172 lines
3.8 KiB
PHP
172 lines
3.8 KiB
PHP
<?php
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//-----------------------------------------------------------------------------
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// ASNValue class by A.Oliinyk
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// contact@pumka.net
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//-----------------------------------------------------------------------------
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class ASNValue
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{
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const TAG_INTEGER = 0x02;
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const TAG_BITSTRING = 0x03;
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const TAG_SEQUENCE = 0x30;
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public $Tag;
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public $Value;
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function __construct($Tag=0x00, $Value='')
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{
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$this->Tag = $Tag;
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$this->Value = $Value;
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}
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function Encode()
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{
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//Write type
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$result = chr($this->Tag);
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//Write size
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$size = strlen($this->Value);
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if ($size < 127) {
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//Write size as is
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$result .= chr($size);
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}
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else {
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//Prepare length sequence
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$sizeBuf = self::IntToBin($size);
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//Write length sequence
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$firstByte = 0x80 + strlen($sizeBuf);
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$result .= chr($firstByte) . $sizeBuf;
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}
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//Write value
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$result .= $this->Value;
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return $result;
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}
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function Decode(&$Buffer)
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{
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//Read type
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$this->Tag = self::ReadByte($Buffer);
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//Read first byte
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$firstByte = self::ReadByte($Buffer);
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if ($firstByte < 127) {
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$size = $firstByte;
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}
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else if ($firstByte > 127) {
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$sizeLen = $firstByte - 0x80;
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//Read length sequence
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$size = self::BinToInt(self::ReadBytes($Buffer, $sizeLen));
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}
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else {
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throw new Exception("Invalid ASN length value");
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}
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$this->Value = self::ReadBytes($Buffer, $size);
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}
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protected static function ReadBytes(&$Buffer, $Length)
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{
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$result = substr($Buffer, 0, $Length);
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$Buffer = substr($Buffer, $Length);
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return $result;
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}
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protected static function ReadByte(&$Buffer)
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{
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return ord(self::ReadBytes($Buffer, 1));
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}
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protected static function BinToInt($Bin)
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{
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$len = strlen($Bin);
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$result = 0;
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for ($i=0; $i<$len; $i++) {
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$curByte = self::ReadByte($Bin);
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$result += $curByte << (($len-$i-1)*8);
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}
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return $result;
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}
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protected static function IntToBin($Int)
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{
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$result = '';
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do {
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$curByte = $Int % 256;
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$result .= chr($curByte);
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$Int = ($Int - $curByte) / 256;
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} while ($Int > 0);
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$result = strrev($result);
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return $result;
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}
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function SetIntBuffer($Value)
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{
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if (strlen($Value) > 1) {
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$firstByte = ord($Value{0});
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if ($firstByte & 0x80) { //first bit set
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$Value = chr(0x00) . $Value;
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}
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}
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$this->Value = $Value;
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}
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function GetIntBuffer()
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{
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$result = $this->Value;
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if (ord($result{0}) == 0x00) {
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$result = substr($result, 1);
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}
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return $result;
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}
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function SetInt($Value)
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{
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$Value = self::IntToBin($Value);
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$this->SetIntBuffer($Value);
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}
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function GetInt()
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{
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$result = $this->GetIntBuffer();
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$result = self::BinToInt($result);
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return $result;
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}
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function SetSequence($Values)
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{
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$result = '';
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foreach ($Values as $item) {
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$result .= $item->Encode();
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}
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$this->Value = $result;
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}
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function GetSequence()
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{
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$result = array();
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$seq = $this->Value;
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while (strlen($seq)) {
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$val = new ASNValue();
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$val->Decode($seq);
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$result[] = $val;
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}
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return $result;
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}
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}
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?>
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