Add uniq(1).

doc/user-guide

@@ -191,6 +191,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `true` - exit with a success status
 * `type` - type raw characters directly into the terminal
 * `uname` - system information
+* `uniq` - report or omit repeated lines
 * `uptime` - time since initialization
 * `wc` - count words and lines
 * `which` - find path to command

utils/.gitignore

@@ -39,6 +39,7 @@ time
 true
 type
 uname
+uniq
 uptime
 wc
 which

utils/Makefile

@@ -55,6 +55,7 @@ time \
 true \
 type \
 uname \
+uniq \
 uptime \
 wc \
 which \

utils/uniq.cpp

@@ -0,0 +1,245 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see <http://www.gnu.org/licenses/>.
+
+    uniq.cpp
+    Report or filter out repeated lines in a file
+
+*******************************************************************************/
+
+#include <errno.h>
+#include <error.h>
+#include <locale.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// TODO: Implement all the features mandated by POSIX.
+// TODO: Implement the useful GNU extensions.
+
+char* read_line(FILE* fp, const char* fpname, int delim)
+{
+	char* line = NULL;
+	size_t line_size = 0;
+	ssize_t amount = getdelim(&line, &line_size, delim, fp);
+	if ( amount < 0 )
+	{
+		if ( ferror(fp) )
+			error(0, errno, "read: `%s'", fpname);
+		return NULL;
+	}
+	if ( amount && (unsigned char) line[amount-1] == (unsigned char) delim )
+		line[amount-1] = '\0';
+	return line;
+}
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [OPTION]... [INPUT [OUTPUT]]\n", argv0);
+	fprintf(fp, "Filter adjacent matching lines from INPUT (or standard input),\n");
+	fprintf(fp, "writing to OUTPUT (or standard output).\n");
+	fprintf(fp, "\n");
+	fprintf(fp, "With no options, matching lines are merged to the first occurrence.\n");
+	fprintf(fp, "\n");
+	fprintf(fp, "Mandatory arguments to long options are mandatory for short options too.\n");
+	fprintf(fp, "  -c, --count           prefix lines by the number of occurrences\n");
+	fprintf(fp, "  -d, --repeated        only print duplicate lines\n");
+#if 0
+	fprintf(fp, "  -D, --all-repeated[=delimit-method]  print all duplicate lines\n");
+	fprintf(fp, "                        delimit-method={none(default),prepend,separate}\n");
+	fprintf(fp, "                        Delimiting is done with blank lines\n");
+	fprintf(fp, "  -f, --skip-fields=N   avoid comparing the first N fields\n");
+	fprintf(fp, "  -i, --ignore-case     ignore differences in case when comparing\n");
+	fprintf(fp, "  -s, --skip-chars=N    avoid comparing the first N characters\n");
+#endif
+	fprintf(fp, "  -u, --unique          only print unique lines\n");
+	fprintf(fp, "  -z, --zero-terminated  end lines with 0 byte, not newline\n");
+#if 0
+	fprintf(fp, "  -w, --check-chars=N   compare no more than N characters in lines\n");
+#endif
+	fprintf(fp, "      --help     display this help and exit\n");
+	fprintf(fp, "      --version  output version information and exit\n");
+	fprintf(fp, "\n");
+#if 0
+	fprintf(fp, "A field is a run of blanks (usually spaces and/or TABs), then non-blank\n");
+	fprintf(fp, "characters.  Fields are skipped before chars.\n");
+	fprintf(fp, "\n");
+#endif
+	fprintf(fp, "Note: 'uniq' does not detect repeated lines unless they are adjacent.\n");
+	fprintf(fp, "You may want to sort the input first, or use `sort -u' without `uniq'.\n");
+	fprintf(fp, "Also, comparisons honor the rules specified by `LC_COLLATE'.\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+	fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
+	fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+	fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	setlocale(LC_ALL, "");
+
+	bool count = false;
+	bool delete_singulars = false;
+	bool delete_duplicates = false;
+	bool zero_terminated = false;
+
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			while ( char c = *++arg ) switch ( c )
+			{
+			case 'c': count = true; break;
+			case 'd': delete_singulars = true; break;
+			case 'u': delete_duplicates = true; break;
+			case 'z': zero_terminated = true; break;
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				help(stderr, argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--count") )
+			count = true;
+		else if ( !strcmp(arg, "--repeated") )
+			delete_singulars = true;
+		else if ( !strcmp(arg, "--unique") )
+			delete_duplicates = true;
+		else if ( !strcmp(arg, "--zero-terminated") )
+			zero_terminated = true;
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			help(stderr, argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	if ( 4 <= argc )
+	{
+		fprintf(stderr, "%s: extra operand `%s'\n", argv0, argv[3]);
+		fprintf(stderr, "Try `%s --help' for more information.\n", argv0);
+		exit(1);
+	}
+
+	const char* inname = "<stdin>";
+	const char* outname = "<stdout>";
+
+	if ( 3 <= argc && !freopen(outname = argv[2], "w", stdout) )
+		error(1, errno, "`%s'", argv[2]);
+
+	if ( 2 <= argc && !freopen(inname = argv[1], "r", stdin) )
+		error(1, errno, "`%s'", argv[1]);
+
+	int delim = zero_terminated ? '\0' : '\n';
+
+	uintmax_t num_repeats = 0;
+	char* prev_line = NULL;
+	while ( true )
+	{
+		char* line = read_line(stdin, inname, delim);
+
+		bool first = !prev_line;
+		bool different = !first && (!line || strcoll(line, prev_line) != 0);
+
+		if ( delete_singulars && delete_duplicates )
+		{
+		}
+		else if ( delete_singulars )
+		{
+			if ( different && 1 < num_repeats )
+			{
+				if ( count )
+					printf("%ju ", num_repeats);
+				fputs(prev_line, stdout);
+				fputc(delim, stdout);
+			}
+		}
+		else if ( delete_duplicates )
+		{
+			if ( different && num_repeats == 1 )
+			{
+				if ( count )
+					printf("%ju ", num_repeats);
+				fputs(prev_line, stdout);
+				fputc(delim, stdout);
+			}
+		}
+		else
+		{
+			if ( count && different )
+			{
+				printf("%ju ", num_repeats);
+				fputs(prev_line, stdout);
+				fputc(delim, stdout);
+			}
+		}
+
+		if ( different )
+			num_repeats = 0;
+
+		if ( !line )
+			break;
+
+		bool original = first || strcoll(line, prev_line) != 0;
+		if ( !count && !delete_singulars && !delete_duplicates && original )
+		{
+			fputs(line, stdout);
+			fputc(delim, stdout);
+		}
+
+		free(prev_line);
+		prev_line = line;
+		num_repeats++;
+	}
+	free(prev_line);
+
+	if ( fflush(stdout) == EOF || ferror(stdout) )
+		return 1;
+
+	return 0;
+}