1 files changed, 85 insertions, 0 deletions
diff --git a/toys/posix/comm.c b/toys/posix/comm.c
new file mode 100644
index 00000000..1c2267ac
--- /dev/null
+++ b/toys/posix/comm.c
@@ -0,0 +1,85 @@
+/* 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
+
+// <# and ># take single digit, so 321 define flags
+USE_COMM(NEWTOY(comm, "<2>2321", TOYFLAG_USR|TOYFLAG_BIN))
+
+config COMM
+	bool "comm"
+	default y
+	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_1 1
+#define FLAG_2 2
+#define FLAG_3 4
+
+static void writeline(const char *line, int col)
+{
+	if (col == 0 && toys.optflags & FLAG_1) return;
+	else if (col == 1) {
+		if (toys.optflags & FLAG_2) return;
+		if (!(toys.optflags & FLAG_1)) putchar('\t');
+	} else if (col == 2) {
+		if (toys.optflags & FLAG_3) return;
+		if (!(toys.optflags & FLAG_1)) putchar('\t');
+		if (!(toys.optflags & FLAG_2)) putchar('\t');
+	}
+	puts(line);
+}
+
+void comm_main(void)
+{
+	int file[2];
+	char *line[2];
+	int i;
+
+	if (toys.optflags == 7) 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]);
+}