utf_tools.php

这些都是我以前学习是用到的源码

<?php
/** 
*
* @package phpBB3
* @version $Id: utf_tools.php,v 1.31 2006/11/26 13:07:43 acydburn Exp $
* @copyright (c) 2006 phpBB Group 
* @license http://opensource.org/licenses/gpl-license.php GNU Public License 
*
* @todo make sure the replacements are called correctly
* already done: strtolower, strtoupper, ucfirst, str_split, strrpos, strlen (hopefully!), strpos, substr, htmlspecialchars
* remaining:	strspn, chr, ord
*/

/**
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

/**
* UTF-8 tools
*
* Whenever possible, these functions will try to use PHP's built-in functions or
* extensions, otherwise they will default to custom routines.
*
* @package phpBB3
*/

if (!extension_loaded('xml'))
{
	/**
	* Implementation of PHP's native utf8_encode for people without XML support
	* This function exploits some nice things that ISO-8859-1 and UTF-8 have in common
	*
	* @param string $str ISO-8859-1 encoded data
	* @return string UTF-8 encoded data
	*/
	function utf8_encode($str)
	{
		$out = '';
		for ($i = 0, $len = strlen($str); $i < $len; $i++)
		{
			$letter = $str[$i];
			$num = ord($letter);
			if ($num < 0x80)
			{
				$out .= $letter;
			}
			else if ($num < 0xC0)
			{
				$out .= "\xC2" . $letter;
			}
			else
			{
				$out .= "\xC3" . chr($num - 64);
			}
		}
		return $out;
	}

	/**
	* Implementation of PHP's native utf8_decode for people without XML support
	*
	* @param string $str UTF-8 encoded data
	* @return string ISO-8859-1 encoded data
	*/
	function utf8_decode($str)
	{
		$pos = 0;
		$len = strlen($str);
		$ret = '';
	
		while ($pos < $len)
		{
			$ord = ord($str[$pos]) & 0xF0;
			if ($ord === 0xC0 || $ord === 0xD0)
			{
				$charval = ((ord($str[$pos]) & 0x1F) << 6) | (ord($str[$pos + 1]) & 0x3F);
				$pos += 2;
				$ret .= (($charval < 256) ? chr($charval) : '?');
			}
			else if ($ord === 0xE0)
			{
				$ret .= '?';
				$pos += 3;
			}
			else if ($ord === 0xF0)
			{
				$ret .= '?';
				$pos += 4;
			}
			else
			{
				$ret .= $str[$pos];
				++$pos;
			}
		}
		return $ret;
	}
}

// mbstring is old and has it's functions around for older versions of PHP.
// if mbstring is not loaded, we go into native mode.
if (extension_loaded('mbstring'))
{
	/**
	* UTF-8 aware alternative to strrpos
	* Find position of last occurrence of a char in a string
	*
	* Notes:
	* - offset for mb_strrpos was added in 5.2.0, we emulate if it is lower
	*/
	if (version_compare(phpversion(), '5.2.0', '>='))
	{
		/**
		* UTF-8 aware alternative to strrpos
		* @ignore
		*/
		function utf8_strrpos($str,	$needle, $offset = null)
		{
			// Emulate behaviour of strrpos rather than raising warning
			if (empty($str))
			{
				return false;
			}

			if (is_null($offset))
			{
				return mb_strrpos($str, $needle);
			}
			else
			{
				return mb_strrpos($str, $needle, $offset);
			}
		}
	}
	else
	{
		/**
		* UTF-8 aware alternative to strrpos
		* @ignore
		*/
		function utf8_strrpos($str,	$needle, $offset = null)
		{
			// offset for mb_strrpos was added in 5.2.0
			if (is_null($offset))
			{
				// Emulate behaviour of strrpos rather than raising warning
				if (empty($str))
				{
					return false;
				}

				return mb_strrpos($str, $needle);
			}
			else
			{
				if (!is_int($offset))
				{
					trigger_error('utf8_strrpos expects parameter 3 to be long', E_USER_WARNING);
					return false;
				}

				$str = mb_substr($str, $offset);

				if (false !== ($pos = mb_strrpos($str, $needle)))
				{
					return $pos + $offset;
				}

				return false;
			}
		}
	}

	/**
	* UTF-8 aware alternative to strpos
	* @ignore
	*/
	function utf8_strpos($str, $needle, $offset = null)
	{
		if (is_null($offset))
		{
			return mb_strpos($str, $needle);
		}
		else
		{
			return mb_strpos($str, $needle, $offset);
		}
	}

	/**
	* UTF-8 aware alternative to strtolower
	* @ignore
	*/
	function utf8_strtolower($str)
	{
		return mb_strtolower($str);
	}

	/**
	* UTF-8 aware alternative to strtoupper
	* @ignore
	*/
	function utf8_strtoupper($str)
	{
		return mb_strtoupper($str);
	}

	/**
	* UTF-8 aware alternative to substr
	* @ignore
	*/
	function utf8_substr($str, $offset, $length = null)
	{
		if (is_null($length))
		{
			return mb_substr($str, $offset);
		}
		else
		{
			return mb_substr($str, $offset, $length);
		}
	}

	/**
	* Return the length (in characters) of a UTF-8 string
	* @ignore
	*/
	function utf8_strlen($text)
	{
		return mb_strlen($text, 'utf-8');
	}
}
else
{
	/**
	* UTF-8 aware alternative to strrpos
	* Find position of last occurrence of a char in a string
	* 
	* @author Harry Fuecks
	* @param string $str haystack
	* @param string $needle needle
	* @param integer $offset (optional) offset (from left)
	* @return mixed integer position or FALSE on failure
	*/
	function utf8_strrpos($str,	$needle, $offset = null)
	{
		if (is_null($offset))
		{
			$ar	= explode($needle, $str);
			
			if (sizeof($ar) > 1)
			{
				// Pop off the end of the string where the last	match was made
				array_pop($ar);
				$str = join($needle, $ar);

				return utf8_strlen($str);
			}
			return false;
		}
		else
		{
			if (!is_int($offset))
			{
				trigger_error('utf8_strrpos	expects	parameter 3	to be long', E_USER_WARNING);
				return false;
			}

			$str = utf8_substr($str, $offset);

			if (false !== ($pos = utf8_strrpos($str, $needle)))
			{
				return $pos	+ $offset;
			}

			return false;
		}
	}

	/**
	* UTF-8 aware alternative to strpos
	* Find position of first occurrence of a string
	*
	* @author Harry Fuecks
	* @param string $str haystack
	* @param string $needle needle
	* @param integer $offset offset in characters (from left)
	* @return mixed integer position or FALSE on failure
	*/
	function utf8_strpos($str, $needle, $offset = null)
	{
		if (is_null($offset))
		{
			$ar = explode($needle, $str);
			if (sizeof($ar) > 1)
			{
				return utf8_strlen($ar[0]);
			}
			return false;
		}
		else
		{
			if (!is_int($offset))
			{
				trigger_error('utf8_strpos:  Offset must  be an integer', E_USER_ERROR);
				return false;
			}

			$str = utf8_substr($str, $offset);

			if (false !== ($pos = utf8_strpos($str, $needle)))
			{
				return $pos + $offset;
			}

			return false;
		}
	}

	$UTF8_UPPER_TO_LOWER = array(
		"\x41" => "\x61", "\x42" => "\x62", "\x43" => "\x63", "\x44" => "\x64",
		"\x45" => "\x65", "\x46" => "\x66", "\x47" => "\x67", "\x48" => "\x68",
		"\x49" => "\x69", "\x4A" => "\x6A", "\x4B" => "\x6B", "\x4C" => "\x6C",
		"\x4D" => "\x6D", "\x4E" => "\x6E", "\x4F" => "\x6F", "\x50" => "\x70",
		"\x51" => "\x71", "\x52" => "\x72", "\x53" => "\x73", "\x54" => "\x74",
		"\x55" => "\x75", "\x56" => "\x76", "\x57" => "\x77", "\x58" => "\x78",
		"\x59" => "\x79", "\x5A" => "\x7A", "\xC3\x80" => "\xC3\xA0", "\xC3\x81" => "\xC3\xA1",
		"\xC3\x82" => "\xC3\xA2", "\xC3\x83" => "\xC3\xA3", "\xC3\x84" => "\xC3\xA4", "\xC3\x85" => "\xC3\xA5",
		"\xC3\x86" => "\xC3\xA6", "\xC3\x87" => "\xC3\xA7", "\xC3\x88" => "\xC3\xA8", "\xC3\x89" => "\xC3\xA9",
		"\xC3\x8A" => "\xC3\xAA", "\xC3\x8B" => "\xC3\xAB", "\xC3\x8C" => "\xC3\xAC", "\xC3\x8D" => "\xC3\xAD",
		"\xC3\x8E" => "\xC3\xAE", "\xC3\x8F" => "\xC3\xAF", "\xC3\x90" => "\xC3\xB0", "\xC3\x91" => "\xC3\xB1",
		"\xC3\x92" => "\xC3\xB2", "\xC3\x93" => "\xC3\xB3", "\xC3\x94" => "\xC3\xB4", "\xC3\x95" => "\xC3\xB5",
		"\xC3\x96" => "\xC3\xB6", "\xC3\x98" => "\xC3\xB8", "\xC3\x99" => "\xC3\xB9", "\xC3\x9A" => "\xC3\xBA",
		"\xC3\x9B" => "\xC3\xBB", "\xC3\x9C" => "\xC3\xBC", "\xC3\x9D" => "\xC3\xBD", "\xC3\x9E" => "\xC3\xBE",
		"\xC4\x80" => "\xC4\x81", "\xC4\x82" => "\xC4\x83", "\xC4\x84" => "\xC4\x85", "\xC4\x86" => "\xC4\x87",
		"\xC4\x88" => "\xC4\x89", "\xC4\x8A" => "\xC4\x8B", "\xC4\x8C" => "\xC4\x8D", "\xC4\x8E" => "\xC4\x8F",
		"\xC4\x90" => "\xC4\x91", "\xC4\x92" => "\xC4\x93", "\xC4\x96" => "\xC4\x97", "\xC4\x98" => "\xC4\x99",