--- ./parser.c_orig	2013-01-22 17:10:44.897083508 +0530
+++ ./parser.c	2013-01-22 17:13:32.021087488 +0530
@@ -3922,7 +3922,7 @@
 	c = CUR_CHAR(l);
     }
     if ((in_space) && (normalize)) {
-        while (buf[len - 1] == 0x20) len--;
+        while ((len > 0) && (buf[len - 1] == 0x20)) len--;
     }
     buf[len] = 0;
     if (RAW == '<') {