<?php
define('INT_SIGNED', 1);
define('INT_LE', 2);
function is32Bit() {
$test = unpack('N', "\xFF\xFF\xFF\xFF");
return current($test) === -1;
}
function unpack_int32($str, $flags = 0) {
$length = strlen($str);
if ($length < 4) {
return false;
} else if ($length > 4) {
$str = substr($str, 0, 4);
}
if ($flags & INT_LE) {
$str = strrev($str);
}
$result = unpack('N', $str);
$result = current($result);
$signBit = (bool) ($result & 0x80000000);
$isSigned = (bool) ($flags & INT_SIGNED);
$is32bit = is32Bit();
if ($signBit && $isSigned && !$is32bit) {
echo '64';
$result = 0xFFFFFFFF00000000 | $result;
} else if ($signBit && !$isSigned && $is32bit) {
$result = (($result & 0x7FFFFFFF) * 2) + ~$result + 1;
}
return $result;
}
function unpack_int64($str, $flags = 0) {
$length = strlen($str);
if ($length < 8) {
return false;
} else if ($length > 8) {
$str = substr($str, 0, 8);
}
if ($flags & INT_LE) {
$str = strrev($str);
}
$longs = array_values(unpack('NN', substr($str, 0, 4), substr($str, 4, 4)));
$signBit = (bool) ($longs[0] & 0x80000000);
if (!is32Bit()) {
$result = ($longs[0] << 32) | $longs[1];
if ($signBit) {
$result = (($result & 0x7FFFFFFFFFFFFFFF) * 2) + ~$result + 1;
}
}
return $result;
}
var_dump(unpack_int32("\x81\x00\x00\x80", INT_SIGNED | INT_LE));
preferences:
53.54 ms | 402 KiB | 5 Q