/*
 * April 15, 1992
 * Copyright 1992 Rick Richardson
 * Copyright 1991 Lance Norskog And Sundry Contributors
 * This source code is freely redistributable and may be used for
 * any purpose.  This copyright notice must be maintained. 
 * Lance Norskog And Sundry Contributors are not responsible for 
 * the consequences of using this software.
 */

/*
 * Windows 3.0 .wav format driver
 */

#include "st.h"

/* Private data for .wav file */
typedef struct wavstuff {
	long	samples;
} *wav_t;

extern float volume, amplitude;
extern long summary, verbose;

/*
 * Do anything required before you start reading samples.
 * Read file header. 
 *	Find out sampling rate, 
 *	size and style of samples, 
 *	mono/stereo/quad.
 */
wavstartread(ft) 
ft_t ft;
{
	wav_t	wav = (wav_t) ft->priv;
	char	magic[4];
	long	len;

	/* If you need to seek around the input file. */
	if (0 && ! ft->seekable)
		fail(".wav input file must be a file, not a pipe");

	fread(magic, 4, 1, ft->fp);
	if (strncmp("RIFF", magic, 4))
		fail("Not a RIFF file");

	len = rllong(ft);

	fread(magic, 4, 1, ft->fp);
	if (strncmp("WAVE", magic, 4))
		fail("Not a WAVE file");

	fread(magic, 4, 1, ft->fp);
	if (strncmp("fmt ", magic, 4))
		fail("Missing fmt spec");

	len = rllong(ft);
	switch (rlshort(ft))
	{
	case 1:		ft->info.style = UNSIGNED; break;
	default:	fail("Don't understand format");
	}
	ft->info.channels = rlshort(ft);
	ft->info.rate = rllong(ft);
	rllong(ft);	/* Average bytes/second */
	rlshort(ft);	/* Block align */
	switch (rlshort(ft))
	{
	case 8:		ft->info.size = BYTE; break;
	case 16:	ft->info.size = WORD; break;
	case 32:	ft->info.size = LONG; break;
	default:	fail("Don't understand size");
	}
	len -= 16;
	while (len) getc(ft->fp);

	fread(magic, 4, 1, ft->fp);
	if (strncmp("data", magic, 4))
		fail("Missing data portion");

	wav->samples = rllong(ft);
}

/*
 * Read up to len samples from file.
 * Convert to signed longs.
 * Place in buf[].
 * Return number of samples read.
 */

wavread(ft, buf, len) 
ft_t ft;
long *buf, len;
{
	wav_t	wav = (wav_t) ft->priv;
	int	done;

	if (len > wav->samples) len = wav->samples;
	if (len == 0) return 0;
	done = rawread(ft, buf, len);
	wav->samples -= len;
	return done;
}

/*
 * Do anything required when you stop reading samples.  
 * Don't close input file! 
 */
wavstopread(ft) 
ft_t ft;
{
}

wavstartwrite(ft) 
ft_t ft;
{
	wav_t	wav = (wav_t) ft->priv;
	int	littlendian = 0;
	char	*endptr;

	if (! ft->seekable)
		fail("Output .wav file must be a file, not a pipe");

	endptr = (char *) &littlendian;
	*endptr = 1;
	if (!littlendian) ft->swap = 1;

	wav->samples = 0;
	wavwritehdr(ft);
}

wavwritehdr(ft) 
ft_t ft;
{
	wav_t	wav = (wav_t) ft->priv;
	int	samsize;
	long	datasize;

	switch (ft->info.size)
	{
	case BYTE:	samsize = 8; break;
	case WORD:	samsize = 16; break;
	default:
	case LONG:	ft->info.size = LONG; samsize = 32; break;
	}
	ft->info.style = UNSIGNED;

	datasize = samsize/8 * ft->info.channels * wav->samples;

	fputs("RIFF", ft->fp);
	wllong(ft, datasize + 8+16+12);	/* Waveform chunk size: FIXUP(4) */
	fputs("WAVE", ft->fp);
	fputs("fmt ", ft->fp);
	wllong(ft, (long)16);		/* fmt chunk size */
	wlshort(ft, 1);			/* FormatTag: WAVE_FORMAT_PCM */
	wlshort(ft, ft->info.channels);
	wllong(ft, (long)ft->info.rate);	/* SamplesPerSec */
					/* Average Bytes/sec */
	wllong(ft, (long)(ft->info.rate * ft->info.channels * samsize + 7) / 8);
					/* nBlockAlign */
	wlshort(ft, (ft->info.channels * samsize + 7) / 8);
	wlshort(ft, samsize);		/* BitsPerSample */
	
	fputs("data", ft->fp);
	wllong(ft, datasize);		/* data chunk size: FIXUP(40) */
}

wavwrite(ft, buf, len) 
ft_t ft;
long *buf, len;
{
	wav_t	wav = (wav_t) ft->priv;

	wav->samples += len * ft->info.size;
	rawwrite(ft, buf, len);
}

void
wavstopwrite(ft) 
ft_t ft;
{
	/* All samples are already written out. */
	/* If file header needs fixing up, for example it needs the */
 	/* the number of samples in a field, seek back and write them here. */
	wav_t	wav = (wav_t) ft->priv;

	if (!ft->seekable)
		return;
	if (fseek(ft->fp, 0L, 0) != 0)
		fail("Can't rewind output file to rewrite .wav header.");
	wavwritehdr(ft);
}