catv: convert this bbox-specific applet into "cat -v"

function                                             old     new   delta
cat_main                                             150     320    +170
packed_usage                                       31511   31552     +41
applet_install_loc                                   190     189      -1
applet_main                                         1516    1512      -4
applet_names                                        2618    2613      -5
catv_main                                            227       -    -227
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 2/3 up/down: 211/-237)          Total: -26 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 122 insertions, 18 deletions

diff --git a/coreutils/cat.c b/coreutils/cat.c
index 96970b19d..4d9147f8a 100644
--- a/coreutils/cat.c
+++ b/coreutils/cat.c
@@ -12,8 +12,15 @@
 //config:	help
 //config:	  cat is used to concatenate files and print them to the standard
 //config:	  output. Enable this option if you wish to enable the 'cat' utility.
+//config:
+//config:config FEATURE_CATV
+//config:	bool "cat -v[etA]"
+//config:	default y
+//config:	depends on CAT
+//config:	help
+//config:	  Display nonprinting characters as escape sequences
 
-//applet:IF_CAT(APPLET_NOFORK(cat, cat, BB_DIR_BIN, BB_SUID_DROP, cat))
+//applet:IF_CAT(APPLET(cat, BB_DIR_BIN, BB_SUID_DROP))
 
 //kbuild:lib-$(CONFIG_CAT) += cat.o
 
@@ -21,22 +28,27 @@
 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cat.html */
 
 //usage:#define cat_trivial_usage
-//usage:       "[-n] [FILE]..."
+//usage:       "[-nb"IF_FEATURE_CATV("vteA")"] [FILE]..."
 //usage:#define cat_full_usage "\n\n"
-//usage:       "Concatenate FILEs and print them to stdout"
+//usage:       "Print FILEs to stdout\n"
 //usage:     "\n	-n	Number output lines"
+//usage:     "\n	-b	Number nonempty lines"
+//usage:	IF_FEATURE_CATV(
+//usage:     "\n	-v	Show nonprinting characters as ^x or M-x"
+//usage:     "\n	-t	...and tabs as ^I"
+//usage:     "\n	-e	...and end lines with $"
+//usage:     "\n	-A	Same as -vte"
+//usage:	)
 /*
   Longopts not implemented yet:
-     --number-nonblank    number nonempty output lines, overrides -n
-     --number             number all output lines
+      --number-nonblank    number nonempty output lines, overrides -n
+      --number             number all output lines
+      --show-nonprinting   use ^ and M- notation, except for LFD and TAB
+      --show-all           equivalent to -vet
   Not implemented yet:
-  -A, --show-all           equivalent to -vET
-  -e                       equivalent to -vE
-  -E, --show-ends          display $ at end of each line
+  -E, --show-ends          display $ at end of each line (-e sans -v)
+  -T, --show-tabs          display TAB characters as ^I (-t sans -v)
   -s, --squeeze-blank      suppress repeated empty output lines
-  -t                       equivalent to -vT
-  -T, --show-tabs          display TAB characters as ^I
-  -v, --show-nonprinting   use ^ and M- notation, except for LFD and TAB
 */
 //usage:
 //usage:#define cat_example_usage
@@ -44,19 +56,111 @@
 //usage:       "110716.72 17.67"
 
 #include "libbb.h"
+#include "common_bufsiz.h"
+
+#if ENABLE_FEATURE_CATV
+/*
+ * cat -v implementation for busybox
+ *
+ * Copyright (C) 2006 Rob Landley <rob@landley.net>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+/* Rob had "cat -v" implemented as a separate applet, catv.
+ * See "cat -v considered harmful" at
+ * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz
+ * From USENIX Summer Conference Proceedings, 1983
+ * """
+ * The talk reviews reasons for UNIX's popularity and shows, using UCB cat
+ * as a primary example, how UNIX has grown fat. cat isn't for printing
+ * files with line numbers, it isn't for compressing multiple blank lines,
+ * it's not for looking at non-printing ASCII characters, it's for
+ * concatenating files.
+ * We are reminded that ls isn't the place for code to break a single column
+ * into multiple ones, and that mailnews shouldn't have its own more
+ * processing or joke encryption code.
+ * """
+ *
+ * I agree with the argument. Unfortunately, this ship has sailed (1983...).
+ * There are dozens of Linux distros and each of them has "cat" which supports -v.
+ * It's unrealistic for us to "reeducate" them to use our, incompatible way
+ * to achieve "cat -v" effect. The actuall effect would be "users pissed off
+ * by gratuitous incompatibility".
+ */
+#define CATV_OPT_e (1<<0)
+#define CATV_OPT_t (1<<1)
+#define CATV_OPT_v (1<<2)
+static int catv(unsigned opts, char **argv)
+{
+	int retval = EXIT_SUCCESS;
+	int fd;
 
-/* This is a NOFORK applet. Be very careful! */
+	BUILD_BUG_ON(CATV_OPT_e != VISIBLE_ENDLINE);
+	BUILD_BUG_ON(CATV_OPT_t != VISIBLE_SHOW_TABS);
+#if 0 /* These consts match, we can just pass "opts" to visible() */
+	if (opts & CATV_OPT_e)
+		flags |= VISIBLE_ENDLINE;
+	if (opts & CATV_OPT_t)
+		flags |= VISIBLE_SHOW_TABS;
+#endif
+
+	/* Read from stdin if there's nothing else to do. */
+	if (!argv[0])
+		*--argv = (char*)"-";
+
+#define read_buf bb_common_bufsiz1
+	setup_common_bufsiz();
+	do {
+		fd = open_or_warn_stdin(*argv);
+		if (fd < 0) {
+			retval = EXIT_FAILURE;
+			continue;
+		}
+		for (;;) {
+			int i, res;
+
+			res = read(fd, read_buf, COMMON_BUFSIZE);
+			if (res < 0)
+				retval = EXIT_FAILURE;
+			if (res <= 0)
+				break;
+			for (i = 0; i < res; i++) {
+				unsigned char c = read_buf[i];
+				char buf[sizeof("M-^c")];
+				visible(c, buf, opts);
+				fputs(buf, stdout);
+			}
+		}
+		if (ENABLE_FEATURE_CLEAN_UP && fd)
+			close(fd);
+	} while (*++argv);
+
+	fflush_stdout_and_exit(retval);
+}
+#endif
 
 int cat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int cat_main(int argc UNUSED_PARAM, char **argv)
 {
 	struct number_state ns;
-	unsigned opt;
+	unsigned opts;
 
-	/* -u is ignored */
-	opt = getopt32(argv, "nbu");
+	IF_FEATURE_CATV(opt_complementary = "Aetv"; /* -A == -vet */)
+	/* -u is ignored ("unbuffered") */
+	opts = getopt32(argv, IF_FEATURE_CATV("etvA")"nbu");
 	argv += optind;
-	if (!(opt & 3)) /* no -n or -b */
+
+#if ENABLE_FEATURE_CATV
+	if (opts & 7)
+		return catv(opts, argv);
+//BUG: -v,-e,-t,-A ignore -nb
+	opts >>= 4;
+#endif
+
+#define CAT_OPT_n (1<<0)
+#define CAT_OPT_b (1<<1)
+#define CAT_OPT_u (1<<2)
+	if (!(opts & (CAT_OPT_n|CAT_OPT_b))) /* no -n or -b */
 		return bb_cat(argv);
 
 	if (!*argv)
@@ -66,8 +170,8 @@ int cat_main(int argc UNUSED_PARAM, char **argv)
 	ns.inc = 1;
 	ns.sep = "\t";
 	ns.empty_str = "\n";
-	ns.all = !(opt & 2); /* -n without -b */
-	ns.nonempty = (opt & 2); /* -b (with or without -n) */
+	ns.all = !(opts & CAT_OPT_b); /* -n without -b */
+	ns.nonempty = (opts & CAT_OPT_b); /* -b (with or without -n) */
 	do {
 		print_numbered_lines(&ns, *argv);
 	} while (*++argv);