Implement comm.

diff --git a/toys/comm.c b/toys/comm.c
new file mode 100644 (file)
index 0000000..1cddf95
--- /dev/null
+++ b/toys/comm.c
@@ -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]);
+       }
+}