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<?php const INT_SIGNED = 1; const INT_LE = 2; function isLittleEndian() { return pack('S', 0x00FF) === "\xFF\x00"; } function is32Bit() { return PHP_INT_MAX < 0x80000000; } function unpack_int32($str, $flags = 0) { $length = strlen($str); if ($length < 4) { return false; } else if ($length > 4) { $str = substr($str, 0, 4); } $format = ($flags & INT_LE) ? 'V' : 'N'; $result = current(unpack($format, $str)); if (($result & 0x80000000) && ($flags & INT_SIGNED) && !is32Bit()) { $result = 0xFFFFFFFF00000000 | $result; } return $result; } var_dump(isLittleEndian(), is32Bit(), unpack_int32("\xFF\xFF\xFF\xFF", INT_SIGNED));

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