simple-machines-forum/Sources/Subs-Compat.php

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PHP

<?php
/**
* This file provides compatibility functions and code for older versions of
* PHP, such as the sha1() function, missing extensions, or 64-bit vs 32-bit
* systems. It is only included for those older versions or when the respective
* extension or function cannot be found.
*
* Simple Machines Forum (SMF)
*
* @package SMF
* @author Simple Machines https://www.simplemachines.org
* @copyright 2022 Simple Machines and individual contributors
* @license https://www.simplemachines.org/about/smf/license.php BSD
*
* @version 2.1.3
*/
if (!defined('SMF'))
die('No direct access...');
/**
* Define the old SMF sha1 function. Uses mhash if available
*
* @param string $str The string
* @return string The sha1 hashed version of $str
*/
function sha1_smf($str)
{
// If we have mhash loaded in, use it instead!
if (function_exists('mhash') && defined('MHASH_SHA1'))
return bin2hex(mhash(MHASH_SHA1, $str));
$nblk = (strlen($str) + 8 >> 6) + 1;
$blks = array_pad(array(), $nblk * 16, 0);
for ($i = 0; $i < strlen($str); $i++)
$blks[$i >> 2] |= ord($str[$i]) << (24 - ($i % 4) * 8);
$blks[$i >> 2] |= 0x80 << (24 - ($i % 4) * 8);
return sha1_core($blks, strlen($str) * 8);
}
/**
* This is the core SHA-1 calculation routine, used by sha1().
*
* @param string $x
* @param int $len
* @return string
*/
function sha1_core($x, $len)
{
@$x[$len >> 5] |= 0x80 << (24 - $len % 32);
$x[(($len + 64 >> 9) << 4) + 15] = $len;
$w = array();
$a = 1732584193;
$b = -271733879;
$c = -1732584194;
$d = 271733878;
$e = -1009589776;
for ($i = 0, $n = count($x); $i < $n; $i += 16)
{
$olda = $a;
$oldb = $b;
$oldc = $c;
$oldd = $d;
$olde = $e;
for ($j = 0; $j < 80; $j++)
{
if ($j < 16)
$w[$j] = isset($x[$i + $j]) ? $x[$i + $j] : 0;
else
$w[$j] = sha1_rol($w[$j - 3] ^ $w[$j - 8] ^ $w[$j - 14] ^ $w[$j - 16], 1);
$t = sha1_rol($a, 5) + sha1_ft($j, $b, $c, $d) + $e + $w[$j] + sha1_kt($j);
$e = $d;
$d = $c;
$c = sha1_rol($b, 30);
$b = $a;
$a = $t;
}
$a += $olda;
$b += $oldb;
$c += $oldc;
$d += $oldd;
$e += $olde;
}
return sprintf('%08x%08x%08x%08x%08x', $a, $b, $c, $d, $e);
}
/**
* Helper function for the core SHA-1 calculation
*
* @param int $t
* @param int $b
* @param int $c
* @param int $d
* @return int
*/
function sha1_ft($t, $b, $c, $d)
{
if ($t < 20)
return ($b & $c) | ((~$b) & $d);
if ($t < 40)
return $b ^ $c ^ $d;
if ($t < 60)
return ($b & $c) | ($b & $d) | ($c & $d);
return $b ^ $c ^ $d;
}
/**
* Helper function for the core SHA-1 calculation
*
* @param int $t
* @return int 1518500249, 1859775393, -1894007588 or -899497514 depending on the value of $t
*/
function sha1_kt($t)
{
return $t < 20 ? 1518500249 : ($t < 40 ? 1859775393 : ($t < 60 ? -1894007588 : -899497514));
}
/**
* Helper function for the core SHA-1 calculation
*
* @param int $num
* @param int $cnt
* @return int
*/
function sha1_rol($num, $cnt)
{
// Unfortunately, PHP uses unsigned 32-bit longs only. So we have to kludge it a bit.
if ($num & 0x80000000)
$a = ($num >> 1 & 0x7fffffff) >> (31 - $cnt);
else
$a = $num >> (32 - $cnt);
return ($num << $cnt) | $a;
}
/**
* Available since: (PHP 5)
* If the optional raw_output is set to TRUE, then the sha1 digest is instead returned in raw binary format with a length of 20,
* otherwise the returned value is a 40-character hexadecimal number.
*
* @param string $text The text to hash
* @return string The sha1 hash of $text
*/
function sha1_raw($text)
{
return sha1($text, true);
}
if (!function_exists('smf_crc32'))
{
/**
* Compatibility function.
* crc32 doesn't work as expected on 64-bit functions - make our own.
* https://php.net/crc32#79567
*
* @param string $number
* @return string The crc32 polynomial of $number
*/
function smf_crc32($number)
{
$crc = crc32($number);
if ($crc & 0x80000000)
{
$crc ^= 0xffffffff;
$crc += 1;
$crc = -$crc;
}
return $crc;
}
}
if (!function_exists('mb_ord'))
{
/**
* Compatibility function.
*
* This is a complete polyfill.
*
* @param string $string A character.
* @param string|null $encoding The character encoding.
* If null, the current SMF encoding will be used, falling back to UTF-8.
* @return int|bool The Unicode code point of the character, or false on failure.
*/
function mb_ord($string, $encoding = null)
{
// Must have a supported encoding.
if (($encoding = mb_ord_chr_encoding($encoding)) === false)
return false;
/* Alternative approach for certain encodings.
*
* This is required because there are some invalid byte sequences in
* these encodings for which native mb_ord() will return false, yet
* mb_convert_encoding() and iconv() will nevertheless convert into
* technically valid but semantically unrelated UTF-8 byte sequences.
*
* For these encodings, mb_encode_numericentity() always produces
* either an entity with the same number that mb_ord() would produce,
* or else malformed output for byte sequences where mb_ord() would
* return false. This allows us to use mb_encode_numericentity() as a
* (slow) alternative method for these encodings.
*
* Note: we cannot use mb_check_encoding() here, because it returns
* false for ALL invalid byte sequences, but mb_ord() only returns false
* for SOME invalid byte sequences.
*/
if (in_array($encoding, array('EUC-CN', 'EUC-KR', 'ISO-2022-KR')))
{
if (!function_exists('mb_encode_numericentity'))
return false;
$entity = mb_encode_numericentity($string, array(0x0,0x10FFFF,0x0,0xFFFFFF), $encoding);
if (strpos($entity, '&#') !== 0)
return false;
return (int) trim($entity, '&#;');
}
// Convert to UTF-8. Return false on failure.
if ($encoding !== 'UTF-8')
{
$temp = false;
if (function_exists('mb_convert_encoding'))
{
$mb_substitute_character = mb_substitute_character();
mb_substitute_character('none');
$temp = mb_convert_encoding($string, 'UTF-8', $encoding);
mb_substitute_character($mb_substitute_character);
}
if ($temp === false && function_exists('iconv'))
$temp = iconv($encoding, 'UTF-8', $string);
if ($temp === false)
return false;
$string = $temp;
}
if (strlen($string) === 1)
return ord($string);
// Get the values of the individual bytes.
$unpacked = unpack('C*', substr($string, 0, 4));
if ($unpacked === false)
{
$ord = 0;
}
elseif ($unpacked[1] >= 0xF0)
{
$ord = ($unpacked[1] - 0xF0) << 18;
$ord += ($unpacked[2] - 0x80) << 12;
$ord += ($unpacked[3] - 0x80) << 6;
$ord += $unpacked[4] - 0x80;
}
elseif ($unpacked[1] >= 0xE0)
{
$ord = ($unpacked[1] - 0xE0) << 12;
$ord += ($unpacked[2] - 0x80) << 6;
$ord += $unpacked[3] - 0x80;
}
elseif ($unpacked[1] >= 0xC0)
{
$ord = ($unpacked[1] - 0xC0) << 6;
$ord += $unpacked[2] - 0x80;
}
else
{
$ord = $unpacked[1];
}
// Surrogate pairs are invalid in UTF-8.
if ($ord >= 0xD800 && $ord <= 0xDFFF)
$ord = 0;
return $ord;
}
}
if (!function_exists('mb_chr'))
{
/**
* Compatibility function.
*
* This is a complete polyfill.
*
* @param int $codepoint A Unicode codepoint value.
* @param string|null $encoding The character encoding.
* If null, the current SMF encoding will be used, falling back to UTF-8.
* @return string|bool The requested character, or false on failure.
*/
function mb_chr($codepoint, $encoding = null)
{
// Must have a supported encoding.
if (($encoding = mb_ord_chr_encoding($encoding)) === false)
return false;
// 0x10FFFF is the highest defined code point as of Unicode 13.0.0
$codepoint %= 0x110000;
if ($codepoint < 0x80)
{
$string = chr($codepoint);
}
elseif ($codepoint < 0x800)
{
$string = chr(0xC0 | $codepoint >> 6) . chr(0x80 | $codepoint & 0x3F);
}
elseif ($codepoint < 0x10000)
{
$string = chr(0xE0 | $codepoint >> 12) . chr(0x80 | $codepoint >> 6 & 0x3F) . chr(0x80 | $codepoint & 0x3F);
}
else
{
$string = chr(0xF0 | $codepoint >> 18) . chr(0x80 | $codepoint >> 12 & 0x3F) . chr(0x80 | $codepoint >> 6 & 0x3F) . chr(0x80 | $codepoint & 0x3F);
}
// Return in the requested encoding, or false on failure.
// Note: native mb_chr() always returns a character in regular UTF-8
// when the encoding is set to one of the UTF-8-Mobile* encodings. If
// that behaviour changes in the future, add version checks here.
if (strpos($encoding, 'UTF-8') !== 0)
{
$temp = false;
if (function_exists('mb_convert_encoding'))
{
$mb_substitute_character = mb_substitute_character();
mb_substitute_character('none');
$temp = mb_convert_encoding($string, $encoding, 'UTF-8');
mb_substitute_character($mb_substitute_character);
}
if ($temp === false && function_exists('iconv'))
$temp = iconv('UTF-8', $encoding, $string);
if ($temp === false)
return false;
$string = $temp;
}
return $string;
}
}
/**
* Helper function for the mb_ord and mb_chr polyfills.
*
* Checks whether $encoding is a supported character encoding for the mb_ord
* and mb_chr functions. If $encoding is null, the current default character
* encoding is used. If the encoding is supported, it is returned as a string.
* If not, false is returned.
*
* @param string $encoding A character encoding to check, or null for default.
* @return string|bool The character encoding, or false if unsupported.
*/
function mb_ord_chr_encoding($encoding = null)
{
global $modSettings, $txt;
if (is_null($encoding))
{
if (isset($modSettings['global_character_set']))
$encoding = $modSettings['global_character_set'];
elseif (isset($txt['lang_character_set']))
$encoding = $txt['lang_character_set'];
elseif (function_exists('mb_internal_encoding'))
$encoding = mb_internal_encoding();
elseif (ini_get('default_charset') != false)
$encoding = ini_get('default_charset');
else
$encoding = 'UTF-8';
}
// Only some mb_string encodings are supported by mb_chr() and mb_ord().
$supported_encodings = array(
'8bit', 'UCS-4', 'UCS-4BE', 'UCS-4LE', 'UCS-2', 'UCS-2BE', 'UCS-2LE',
'UTF-32', 'UTF-32BE', 'UTF-32LE', 'UTF-16', 'UTF-16BE', 'UTF-16LE',
'UTF-8', 'ASCII', 'EUC-JP', 'SJIS', 'eucJP-win', 'EUC-JP-2004',
'SJIS-win', 'SJIS-Mobile#DOCOMO', 'SJIS-Mobile#KDDI',
'SJIS-Mobile#SOFTBANK', 'SJIS-mac', 'SJIS-2004', 'UTF-8-Mobile#DOCOMO',
'UTF-8-Mobile#KDDI-A', 'UTF-8-Mobile#KDDI-B', 'UTF-8-Mobile#SOFTBANK',
'CP932', 'CP51932', 'GB18030', 'Windows-1252', 'Windows-1254',
'ISO-8859-1', 'ISO-8859-2', 'ISO-8859-3', 'ISO-8859-4', 'ISO-8859-5',
'ISO-8859-6', 'ISO-8859-7', 'ISO-8859-8', 'ISO-8859-9', 'ISO-8859-10',
'ISO-8859-13', 'ISO-8859-14', 'ISO-8859-15', 'ISO-8859-16', 'EUC-CN',
'CP936', 'HZ', 'EUC-TW', 'BIG-5', 'CP950', 'EUC-KR', 'UHC',
'ISO-2022-KR', 'Windows-1251', 'CP866', 'KOI8-R', 'KOI8-U', 'ArmSCII-8',
'CP850', 'JIS-ms',
);
// Found it.
if (in_array($encoding, $supported_encodings))
return $encoding;
// Gracefully handle aliases and incorrect lettercase.
$encoding_l = strtolower($encoding);
foreach ($supported_encodings as $possible_encoding)
{
$aliases = array_merge(array($possible_encoding), mb_encoding_aliases($possible_encoding));
foreach ($aliases as $alias)
{
if (strtolower($alias) === $encoding_l)
return $possible_encoding;
}
}
return false;
}
/**
* IDNA_* constants used as flags for the idn_to_* functions.
*/
foreach (
array(
'IDNA_DEFAULT' => 0,
'IDNA_ALLOW_UNASSIGNED' => 1,
'IDNA_USE_STD3_RULES' => 2,
'IDNA_CHECK_BIDI' => 4,
'IDNA_CHECK_CONTEXTJ' => 8,
'IDNA_NONTRANSITIONAL_TO_ASCII' => 16,
'IDNA_NONTRANSITIONAL_TO_UNICODE' => 32,
'INTL_IDNA_VARIANT_2003' => 0,
'INTL_IDNA_VARIANT_UTS46' => 1,
)
as $name => $value
)
{
if (!defined($name))
define($name, $value);
};
if (!function_exists('idn_to_ascii'))
{
/**
* Compatibility function.
*
* This is not a complete polyfill:
*
* - $flags only supports IDNA_DEFAULT, IDNA_NONTRANSITIONAL_TO_ASCII,
* and IDNA_USE_STD3_RULES.
* - $variant is ignored, because INTL_IDNA_VARIANT_UTS46 is always used.
* - $idna_info is ignored.
*
* @param string $domain The domain to convert, which must be UTF-8 encoded.
* @param int $flags A subset of possible IDNA_* flags.
* @param int $variant Ignored in this compatibility function.
* @param array|null $idna_info Ignored in this compatibility function.
* @return string|bool The domain name encoded in ASCII-compatible form, or false on failure.
*/
function idn_to_ascii($domain, $flags = 0, $variant = 1, &$idna_info = null)
{
global $sourcedir;
static $Punycode;
require_once($sourcedir . '/Class-Punycode.php');
if (!is_object($Punycode))
$Punycode = new Punycode();
if (method_exists($Punycode, 'useStd3'))
$Punycode->useStd3($flags === ($flags | IDNA_USE_STD3_RULES));
if (method_exists($Punycode, 'useNonTransitional'))
$Punycode->useNonTransitional($flags === ($flags | IDNA_NONTRANSITIONAL_TO_ASCII));
return $Punycode->encode($domain);
}
}
if (!function_exists('idn_to_utf8'))
{
/**
* Compatibility function.
*
* This is not a complete polyfill:
*
* - $flags only supports IDNA_DEFAULT, IDNA_NONTRANSITIONAL_TO_UNICODE,
* and IDNA_USE_STD3_RULES.
* - $variant is ignored, because INTL_IDNA_VARIANT_UTS46 is always used.
* - $idna_info is ignored.
*
* @param string $domain Domain to convert, in an IDNA ASCII-compatible format.
* @param int $flags Ignored in this compatibility function.
* @param int $variant Ignored in this compatibility function.
* @param array|null $idna_info Ignored in this compatibility function.
* @return string|bool The domain name in Unicode, encoded in UTF-8, or false on failure.
*/
function idn_to_utf8($domain, $flags = 0, $variant = 1, &$idna_info = null)
{
global $sourcedir;
static $Punycode;
require_once($sourcedir . '/Class-Punycode.php');
if (!is_object($Punycode))
$Punycode = new Punycode();
$Punycode->useStd3($flags === ($flags | IDNA_USE_STD3_RULES));
$Punycode->useNonTransitional($flags === ($flags | IDNA_NONTRANSITIONAL_TO_UNICODE));
return $Punycode->decode($domain);
}
}
/**
* Prevent fatal errors under PHP 8 when a disabled internal function is called.
*
* Before PHP 8, calling a disabled internal function merely generated a
* warning that could be easily suppressed by the @ operator. But as of PHP 8
* a disabled internal function is treated like it is undefined, which means
* a fatal error will be thrown and execution will halt. SMF expects the old
* behaviour, so these no-op polyfills make sure that is what happens.
*/
if (version_compare(PHP_VERSION, '8.0.0', '>='))
{
/*
* This array contains function names that meet the following conditions:
*
* 1. SMF assumes they are defined, even if disabled. Note that prior to
* PHP 8, this was always true for internal functions.
*
* 2. Some hosts are known to disable them.
*
* 3. SMF can get by without them (as opposed to missing functions that
* really SHOULD cause execution to halt).
*/
foreach (array('set_time_limit') as $func)
{
if (!function_exists($func))
eval('function ' . $func . '() { trigger_error("' . $func . '() has been disabled for security reasons", E_USER_WARNING); }');
}
unset($func);
}
?>