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

  * This file is part of FFmpeg.
  *
  * FFmpeg 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.

  *

  * FFmpeg 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 FFmpeg; if not, write to the Free Software

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

  */
 //#define DEBUG
 
 #include "avcodec.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 WINAPI attribute_align_arg 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 do not 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, int size){

     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= (char*)arg + i*size;

         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;
 }