From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 17 Jul 2018 12:33:19 +0000 (+0200)
Subject: hush: faster/smaller code to check for presense of multiple chars in string
X-Git-Tag: 1_30_0~533
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=0d2e0de42bab54c31ba37f1c6fd10dcdc7008ccf;p=oweals%2Fbusybox.git

hush: faster/smaller code to check for presense of multiple chars in string

Go over the string only once.

function                                             old     new   delta
encode_then_expand_string                            126     105     -21
encode_then_expand_vararg                            443     399     -44
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-65)             Total: -65 bytes

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

diff --git a/shell/hush.c b/shell/hush.c
index 415993e71..238f997da 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -5730,14 +5730,17 @@ static char *encode_then_expand_string(const char *str)
 	char *exp_str;
 	struct in_str input;
 	o_string dest = NULL_O_STRING;
+	const char *cp;
 
-	if (!strchr(str, '$')
-	 && !strchr(str, '\\')
+	cp = str;
+	for (;;) {
+		if (!*cp) return NULL; /* string has no special chars */
+		if (*cp == '$') break;
+		if (*cp == '\\') break;
 #if ENABLE_HUSH_TICK
-	 && !strchr(str, '`')
+		if (*cp == '`') break;
 #endif
-	) {
-		return NULL;
+		cp++;
 	}
 
 	/* We need to expand. Example:
@@ -5768,17 +5771,19 @@ static char *encode_then_expand_vararg(const char *str, int handle_squotes, int
 	char *exp_str;
 	struct in_str input;
 	o_string dest = NULL_O_STRING;
+	const char *cp;
 
-	if (!strchr(str, '$')
-	 && !strchr(str, '\\')
-	 && !strchr(str, '\'')
-//todo:better code
-	 && !strchr(str, '"')
+	cp = str;
+	for (;;) {
+		if (!*cp) return NULL; /* string has no special chars */
+		if (*cp == '$') break;
+		if (*cp == '\\') break;
+		if (*cp == '\'') break;
+		if (*cp == '"') break;
 #if ENABLE_HUSH_TICK
-	 && !strchr(str, '`')
+		if (*cp == '`') break;
 #endif
-	) {
-		return NULL;
+		cp++;
 	}
 
 	/* Expanding ARG in ${var#ARG}, ${var%ARG}, or ${var/ARG/ARG}.