3rdPartyLibraries/iTechSharp/srcbc/asn1/IndefiniteLengthInputStream.cs
2023-06-21 12:46:23 -04:00

96 lines
1.8 KiB
C#

using System.IO;
namespace Org.BouncyCastle.Asn1
{
class IndefiniteLengthInputStream
: LimitedInputStream
{
private int _b1;
private int _b2;
private bool _eofReached = false;
private bool _eofOn00 = true;
internal IndefiniteLengthInputStream(
Stream inStream)
: base(inStream)
{
_b1 = inStream.ReadByte();
_b2 = inStream.ReadByte();
_eofReached = (_b2 < 0);
}
internal void SetEofOn00(
bool eofOn00)
{
_eofOn00 = eofOn00;
}
internal bool CheckForEof()
{
if (_eofOn00 && (_b1 == 0x00 && _b2 == 0x00))
{
_eofReached = true;
SetParentEofDetect(true);
}
return _eofReached;
}
public override int Read(
byte[] buffer,
int offset,
int count)
{
// Only use this optimisation if we aren't checking for 00
if (_eofOn00 || count < 3)
return base.Read(buffer, offset, count);
if (_eofReached)
return 0;
int numRead = _in.Read(buffer, offset + 2, count - 2);
if (numRead <= 0)
{
// Corrupted stream
throw new EndOfStreamException();
}
buffer[offset] = (byte)_b1;
buffer[offset + 1] = (byte)_b2;
_b1 = _in.ReadByte();
_b2 = _in.ReadByte();
if (_b2 < 0)
{
// Corrupted stream
throw new EndOfStreamException();
}
return numRead + 2;
}
public override int ReadByte()
{
if (CheckForEof())
return -1;
int b = _in.ReadByte();
if (b < 0)
{
// Corrupted stream
throw new EndOfStreamException();
}
int v = _b1;
_b1 = _b2;
_b2 = b;
return v;
}
}
}