mpv/liba52/compare.c

// File written by Michael Niedermayer and it is under GPL.
// Simple file compare program, it finds the number of rounding errors
// and dies if there is too large an error ( ABS(a-b)>1 ).

#include <stdio.h>

// FIXME: No checks but it is just for debugging so who cares ;)

int main(int argc, char **argv)
{
	FILE *f0, *f1;
	int dif=0;
	
	if(argc!=3) 
	{
		printf("compare <file1> <file2>\n");
		exit(2);
	}
	
	f0= fopen(argv[1], "rb");
	f1= fopen(argv[2], "rb");
	
	for(;;)
	{
		short c0;
		short c1;
		int d;
		
		int e0= fread(&c0, 2, 1, f0);
		int e1= fread(&c1, 2, 1, f1);
		
		d=c0-c1;
		if(e0==0 && e1==0) break;
		if(e0==0 || e1==0)
		{
			printf("FATAL error, files have different size!\n");
			exit(1);
		}
		
		if(d<0) d=-d; // ABS
		if(d>1)
		{
			printf("FATAL error, too large a difference found (%d)!\n", d);
			exit(1);
		}
		
		if(d) dif++;
	}
	
	fclose(f0);
	fclose(f1);
	
	printf("%d (+/-1)differences found\n", dif);
	exit(0);
}