic_generic_t atomic_ptrdiff_t;
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//typedef atomic_generic_t atomic_intmax_t;
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//typedef atomic_generic_t atomic_uintmax_t;
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#define atomic_store(object,desired) \
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do { \
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vlc_global_lock(VLC_ATOMIC_MUTEX); \
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*(object) = (desired); \
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vlc_global_unlock(VLC_ATOMIC_MUTEX); \
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} while (0)
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# define atomic_store_explicit(object,desired,order) \
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atomic_store(object,desired)
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static inline uintptr_t atomic_load(atomic_generic_t *object)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_load_explicit(object,order) \
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atomic_load(object)
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static inline
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uintptr_t atomic_exchange(atomic_generic_t *object, uintptr_t desired)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object = desired;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_exchange_explicit(object,desired,order) \
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atomic_exchange(object,desired)
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static inline
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bool vlc_atomic_compare_exchange(atomic_generic_t *object,
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uintptr_t *expected, uintptr_t desired)
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{
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bool ret;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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ret = *object == *expected;
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if (ret)
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*object = desired;
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else
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*expected = *object;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return ret;
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}
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# define atomic_compare_exchange_strong(object,expected,desired) \
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vlc_atomic_compare_exchange(object, expected, desired)
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# define atomic_compare_exchange_strong_explicit(object,expected,desired,order) \
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atomic_compare_exchange_strong(object, expected, desired)
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# define atomic_compare_exchange_weak(object,expected,desired) \
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vlc_atomic_compare_exchange(object, expected, desired)
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# define atomic_compare_exchange_weak_explicit(object,expected,desired,order) \
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atomic_compare_exchange_weak(object, expected, desired)
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static inline
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uintmax_t atomic_fetch_add(atomic_generic_t *object, uintptr_t operand)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object += operand;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_fetch_add_explicit(object,operand,order) \
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atomic_fetch_add(object,operand)
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static inline
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uintptr_t atomic_fetch_sub(atomic_generic_t *object, uintptr_t operand)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object -= operand;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_fetch_sub_explicit(object,operand,order) \
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atomic_fetch_sub(object,operand)
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static inline
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uintptr_t atomic_fetch_or(atomic_generic_t *object, uintptr_t operand)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object |= operand;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_fetch_or_explicit(object,operand,order) \
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atomic_fetch_or(object,operand)
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static inline
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uintptr_t atomic_fetch_xor(atomic_generic_t *object, uintptr_t operand)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object ^= operand;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_fetch_xor_explicit(object,operand,order) \
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atomic_fetch_sub(object,operand)
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static inline
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uintptr_t atomic_fetch_and(atomic_generic_t *object, uintptr_t operand)
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{
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uintptr_t value;
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vlc_global_lock(VLC_ATOMIC_MUTEX);
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value = *object;
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*object &= operand;
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vlc_global_unlock(VLC_ATOMIC_MUTEX);
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return value;
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}
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# define atomic_fetch_and_explicit(object,operand,order) \
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atomic_fetch_and(object,operand)
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# define atomic_flag_test_and_set(object) \
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atomic_exchange(object, true)
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# define atomic_flag_test_and_set_explicit(object,order) \
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atomic_flag_test_and_set(object)
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# define atomic_flag_clear(object) \
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atomic_store(object, false)
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# define atomic_flag_clear_explicit(object,order) \
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atomic_flag_clear(object)
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# endif
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/**
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* Memory storage space for an atom. Never access it directly.
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*/
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typedef union
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{
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atomic_uintptr_t u;
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} vlc_atomic_t;
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/** Static initializer for \ref vlc_atomic_t */
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# define VLC_ATOMIC_INIT(val) { (val) }
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/* All functions return the atom value _after_ the operation. */
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static inline uintptr_t vlc_atomic_get(vlc_atomic_t *atom)
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{
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return atomic_load(&atom->u);
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}
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static inline uintptr_t vlc_atomic_set(vlc_atomic_t *atom, uintptr_t v)
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{
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atomic_store(&atom->u, v);
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return v;
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}
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static inline uintptr_t vlc_atomic_add(vlc_atomic_t *atom, uintptr_t v)
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{
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return atomic_fetch_add(&atom->u, v) + v;
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}
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static inline uintptr_t vlc_atomic_sub (vlc_atomic_t *atom, uintptr_t v)
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{
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return atomic_fetch_sub (&atom->u, v) - v;
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}
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static inline uintptr_t vlc_atomic_inc (vlc_atomic_t *atom)
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{
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return vlc_atomic_add (atom, 1);
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}
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static inline uintptr_t vlc_atomic_dec (vlc_atomic_t *atom)
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{
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return vlc_atomic_sub (atom, 1);
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}
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static inline uintptr_t vlc_atomic_swap(vlc_atomic_t *atom, uintptr_t v)
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{
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return atomic_exchange(&atom->u, v);
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}
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static inline uintptr_t vlc_atomic_compare_swap(vlc_atomic_t *atom,
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uintptr_t u, uintptr_t v)
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{
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atomic_compare_exchange_strong(&atom->u, &u, v);
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return u;
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}
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/** Helper to retrieve a single precision from an atom. */
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static inline float vlc_atomic_getf(vlc_atomic_t *atom)
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{
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union { float f; uintptr_t i; } u;
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u.i = vlc_atomic_get(atom);
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return u.f;
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}
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/** Helper to store a single precision into an atom. */
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static inline float vlc_atomic_setf(vlc_atomic_t *atom, float f)
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{
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union { float f; uintptr_t i; } u;
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u.f = f;
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vlc_atomic_set(atom, u.i);
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return f;
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}
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#endif
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