/*-------------- Telecommunications & Signal Processing Lab ---------------
                             McGill University

Routine:
  AFILE *AFgetTApar (FILE *fp, const char Fname[], long int *Nsamp,
                     long int *Nchan, float *Sfreq, FILE *fpout)

Purpose:
  Get file format information from a text audio file

Description:
  This routine reads the header for a text audio file.  The header information
  is used to set the file data format information in the audio file pointer
  structure and to set the returned argument values.  A banner identifying the
  audio file and its parameters is printed.

  Text audio files have been used to store audio information (specifically
  noise samples) on CDROM's.  The audio data itself is stored as text.  The
  text specifies integer values, with one value per line.  Non-sequential
  access to the data involves rewinding the file for each such access.

  Text audio header:
   Offset Length Type    Contents
      0     4    char   File identifier ("%//")
      -     -    char   Sampling frequency ("%sampling rate: <value> KHz")
      -     -    char   Audio data
  For text audio files, the audio data is the character representation of
  integer values, with one value per line.

Parameters:
  <-  AFILE *AFgetSFpar
      Audio file pointer for the audio file
   -> FILE *fp
      File pointer for the file
   -> const char Fname[]
      File name
  <-  long int *Nsamp
      Total number of samples in the file (all channels)
  <-  long int *Nchan
      Number of channels
  <-  float *Sfreq
      Sampling frequency from the file header
   -> FILE *fpout
      File pointer for printing the audio file identification information.  If
      fpout is NULL, no information is printed.

Author / revision:
  P. Kabal  Copyright (C) 1996
  $Revision: 1.2 $  $Date: 1996/05/07 01:52:47 $

-------------------------------------------------------------------------*/

static char rcsid [] = "$Id: AFgetTApar.c 1.2 1996/05/07 AFsp-V2R1 $";

#include <stdio.h>
#include <string.h>
#include <libtsp.h>
#include <libtsp/nucleus.h>
#include <libtsp/AFpar.h>

#ifndef SEEK_SET	/* normally defined in stdio.h */
#  include <unistd.h>
#endif

#define LHMIN		21
#define FM_TXAUD	"\045\057\057"		/* "%//" */

AFILE *
AFgetTApar (fp, Fname, Nsamp, Nchan, Sfreq, fpout)

     FILE *fp;
     const char Fname[];
     long int *Nsamp;
     long int *Nchan;
     float *Sfreq;
     FILE *fpout;

{
  AFILE *AFp;
  long int Lhead, Nbytes, Ldata, Nsampx;
  char *line;
  float Sfreqx;

/* Get the size of the file
   The minimum header length is the length of the file identifier plus the
   the sampling rate line */
  Nbytes = FLfileSize (fp);
  if (Nbytes < LHMIN)
    UThalt ("AFgetTApar: File header too short");

/* Check the file magic */
  line = FLgetLine (fp);
  if (strcmp (line, FM_TXAUD) != 0)
    UThalt ("AFgetTApar: Invalid file identifier");

/* Look for the sampling rate field */
  Sfreqx = 0.0;
  while (1) {
    Lhead = ftell (fp);
    if (Lhead < 0)
      UTerror ("AFgetTApar: Error from ftell");
    line = FLgetLine (fp);
    if (line == NULL)
      UThalt ("AFgetTApar: Unexpected end-of-file");
    if (line[0] != '%')
      break;
    sscanf (line, "%%sampling rate:%g KHz", &Sfreqx);	/* "KHz" is ignored */
  }
  if (Sfreqx <= 0.0)
    UThalt ("AFgetTApar: Missing or invalid sampling frequency");
  Sfreqx = 1000. * Sfreqx;

  Ldata = Nbytes - Lhead;	/* Data size is implicit */

/* Find the number of samples */
  if (fseek (fp, Lhead, SEEK_SET) != 0)
    UThalt ("AFgetTApar: Error from fseek");
  Nsampx = 0;
  while (FLgetLine (fp) != NULL)
    ++Nsampx;
  if (fseek (fp, Lhead, SEEK_SET) != 0)
    UThalt ("AFgetTApar: Error from fseek");

/* Set the parameters for file access */
  AFp = AFsetAFp (fp, FO_RO, FT_TXAUD, FD_TEXT, DS_NATIVE, 1.0, 1L,
		  Lhead, Ldata, Nsampx);

/* Check and print the header information */
  AFprintAFh (AFp, Fname, "", Sfreqx, fpout);

/* Set the return parameters */
  *Nsamp = Nsampx;
  *Nchan = 1;
  *Sfreq = Sfreqx;

  return AFp;
}