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authorJakob Kaivo <jkk@ung.org>2019-03-13 21:10:54 -0400
committerJakob Kaivo <jkk@ung.org>2019-03-13 21:10:54 -0400
commit23b68d3a7356f9cf3182759fa559af58704497f0 (patch)
tree8843126e6dd04f134293e5939ec835a16663cf4d
migrate to gitlab
-rw-r--r--cmp.c114
1 files changed, 114 insertions, 0 deletions
diff --git a/cmp.c b/cmp.c
new file mode 100644
index 0000000..6a03002
--- /dev/null
+++ b/cmp.c
@@ -0,0 +1,114 @@
+/*
+ * 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 _XOPEN_SOURCE 700
+#include <errno.h>
+#include <stdio.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: Couldn't open %s: %s\n", path, strerror(errno));
+ exit(1);
+ }
+
+ return f;
+}
+
+int main(int argc, char *argv[])
+{
+ int c = 0;
+ 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: Two files are required\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;
+ }
+ }
+
+ for (int byte = 1, line = 1; !(feof(f1) || feof(f2)); byte++) {
+ int c1 = fgetc(f1);
+ int c2 = fgetc(f2);
+
+ if (c1 == c2) {
+ 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("%d %o %o\n", byte, c1, c2);
+ continue;
+ } else if (output != SILENT) {
+ printf("%s %s differ: char %d, line %d\n", file1, file2, byte, line);
+ }
+ return 1;
+ }
+
+ return 0;
+}