0
0
mirror of https://github.com/mpv-player/mpv.git synced 2024-09-20 12:02:23 +02:00
mpv/osdep/atomics.h
wm4 8a9b64329c Relicense some non-MPlayer source files to LGPL 2.1 or later
This covers source files which were added in mplayer2 and mpv times
only, and where all code is covered by LGPL relicensing agreements.

There are probably more files to which this applies, but I'm being
conservative here.

A file named ao_sdl.c exists in MPlayer too, but the mpv one is a
complete rewrite, and was added some time after the original ao_sdl.c
was removed. The same applies to vo_sdl.c, for which the SDL2 API is
radically different in addition (MPlayer supports SDL 1.2 only).

common.c contains only code written by me. But common.h is a strange
case: although it originally was named mp_common.h and exists in MPlayer
too, by now it contains only definitions written by uau and me. The
exceptions are the CONTROL_ defines - thus not changing the license of
common.h yet.

codec_tags.c contained once large tables generated from MPlayer's
codecs.conf, but all of these tables were removed.

From demux_playlist.c I'm removing a code fragment from someone who was
not asked; this probably could be done later (see commit 15dccc37).

misc.c is a bit complicated to reason about (it was split off mplayer.c
and thus contains random functions out of this file), but actually all
functions have been added post-MPlayer. Except get_relative_time(),
which was written by uau, but looks similar to 3 different versions of
something similar in each of the Unix/win32/OSX timer source files. I'm
not sure what that means in regards to copyright, so I've just moved it
into another still-GPL source file for now.

screenshot.c once had some minor parts of MPlayer's vf_screenshot.c, but
they're all gone.
2016-01-19 18:36:06 +01:00

103 lines
3.6 KiB
C

/*
* This file is part of mpv.
* Copyright (c) 2013 Stefano Pigozzi <stefano.pigozzi@gmail.com>
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MP_ATOMICS_H
#define MP_ATOMICS_H
#include <inttypes.h>
#include "config.h"
#if HAVE_STDATOMIC
#include <stdatomic.h>
#else
// Emulate the parts of C11 stdatomic.h needed by mpv.
// Still relies on gcc/clang atomic builtins.
// The t field is a hack to make the non-atomic fallback macro mess work.
typedef struct { volatile unsigned long v, t; } atomic_ulong;
typedef struct { volatile int v, t; } atomic_int;
typedef struct { volatile unsigned int v, t; } atomic_uint;
typedef struct { volatile _Bool v, t; } atomic_bool;
typedef struct { volatile long long v, t; } atomic_llong;
typedef struct { volatile uint_least32_t v, t; } atomic_uint_least32_t;
typedef struct { volatile unsigned long long v, t; } atomic_ullong;
#define ATOMIC_VAR_INIT(x) \
{.v = (x)}
#define memory_order_relaxed 1
#define memory_order_seq_cst 2
#define atomic_load_explicit(p, e) atomic_load(p)
#if HAVE_ATOMIC_BUILTINS
#define atomic_load(p) \
__atomic_load_n(&(p)->v, __ATOMIC_SEQ_CST)
#define atomic_store(p, val) \
__atomic_store_n(&(p)->v, val, __ATOMIC_SEQ_CST)
#define atomic_fetch_add(a, b) \
__atomic_fetch_add(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_fetch_and(a, b) \
__atomic_fetch_and(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_fetch_or(a, b) \
__atomic_fetch_or(&(a)->v, b, __ATOMIC_SEQ_CST)
#define atomic_compare_exchange_strong(a, b, c) \
__atomic_compare_exchange_n(&(a)->v, b, c, 0, __ATOMIC_SEQ_CST, \
__ATOMIC_SEQ_CST)
#elif HAVE_SYNC_BUILTINS
#define atomic_load(p) \
__sync_fetch_and_add(&(p)->v, 0)
#define atomic_store(p, val) \
(__sync_synchronize(), (p)->v = (val), __sync_synchronize())
#define atomic_fetch_add(a, b) \
__sync_fetch_and_add(&(a)->v, b)
#define atomic_fetch_and(a, b) \
__sync_fetch_and_and(&(a)->v, b)
#define atomic_fetch_or(a, b) \
__sync_fetch_and_or(&(a)->v, b)
// Assumes __sync_val_compare_and_swap is "strong" (using the C11 meaning).
#define atomic_compare_exchange_strong(p, old, new) \
({ __typeof__((p)->v) val_ = __sync_val_compare_and_swap(&(p)->v, *(old), new); \
bool ok_ = val_ == *(old); \
if (!ok_) *(old) = val_; \
ok_; })
#else
// This is extremely wrong. The build system actually disables code that has
// a serious dependency on working atomics, so this is barely ok.
#define atomic_load(p) ((p)->v)
#define atomic_store(p, val) ((p)->v = (val))
#define atomic_fetch_op_(a, b, op) \
((a)->t = (a)->v, (a)->v = (a)->v op (b), (a)->t)
#define atomic_fetch_add(a, b) atomic_fetch_op_(a, b, +)
#define atomic_fetch_and(a, b) atomic_fetch_op_(a, b, &)
#define atomic_fetch_or(a, b) atomic_fetch_op_(a, b, |)
#define atomic_compare_exchange_strong(p, old, new) \
((p)->v == *(old) ? ((p)->v = (new), 1) : (*(old) = (p)->v, 0))
#endif /* no atomics */
#endif /* else HAVE_STDATOMIC */
#endif