ENH: Add cmCTest::DecodeURL method

This new method decodes the "percent-encoding" used in URL syntax.

Source/cmCTest.cxx

@@ -47,6 +47,7 @@
 #include <stdlib.h>
 #include <math.h>
 #include <float.h>
+#include <ctype.h>
 
 #include <memory> // auto_ptr
 
@@ -180,6 +181,26 @@ std::string cmCTest::MakeURLSafe(const std::string& str)
   return ost.str();
 }
 
+//----------------------------------------------------------------------------
+std::string cmCTest::DecodeURL(const std::string& in)
+{
+  std::string out;
+  for(const char* c = in.c_str(); *c; ++c)
+    {
+    if(*c == '%' && isxdigit(*(c+1)) && isxdigit(*(c+2)))
+      {
+      char buf[3] = {*(c+1), *(c+2), 0};
+      out.append(1, char(strtoul(buf, 0, 16)));
+      c += 2;
+      }
+    else
+      {
+      out.append(1, *c);
+      }
+    }
+  return out;
+}
+
 //----------------------------------------------------------------------
 cmCTest::cmCTest()
 {

Source/cmCTest.h

@@ -310,6 +310,9 @@ public:
   //! Make string safe to be send as an URL
   static std::string MakeURLSafe(const std::string&);
 
+  /** Decode a URL to the original string.  */
+  static std::string DecodeURL(const std::string&);
+
   //! Should ctect configuration be updated. When using new style ctest
   // script, this should be true.
   void SetSuppressUpdatingCTestConfiguration(bool val)