PeerStreamer

/*

 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>

 *

 * 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

 *

 */

//#define DEBUG

#include "avcodec.h"

#include "common.h"

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

#include <process.h>

typedef struct ThreadContext{

    AVCodecContext *avctx;

    HANDLE thread;

    HANDLE work_sem;

    HANDLE done_sem;

    int (*func)(AVCodecContext *c, void *arg);

    void *arg;

    int ret;

}ThreadContext;

static unsigned __stdcall thread_func(void *v){

    ThreadContext *c= v;

    for(;;){

//printf("thread_func %X enter wait\n", (int)v); fflush(stdout);

        WaitForSingleObject(c->work_sem, INFINITE);

//printf("thread_func %X after wait (func=%X)\n", (int)v, (int)c->func); fflush(stdout);

        if(c->func)

            c->ret= c->func(c->avctx, c->arg);

        else

            return 0;

//printf("thread_func %X signal complete\n", (int)v); fflush(stdout);

        ReleaseSemaphore(c->done_sem, 1, 0);

    }

    return 0;

}

/**

 * free what has been allocated by avcodec_thread_init().

 * must be called after decoding has finished, especially dont call while avcodec_thread_execute() is running

 */

void avcodec_thread_free(AVCodecContext *s){

    ThreadContext *c= s->thread_opaque;

    int i;

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

        c[i].func= NULL;

        ReleaseSemaphore(c[i].work_sem, 1, 0);

        WaitForSingleObject(c[i].thread, INFINITE);

        if(c[i].work_sem) CloseHandle(c[i].work_sem);

        if(c[i].done_sem) CloseHandle(c[i].done_sem);

    }

    av_freep(&s->thread_opaque);

}

int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count){

    ThreadContext *c= s->thread_opaque;

    int i;

    assert(s == c->avctx);

    assert(count <= s->thread_count);

    /* note, we can be certain that this is not called with the same AVCodecContext by different threads at the same time */

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

        c[i].arg= arg[i];

        c[i].func= func;

        c[i].ret= 12345;

        ReleaseSemaphore(c[i].work_sem, 1, 0);

    }

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

        WaitForSingleObject(c[i].done_sem, INFINITE);

        c[i].func= NULL;

        if(ret) ret[i]= c[i].ret;

    }

    return 0;

}

int avcodec_thread_init(AVCodecContext *s, int thread_count){

    int i;

    ThreadContext *c;

    uint32_t threadid;

    s->thread_count= thread_count;

    assert(!s->thread_opaque);

    c= av_mallocz(sizeof(ThreadContext)*thread_count);

    s->thread_opaque= c;

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

//printf("init semaphors %d\n", i); fflush(stdout);

        c[i].avctx= s;

        if(!(c[i].work_sem = CreateSemaphore(NULL, 0, s->thread_count, NULL)))

            goto fail;

        if(!(c[i].done_sem = CreateSemaphore(NULL, 0, s->thread_count, NULL)))

            goto fail;

//printf("create thread %d\n", i); fflush(stdout);

        c[i].thread = (HANDLE)_beginthreadex(NULL, 0, thread_func, &c[i], 0, &threadid );

        if( !c[i].thread ) goto fail;

    }

//printf("init done\n"); fflush(stdout);

    s->execute= avcodec_thread_execute;

    return 0;

fail:

    avcodec_thread_free(s);

    return -1;

}