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/*
* UNG's Not GNU
*
* Copyright (c) 2011-2017, Jakob Kaivo <jkk@ung.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#define _POSIX_C_SOURCE 2
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
FILE *fileopen(const char *path)
{
if (!strcmp(path, "-")) {
return stdin;
}
FILE *f = fopen(path, "rb");
if (f == NULL) {
fprintf(stderr, "cmp: %s: %s\n", path, strerror(errno));
exit(1);
}
return f;
}
int main(int argc, char *argv[])
{
int c;
enum { FIRSTONLY, ALL, SILENT } output = FIRSTONLY;
while ((c = getopt(argc, argv, "ls")) != EOF) {
switch (c) {
case 'l':
output = ALL;
break;
case 's':
output = SILENT;
break;
default:
return 1;
}
}
if (optind != argc - 2) {
fprintf(stderr, "cmp: missing operand\n");
return 1;
}
char *file1 = argv[optind++];
char *file2 = argv[optind];
FILE *f1 = fileopen(file1);
FILE *f2 = fileopen(file2);
if (f1 == stdin && f2 == stdin) {
fprintf(stderr, "cmp: Comparing stdin to itself is undefined\n");
return 1;
}
struct stat st1;
fstat(fileno(f1), &st1);
if (S_ISBLK(st1.st_mode) || S_ISCHR(st1.st_mode) || S_ISFIFO(st1.st_mode)) {
struct stat st2;
fstat(fileno(f2), &st2);
if (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino) {
fprintf(stderr, "cmp: Comparing special file to itself is undefined\n");
return 1;
}
}
intmax_t byte = 0;
intmax_t line = 1;
while (++byte) {
int c1 = fgetc(f1);
int c2 = fgetc(f2);
if (c1 == c2) {
if (c1 == EOF) {
return 0;
}
if (c1 == '\n') {
line++;
}
continue;
}
if (c1 == EOF && output != SILENT) {
fprintf(stderr, "cmp: EOF on %s\n", file1);
} else if (c2 == EOF && output != SILENT) {
fprintf(stderr, "cmp: EOF on %s\n", file2);
} else if (output == ALL) {
printf("%zd %o %o\n", byte, c1, c2);
continue;
} else if (output != SILENT) {
printf("%s %s differ: char %zd, line %zd\n",
file1, file2, byte, line);
}
return 1;
}
return 0;
}
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