Modbus TCP and UDP library for PHP., originally from code.google.com/p/phpmodbus
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php-modbus/Phpmodbus/PhpType.php

219 lines
6.3 KiB

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