Adding a helper function that translates single characters in a string.

src/libstrongswan/utils.h

@@ -310,6 +310,14 @@ void memxor(u_int8_t dest[], u_int8_t src[], size_t n);
  */
 void *memstr(const void *haystack, const char *needle, size_t n);
 
+/**
+ * Translates the characters in the given string, searching for characters
+ * in 'from' and mapping them to characters in 'to'.
+ * The two characters sets 'from' and 'to' must contain the same number of
+ * characters.
+ */
+char *translate(char *str, const char *from, const char *to);
+
 /**
  * Creates a directory and all required parent directories.
  *