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/*
A simple sound library for CSE 20211 by Douglas Thain
For course assignments, you should not change this file.
For complete documentation, see:
http://www.nd.edu/~dthain/courses/cse20211/fall2013/wavfile
*/
#include "wavfile.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct wavfile_header {
char riff_tag[4];
int riff_length;
char wave_tag[4];
char fmt_tag[4];
int fmt_length;
short audio_format;
short num_channels;
int sample_rate;
int byte_rate;
short block_align;
short bits_per_sample;
char data_tag[4];
int data_length;
};
FILE * wavfile_open( const char *filename, int rate )
{
struct wavfile_header header;
int samples_per_second = rate;
int bits_per_sample = 16;
strncpy(header.riff_tag,"RIFF",4);
strncpy(header.wave_tag,"WAVE",4);
strncpy(header.fmt_tag,"fmt ",4);
strncpy(header.data_tag,"data",4);
int channels = 2;
header.riff_length = 0;
header.fmt_length = 16;
header.audio_format = 1;
header.num_channels = channels;
header.sample_rate = samples_per_second;
header.byte_rate = samples_per_second*(bits_per_sample/8)*channels;
header.block_align = channels*bits_per_sample/8;
header.bits_per_sample = bits_per_sample;
header.data_length = 0;
FILE * file = fopen(filename,"w+");
if(!file) return 0;
fwrite(&header,sizeof(header),1,file);
fflush(file);
return file;
}
void wavfile_write( FILE *file, short data[], int length )
{
fwrite(data,sizeof(short),length,file);
}
void wavfile_close( FILE *file )
{
int file_length = ftell(file);
int data_length = file_length - sizeof(struct wavfile_header);
fseek(file,sizeof(struct wavfile_header) - sizeof(int),SEEK_SET);
fwrite(&data_length,sizeof(data_length),1,file);
int riff_length = file_length - 8;
fseek(file,4,SEEK_SET);
fwrite(&riff_length,sizeof(riff_length),1,file);
fclose(file);
}
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