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219 lines
6.3 KiB
219 lines
6.3 KiB
12 years ago
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<?
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/**
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* Phpmodbus Copyright (c) 2004, 2009 Jan Krakora, WAGO Kontakttechnik GmbH & Co. KG (http://www.wago.com)
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*
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* This source file is subject to the "PhpModbus license" that is bundled
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* with this package in the file license.txt.
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*
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* @author Jan Krakora
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* @copyright Copyright (c) 2004, 2009 Jan Krakora, WAGO Kontakttechnik GmbH & Co. KG (http://www.wago.com)
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* @license PhpModbus license
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* @category Phpmodbus
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* @package Phpmodbus
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* @version $id$
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*
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*/
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/**
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* PhpType
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*
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* The class includes set of methods that convert the received Modbus data
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* (array of bytes) to the PHP data type, i.e. signed int, unsigned int and float.
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*
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* @author Jan Krakora
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* @copyright Copyright (c) 2004, 2009 Jan Krakora, WAGO Kontakttechnik GmbH & Co. KG (http://www.wago.com)
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* @package Phpmodbus
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*
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*/
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class PhpType {
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/**
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* bytes2float
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*
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* The function converts array of 4 bytes to float. The return value
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* depends on order of the input bytes (endianning).
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*
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* @param array $values
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* @param bool $endianness
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* @return float
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*/
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public static function bytes2float($values, $endianness = 0){
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$data = array();
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$real = 0;
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// Set the array to correct form
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$data = self::checkData($values);
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// Combine bytes
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$real = self::combineBytes($data, $endianness);
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// Convert the real value to float
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return (float) self::real2float($real);
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}
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/**
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* bytes2signedInt
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*
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* The function converts array of 2 or 4 bytes to signed integer.
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* The return value depends on order of the input bytes (endianning).
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*
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* @param array $values
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* @param bool $endianness
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* @return int
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*/
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public static function bytes2signedInt($values, $endianness = 0){
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$data = array();
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$int = 0;
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// Set the array to correct form
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$data = self::checkData($values);
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// Combine bytes
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$int = self::combineBytes($data, $endianness);
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// In the case of signed 2 byte value convert it to 4 byte one
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if ((count($values) == 2) && ((0x8000 & $int) > 0)){
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$int = 0xFFFF8000 | $int;
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}
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// Convert the value
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return (int) self::dword2signedInt($int);
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}
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/**
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* bytes2unsignedInt
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*
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* The function converts array of 2 or 4 bytes to unsigned integer.
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* The return value depends on order of the input bytes (endianning).
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*
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* @param array $values
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* @param bool $endianness
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* @return int|float
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*/
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public static function bytes2unsignedInt($values, $endianness = 0){
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$data = array();
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$int = 0;
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// Set the array to correct form
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$data = self::checkData($values);
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// Combine bytes
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$int = self::combineBytes($data, $endianness);
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// Convert the value
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return self::dword2unsignedInt($int);
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}
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/**
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* real2float
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*
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* This function converts a value in IEC-1131 REAL single precision form to float.
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*
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* For more see [{@link http://en.wikipedia.org/wiki/Single_precision Single precision on Wiki}] or
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* [{@link http://de.php.net/manual/en/function.base-convert.php PHP base_convert function commentary}, Todd Stokes @ Georgia Tech 21-Nov-2007]
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*
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* @param value value in IEC REAL data type to be converted
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* @return float float value
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*/
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private static function real2float($value){
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$two_pow_minus_x = array(
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1, 0.5, 0.25, 0.125, 0.0625, 0.03125, 0.015625,
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0.0078125, 0.00390625, 0.001953125, 0.0009765625,
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0.00048828125, 0.000244140625, 0.0001220703125,
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0.00006103515625, 0.000030517578125, 0.0000152587890625,
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0.00000762939453125, 0.000003814697265625, 0.0000019073486328125,
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0.00000095367431640625, 0.000000476837158203125,
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0.0000002384185791015625, 0.00000011920928955078125);
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// get sign, mantisa, exponent
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$real_mantisa = $value & 0x7FFFFF | 0x800000;
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$real_exponent = ($value>>23) & 0xFF;
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$real_sign = ($value>>31) & 0x01;
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$bin_exponent = $real_exponent - 127;
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// decode value
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if (( $bin_exponent >= -126) && ($bin_exponent <= 127)) {
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// Mantissa decoding
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for ($i=0; $i<24; $i++) {
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if ($real_mantisa & 0x01)
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$val += $two_pow_minus_x[23-$i];
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$real_mantisa = $real_mantisa >> 1;
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}
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// Base
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$val = $val * pow(2,$bin_exponent);
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if (($real_sign == 1)) $val = -$val;
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}
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return (float)$val;
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}
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/**
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* dword2signedInt
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*
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* Switch double word to signed integer
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*
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* @param int $value
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* @return int
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*/
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private static function dword2signedInt($value){
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if ((0x80000000 & $value) != 0) {
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return -(0x7FFFFFFF & ~$value)-1;
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} else {
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return (0x7FFFFFFF & $value);
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}
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}
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/**
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* dword2signedInt
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*
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* Switch double word to unsigned integer
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*
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* @param int $value
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* @return int|float
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*/
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private static function dword2unsignedInt($value){
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if ((0x80000000 & $value) != 0) {
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return ((float) (0x7FFFFFFF & $value)) + 2147483648;
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} else {
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return (int) (0x7FFFFFFF & $value);
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}
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}
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/**
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* checkData
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*
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* Check if the data variable is array, and check if the values are numeric
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*
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* @param int $data
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* @return int
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*/
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private static function checkData($data){
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// Check the data
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if (!is_array($data)) {
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throw new Exception('The input data should be an array of bytes.');
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}
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// Check the values to be number - must be
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if (!is_numeric($data[0]) || !is_numeric($data[1])) {
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throw new Exception('Data are not numeric.');
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}
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if (!is_numeric($data[2])) $data[2] = 0;
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if (!is_numeric($data[3])) $data[3] = 0;
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return $data;
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}
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/**
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* combineBytes
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*
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* Combine bytes together
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*
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* @param int $data
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* @param bool $endianness
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* @return int
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*/
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private static function combineBytes($data, $endianness){
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$value = 0;
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// Combine bytes
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if ($endianness == 0)
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$value = (($data[3] & 0xFF)<<16) |
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(($data[2] & 0xFF)<<24) |
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(($data[1] & 0xFF)) |
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(($data[0] & 0xFF)<<8);
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else
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$value = (($data[3] & 0xFF)<<24) |
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(($data[2] & 0xFF)<<16) |
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(($data[1] & 0xFF)<<8) |
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(($data[0] & 0xFF));
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return $value;
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}
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}
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?>
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