--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/druntime/src/compiler/dmd/util/ctype.d	Tue Jun 02 17:43:06 2009 +0100
@@ -0,0 +1,92 @@
+/**
+ * Simple ASCII char classification functions.
+ *
+ * Copyright: Copyright Digital Mars 2004 - 2009.
+ * License:   <a href="http://www.boost.org/LICENSE_1_0.txt>Boost License 1.0</a>.
+ * Authors:   Walter Bright
+ *
+ *          Copyright Digital Mars 2004 - 2009.
+ * Distributed under the Boost Software License, Version 1.0.
+ *    (See accompanying file LICENSE_1_0.txt or copy at
+ *          http://www.boost.org/LICENSE_1_0.txt)
+ */
+module rt.util.ctype;
+
+int isalnum(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_ALP|_DIG) : 0; }
+int isalpha(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_ALP)      : 0; }
+int iscntrl(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_CTL)      : 0; }
+int isdigit(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_DIG)      : 0; }
+int islower(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_LC)       : 0; }
+int ispunct(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_PNC)      : 0; }
+int isspace(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_SPC)      : 0; }
+int isupper(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_UC)       : 0; }
+int isxdigit(dchar c) { return (c <= 0x7F) ? _ctype[c] & (_HEX)      : 0; }
+int isgraph(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_ALP|_DIG|_PNC) : 0; }
+int isprint(dchar c)  { return (c <= 0x7F) ? _ctype[c] & (_ALP|_DIG|_PNC|_BLK) : 0; }
+int isascii(dchar c)  { return c <= 0x7F; }
+
+dchar tolower(dchar c)
+out (result)
+{
+    assert(!isupper(result));
+}
+body
+{
+    return isupper(c) ? c + (cast(dchar)'a' - 'A') : c;
+}
+
+dchar toupper(dchar c)
+out (result)
+{
+    assert(!islower(result));
+}
+body
+{
+    return islower(c) ? c - (cast(dchar)'a' - 'A') : c;
+}
+
+private:
+
+enum
+{
+    _SPC =	8,
+    _CTL =	0x20,
+    _BLK =	0x40,
+    _HEX =	0x80,
+    _UC  =	1,
+    _LC  =	2,
+    _PNC =	0x10,
+    _DIG =	4,
+    _ALP =	_UC|_LC,
+}
+
+immutable ubyte _ctype[128] =
+[
+	_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,
+	_CTL,_CTL|_SPC,_CTL|_SPC,_CTL|_SPC,_CTL|_SPC,_CTL|_SPC,_CTL,_CTL,
+	_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,
+	_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,_CTL,
+	_SPC|_BLK,_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,
+	_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,
+	_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,
+	_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,_DIG|_HEX,
+	_PNC,_PNC,_PNC,_PNC,_PNC,_PNC,
+	_PNC,_UC|_HEX,_UC|_HEX,_UC|_HEX,_UC|_HEX,_UC|_HEX,_UC|_HEX,_UC,
+	_UC,_UC,_UC,_UC,_UC,_UC,_UC,_UC,
+	_UC,_UC,_UC,_UC,_UC,_UC,_UC,_UC,
+	_UC,_UC,_UC,_PNC,_PNC,_PNC,_PNC,_PNC,
+	_PNC,_LC|_HEX,_LC|_HEX,_LC|_HEX,_LC|_HEX,_LC|_HEX,_LC|_HEX,_LC,
+	_LC,_LC,_LC,_LC,_LC,_LC,_LC,_LC,
+	_LC,_LC,_LC,_LC,_LC,_LC,_LC,_LC,
+	_LC,_LC,_LC,_PNC,_PNC,_PNC,_PNC,_CTL
+];
+
+
+unittest
+{
+    assert(isspace(' '));
+    assert(!isspace('z'));
+    assert(toupper('a') == 'A');
+    assert(tolower('Q') == 'q');
+    assert(!isxdigit('G'));
+}