toaruos/userspace/compare.c
Kevin Lange c88d6dcb4f Add or update the heading comments for user apps.
Adds useful descriptions to ones that were lacking them, updates ones
that were innacurate, etc.
2012-07-06 21:08:28 -07:00

65 lines
1.1 KiB
C

/*
* compare
*
* Compares two files and prints out some
* statistics on how they differ.
*
* This is *NOT* diff.
*/
#include <stdio.h>
#include <string.h>
#define CHUNK_SIZE 1024
int main(int argc, char * argv[]) {
if (argc < 3) {
fprintf(stderr, "Need two files to compare.\n");
return 1;
}
FILE * a = fopen(argv[1], "r");
FILE * b = fopen(argv[2], "r");
size_t lengtha, lengthb;
fseek(a, 0, SEEK_END);
lengtha = ftell(a);
fseek(a, 0, SEEK_SET);
fseek(b, 0, SEEK_END);
lengthb = ftell(b);
fseek(b, 0, SEEK_SET);
fprintf(stderr,"[%d bytes and %d bytes]\n", lengtha, lengthb);
char bufa[CHUNK_SIZE];
char bufb[CHUNK_SIZE];
int chunk = 0;
size_t read = 0;
while (read < lengtha) {
memset(bufa, 0x0, CHUNK_SIZE);
memset(bufb, 0x0, CHUNK_SIZE);
fread(bufa, 1, CHUNK_SIZE, a);
fread(bufb, 1, CHUNK_SIZE, b);
size_t different = 0;
for (int i = 0; i < CHUNK_SIZE; ++i) {
if (bufa[i] != bufb[i])
different++;
}
if (different > 0) {
printf("Chunk %d has %d differing bytes.\n", chunk, different);
}
read += CHUNK_SIZE;
chunk++;
}
fclose(a);
fclose(b);
return 0;
}