From bf66fbc8e2380717c1fab860cfc60c78582839dd Mon Sep 17 00:00:00 2001
From: Denis Vlasenko
Date: Thu, 21 Dec 2006 13:23:14 +0000
Subject: introduce LONE_CHAR (optimized strcmp with one-char string)

---
 coreutils/Kbuild                  |  3 +++
 coreutils/cat.c                   | 22 +++++++++++++---------
 coreutils/diff.c                  |  2 +-
 coreutils/echo.c                  |  4 ++--
 coreutils/expr.c                  |  2 +-
 coreutils/test.c                  | 10 ++++++----
 e2fsprogs/blkid/devname.c         |  4 ++--
 e2fsprogs/chattr.c                |  7 ++++---
 e2fsprogs/ext2fs/ismounted.c      |  2 +-
 e2fsprogs/fsck.c                  |  4 ++--
 include/libbb.h                   |  6 +++++-
 init/init.c                       |  5 +++--
 libbb/correct_password.c          |  5 ++---
 miscutils/last.c                  |  2 +-
 networking/inetd.c                |  2 +-
 networking/libiproute/ipaddress.c |  2 +-
 shell/ash.c                       |  2 +-
 17 files changed, 49 insertions(+), 35 deletions(-)

diff --git a/coreutils/Kbuild b/coreutils/Kbuild
index cfb508d..55f19b4 100644
--- a/coreutils/Kbuild
+++ b/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
diff --git a/coreutils/cat.c b/coreutils/cat.c
index a959805..db4d33d 100644
--- a/coreutils/cat.c
+++ b/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);
+}
diff --git a/coreutils/diff.c b/coreutils/diff.c
index 887679a..a49d519 100644
--- a/coreutils/diff.c
+++ b/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);
 		}
diff --git a/coreutils/echo.c b/coreutils/echo.c
index 99063ae..0c8eac3 100644
--- a/coreutils/echo.c
+++ b/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);
 }
 
diff --git a/coreutils/expr.c b/coreutils/expr.c
index 1914734..51e553d 100644
--- a/coreutils/expr.c
+++ b/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).  */
diff --git a/coreutils/test.c b/coreutils/test.c
index ebb4f90..d3d7604 100644
--- a/coreutils/test.c
+++ b/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);
 }
 
diff --git a/e2fsprogs/blkid/devname.c b/e2fsprogs/blkid/devname.c
index d69000b..3d11734 100644
--- a/e2fsprogs/blkid/devname.c
+++ b/e2fsprogs/blkid/devname.c
@@ -189,7 +189,7 @@ static void lvm_probe_all(blkid_cache cache)
 		struct dirent	*lv_iter;
 
 		vg_name = vg_iter->d_name;
-		if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))
+		if (LONE_CHAR(vg_name, '.') || !strcmp(vg_name, ".."))
 			continue;
 		vdirname = xmalloc(vg_len + strlen(vg_name) + 8);
 		sprintf(vdirname, "%s/%s/LVs", VG_DIR, vg_name);
@@ -203,7 +203,7 @@ static void lvm_probe_all(blkid_cache cache)
 			char		*lv_name, *lvm_device;
 
 			lv_name = lv_iter->d_name;
-			if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))
+			if (LONE_CHAR(lv_name, '.') || !strcmp(lv_name, ".."))
 				continue;
 
 			lvm_device = xmalloc(vg_len + strlen(vg_name) +
diff --git a/e2fsprogs/chattr.c b/e2fsprogs/chattr.c
index 4c34162..4848e1e 100644
--- a/e2fsprogs/chattr.c
+++ b/e2fsprogs/chattr.c
@@ -157,9 +157,10 @@ skip_setflags:
 static int chattr_dir_proc(const char *dir_name, struct dirent *de,
 			   void *private EXT2FS_ATTR((unused)))
 {
-	/*if (strcmp(de->d_name, ".") && strcmp(de->d_name, "..")) {*/
-	if (de->d_name[0] == '.' && (de->d_name[1] == '\0' || \
-	   (de->d_name[1] == '.' && de->d_name[2] == '\0'))) {
+	/*if (strcmp(de->d_name, ".") || strcmp(de->d_name, "..")) {*/
+	if (de->d_name[0] == '.'
+	 && (!de->d_name[1] || (de->d_name[1] == '.' && !de->d_name[2]))
+	) {
 		char *path = concat_subpath_file(dir_name, de->d_name);
 		if (path) {
 			change_attributes(path);
diff --git a/e2fsprogs/ext2fs/ismounted.c b/e2fsprogs/ext2fs/ismounted.c
index cace771..d943f11 100644
--- a/e2fsprogs/ext2fs/ismounted.c
+++ b/e2fsprogs/ext2fs/ismounted.c
@@ -144,7 +144,7 @@ static errcode_t check_mntent_file(const char *mtab_file, const char *file,
 	 * read/write, since if the root is mounted read/only, the
 	 * contents of /etc/mtab may not be accurate.
 	 */
-	if (!strcmp(mnt->mnt_dir, "/")) {
+	if (LONE_CHAR(mnt->mnt_dir, '/')) {
 is_root:
 #define TEST_FILE "/.ismount-test-file"
 		*mount_flags |= EXT2_MF_ISROOT;
diff --git a/e2fsprogs/fsck.c b/e2fsprogs/fsck.c
index 3b01c10..da66250 100644
--- a/e2fsprogs/fsck.c
+++ b/e2fsprogs/fsck.c
@@ -1080,7 +1080,7 @@ static int check_all(void)
 	 */
 	if (!parallel_root) {
 		for (fs = filesys_info; fs; fs = fs->next) {
-			if (!strcmp(fs->mountpt, "/"))
+			if (LONE_CHAR(fs->mountpt, '/'))
 				break;
 		}
 		if (fs) {
@@ -1099,7 +1099,7 @@ static int check_all(void)
 	 */
 	if (skip_root)
 		for (fs = filesys_info; fs; fs = fs->next)
-			if (!strcmp(fs->mountpt, "/"))
+			if (LONE_CHAR(fs->mountpt, '/'))
 				fs->flags |= FLAG_DONE;
 
 	while (not_done_yet) {
diff --git a/include/libbb.h b/include/libbb.h
index 7dc7abd..2fd54e7 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -263,6 +263,8 @@ extern char *xasprintf(const char *format, ...) __attribute__ ((format (printf,
 //int NOT_LONE_DASH(const char *s) { return s[0] != '-' || s[1]; }
 #define LONE_DASH(s) ((s)[0] == '-' && !(s)[1])
 #define NOT_LONE_DASH(s) ((s)[0] != '-' || (s)[1])
+#define LONE_CHAR(s,c) ((s)[0] == (c) && !(s)[1])
+#define NOT_LONE_CHAR(s,c) ((s)[0] != (c) || (s)[1])
 
 /* dmalloc will redefine these to it's own implementation. It is safe
  * to have the prototypes here unconditionally.  */
@@ -386,7 +388,9 @@ extern void bb_vperror_msg(const char *s, va_list p);
 extern void bb_vinfo_msg(const char *s, va_list p);
 
 
-extern int bb_echo(int argc, char** argv);
+/* applets which are useful from another applets */
+extern int bb_cat(char** argv);
+extern int bb_echo(char** argv);
 extern int bb_test(int argc, char** argv);
 
 #ifndef BUILD_INDIVIDUAL
diff --git a/init/init.c b/init/init.c
index 213a5c1..bc53fee 100644
--- a/init/init.c
+++ b/init/init.c
@@ -1047,8 +1047,9 @@ int init_main(int argc, char **argv)
 	}
 
 	/* Check if we are supposed to be in single user mode */
-	if (argc > 1 && (!strcmp(argv[1], "single") ||
-					 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
+	if (argc > 1
+	 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
+	) {
 		/* Start a shell on console */
 		new_init_action(RESPAWN, bb_default_login_shell, "");
 	} else {
diff --git a/libbb/correct_password.c b/libbb/correct_password.c
index fd7e0b5..d031b21 100644
--- a/libbb/correct_password.c
+++ b/libbb/correct_password.c
@@ -40,15 +40,14 @@ int correct_password(const struct passwd *pw)
 	char *unencrypted, *encrypted, *correct;
 
 #ifdef CONFIG_FEATURE_SHADOWPASSWDS
-	if (!strcmp(pw->pw_passwd, "x") || !strcmp(pw->pw_passwd, "*")) {
+	if (LONE_CHAR(pw->pw_passwd, 'x') || LONE_CHAR(pw->pw_passwd, '*')) {
 		struct spwd *sp = getspnam(pw->pw_name);
 
 		if (!sp)
 			bb_error_msg_and_die("no valid shadow password");
 
 		correct = sp->sp_pwdp;
-	}
-	else
+	} else
 #endif
 		correct = pw->pw_passwd;
 
diff --git a/miscutils/last.c b/miscutils/last.c
index 668f0c1..fd1033b 100644
--- a/miscutils/last.c
+++ b/miscutils/last.c
@@ -44,7 +44,7 @@ int last_main(int argc, char **argv)
 			bb_perror_msg_and_die("short read");
 		}
 
-		if (strncmp(ut.ut_line, "~", 1) == 0) {
+		if (ut.ut_line[0] == '~') {
 			if (strncmp(ut.ut_user, "shutdown", 8) == 0)
 				ut.ut_type = SHUTDOWN_TIME;
 			else if (strncmp(ut.ut_user, "reboot", 6) == 0)
diff --git a/networking/inetd.c b/networking/inetd.c
index 4856b11..7c89be2 100644
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -759,7 +759,7 @@ static servtab_t *getconfigent(void)
 	while (nsep != NULL) {
 		nsep->se_checked = 1;
 		if (nsep->se_family == AF_INET) {
-			if (!strcmp(nsep->se_hostaddr, "*"))
+			if (LONE_CHAR(nsep->se_hostaddr, '*'))
 				nsep->se_ctrladdr_in.sin_addr.s_addr = INADDR_ANY;
 			else if (!inet_aton(nsep->se_hostaddr, &nsep->se_ctrladdr_in.sin_addr)) {
 				struct hostent *hp;
diff --git a/networking/libiproute/ipaddress.c b/networking/libiproute/ipaddress.c
index 9fb08e6..e6130e4 100644
--- a/networking/libiproute/ipaddress.c
+++ b/networking/libiproute/ipaddress.c
@@ -678,7 +678,7 @@ static int ipaddr_modify(int cmd, int argc, char **argv)
 				if (brd_len) {
 					duparg("broadcast", *argv);
 				}
-				if (strcmp(*argv, "+") == 0) {
+				if (LONE_CHAR(*argv, '+')) {
 					brd_len = -1;
 				}
 				else if (LONE_DASH(*argv)) {
diff --git a/shell/ash.c b/shell/ash.c
index 97f0d6b..591e0a6 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -8172,7 +8172,7 @@ exitcmd(int argc, char **argv)
 static int
 echocmd(int argc, char **argv)
 {
-	return bb_echo(argc, argv);
+	return bb_echo(argv);
 }
 #endif
 
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