I18N

- One does not simply std::string::substr a UTF8 string, like a bloody caveman.
  Implemented utf8_substr, and added unit tests.

test/utf8.t.cpp

@@ -0,0 +1,58 @@
+////////////////////////////////////////////////////////////////////////////////
+// taskwarrior - a command line task list manager.
+//
+// Copyright 2006-2012, Paul Beckingham, Federico Hernandez.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// http://www.opensource.org/licenses/mit-license.php
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <iostream>
+#include <utf8.h>
+#include <test.h>
+
+////////////////////////////////////////////////////////////////////////////////
+int main (int argc, char** argv)
+{
+  UnitTest t (4);
+
+  std::string ascii_text = "This is a test";
+  std::string utf8_text  = "más sábado miércoles";
+
+  // TODO unsigned int utf8_codepoint (const std::string&);
+  // TODO unsigned int utf8_next_char (const std::string&, std::string::size_type&);
+  // TODO std::string utf8_character (unsigned int);
+  // TODO int utf8_sequence (unsigned int);
+
+  // unsigned int utf8_length (const std::string&);
+  t.is (utf8_length (ascii_text), 14, "ASCII utf8_length");
+  t.is (utf8_length (utf8_text),  20, "UTF8 utf8_length");
+
+  // TODO unsigned int utf8_text_length (const std::string&);
+
+  // const std::string utf8_substr (const std::string&, unsigned int, unsigned int length = 0);
+  t.is (utf8_substr (ascii_text, 0, 2), "Th", "ASCII utf8_substr");
+  t.is (utf8_substr (utf8_text, 0, 2),  "má", "UTF8 utf8_substr");
+
+  return 0;
+}
+
+////////////////////////////////////////////////////////////////////////////////