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