PeerStreamer

/*

 * Copyright (c) 2004 Roman Shaposhnik.

 *

 * Many thanks to Steven M. Schultz for providing clever ideas and

 * to Michael Niedermayer <michaelni@gmx.at> for writing initial

 * implementation.

 *

 * This library 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 of the License, or (at your option) any later version.

 *

 * This library 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 this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 *

 */

#include <pthread.h>

#include "avcodec.h"

#include "common.h"

typedef int (action_t)(AVCodecContext *c, void *arg);

typedef struct ThreadContext {

    pthread_t *workers;

    action_t *func;

    void **args;

    int *rets;

    int rets_count;

    int job_count;

    pthread_cond_t last_job_cond;

    pthread_cond_t current_job_cond;

    pthread_mutex_t current_job_lock;

    int current_job;

    int done;

} ThreadContext;

static void* worker(void *v)

{

    AVCodecContext *avctx = v;

    ThreadContext *c = avctx->thread_opaque;

    int our_job = c->job_count;

    int thread_count = avctx->thread_count;

    int self_id;

    pthread_mutex_lock(&c->current_job_lock);

    self_id = c->current_job++;

    for (;;){

        while (our_job >= c->job_count) {

            if (c->current_job == thread_count + c->job_count)

                pthread_cond_signal(&c->last_job_cond);

            pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);

            our_job = self_id;

            if (c->done) {

                pthread_mutex_unlock(&c->current_job_lock);

                return NULL;

            }

        }

        pthread_mutex_unlock(&c->current_job_lock);

        c->rets[our_job%c->rets_count] = c->func(avctx, c->args[our_job]);

        pthread_mutex_lock(&c->current_job_lock);

        our_job = c->current_job++;

    }

}

static always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)

{

    pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);

    pthread_mutex_unlock(&c->current_job_lock);

}

void avcodec_thread_free(AVCodecContext *avctx)

{

    ThreadContext *c = avctx->thread_opaque;

    int i;

    pthread_mutex_lock(&c->current_job_lock);

    c->done = 1;

    pthread_cond_broadcast(&c->current_job_cond);

    pthread_mutex_unlock(&c->current_job_lock);

    for (i=0; i<avctx->thread_count; i++)

         pthread_join(c->workers[i], NULL);

    pthread_mutex_destroy(&c->current_job_lock);

    pthread_cond_destroy(&c->current_job_cond);

    pthread_cond_destroy(&c->last_job_cond);

    av_free(c->workers);

    av_free(c);

}

int avcodec_thread_execute(AVCodecContext *avctx, action_t* func, void **arg, int *ret, int job_count)

{

    ThreadContext *c= avctx->thread_opaque;

    int dummy_ret;

    if (job_count <= 0)

        return 0;

    pthread_mutex_lock(&c->current_job_lock);

    c->current_job = avctx->thread_count;

    c->job_count = job_count;

    c->args = arg;

    c->func = func;

    if (ret) {

        c->rets = ret;

        c->rets_count = job_count;

    } else {

        c->rets = &dummy_ret;

        c->rets_count = 1;

    }

    pthread_cond_broadcast(&c->current_job_cond);

    avcodec_thread_park_workers(c, avctx->thread_count);

    return 0;

}

int avcodec_thread_init(AVCodecContext *avctx, int thread_count)

{

    int i;

    ThreadContext *c;

    c = av_mallocz(sizeof(ThreadContext));

    if (!c)

        return -1;

    c->workers = av_mallocz(sizeof(pthread_t)*thread_count);

    if (!c->workers) {

        av_free(c);

        return -1;

    }

    avctx->thread_opaque = c;

    avctx->thread_count = thread_count;

    c->current_job = 0;

    c->job_count = 0;

    c->done = 0;

    pthread_cond_init(&c->current_job_cond, NULL);

    pthread_cond_init(&c->last_job_cond, NULL);

    pthread_mutex_init(&c->current_job_lock, NULL);

    pthread_mutex_lock(&c->current_job_lock);

    for (i=0; i<thread_count; i++) {

        if(pthread_create(&c->workers[i], NULL, worker, avctx)) {

           avctx->thread_count = i;

           pthread_mutex_unlock(&c->current_job_lock);

           avcodec_thread_free(avctx);

           return -1;

        }

    }

    avcodec_thread_park_workers(c, thread_count);

    avctx->execute = avcodec_thread_execute;

    return 0;

}