186 lines
6.5 KiB
PHP
186 lines
6.5 KiB
PHP
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<?php
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/**
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* @version $Id$
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* Tools for validing a UTF-8 string is well formed.
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* The Original Code is Mozilla Communicator client code.
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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* Ported to PHP by Henri Sivonen (http://hsivonen.iki.fi)
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* Slight modifications to fit with phputf8 library by Harry Fuecks (hfuecks gmail com)
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* @see http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUTF8ToUnicode.cpp
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* @see http://lxr.mozilla.org/seamonkey/source/intl/uconv/src/nsUnicodeToUTF8.cpp
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* @see http://hsivonen.iki.fi/php-utf8/
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* @package utf8
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* @subpackage validation
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*/
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//--------------------------------------------------------------------
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/**
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* Tests a string as to whether it's valid UTF-8 and supported by the
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* Unicode standard
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* Note: this function has been modified to simple return true or false
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* @author <hsivonen@iki.fi>
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* @param string UTF-8 encoded string
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* @return boolean true if valid
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* @see http://hsivonen.iki.fi/php-utf8/
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* @see utf8_compliant
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* @package utf8
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* @subpackage validation
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*/
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function utf8_is_valid($str) {
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$mState = 0; // cached expected number of octets after the current octet
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// until the beginning of the next UTF8 character sequence
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$mUcs4 = 0; // cached Unicode character
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$mBytes = 1; // cached expected number of octets in the current sequence
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$len = strlen($str);
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for($i = 0; $i < $len; $i++) {
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$in = ord($str{$i});
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if ( $mState == 0) {
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// When mState is zero we expect either a US-ASCII character or a
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// multi-octet sequence.
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if (0 == (0x80 & ($in))) {
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// US-ASCII, pass straight through.
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$mBytes = 1;
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} else if (0xC0 == (0xE0 & ($in))) {
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// First octet of 2 octet sequence
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$mUcs4 = ($in);
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$mUcs4 = ($mUcs4 & 0x1F) << 6;
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$mState = 1;
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$mBytes = 2;
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} else if (0xE0 == (0xF0 & ($in))) {
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// First octet of 3 octet sequence
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$mUcs4 = ($in);
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$mUcs4 = ($mUcs4 & 0x0F) << 12;
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$mState = 2;
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$mBytes = 3;
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} else if (0xF0 == (0xF8 & ($in))) {
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// First octet of 4 octet sequence
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$mUcs4 = ($in);
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$mUcs4 = ($mUcs4 & 0x07) << 18;
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$mState = 3;
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$mBytes = 4;
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} else if (0xF8 == (0xFC & ($in))) {
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/* First octet of 5 octet sequence.
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*
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* This is illegal because the encoded codepoint must be either
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* (a) not the shortest form or
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* (b) outside the Unicode range of 0-0x10FFFF.
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* Rather than trying to resynchronize, we will carry on until the end
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* of the sequence and let the later error handling code catch it.
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*/
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$mUcs4 = ($in);
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$mUcs4 = ($mUcs4 & 0x03) << 24;
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$mState = 4;
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$mBytes = 5;
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} else if (0xFC == (0xFE & ($in))) {
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// First octet of 6 octet sequence, see comments for 5 octet sequence.
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$mUcs4 = ($in);
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$mUcs4 = ($mUcs4 & 1) << 30;
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$mState = 5;
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$mBytes = 6;
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} else {
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/* Current octet is neither in the US-ASCII range nor a legal first
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* octet of a multi-octet sequence.
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*/
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return FALSE;
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}
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} else {
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// When mState is non-zero, we expect a continuation of the multi-octet
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// sequence
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if (0x80 == (0xC0 & ($in))) {
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// Legal continuation.
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$shift = ($mState - 1) * 6;
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$tmp = $in;
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$tmp = ($tmp & 0x0000003F) << $shift;
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$mUcs4 |= $tmp;
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/**
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* End of the multi-octet sequence. mUcs4 now contains the final
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* Unicode codepoint to be output
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*/
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if (0 == --$mState) {
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/*
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* Check for illegal sequences and codepoints.
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*/
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// From Unicode 3.1, non-shortest form is illegal
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if (((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
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((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
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((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
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(4 < $mBytes) ||
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// From Unicode 3.2, surrogate characters are illegal
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(($mUcs4 & 0xFFFFF800) == 0xD800) ||
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// Codepoints outside the Unicode range are illegal
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($mUcs4 > 0x10FFFF)) {
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return FALSE;
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}
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//initialize UTF8 cache
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$mState = 0;
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$mUcs4 = 0;
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$mBytes = 1;
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}
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} else {
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/**
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*((0xC0 & (*in) != 0x80) && (mState != 0))
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* Incomplete multi-octet sequence.
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*/
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return FALSE;
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}
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}
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}
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return TRUE;
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}
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//--------------------------------------------------------------------
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/**
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* Tests whether a string complies as UTF-8. This will be much
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* faster than utf8_is_valid but will pass five and six octet
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* UTF-8 sequences, which are not supported by Unicode and
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* so cannot be displayed correctly in a browser. In other words
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* it is not as strict as utf8_is_valid but it's faster. If you use
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* is to validate user input, you place yourself at the risk that
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* attackers will be able to inject 5 and 6 byte sequences (which
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* may or may not be a significant risk, depending on what you are
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* are doing)
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* @see utf8_is_valid
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* @see http://www.php.net/manual/en/reference.pcre.pattern.modifiers.php#54805
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* @param string UTF-8 string to check
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* @return boolean TRUE if string is valid UTF-8
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* @package utf8
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* @subpackage validation
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*/
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function utf8_compliant($str) {
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if ( strlen($str) == 0 ) {
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return TRUE;
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}
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// If even just the first character can be matched, when the /u
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// modifier is used, then it's valid UTF-8. If the UTF-8 is somehow
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// invalid, nothing at all will match, even if the string contains
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// some valid sequences
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return (preg_match('/^.{1}/us',$str,$ar) == 1);
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}
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