Sound, Music & MIDI Collection 2/SMMVOL2.bin/WAVUTIL/SOX7.ZIP/WAV.C

C/C++ Source or Header | 1993-02-11 | 4.3 KB | 194 lines

/*
 * 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.
 */

 /* TODO: FIX 16 bits samples to be signed instead of unsigned */

/*
 * Windows 3.0 .wav format driver
 */

#include "st.h"

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

IMPORT float volume, amplitude;
IMPORT 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; ft->info.style = UNSIGNED; break;
    case WORD:    samsize = 16; ft->info.style = SIGN2; break;
    default:
    case LONG:    ft->info.size = LONG; ft->info.style = SIGN2;
            samsize = 32; break;
    }


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