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
@@ -10,56 +10,64 @@ namespace opkele {
     using std::string;
     using std::vector;
 
     /**
      * @brief opkele utils namespace
      */
     namespace util {
 
         /**
          * Convert internal time representation to w3c format
          * @param t internal representation
          * @return w3c time
          * @throw failed_conversion in case of error
          */
         string time_to_w3c(time_t t);
         /**
          * Convert W3C time representation to  internal time_t
          * @param w w3c representation
          * @return converted time
          * @throw failed_conversion in case of error
          */
         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
          */
         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
          */
         string attr_escape(const string& str);
 
         /**
          * Convert number to string
          * @param l number
          * @return string representation
          * @throw failed_conversion in case of failure
          */
         string long_to_string(long l);
         /**
          * Convert string to number
          * @param s string, containing the number
          * @return the number
          * @throw failed_conversion in case of failure
          */
         long string_to_long(const string& s);
 
         /**
          * Encode binary data using base64.
          * @param data pointer to binary data
diff --git a/lib/util.cc b/lib/util.cc
index a6e08e2..3e7f3aa 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -171,48 +171,76 @@ namespace opkele {
             public:
                 string& rv;
 
                 __url_encoder(string& r) : rv(r) { }
 
                 result_type operator()(argument_type c) {
                     if(isrfc3986unreserved(c))
                         rv += c;
                     else{
                         char tmp[4];
                         snprintf(tmp,sizeof(tmp),"%%%02X",
                                 (c&0xff));
                         rv += tmp;
                     }
                 }
         };
 
         string url_encode(const string& str) {
             string rv;
             for_each(str.begin(),str.end(),
                     __url_encoder(rv));
             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;
             string::size_type p=0;
             while(true) {
                 string::size_type us = str.find_first_of(unsafechars,p);
                 if(us==string::npos) {
                     if(p!=str.length())
                         rv.append(str,p,str.length()-p);
                     return rv;
                 }
                 rv.append(str,p,us-p);
                 rv += "&#";
                 rv += long_to_string((long)str[us]);
                 rv += ';';
                 p = us+1;
             }
         }
 
         string long_to_string(long l) {
             char rv[32];
             int r=snprintf(rv,sizeof(rv),"%ld",l);
             if(r<0 || r>=(int)sizeof(rv))
                 throw failed_conversion(OPKELE_CP_ "failed to snprintf()");