ucs2utf.pl

来自「postgresql8.3.4源码,开源数据库」· PL 代码 · 共 28 行

#
# Copyright (c) 2001-2008, PostgreSQL Global Development Group
#
# $PostgreSQL: pgsql/src/backend/utils/mb/Unicode/ucs2utf.pl,v 1.4 2008/01/01 19:45:53 momjian Exp $
# convert UCS-4 to UTF-8
#
sub ucs2utf {
	local($ucs) = @_;
	local $utf;

	if ($ucs <= 0x007f) {
		$utf = $ucs;
	} elsif ($ucs > 0x007f && $ucs <= 0x07ff) {
		$utf = (($ucs & 0x003f) | 0x80) | ((($ucs >> 6) | 0xc0) << 8);
	} elsif ($ucs > 0x07ff && $ucs <= 0xffff) {
		$utf = ((($ucs >> 12) | 0xe0) << 16) | 
			(((($ucs & 0x0fc0) >> 6) | 0x80) << 8) |
				(($ucs & 0x003f) | 0x80);
	} else {
	   $utf = ((($ucs >> 18) | 0xf0) << 24) |
		   (((($ucs & 0x3ffff) >> 12) | 0x80) << 16) |		  
		   (((($ucs & 0x0fc0) >> 6) | 0x80) << 8) |
		   (($ucs & 0x003f) | 0x80);
    }
	return($utf);
}
1;