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>

1 files changed, 18 insertions, 13 deletions

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}.