basic implementation

still TODO:
- handle skipping fields and characters
- handle + options
- handle obsolete options
- validate -f and -s arguments

1 files changed, 171 insertions, 0 deletions

diff --git a/uniq.c b/uniq.c
new file mode 100644
index 0000000..e96fd7a
--- /dev/null
+++ b/uniq.c
@@ -0,0 +1,171 @@
+/*
+ * UNG's Not GNU
+ *
+ * Copyright (c) 2020, Jakob Kaivo <jkk@ung.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#define _XOPEN_SOURCE 700
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef LINE_MAX
+#define LINE_MAX _POSIX_LINE_MAX
+#endif
+
+enum {
+	COUNT = (1<<0),
+	DUPLICATES = (1<<1),
+	UNIQUES = (1<<2),
+};
+
+static void print_line(FILE *out, const char *line, uintmax_t count, unsigned int flags)
+{
+	if (count == 0) {
+		return;
+	}
+
+	if ((flags & DUPLICATES) && (count == 1)) {
+		return;
+	}
+
+	if ((flags & UNIQUES) && (count != 1)) {
+		return;
+	}
+
+	if (flags & COUNT) {
+		fprintf(out, "%ju ", count);
+	}
+	fprintf(out, "%s", line);
+}
+
+int are_duplicates(const char *s1, const char *s2, size_t fields, size_t chars)
+{
+	/* TODO: skip first fields */
+	/* TODO: skip first chars */
+	return strcmp(s1, s2) == 0;
+}
+
+static int uniq(const char *input, const char *output, size_t fields, size_t chars, unsigned int flags)
+{
+	(void)fields;
+	(void)chars;
+	uintmax_t count = 0;
+	char cur[LINE_MAX] = "";
+	char prev[LINE_MAX] = "";
+
+	FILE *in = stdin;
+	if (strcmp(input, "-")) {
+		in = fopen(input, "r");
+	}
+	if (in == NULL) {
+		fprintf(stderr, "uniq: %s: %s\n", input, strerror(errno));
+		return 1;
+	}
+
+	FILE *out = stdout;
+	if (strcmp(output, "-")) {
+		out = fopen(output, "w");
+	}
+	if (out == NULL) {
+		fprintf(stderr, "uniq: %s: %s\n", output, strerror(errno));
+		return 1;
+	}
+
+	while (fgets(cur, sizeof(cur), in) != NULL) {
+		if (are_duplicates(cur, prev, fields, chars)) {
+			count++;
+			continue;
+		}
+		
+		print_line(out, prev, count, flags);
+		strcpy(prev, cur);
+		count = 1;
+	}
+	print_line(out, prev, count, flags);
+
+	fclose(out);
+	fclose(in);
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	uintmax_t chars = 0;
+	uintmax_t fields = 0;
+	unsigned int flags = 0;
+	char *input = "-";
+	char *output = "-";
+
+	/* TODO: handle + prefixed options */
+
+	int c;
+	while ((c = getopt(argc, argv, "cduf:s:")) != -1) {
+		switch (c) {
+		case 'c':
+			flags |= COUNT;
+			break;
+
+		case 'd':
+			flags |= DUPLICATES;
+			break;
+
+		case 'u':
+			flags |= UNIQUES;
+			break;
+
+		case 'f':
+			fields = strtoumax(optarg, NULL, 0);
+			/* TODO: verify < SIZE_MAX */
+			break;
+
+		case 's':
+			chars = strtoumax(optarg, NULL, 0);
+			/* TODO: verify < SIZE_MAX */
+			break;
+		}
+	}
+
+	if (argc > optind + 2) {
+		fprintf(stderr, "uniq: too many operands\n");
+		return 1;
+	}
+
+	if (argc > optind + 1) {
+		output = argv[optind + 1];
+	}
+
+	if (argc > optind) {
+		input = argv[optind];
+	}
+
+	if (!strcmp(input, output) && !strcmp(input, "-")) {
+		fprintf(stderr, "uniq: output clobbers input, bailing\n");
+		return 1;
+	}
+
+	return uniq(input, output, fields, chars, flags);
+}