Implement 'string-utf8-length' and 'scm_c_string_utf8_length'.

* libguile/strings.c (utf8_length, scm_c_string_utf8_length)
  (scm_string_utf8_length): New functions.
* libguile/strings.h (scm_c_string_utf8_length, scm_string_utf8_length):
  New prototypes.
* doc/ref/api-data.texi (Bytevectors as Strings): Add docs.
* doc/ref/guile.texi: Update manual copyright date to 2015.
* test-suite/tests/strings.test (string-utf8-length): Add tests.

1 files changed, 18 insertions, 2 deletions

diff --git a/test-suite/tests/strings.test b/test-suite/tests/strings.test
index 56c898c8b..66c8a6b95 100644
--- a/test-suite/tests/strings.test
+++ b/test-suite/tests/strings.test
@@ -1,8 +1,8 @@
 ;;;; strings.test --- test suite for Guile's string functions    -*- scheme -*-
 ;;;; Jim Blandy <jimb@red-bean.com> --- August 1999
 ;;;;
-;;;; Copyright (C) 1999, 2001, 2004, 2005, 2006, 2008, 2009, 2010,
-;;;;   2011, 2013 Free Software Foundation, Inc.
+;;;; Copyright (C) 1999, 2001, 2004-2006, 2008-2011, 2013,
+;;;;   2015 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -458,6 +458,22 @@
     (equal? (string-normalize-nfkc "\u1e9b\u0323") "\u1e69")))
 
 ;;
+;; string-utf8-length
+;;
+
+(with-test-prefix "string-utf8-length"
+
+  (pass-if-exception "wrong type argument"
+      exception:wrong-type-arg
+    (string-utf8-length 50))
+
+  (pass-if-equal 0 (string-utf8-length ""))
+  (pass-if-equal 1 (string-utf8-length "\0"))
+  (pass-if-equal 5 (string-utf8-length "hello"))
+  (pass-if-equal 7 (string-utf8-length "helloλ"))
+  (pass-if-equal 9 (string-utf8-length "ሠላም")))
+
+;;
 ;; string-ref
 ;;