audio.c

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/*
 * Fake audio coding functions for simulating audio coder
 */

#include "standard.h"
#include "bits.h"
#include "config.h"
#include "audio.h"

extern int debug;



#define DEF_AUD_INPUT_FILE    "audio.in"
#define DEF_AUD_OUTPUT_FILE   "audio.rec"

audio_codec *new_audio_codec(char *name)
/*
 * Sets up an audio codec and returns a pointer to it.
 */
{
  char s[256];
  int x;
  audio_codec *a;

  a = (audio_codec *) malloc(sizeof(audio_codec));
  if (a == NULL)
    error("new_audio_codec","can't malloc audio codec");

  strcpy(a->name, name);

  strcpy(a->input_filename, DEF_AUD_INPUT_FILE);
  strcpy(a->output_filename, DEF_AUD_OUTPUT_FILE);

  a->input_file=NULL;

  return a;
}


void close_audio_codec(audio_codec *a)
/*
 * Closes up the audio codec; closes files and frees variables
 */
{
  if (a->input_file != NULL) {
    printf("%s AUDIO [%s] closing input file.\n", print_time(), a->name);
    fclose(a->input_file);
  }
  free(a);
}


void code_audio(audio_codec *a)
/*
 * Fakes audio coding, either from file or random
 */
{
  bytes *b;
  int size,r,i,sendok;

  if (get_clock() % 30 == 0) /* encode every 30 ms */
  {
    /* generate bytes structure to send of size 27 23 or 6*/
    r = rand() % 3;
    switch (r) {
      case 0:
        size = 27;
        break;
      case 1:
        size = 23;
        break;
      case 2:
        size = 6;
        break;
    }

    if (debug) {
      printf("%s AUDIO [%s] sent %d bytes\n", print_time(), a->name, size);
    }

    b = new_bytes(size);
    if (!a->input_file) {
      a->input_file=fopen(a->input_filename, "r");
      if (!a->input_file) {
        warn("code_audio", "input audio file does not exist.\n");
        a->input_filename[0]=0;
      }
    }
    for (i=0;i<size;i++) {
      if (a->input_filename[0]) {
          if (feof(a->input_file))
            fseek(a->input_file,0,0);
          b->block[i] = fgetc(a->input_file);
      }
      else {
        randomize_byte((b->block)+i);
      }
    }

    /* send it to the al sending entity */
    sendok = al_send_request(a->output, b);
    if (!sendok)
      error("code_audio","Sending bytes to AL failed");
  }
}



void decode_audio(audio_codec *a)
/*
 * Sees if there's anything in the AL to receive.  If so, receives
 * and decodes it (just writes to the output file)
 */
{
  byte b;

  FILE *outfile=NULL;

  if (al_indication(a->input)) {
    outfile = fopen(a->output_filename, "a");
    if (outfile == NULL) {
      error("decode_audio", "couldn't open output file");
    }
  }

  while (al_indication(a->input)) { 
    b = al_receive(a->input);
        
    fputc(b, outfile);
  }

  if (outfile) {
    fclose(outfile);
  }
}

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