# HG changeset patch
# User Ilya Kuzmich <ilya.kuzmich@gmail.com>
# Date 1332424894 18000
# Node ID feb909b2e6aa11662a3ed860027022ee35d15666
# Parent  56a53ff54096dbae2a94f1ec5f4e92df770046bc
Implement comm.

diff -r 56a53ff54096 -r feb909b2e6aa toys/comm.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/comm.c	Thu Mar 22 09:01:34 2012 -0500
@@ -0,0 +1,91 @@
+/* vi: set sw=4 ts=4:
+ *
+ * comm.c - select or reject lines common to two files
+ *
+ * Copyright 2012 Ilya Kuzmich <ikv@safe-mail.net>
+ *
+ * See http://pubs.opengroup.org/onlinepubs/009695399/utilities/comm.html
+
+USE_COMM(NEWTOY(comm, "123", TOYFLAG_USR|TOYFLAG_BIN))
+
+config COMM
+	bool "comm"
+	default n
+	help
+	  usage: comm [-123] FILE1 FILE2
+
+	  Reads FILE1 and FILE2, which should be ordered, and produces three text
+	  columns as output: lines only in FILE1; lines only in FILE2; and lines
+	  in both files. Filename "-" is a synonym for stdin.
+
+	  -1 suppress the output column of lines unique to FILE1
+	  -2 suppress the output column of lines unique to FILE2
+	  -3 suppress the output column of lines duplicated in FILE1 and FILE2
+*/
+
+#include "toys.h"
+
+#define FLAG_SUPPRESS_3 1
+#define FLAG_SUPPRESS_2 2
+#define FLAG_SUPPRESS_1 4
+
+static void writeline(const char *line, int col)
+{
+	if (col == 0 && toys.optflags & FLAG_SUPPRESS_1) return;
+	else if (col == 1) {
+		if (toys.optflags & FLAG_SUPPRESS_2) return;
+		if (!(toys.optflags & FLAG_SUPPRESS_1)) putchar('\t');
+	} else if (col == 2) {
+		if (toys.optflags & FLAG_SUPPRESS_3) return;
+		if (!(toys.optflags & FLAG_SUPPRESS_1)) putchar('\t');
+		if (!(toys.optflags & FLAG_SUPPRESS_2)) putchar('\t');
+	}
+	puts(line);
+}
+
+void comm_main(void)
+{
+	int file[2];
+	char *line[2];
+	int i;
+
+	if (toys.optc != 2)
+		perror_exit("exactly 2 operands required");
+
+	if (toys.optflags == (FLAG_SUPPRESS_1 | FLAG_SUPPRESS_2 | FLAG_SUPPRESS_3))
+		return;
+
+	for (i = 0; i < 2; i++) {
+		file[i] = strcmp("-", toys.optargs[i]) ? xopen(toys.optargs[i], O_RDONLY) : 0;
+		line[i] = get_line(file[i]);
+	}
+
+	while (line[0] && line[1]) {
+		int order = strcmp(line[0], line[1]);
+
+		if (order == 0) {
+			writeline(line[0], 2);
+			for (i = 0; i < 2; i++) {
+				free(line[i]);
+				line[i] = get_line(file[i]);
+			}
+		} else {
+			i = order < 0 ? 0 : 1;
+			writeline(line[i], i);
+			free(line[i]);
+			line[i] = get_line(file[i]);
+		}
+	}
+
+	/* print rest of the longer file */
+	for (i = line[0] ? 0 : 1; line[i];) {
+		writeline(line[i], i);
+		free(line[i]);
+		line[i] = get_line(file[i]);
+	}
+
+	if (CFG_TOYBOX_FREE) {
+		for (i = 0; i < 2; i--)
+			xclose(file[i]);
+	}
+}