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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
int cmp_main(int argc, char *argv[])
{
int c;
int fd1, fd2;
char buf1[4096], buf2[4096];
int res, res1, res2;
int rv = 0;
int i;
int filepos = 0;
int show_byte = 0;
int show_all = 0;
int limit = 0;
do {
c = getopt(argc, argv, "bln:");
if (c == EOF)
break;
switch (c) {
case 'b':
show_byte = 1;
break;
case 'l':
show_all = 1;
break;
case 'n':
limit = atoi(optarg);
break;
case '?':
fprintf(stderr, "%s: invalid option -%c\n",
argv[0], optopt);
exit(1);
}
} while (1);
if (optind + 2 != argc) {
fprintf(stderr, "Usage: %s [-b] [-l] [-n count] file1 file2\n", argv[0]);
exit(1);
}
fd1 = open(argv[optind], O_RDONLY);
if(fd1 < 0) {
fprintf(stderr, "could not open %s, %s\n", argv[optind], strerror(errno));
return 1;
}
fd2 = open(argv[optind+1], O_RDONLY);
if(fd2 < 0) {
fprintf(stderr, "could not open %s, %s\n", argv[optind+1], strerror(errno));
return 1;
}
while(1) {
res1 = read(fd1, &buf1, sizeof(buf1));
res2 = read(fd2, &buf2, sizeof(buf2));
res = res1 < res2 ? res1 : res2;
if(res1 == 0 && res2 == 0) {
return rv;
}
for(i = 0; i < res; i++) {
if(buf1[i] != buf2[i]) {
printf("%s %s differ byte %d", argv[optind], argv[optind+1], filepos + i);
if(show_byte)
printf(" 0x%02x 0x%02x", buf1[i], buf2[i]);
printf("\n");
if(!show_all)
return 1;
rv = 1;
}
if(limit) {
limit--;
if(limit == 0)
return rv;
}
}
if(res1 != res2 || res < 0) {
printf("%s on %s\n", res < 0 ? "Read error" : "EOF", res1 < res2 ? argv[optind] : argv[optind+1]);
return 1;
}
filepos += res;
}
}
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