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ffmpeg / libavcodec / beosthread.c @ 5509bffa

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/*
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 * Copyright (c) 2004 Fran├žois Revol <revol@free.fr>
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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 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, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 *
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 */
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//#define DEBUG
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#include "avcodec.h"
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#include "common.h"
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#include <OS.h>
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typedef struct ThreadContext{
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    AVCodecContext *avctx;
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    thread_id thread;
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    sem_id work_sem;
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    sem_id done_sem;
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    int (*func)(AVCodecContext *c, void *arg);
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    void *arg;
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    int ret;
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}ThreadContext;
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// it's odd Be never patented that :D
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struct benaphore {
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        vint32 atom;
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        sem_id sem;
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};
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static inline int lock_ben(struct benaphore *ben)
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{
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        if (atomic_add(&ben->atom, 1) > 0)
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                return acquire_sem(ben->sem);
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        return B_OK;
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}
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static inline int unlock_ben(struct benaphore *ben)
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{
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        if (atomic_add(&ben->atom, -1) > 1)
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                return release_sem(ben->sem);
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        return B_OK;
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}
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static struct benaphore av_thread_lib_ben;
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static int32 ff_thread_func(void *v){
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    ThreadContext *c= v;
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    for(;;){
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//printf("thread_func %X enter wait\n", (int)v); fflush(stdout);
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        acquire_sem(c->work_sem);
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//printf("thread_func %X after wait (func=%X)\n", (int)v, (int)c->func); fflush(stdout);
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        if(c->func)
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            c->ret= c->func(c->avctx, c->arg);
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        else
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            return 0;
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//printf("thread_func %X signal complete\n", (int)v); fflush(stdout);
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        release_sem(c->done_sem);
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    }
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    return B_OK;
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}
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/**
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 * free what has been allocated by avcodec_thread_init().
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 * must be called after decoding has finished, especially dont call while avcodec_thread_execute() is running
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 */
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void avcodec_thread_free(AVCodecContext *s){
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    ThreadContext *c= s->thread_opaque;
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    int i;
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    int32 ret;
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    for(i=0; i<s->thread_count; i++){
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        c[i].func= NULL;
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        release_sem(c[i].work_sem);
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        wait_for_thread(c[i].thread, &ret);
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        if(c[i].work_sem > B_OK) delete_sem(c[i].work_sem);
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        if(c[i].done_sem > B_OK) delete_sem(c[i].done_sem);
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    }
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    av_freep(&s->thread_opaque);
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}
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int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count){
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    ThreadContext *c= s->thread_opaque;
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    int i;
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    assert(s == c->avctx);
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    assert(count <= s->thread_count);
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    /* note, we can be certain that this is not called with the same AVCodecContext by different threads at the same time */
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    for(i=0; i<count; i++){
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        c[i].arg= arg[i];
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        c[i].func= func;
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        c[i].ret= 12345;
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        release_sem(c[i].work_sem);
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    }
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    for(i=0; i<count; i++){
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        acquire_sem(c[i].done_sem);
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        c[i].func= NULL;
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        if(ret) ret[i]= c[i].ret;
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    }
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    return 0;
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}
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int avcodec_thread_init(AVCodecContext *s, int thread_count){
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    int i;
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    ThreadContext *c;
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    s->thread_count= thread_count;
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    assert(!s->thread_opaque);
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    c= av_mallocz(sizeof(ThreadContext)*thread_count);
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    s->thread_opaque= c;
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    for(i=0; i<thread_count; i++){
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//printf("init semaphors %d\n", i); fflush(stdout);
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        c[i].avctx= s;
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        if((c[i].work_sem = create_sem(0, "ff work sem")) < B_OK)
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            goto fail;
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        if((c[i].done_sem = create_sem(0, "ff done sem")) < B_OK)
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            goto fail;
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//printf("create thread %d\n", i); fflush(stdout);
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        c[i].thread = spawn_thread(ff_thread_func, "libavcodec thread", B_LOW_PRIORITY, &c[i] );
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        if( c[i].thread < B_OK ) goto fail;
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        resume_thread(c[i].thread );
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    }
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//printf("init done\n"); fflush(stdout);
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    s->execute= avcodec_thread_execute;
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    return 0;
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fail:
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    avcodec_thread_free(s);
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    return -1;
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}
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/* provide a mean to serialize calls to avcodec_*() for thread safety. */
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int avcodec_thread_lock_lib(void)
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{
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        return lock_ben(&av_thread_lib_ben);
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}
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int avcodec_thread_unlock_lib(void)
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{
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        return unlock_ben(&av_thread_lib_ben);
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}
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/* our versions of _init and _fini (which are called by those actually from crt.o) */
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void initialize_after(void)
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{
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        av_thread_lib_ben.atom = 0;
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        av_thread_lib_ben.sem = create_sem(0, "libavcodec benaphore");
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}
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void uninitialize_before(void)
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{
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        delete_sem(av_thread_lib_ben.sem);
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}
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