1 files changed, 70 insertions, 0 deletions
diff --git a/cksum.c b/cksum.c
new file mode 100644
index 0000000..35d373a
--- /dev/null
+++ b/cksum.c
@@ -0,0 +1,70 @@
+/*
+ * 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 <inttypes.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+/* G(x)=x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1 */
+const uint64_t polynomial = UINT64_C(0x104C11DB7);
+
+int cksum(const char *path)
+{
+	uint64_t checksum = 0;
+	intmax_t octets = 0;
+
+	FILE *f = stdin;
+	if (path && strcmp(path, "-")) {
+		f = fopen(path, "rb");
+	}
+
+	if (f == NULL) {
+		return 1;
+	}
+
+	while (!feof(f)) {
+		uint64_t next = 0;
+		octets += fread(&next, sizeof(next), 1, f);
+		checksum ^= next;
+	}
+
+	if (f != stdin) {
+		fclose(f);
+	}
+
+	printf("%"PRIu64" %"PRIdMAX" %s\n", checksum, octets, path);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	while (getopt(argc, argv, "") != -1) {
+		return 1;
+	}
+
+	int r = 0;
+
+	do {
+		r |= cksum(argv[optind++]);
+	} while (optind < argc);
+
+	return 0;
+}