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<?php define('INT_SIGNED', 1); define('INT_LE', 2); function is32Bit() { // This is for max compatibility: // PHP_INT_MAX doesn't exist in PHP4 // current() *requires* a reference in PHP <5.1.0 (except 4.4.1, dafuq) $test = unpack('N', "\xFF\xFF\xFF\xFF"); return current($test) === -1; } function unpack_int32($str, $flags = 0) { // Make sure data is sane $str = (string) $str; $length = strlen($str); if ($length < 4) { return false; } else if ($length > 4) { $str = substr($str, 0, 4); } // Normalize to big endian and unpack to int32 if ($flags & INT_LE) { $str = strrev($str); } $result = unpack('N', $str); $result = current($result); // Sign and word size info $signBit = (bool) ($result & 0x80000000); $isSigned = (bool) ($flags & INT_SIGNED); $is32bit = is32Bit(); if ($signBit && $isSigned && !$is32bit) { // Left pad with set bits for negative numbers on 64-bit $result = (0x00000000FFFFFFFF << 32) | $result; } else if ($signBit && !$isSigned && $is32bit) { // Convert int32 to unsigned float $result = (($result & 0x7FFFFFFF) * 2) + ~$result + 1; } return $result; } function unpack_int64($str, $flags = 0) { // Make sure data is sane $str = (string) $str; $length = strlen($str); if ($length < 8) { return false; } else if ($length > 8) { $str = substr($str, 0, 8); } // Normalize to big endian and unpack to int32s if ($flags & INT_LE) { $str = strrev($str); } $int32s = array_values(unpack('N*', $str)); // Sign and word size info $signBit = (bool) ($int32s[0] & 0x80000000); $isSigned = (bool) ($flags & INT_SIGNED); $is32bit = is32Bit(); if ($is32bit) { if ($int32s[1] & 0x80000000) { // Convert second int32 to unsigned float $int32s[1] = (($int32s[1] & 0x7FFFFFFF) * 2) + ~$int32s[1] + 1; } if ($isSigned && $signBit) { // Negative $result = ($int32s[0] * pow(2, 32)) + $int32s[1]; } else { // Positive if ($signBit) { // Convert first int32 to unsigned float $int32s[0] = (($int32s[0] & 0x7FFFFFFF) * 2) + ~$int32s[0] + 1; } $result = ($int32s[0] * pow(2, 32)) + $int32s[1]; } } else { // Combine int32s into int64 $result = ($int32s[0] << 32) | $int32s[1]; if ($signBit && !$isSigned) { // Convert to negative $result = (($result & 0x7FFFFFFFFFFFFFFF) * 2) + ~$result + 1; } } return $result; } echo "int32:\n"; printf("%f\n", unpack_int32("\xFF\xFC\x00\x80")); printf("%f\n", unpack_int32("\xFF\xFC\x00\x80", INT_SIGNED)); printf("%f\n", unpack_int32("\xFF\xFC\x00\x80", INT_LE)); printf("%f\n", unpack_int32("\xFF\xFC\x00\x80", INT_LE | INT_SIGNED)); echo "\n"; echo "int64:\n"; printf("%f\n", unpack_int64("\xFF\xFF\xFF\xFC\x00\x00\x00\x80")); printf("%f\n", unpack_int64("\xFF\xFF\xFF\xFC\x00\x00\x00\x80", INT_SIGNED)); printf("%f\n", unpack_int64("\xFF\xFF\xFF\xFC\x00\x00\x00\x80", INT_LE)); printf("%f\n", unpack_int64("\xFF\xFF\xFF\xFC\x00\x00\x00\x80", INT_LE | INT_SIGNED));