2 files changed, 37 insertions, 1 deletions

diff --git a/include/opkele/util.h b/include/opkele/util.h
index fd974a1..0130bff 100644
--- a/include/opkele/util.h
+++ b/include/opkele/util.h
@@ -31,7 +31,7 @@ namespace opkele {
         time_t w3c_to_time(const string& w);
 
         /**
-         * Encode string to the representation suitable for using in URL.
+         * Encode string to the representation suitable for using in URL
          * @param str string to encode
          * @return encoded string
          * @throw failed_conversion in case of failure
@@ -39,6 +39,14 @@ namespace opkele {
         string url_encode(const string& str);
 
         /**
+         * Decode url-encoded string back to normal
+         * @param str url-encoded string
+         * @return decoded string
+         * @throw failed_conversion in case of failure
+         */
+        string url_decode(const string& str);
+
+        /**
          * Make string suitable for using as x(ht)ml attribute.
          * @param str string to escape
          * @return escaped string
diff --git a/lib/util.cc b/lib/util.cc
index a6e08e2..3e7f3aa 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -192,6 +192,34 @@ namespace opkele {
             return rv;
         }
 
+        string url_decode(const string& str) {
+            string rv;
+            back_insert_iterator<string> ii(rv);
+            for(string::const_iterator i=str.begin(),ie=str.end();
+                    i!=ie;++i) {
+                switch(*i) {
+                    case '+':
+                        *(ii++) = ' '; break;
+                    case '%':
+                        ++i;
+                        static char tmp[3] = {0,0,0};
+                        if(i==ie)
+                            throw failed_conversion(OPKELE_CP_ "trailing percent in the url-encoded string");
+                        tmp[0] == *(i++);
+                        if(i==ie)
+                            throw failed_conversion(OPKELE_CP_ "not enough hexadecimals after the percent sign in url-encoded string");
+                        tmp[1] == *i;
+                        if(!(isxdigit(tmp[0]) && isxdigit(tmp[1])))
+                            throw failed_conversion(OPKELE_CP_ "non-hex follows percent in url-encoded string");
+                        *(ii++) = strtol(tmp,0,16);
+                        break;
+                    default:
+                        *(ii++) = *i; break;
+                }
+            }
+            return rv;
+        }
+
         string attr_escape(const string& str) {
             static const char *unsafechars = "<>&\n\"'";
             string rv;