source: trunk/web/punbb/include/utf8/utils/bad.php @ 10

<?php

/**
* @version $Id: bad.php,v 1.2 2006/02/26 13:20:44 harryf Exp $
* Tools for locating / replacing bad bytes in UTF-8 strings
* The Original Code is Mozilla Communicator client code.
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
* Ported to PHP by Henri Sivonen (http://hsivonen.iki.fi)
* Slight modifications to fit with phputf8 library by Harry Fuecks (hfuecks gmail com)
* @see http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUTF8ToUnicode.cpp
* @see http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUnicodeToUTF8.cpp
* @see http://hsivonen.iki.fi/php-utf8/
* @package utf8
* @subpackage bad
* @see utf8_is_valid
*/

/**
* Locates the first bad byte in a UTF-8 string returning it's
* byte index in the string
* PCRE Pattern to locate bad bytes in a UTF-8 string
* Comes from W3 FAQ: Multilingual Forms
* Note: modified to include full ASCII range including control chars
* @see http://www.w3.org/International/questions/qa-forms-utf-8
* @param string
* @return mixed integer byte index or FALSE if no bad found
* @package utf8
* @subpackage bad
*/
function utf8_bad_find($str)
{
        $UTF8_BAD =
                '([\x00-\x7F]'.                          # ASCII (including control chars)
                '|[\xC2-\xDF][\x80-\xBF]'.               # Non-overlong 2-byte
                '|\xE0[\xA0-\xBF][\x80-\xBF]'.           # Excluding overlongs
                '|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}'.    # Straight 3-byte
                '|\xED[\x80-\x9F][\x80-\xBF]'.           # Excluding surrogates
                '|\xF0[\x90-\xBF][\x80-\xBF]{2}'.        # Planes 1-3
                '|[\xF1-\xF3][\x80-\xBF]{3}'.            # Planes 4-15
                '|\xF4[\x80-\x8F][\x80-\xBF]{2}'.        # Plane 16
                '|(.{1}))';                              # Invalid byte
        $pos = 0;
        $badList = array();

        while (preg_match('/'.$UTF8_BAD.'/S', $str, $matches))
        {
                $bytes = strlen($matches[0]);

                if (isset($matches[2]))
                        return $pos;

                $pos += $bytes;
                $str = substr($str,$bytes);
        }

        return false;
}

/**
* Locates all bad bytes in a UTF-8 string and returns a list of their
* byte index in the string
* PCRE Pattern to locate bad bytes in a UTF-8 string
* Comes from W3 FAQ: Multilingual Forms
* Note: modified to include full ASCII range including control chars
* @see http://www.w3.org/International/questions/qa-forms-utf-8
* @param string
* @return mixed array of integers or FALSE if no bad found
* @package utf8
* @subpackage bad
*/
function utf8_bad_findall($str)
{
        $UTF8_BAD =
                '([\x00-\x7F]'.                          # ASCII (including control chars)
                '|[\xC2-\xDF][\x80-\xBF]'.               # Non-overlong 2-byte
                '|\xE0[\xA0-\xBF][\x80-\xBF]'.           # Excluding overlongs
                '|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}'.    # Straight 3-byte
                '|\xED[\x80-\x9F][\x80-\xBF]'.           # Excluding surrogates
                '|\xF0[\x90-\xBF][\x80-\xBF]{2}'.        # Planes 1-3
                '|[\xF1-\xF3][\x80-\xBF]{3}'.            # Planes 4-15
                '|\xF4[\x80-\x8F][\x80-\xBF]{2}'.        # Plane 16
                '|(.{1}))';                              # Invalid byte
        $pos = 0;
        $badList = array();

        while (preg_match('/'.$UTF8_BAD.'/S', $str, $matches))
        {
                $bytes = strlen($matches[0]);

                if (isset($matches[2]))
                        $badList[] = $pos;

                $pos += $bytes;
                $str = substr($str,$bytes);
        }

        if (count($badList) > 0)
                return $badList;

        return false;
}

/**
* Strips out any bad bytes from a UTF-8 string and returns the rest
* PCRE Pattern to locate bad bytes in a UTF-8 string
* Comes from W3 FAQ: Multilingual Forms
* Note: modified to include full ASCII range including control chars
* @see http://www.w3.org/International/questions/qa-forms-utf-8
* @param string
* @return string
* @package utf8
* @subpackage bad
*/
function utf8_bad_strip($str)
{
        $UTF8_BAD =
                '([\x00-\x7F]'.                          # ASCII (including control chars)
                '|[\xC2-\xDF][\x80-\xBF]'.               # Non-overlong 2-byte
                '|\xE0[\xA0-\xBF][\x80-\xBF]'.           # Excluding overlongs
                '|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}'.    # Straight 3-byte
                '|\xED[\x80-\x9F][\x80-\xBF]'.           # Excluding surrogates
                '|\xF0[\x90-\xBF][\x80-\xBF]{2}'.        # Planes 1-3
                '|[\xF1-\xF3][\x80-\xBF]{3}'.            # Planes 4-15
                '|\xF4[\x80-\x8F][\x80-\xBF]{2}'.        # Plane 16
                '|(.{1}))';                              # Invalid byte

        ob_start();

        while (preg_match('/'.$UTF8_BAD.'/S', $str, $matches))
        {
                if (!isset($matches[2]))
                        echo $matches[0];

                $str = substr($str, strlen($matches[0]));
        }

        $result = ob_get_contents();
        ob_end_clean();

        return $result;
}

/**
* Replace bad bytes with an alternative character - ASCII character
* recommended is replacement char
* PCRE Pattern to locate bad bytes in a UTF-8 string
* Comes from W3 FAQ: Multilingual Forms
* Note: modified to include full ASCII range including control chars
* @see http://www.w3.org/International/questions/qa-forms-utf-8
* @param string to search
* @param string to replace bad bytes with (defaults to '?') - use ASCII
* @return string
* @package utf8
* @subpackage bad
*/
function utf8_bad_replace($str, $replace='?')
{
        $UTF8_BAD =
                '([\x00-\x7F]'.                          # ASCII (including control chars)
                '|[\xC2-\xDF][\x80-\xBF]'.               # Non-overlong 2-byte
                '|\xE0[\xA0-\xBF][\x80-\xBF]'.           # Excluding overlongs
                '|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}'.    # Straight 3-byte
                '|\xED[\x80-\x9F][\x80-\xBF]'.           # Excluding surrogates
                '|\xF0[\x90-\xBF][\x80-\xBF]{2}'.        # Planes 1-3
                '|[\xF1-\xF3][\x80-\xBF]{3}'.            # Planes 4-15
                '|\xF4[\x80-\x8F][\x80-\xBF]{2}'.        # Plane 16
                '|(.{1}))';                              # Invalid byte

        ob_start();

        while (preg_match('/'.$UTF8_BAD.'/S', $str, $matches))
        {
                if (!isset($matches[2]))
                        echo $matches[0];
                else
                        echo $replace;

                $str = substr($str, strlen($matches[0]));
        }

        $result = ob_get_contents();
        ob_end_clean();

        return $result;
}

/**
* Return code from utf8_bad_identify() when a five octet sequence is detected.
* Note: 5 octets sequences are valid UTF-8 but are not supported by Unicode so
* do not represent a useful character
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_5OCTET', 1);

/**
* Return code from utf8_bad_identify() when a six octet sequence is detected.
* Note: 6 octets sequences are valid UTF-8 but are not supported by Unicode so
* do not represent a useful character
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_6OCTET', 2);

/**
* Return code from utf8_bad_identify().
* Invalid octet for use as start of multi-byte UTF-8 sequence
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_SEQID', 3);

/**
* Return code from utf8_bad_identify().
* From Unicode 3.1, non-shortest form is illegal
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_NONSHORT', 4);

/**
* Return code from utf8_bad_identify().
* From Unicode 3.2, surrogate characters are illegal
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_SURROGATE', 5);

/**
* Return code from utf8_bad_identify().
* Codepoints outside the Unicode range are illegal
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_UNIOUTRANGE', 6);

/**
* Return code from utf8_bad_identify().
* Incomplete multi-octet sequence
* Note: this is kind of a "catch-all"
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
define('UTF8_BAD_SEQINCOMPLETE', 7);

/**
* Reports on the type of bad byte found in a UTF-8 string. Returns a
* status code on the first bad byte found
* @author <hsivonen@iki.fi>
* @param string UTF-8 encoded string
* @return mixed integer constant describing problem or FALSE if valid UTF-8
* @see utf8_bad_explain
* @see http://hsivonen.iki.fi/php-utf8/
* @package utf8
* @subpackage bad
*/
function utf8_bad_identify($str, &$i)
{
        $mState = 0;    // Cached expected number of octets after the current octet
                                        // until the beginning of the next UTF8 character sequence
        $mUcs4  = 0;    // Cached Unicode character
        $mBytes = 1;    // Cached expected number of octets in the current sequence

        $len = strlen($str);

        for($i=0; $i < $len; $i++)
        {
                $in = ord($str{$i});

                if ( $mState == 0)
                {
                        // When mState is zero we expect either a US-ASCII character or a multi-octet sequence.
                        if (0 == (0x80 & ($in)))
                        {
                                // US-ASCII, pass straight through.
                                $mBytes = 1;
                        }
                        else if (0xC0 == (0xE0 & ($in)))
                        {
                                // First octet of 2 octet sequence
                                $mUcs4 = ($in);
                                $mUcs4 = ($mUcs4 & 0x1F) << 6;
                                $mState = 1;
                                $mBytes = 2;
                        }
                        else if (0xE0 == (0xF0 & ($in)))
                        {
                                // First octet of 3 octet sequence
                                $mUcs4 = ($in);
                                $mUcs4 = ($mUcs4 & 0x0F) << 12;
                                $mState = 2;
                                $mBytes = 3;
                        }
                        else if (0xF0 == (0xF8 & ($in)))
                        {
                                // First octet of 4 octet sequence
                                $mUcs4 = ($in);
                                $mUcs4 = ($mUcs4 & 0x07) << 18;
                                $mState = 3;
                                $mBytes = 4;
                        }
                        else if (0xF8 == (0xFC & ($in)))
                        {
                                /* First octet of 5 octet sequence.
                                *
                                * This is illegal because the encoded codepoint must be either
                                * (a) not the shortest form or
                                * (b) outside the Unicode range of 0-0x10FFFF.
                                */
                                return UTF8_BAD_5OCTET;
                        }
                        else if (0xFC == (0xFE & ($in)))
                        {
                                // First octet of 6 octet sequence, see comments for 5 octet sequence.
                                return UTF8_BAD_6OCTET;
                        }
                        else
                        {
                                // Current octet is neither in the US-ASCII range nor a legal first
                                // octet of a multi-octet sequence.
                                return UTF8_BAD_SEQID;
                        }
                }
                else
                {
                        // When mState is non-zero, we expect a continuation of the multi-octet sequence
                        if (0x80 == (0xC0 & ($in)))
                        {
                                // Legal continuation.
                                $shift = ($mState - 1) * 6;
                                $tmp = $in;
                                $tmp = ($tmp & 0x0000003F) << $shift;
                                $mUcs4 |= $tmp;

                                /**
                                * End of the multi-octet sequence. mUcs4 now contains the final
                                * Unicode codepoint to be output
                                */
                                if (0 == --$mState)
                                {
                                        // From Unicode 3.1, non-shortest form is illegal
                                        if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
                                        ((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
                                        ((4 == $mBytes) && ($mUcs4 < 0x10000)) )
                                                return UTF8_BAD_NONSHORT;
                                        else if (($mUcs4 & 0xFFFFF800) == 0xD800) // From Unicode 3.2, surrogate characters are illegal
                                                return UTF8_BAD_SURROGATE;
                                        else if ($mUcs4 > 0x10FFFF) // Codepoints outside the Unicode range are illegal
                                                return UTF8_BAD_UNIOUTRANGE;

                                        // Initialize UTF8 cache
                                        $mState = 0;
                                        $mUcs4  = 0;
                                        $mBytes = 1;
                                }

                        }
                        else
                        {
                                // ((0xC0 & (*in) != 0x80) && (mState != 0))
                                // Incomplete multi-octet sequence.
                                $i--;
                                return UTF8_BAD_SEQINCOMPLETE;
                        }
                }
        }

        // Incomplete multi-octet sequence
        if ($mState != 0)
        {
                $i--;
                return UTF8_BAD_SEQINCOMPLETE;
        }

        // No bad octets found
        $i = null;
        return false;
}

/**
* Takes a return code from utf8_bad_identify() are returns a message
* (in English) explaining what the problem is.
* @param int return code from utf8_bad_identify
* @return mixed string message or FALSE if return code unknown
* @see utf8_bad_identify
* @package utf8
* @subpackage bad
*/
function utf8_bad_explain($code)
{
        switch ($code)
        {
                case UTF8_BAD_5OCTET:
                return 'Five octet sequences are valid UTF-8 but are not supported by Unicode';
                break;

                case UTF8_BAD_6OCTET:
                return 'Six octet sequences are valid UTF-8 but are not supported by Unicode';
                break;

                case UTF8_BAD_SEQID:
                return 'Invalid octet for use as start of multi-byte UTF-8 sequence';
                break;

                case UTF8_BAD_NONSHORT:
                return 'From Unicode 3.1, non-shortest form is illegal';
                break;

                case UTF8_BAD_SURROGATE:
                return 'From Unicode 3.2, surrogate characters are illegal';
                break;

                case UTF8_BAD_UNIOUTRANGE:
                return 'Codepoints outside the Unicode range are illegal';
                break;

                case UTF8_BAD_SEQINCOMPLETE:
                return 'Incomplete multi-octet sequence';
                break;
        }

        trigger_error('Unknown error code: '.$code, E_USER_WARNING);

        return false;
}