39871: cut down number of strlen()s in getstrvalue()

3 files changed, 32 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index e89b0c616..629a7a5b7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2016-11-08  Peter Stephenson  <p.stephenson@samsung.com>
+
+	* Sebastian: 39871: cut down number of strlen()s in getstrvalue().
+
 2016-11-08  Jun-ichi Takimoto <takimoto-j@kba.biglobe.ne.jp>
 
 	* 39857: Completion/Unix/Command/_top: add support for darwin,
@@ -5,8 +9,8 @@
 
 2016-11-08  Peter Stephenson  <p.stephenson@samsung.com>
 
-	* Src/builtin.c, Test/C03traps.ztst: ensure exit trap can always
-	run.
+	* 39870: Src/builtin.c, Test/C03traps.ztst: ensure exit trap can
+	always run.
 
 	* unposted: Src/utils.c: follow up to 39867: don't need test
 	against zero any more.
diff --git a/Src/params.c b/Src/params.c
index 0894241b9..19a8c291d 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2060,6 +2060,7 @@ getstrvalue(Value v)
 {
     char *s, **ss;
     char buf[BDIGBUFSIZE];
+    int len = -1;
 
     if (!v)
 	return hcalloc(1);
@@ -2237,22 +2238,30 @@ getstrvalue(Value v)
 	return s;
 
     if (v->start < 0) {
-	v->start += strlen(s);
+	len = strlen(s);
+	v->start += len;
 	if (v->start < 0)
 	    v->start = 0;
     }
     if (v->end < 0) {
-	v->end += strlen(s);
+	if (len < 0)
+	    len = strlen(s);
+	v->end += len;
 	if (v->end >= 0) {
 	    char *eptr = s + v->end;
 	    if (*eptr)
 		v->end += MB_METACHARLEN(eptr);
 	}
     }
-    s = (v->start > (int)strlen(s)) ? dupstring("") : dupstring(s + v->start);
+
+    if (len < 0)
+	len = strlen(s);
+    s = (v->start > len) ? dupstring("") :
+	dupstring_wlen(s + v->start, len - v->start);
+
     if (v->end <= v->start)
 	s[0] = '\0';
-    else if (v->end - v->start <= (int)strlen(s))
+    else if (v->end - v->start <= len - v->start)
 	s[v->end - v->start] = '\0';
 
     return s;
diff --git a/Src/string.c b/Src/string.c
index 04e7446c9..b46ea60cf 100644
--- a/Src/string.c
+++ b/Src/string.c
@@ -43,6 +43,19 @@ dupstring(const char *s)
 
 /**/
 mod_export char *
+dupstring_wlen(const char *s, unsigned len)
+{
+    char *t;
+
+    if (!s)
+	return NULL;
+    t = (char *) zhalloc(len + 1);
+    strcpy(t, s);
+    return t;
+}
+
+/**/
+mod_export char *
 ztrdup(const char *s)
 {
     char *t;