/**
* @return array
*/
function crc64Table(){
$crc64tab = array();
// ECMA polynomial
$poly64rev = (0xC96C5795 << 32) | 0xD7870F42;
// ISO polynomial
// $poly64rev = (0xD8 << 56);
for ($i = 0; $i < 256; $i++)
{
for ($part = $i, $bit = 0; $bit < 8; $bit++) {
if ($part & 1) {
$part = (($part >> 1) & ~(0x8 << 60)) ^ $poly64rev;
} else {
$part = ($part >> 1) & ~(0x8 << 60);
}
}
$crc64tab[$i] = $part;
}
return $crc64tab;
}
/**
* get crc64 function
* @param string $string
* @param string $format
* @return mixed
*
* Formats:
* crc64('php'); // afe4e823e7cef190
* crc64('php', '0x%x'); // 0xafe4e823e7cef190
* crc64('php', '0x%X'); // 0xAFE4E823E7CEF190
* crc64('php', '%d'); // -5772233581471534704 signed int
* crc64('php', '%u'); // 12674510492238016912 unsigned int
*/
function crc64($string, $format = '%x'){
static $crc64tab;
if ($crc64tab === null) {
$crc64tab = crc64Table();
}
$crc = 0;
for ($i = 0; $i < strlen($string); $i++) {
$crc = ~$crc;
$crc = $crc64tab[($crc ^ ord($string[$i])) & 0xff] ^ (($crc >> 8) & ~(0xff << 56));
$crc = ~$crc;
}
return sprintf($format, $crc);
}
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