hush: tweak ${var/pattern/repl} optimization

function                                             old     new   delta
expand_one_var                                      2507    2502      -5

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

1 files changed, 4 insertions, 5 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 179155f66..c970d9097 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -6466,17 +6466,16 @@ static arith_t expand_and_evaluate_arith(const char *arg, const char **errmsg_p)
 /* ${var/[/]pattern[/repl]} helpers */
 static char *strstr_pattern(char *val, const char *pattern, int *size)
 {
-        if (!strpbrk(pattern, "*?[\\")) {
+        int sz = strcspn(pattern, "*?[\\");
+        if (pattern[sz] == '\0') {
                 /* Optimization for trivial patterns.
                  * Testcase for very slow replace (performs about 22k replaces):
                  * x=::::::::::::::::::::::
                  * x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;x=$x$x;echo ${#x}
                  * echo "${x//:/|}"
                  */
-                char *found = strstr(val, pattern);
-                if (found)
-                        *size = strlen(pattern);
-                return found;
+                *size = sz;
+                return strstr(val, pattern);
         }
 
         while (1) {