diff --git a/urjtag/ChangeLog b/urjtag/ChangeLog
index ffd3e510..904ea7f4 100644
--- a/urjtag/ChangeLog
+++ b/urjtag/ChangeLog
@@ -4,6 +4,10 @@
     whatever pkg-config tells us.  Also allow libusb-1.0 + ftdi w/out async
     since it isn't required for things to work.
 
+  * src/svf/svf_flex.l: Have align_string return the length of the string to
+    the caller, and have the callers re-use that.  This avoids useless overhead
+    of calling strlen() over and over.  Fix by Frans Meulenbroeks.
+
 2010-08-26  Mike Frysinger  <vapier@gentoo.org>
 
   * src/tap/cable/gpio.c: Rewrite to use raw file descriptors when working with
diff --git a/urjtag/src/svf/svf_flex.l b/urjtag/src/svf/svf_flex.l
index 37e996ae..ad197633 100644
--- a/urjtag/src/svf/svf_flex.l
+++ b/urjtag/src/svf/svf_flex.l
@@ -49,7 +49,7 @@
 #define YY_EXTRA_TYPE urj_svf_scanner_extra_t *
 
 static int map_keyw_ident(YYSTYPE *, char *);
-static void align_string(char *);
+static int align_string(char *);
 
 static void fix_yylloc(YYLTYPE *, char *);
 static void fix_yylloc_nl(YYLTYPE *, char *, YY_EXTRA_TYPE);
@@ -143,11 +143,12 @@ COMMENT         (!.*)|("//".*)[^\n]
      This is enabled with <expect_vector>. */
   /* token is a vector string */
   char *cstring;
+  int len;
 
   fix_yylloc_nl(yylloc, yytext, yyget_extra(yyscanner));
-  align_string(yytext);
+  len = align_string(yytext);
 
-  cstring = malloc(strlen(yytext) + 1);
+  cstring = malloc(len + 1);
   strcpy(cstring, yytext);
   yylval->cvalue = cstring;
   return(VECTOR_STRING);
@@ -161,13 +162,16 @@ COMMENT         (!.*)|("//".*)[^\n]
      1024 is chosen arbitrarily, increasing to e.g. 4096 enhances scanner
      performance, trading off against huge table sizes.
      This whole strategy needs to be revisited with support of flex experts.
+     Actually svf files generated by Quartus II SVF converter 10.0 have 
+     fragments of 255 bytes as that is the data on a line
   */
   char *cstring;
+  int len;
 
   fix_yylloc_nl(yylloc, yytext, yyget_extra(yyscanner));
-  align_string(yytext);
+  len = align_string(yytext);
 
-  cstring = (char *)malloc(strlen(yytext) + 1);
+  cstring = (char *)malloc(len + 1);
   strcpy(cstring, yytext);
   yylval->cvalue = cstring;
   return(HEXA_NUM_FRAGMENT);
@@ -333,20 +337,19 @@ map_keyw_ident (YYSTYPE *mylval, char *str)
 }
 
 
-static void
+static int
 align_string (char *str)
 {
-    int src, dst, len;
-
-    dst = 0;
-    len = strlen (str);
+    char *src = str;
+    char *dst;
 
-    for (src = 0; src < len; src++)
+    for (dst = src; *src; src++)
     {
-        if (isxdigit (str[src]))
-            str[dst++] = str[src];
+        if (isxdigit (*src))
+	    *dst++ = *src;
     }
-    str[dst] = '\0';
+    *dst = '\0';
+    return (dst - str);
 }