introduce LONE_CHAR (optimized strcmp with one-char string)

coreutils/Kbuild

@@ -10,6 +10,7 @@ lib-y:=
 lib-$(CONFIG_BASENAME)  += basename.o
 lib-$(CONFIG_CAL)       += cal.o
 lib-$(CONFIG_CAT)       += cat.o
+lib-$(CONFIG_LESS)      += cat.o # less uses it if stdout isn't a tty
 lib-$(CONFIG_CATV)      += catv.o
 lib-$(CONFIG_CHGRP)     += chgrp.o chown.o
 lib-$(CONFIG_CHMOD)     += chmod.o
@@ -28,6 +29,7 @@ lib-$(CONFIG_DIRNAME)   += dirname.o
 lib-$(CONFIG_DOS2UNIX)  += dos2unix.o
 lib-$(CONFIG_DU)        += du.o
 lib-$(CONFIG_ECHO)      += echo.o
+lib-$(CONFIG_ASH)       += echo.o # used by ash
 lib-$(CONFIG_ENV)       += env.o
 lib-$(CONFIG_EXPR)      += expr.o
 lib-$(CONFIG_FALSE)     += false.o
@@ -65,6 +67,7 @@ lib-$(CONFIG_SYNC)      += sync.o
 lib-$(CONFIG_TAIL)      += tail.o
 lib-$(CONFIG_TEE)       += tee.o
 lib-$(CONFIG_TEST)      += test.o
+lib-$(CONFIG_ASH)       += test.o # used by ash
 lib-$(CONFIG_TOUCH)     += touch.o
 lib-$(CONFIG_TR)        += tr.o
 lib-$(CONFIG_TRUE)      += true.o

coreutils/cat.c

@@ -11,20 +11,12 @@
 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cat.html */
 
 #include "busybox.h"
-#include <unistd.h>
 
-int cat_main(int argc, char **argv)
+int bb_cat(char **argv)
 {
 	FILE *f;
 	int retval = EXIT_SUCCESS;
 
-	getopt32(argc, argv, "u");
-
-	argv += optind;
-	if (!*argv) {
-		*--argv = "-";
-	}
-
 	do {
 		f = fopen_or_warn_stdin(*argv);
 		if (f) {
@@ -39,3 +31,15 @@ int cat_main(int argc, char **argv)
 
 	return retval;
 }
+
+int cat_main(int argc, char **argv)
+{
+	getopt32(argc, argv, "u");
+
+	argv += optind;
+	if (!*argv) {
+		*--argv = "-";
+	}
+
+	return bb_cat(argv);
+}

coreutils/diff.c

@@ -1079,7 +1079,7 @@ static char **get_dir(char *path)
 
 		dp = warn_opendir(path);
 		while ((ep = readdir(dp))) {
-			if ((!strcmp(ep->d_name, "..")) || (!strcmp(ep->d_name, ".")))
+			if (!strcmp(ep->d_name, "..") || LONE_CHAR(ep->d_name, '.'))
 				continue;
 			add_to_dirlist(ep->d_name, NULL, NULL, 0);
 		}

coreutils/echo.c

@@ -29,7 +29,7 @@
 #include <stdlib.h>
 #include "busybox.h"
 
-int bb_echo(int ATTRIBUTE_UNUSED argc, char **argv)
+int bb_echo(char **argv)
 {
 #ifndef CONFIG_FEATURE_FANCY_ECHO
 #define eflag '\\'
@@ -114,7 +114,7 @@ just_echo:
 
 int echo_main(int argc, char** argv)
 {
-	(void)bb_echo(argc, argv);
+	(void)bb_echo(argv);
 	fflush_stdout_and_exit(EXIT_SUCCESS);
 }
 

coreutils/expr.c

@@ -136,7 +136,7 @@ static int null(VALUE * v)
 	if (v->type == integer)
 		return v->u.i == 0;
 	else				/* string: */
-		return v->u.s[0] == '\0' || strcmp(v->u.s, "0") == 0;
+		return v->u.s[0] == '\0' || LONE_CHAR(v->u.s, '0');
 }
 
 /* Coerce V to a string value (can't fail).  */

coreutils/test.c

@@ -175,14 +175,16 @@ int bb_test(int argc, char **argv)
 {
 	int res;
 
-	if (strcmp(argv[0], "[") == 0) {
-		if (strcmp(argv[--argc], "]")) {
+	if (LONE_CHAR(argv[0], '[')) {
+		--argc;
+		if (NOT_LONE_CHAR(argv[argc], ']')) {
 			bb_error_msg("missing ]");
 			return 2;
 		}
 		argv[argc] = NULL;
 	} else if (strcmp(argv[0], "[[") == 0) {
-		if (strcmp(argv[--argc], "]]")) {
+		--argc;
+		if (strcmp(argv[argc], "]]")) {
 			bb_error_msg("missing ]]");
 			return 2;
 		}
@@ -578,6 +580,6 @@ static int is_a_group_member(gid_t gid)
 
 int test_main(int argc, char **argv)
 {
-	exit(bb_test(argc, argv));
+	return bb_test(argc, argv);
 }