/*
  * 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"

 #include "thread.h"

 
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #include <process.h>
 
 typedef struct ThreadContext{
     AVCodecContext *avctx;
     HANDLE thread;
     HANDLE work_sem;

     HANDLE job_sem;

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

     int (*func2)(AVCodecContext *c, void *arg, int, int);

     void *arg;

     int argsize;
     int *jobnr;
     int *ret;

     int threadnr;

 }ThreadContext;
 
 

 static unsigned WINAPI attribute_align_arg thread_func(void *v){

     ThreadContext *c= v;
 
     for(;;){

         int ret, jobnr;

 //printf("thread_func %X enter wait\n", (int)v); fflush(stdout);
         WaitForSingleObject(c->work_sem, INFINITE);

         // avoid trying to access jobnr if we should quit
         if (!c->func && !c->func2)
             break;

         WaitForSingleObject(c->job_sem, INFINITE);
         jobnr = (*c->jobnr)++;
         ReleaseSemaphore(c->job_sem, 1, 0);

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

             ret= c->func(c->avctx, (uint8_t *)c->arg + jobnr*c->argsize);

         else

             ret= c->func2(c->avctx, c->arg, jobnr, c->threadnr);

         if (c->ret)
             c->ret[jobnr] = ret;

 //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 ff_thread_init().

  * Must be called after decoding has finished, especially do not call while avcodec_thread_execute() is running.

  */

 void ff_thread_free(AVCodecContext *s){

     ThreadContext *c= s->thread_opaque;
     int i;
 
     for(i=0; i<s->thread_count; i++){

         c[i].func= NULL;

         c[i].func2= NULL;

     }
     ReleaseSemaphore(c[0].work_sem, s->thread_count, 0);
     for(i=0; i<s->thread_count; i++){

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

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

     }

     if(c[0].work_sem) CloseHandle(c[0].work_sem);
     if(c[0].job_sem)  CloseHandle(c[0].job_sem);
     if(c[0].done_sem) CloseHandle(c[0].done_sem);

 
     av_freep(&s->thread_opaque);
 }
 

 static 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;

     int jobnr = 0;

     assert(s == c->avctx);

     /* 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<s->thread_count; i++){
         c[i].arg= arg;
         c[i].argsize= size;

         c[i].func= func;

         c[i].ret= ret;
         c[i].jobnr = &jobnr;

     }

     ReleaseSemaphore(c[0].work_sem, count, 0);
     for(i=0; i<count; i++)
         WaitForSingleObject(c[0].done_sem, INFINITE);

     return 0;
 }
 

 static int avcodec_thread_execute2(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count){

     ThreadContext *c= s->thread_opaque;
     int i;
     for(i=0; i<s->thread_count; i++)
         c[i].func2 = func;
     avcodec_thread_execute(s, NULL, arg, ret, count, 0);
 }
 

 int ff_thread_init(AVCodecContext *s){

     int i;
     ThreadContext *c;
     uint32_t threadid;
 

     if(!(s->thread_type & FF_THREAD_SLICE)){
         av_log(s, AV_LOG_WARNING, "The requested thread algorithm is not supported with this thread library.\n");
         return 0;
     }
 

     if (s->thread_count <= 1)

         return 0;
 

     s->active_thread_type= FF_THREAD_SLICE;
 

     assert(!s->thread_opaque);

     c= av_mallocz(sizeof(ThreadContext)*s->thread_count);

     s->thread_opaque= c;

     if(!(c[0].work_sem = CreateSemaphore(NULL, 0, INT_MAX, NULL)))
         goto fail;
     if(!(c[0].job_sem  = CreateSemaphore(NULL, 1, 1, NULL)))
         goto fail;
     if(!(c[0].done_sem = CreateSemaphore(NULL, 0, INT_MAX, NULL)))
         goto fail;

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

 //printf("init semaphors %d\n", i); fflush(stdout);
         c[i].avctx= s;

         c[i].work_sem = c[0].work_sem;
         c[i].job_sem  = c[0].job_sem;
         c[i].done_sem = c[0].done_sem;

         c[i].threadnr = i;

 
 //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;

     s->execute2= avcodec_thread_execute2;

 
     return 0;
 fail:

     ff_thread_free(s);

     return -1;
 }