Interesting byte read

[bvkim]

I've just try to check a MS Multimedia signature; specifically, a WAV file (RIFF) as a test.

So the header contains first 4-byte like: RIFF

This is my little script:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define byte	char
#define word	short int
#define dword	int

#define DEBUG
int
main( int argc, char *argv[] )
{
	FILE *file;
	const char *fname = "sound.wav";
	const char *mode  = "rb";
	byte id[4] = { 0 };
	int i;

	file = fopen( fname, mode );
	if( file == NULL ) {
		printf("[error] file not found.\n");
		exit( 1 );
	}

	fread( id, sizeof( byte ), 4, file );

#if defined DEBUG
	printf("[DEBUG]\n");
	for( i = 0; i < 4; ++i )
		printf("%c", id[i]);
	printf("\nString: %s", id);
	printf("\nLength: %d\n", strlen(id));
	printf("[/DEBUG]\n");
#endif

	if( 0 == strcmp( id, "RIFF") )
		printf("RIFF type\n");
	else
		printf("non-RIFF type\n");

	fclose( file );
	return 0;
}

Here the result:

RIFF
String: RIFF�t	��
Length: 17
[/DEBUG]
non-RIFF type

The ID is supposed to have 4-byte size in length, but the debug result showed up w/ 17 bytes in length.

Environment: Linux/Mandriva 2k9.1

Do you know what's wrong w/ code? What's the result running under your system?
Just try w/ any WAV file.

[MK27]

Do you know what's wrong w/ code?

fread() does not add a '\0', and id does not have room for one either. Change this:

byte id[5] = { 0 };