/* wavfile.h */

struct WavHdr
{
  char                riff[4];        /* "RIFF" */
  unsigned long       file_dim;       /* filesize */
  char                wave_format[8]; /* "WAVEfmt " */
  unsigned long       reserved1;      /* 16L */
  unsigned short int  reserved2;      /* 1 */
  unsigned short int  channels;       /* numero di canali */
  unsigned long       samp_rate;      /* samplerate */
  unsigned long       fc;             /* byte al secondo */
  unsigned short int  reserved3;      /* numero di byte del campione (reserved3*bit_num/8) */
  unsigned short int  bit_num;        /* numero di bytet del campione */
  char                data[4];        /* "data" */
  unsigned long       samp_num;       /* numero totale di campioni */
};

// Stampa le info estratte da un header
void printWaveInfo (struct WavHdr header)
{
    //printf ("RIFF:        %10s\n",      header.riff);
	printf ("File dim:    %10ld\n", header.file_dim);
	//printf ("Wave format: %10s\n",header.wave_format);
	printf ("Reserved1:   %10ld\n", header.reserved1);
	printf ("Reserved2:   %10d\n",  header.reserved2);
	printf ("Channels:    %10d\n",  header.channels);
	printf ("Samp rate:   %10ld\n", header.samp_rate);
	printf ("FC:          %10ld\n", header.fc);
	printf ("Reserved3:   %10d\n",  header.reserved3);
	printf ("Bit num:     %10d\n",  header.bit_num);
	//printf ("Data:        %10s\n",      header.data);
	printf ("Samp num:    %10ld\n", header.samp_num);
	printf ("\n");
}

// Legge un file wave *filename
// mette l'header in *hrd e il contenuto in **buffer
// Ritorna il numero di campioni o -1 in caso d'errore
int readWaveFile (char *filename, struct WavHdr *hdr, short int **buffer)
{
 	FILE *fp;
	int samples;
    int read;

    fp = fopen (filename,"rb");     // "rb": read, bynary

	if (fp == NULL) {
        printf ("ERROR reading %s\n", filename);
        return -1;
	}

    // Leggo l'header in *hdr
	fread ((void *)hdr, sizeof(*hdr), 1 , fp);
	samples = hdr->samp_num / 2;

	// Leggo i campioni in **buffer (puntatore a puntatore)
    *buffer = (short int *) calloc (samples, 2);
    read = fread (*buffer, 2 , samples, fp);
    //printf ("FREAD: %d\n",read);
    // chiudo il file
    fclose (fp);
    return read;
}

// Scrive **buffer su un file wave *filename
// usa *hdr per scrivere l'header
// Ritorna il numero di campioni scritti o -1 in caso d'errore
int writeWaveFile (char *filename, struct WavHdr *hdr, short int **buffer)
{
 	FILE *fp;
	int samples;
	int wrotenum;

    fp = fopen (filename,"wb");

	if (fp == NULL) {
        printf ("ERROR writing %s\n", filename);
        return -1;
	}

	samples = hdr->samp_num / 2;
    // Scrivo l'header contenuto in hdr
    fwrite ( (void *) hdr, sizeof(*hdr), 1 , fp);
    // Poi scrivo il buffer
    wrotenum = fwrite ((void *) *buffer, 2 , samples, fp);
    // Chiudo il file
    fclose (fp);
    printf ("wrote %d bytes ",wrotenum*2 + sizeof (*hdr));
    return wrotenum;
}