aded util::url_decode()

Signed-off-by: Michael Krelin <hacker@klever.net>

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;