function Combine_CRC32($crc1, $crc2, $len2)
{
$odd[0] = 0xedb88320;
$row = 0x1;
for ($n = 1; $n < 32; $n++) {
$odd[$n] = $row;
$row <<= 0x1;
}
WPOnlineBackup_Functions::GF2_Matrix_Square($even, $odd);
WPOnlineBackup_Functions::GF2_Matrix_Square($odd, $even);
do {
// apply zeros operator for this bit of len2
WPOnlineBackup_Functions::GF2_Matrix_Square($even, $odd);
if ($len2 & 0x1) {
$crc1 = WPOnlineBackup_Functions::GF2_Matrix_Times($even, $crc1);
}
$len2 >>= 0x1;
// if no more bits set, then done
if ($len2 == 0x0) {
break;
}
// another iteration of the loop with odd and even swapped
WPOnlineBackup_Functions::GF2_Matrix_Square($odd, $even);
if ($len2 & 0x1) {
$crc1 = WPOnlineBackup_Functions::GF2_Matrix_Times($odd, $crc1);
}
$len2 >>= 0x1;
} while ($len2 != 0x0);
$crc1 ^= $crc2;
return $crc1;
}
