#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <mad.h>
#include <sys/audio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

#define MP3BUFFERSIZE	8192


int open_audio(void)
{
 int err;
 int audiofd;
 audio_info_t audioinfo;
 AUDIO_INITINFO(&audioinfo);
 audioinfo.output_muted=0;
 audioinfo.play.sample_rate=44100;
 audioinfo.play.channels=2;
 audioinfo.play.precision=16;
 audioinfo.play.encoding=AUDIO_ENCODING_LINEAR;
 audioinfo.play.gain=255;
 audioinfo.play.port=AUDIO_HEADPHONE;
 audioinfo.play.pause=0;
 audiofd=open("/dev/audio",O_RDWR);
 if(audiofd < 0) { printf("Error during opening!\n"); exit(1); }
 err=ioctl(audiofd,AUDIO_SETINFO,&audioinfo);
 if(err < 0) { printf("Error during ioctl!\n"); exit(1); }
 return audiofd;
}

void close_audio(int audiofd)
{
 close(audiofd);
}

class Mp3Player
{
 public:Mp3Player(char *file,int aaudiofd,int msoffset=0);
        ~Mp3Player();
	int play(int skip=0);
 private:
         FILE *mp3in;
         struct mad_stream mp3stream;
         struct mad_frame mp3frame;
         struct mad_synth mp3synth;
         mad_timer_t mp3timer;
         unsigned char InputBuffer[MP3BUFFERSIZE];
         unsigned char OutputBuffer[MP3BUFFERSIZE];
	 int audiofd;

};

Mp3Player::Mp3Player(char *file,int aaudiofd,int mstime)
{
 mp3in=fopen(file,"rb");
 if(mp3in == NULL)
 {
  printf("Cannot open file %s\n",file);
  exit(1);
 }
 mad_stream_init(&mp3stream);
 mad_frame_init(&mp3frame);
 mad_synth_init(&mp3synth);
 mad_timer_reset(&mp3timer);
 audiofd=aaudiofd;
 while(((double)mp3timer.seconds+(double)mp3timer.fraction/(double)MAD_TIMER_RESOLUTION)*1000.0 < mstime)
 {
  play(1);
 }
 printf("%f\n",(double)mp3timer.seconds+(double)mp3timer.fraction/(double)MAD_TIMER_RESOLUTION);
}


int Mp3Player::play(int skip)
{
 int outputbytes;
 size_t ReadSize, Remaining;
 unsigned char *ReadStart;
 int i;
 unsigned short Sample;

 if(mp3stream.buffer==NULL || mp3stream.error==MAD_ERROR_BUFLEN)
 {
  if(mp3stream.next_frame!=NULL)
  {
   Remaining=mp3stream.bufend-mp3stream.next_frame;
   memmove(InputBuffer,mp3stream.next_frame,Remaining);
   ReadStart=InputBuffer+Remaining;
   ReadSize=MP3BUFFERSIZE-Remaining;
  }
  else
  {
   ReadSize=MP3BUFFERSIZE;
   ReadStart=InputBuffer;
   Remaining=0;
  } 
  ReadSize=fread(ReadStart,1,ReadSize,mp3in);
  if(ReadSize<=0) return 1;
  mad_stream_buffer(&mp3stream,InputBuffer,ReadSize+Remaining);
  mp3stream.error=(mad_error) 0;
 }
 if(mad_frame_decode(&mp3frame,&mp3stream))
  if(!MAD_RECOVERABLE(mp3stream.error) && mp3stream.error != MAD_ERROR_BUFLEN) return 1;
 mad_timer_add(&mp3timer,mp3frame.header.duration);
 if(skip) return 0;
 mad_synth_frame(&mp3synth,&mp3frame);
 outputbytes=0;
 for(i=0;i<mp3synth.pcm.length;i++)
 {
  Sample=mp3synth.pcm.samples[0][i]>>(MAD_F_FRACBITS-15);

  OutputBuffer[outputbytes++]=Sample>>8;
  OutputBuffer[outputbytes++]=Sample&0xff;

  if(MAD_NCHANNELS(&mp3frame.header)==2) Sample=mp3synth.pcm.samples[0][i]>>(MAD_F_FRACBITS-15);
  OutputBuffer[outputbytes++]=Sample>>8;
  OutputBuffer[outputbytes++]=Sample&0xff;
 } 
 write(audiofd,OutputBuffer,outputbytes);
 return 0;
}

Mp3Player::~Mp3Player(void)
{
 mad_synth_finish(&mp3synth);
 mad_frame_finish(&mp3frame);
 mad_stream_finish(&mp3stream);
 fclose(mp3in);
 printf("total time=%f\n",(double)mp3timer.seconds+(double)mp3timer.fraction/(double)MAD_TIMER_RESOLUTION);
}

int main(int argc,char *argv[])
{
 int status;
 int audiofd;
 Mp3Player *player;
 if(argc != 2)
 {
  printf("Syntax: mp3play <mp3file>\n");
  exit(1);
 }
 audiofd=open_audio();
 player = new Mp3Player(argv[1],audiofd,0);
 do
 {
  status=player->play();
 } 
 while(status == 0);
 close_audio(audiofd);
 return 0;
}