/*
 * Read RIFF header
 * spd@daphne.cps.unizar.es
 * Mon Jul 29 21:21:40 CEST 2002
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>

#if defined(__i386__) || defined (_M_IX86) || defined (__osf__)
#   define  LITTLEENDIAN
#else
#	define  BIGENDIAN
#endif


#define swap_word(a) ( ((a) << 24) | \
    (((a) << 8) & 0x00ff0000) | \
	(((a) >> 8) & 0x0000ff00) | \
	((unsigned long)(a) >>24) )

#define swap_half(a) ( ((a & 0xff) << 8) | ((unsigned short)(a) >> 8) )

#ifdef BIGENDIAN
#	define SWAP_WORD(a) { a = swap_word(a); }
#	define SWAP_HALF(a) { a = swap_half(a); }
#else
#	define SWAP_WORD(a)
#	define SWAP_HALF(a)
#endif


/* <http://homepages.nildram.co.uk/~abcomp/pcaudiofaq.htm> */


typedef struct WAV_format
{
	char riff[4];               /* the characters "RIFF" */
	unsigned long file_length;  /* file length - 8 */
	char wave[8];               /* the characters "WAVEfmt " */
	unsigned long offset;       /* position of "data"-20 (usually 16) */
	unsigned short format;      /* 1 = PCM */
	unsigned short nchans;      /* #channels (eg. 2=stereo) */
	unsigned long sampsec;      /* #samples/sec (eg. 44100 for CD rate) */
	unsigned long bytesec;      /* #bytes/sec (see note 1) */
	unsigned short bytesamp;    /* #bytes/sample (see note 1) */
	unsigned short bitsamp;     /* #bits/sample (see note 1) */
/*	char otherstuff[N];         /* N = offset-16 (see note 5) */
	char *otherstuff;
	char dataheader[4];         /* the characters "data" */
	unsigned long datalen;      /* #bytes of actual data */

} wav_header;

char *formats[256]={
/* 00 */
	"unknown",
	"PCM",
	"MS ADPCM",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 10 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 20 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 30 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 40 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 50 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 60 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 70 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


/* 80 */
	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"MP3",
	"unknown",
	"unknown",
	"unknown",
	"unknown",


	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",
	"unknown"


};


int main(int argc, char **argv)
{
#ifndef BS
#define BS  512
#endif

    int         i;
    int         o;
    char        buffer[BS];
	struct stat sbp;
    size_t      n;
	wav_header	wav;

	assert (sizeof(long)==4);
	assert (sizeof(short)==2);

	if ( lstat(argv[1],&sbp)==-1)
	{
		perror("stat");
        return 1;
	}

	printf("Size:      %ld\n", sbp.st_size);
	printf("Head:      %d\n", sizeof(wav_header)-4);

    if ( -1 == ( i = open( argv[1], O_RDONLY)))
    {
        perror("open");
        return 1;
    }

	read( i, &wav, sizeof(wav_header)-12);

	SWAP_WORD(wav.file_length);
	SWAP_WORD(wav.offset);
	SWAP_HALF(wav.format);
	SWAP_HALF(wav.nchans);
	SWAP_WORD(wav.sampsec);
	SWAP_WORD(wav.bytesec);
	SWAP_HALF(wav.bytesamp);
	SWAP_HALF(wav.bitsamp);

	printf("riff:      \"%.4s\"\n",wav.riff);
	printf("length:    %lu\n",wav.file_length+8);
	printf("wave:      \"%.8s\"\n",wav.wave);
	printf("offset:    %lu\n",wav.offset);
	printf("format:    %hu (%s)\n",wav.format, formats[wav.format]);
	printf("channels:  %hu\n",wav.nchans);
	printf("samples/s: %lu\n",wav.sampsec);
	printf("bytes/s:   %lu\n",wav.bytesec);
	printf("bytesamp:  %hu\n",wav.bytesamp);
	printf("bitsamp:   %hu\n",wav.bitsamp);
/*	char otherstuff[N];         /* N = offset-16 (see note 5) */

	wav.otherstuff=buffer;
	n=0;
	if ( wav.offset != 16 )
	{
		read( i, buffer, wav.offset - 4);
		printf("otherstuff:\"%s\"\n",wav.otherstuff);
		n=wav.offset - 4;
	}

	read( i, &wav.dataheader, 4);
	printf("datahead:  \"%.4s\"\n",wav.dataheader);
	read( i, &wav.datalen, 4);
	SWAP_WORD(wav.datalen);
	printf("datalen:   %lu\n",wav.datalen);
	printf("\n%d+%d+%lu=%lu (%lu)\n",
		sizeof(wav_header)-4,
		n,
		wav.datalen,
		sizeof(wav_header)-4 + n + wav.datalen,
		sbp.st_size
		);

    close(i);
}