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using System;
using System.IO;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.IO;
namespace Org.BouncyCastle.Asn1
{
internal class ConstructedBitStream
: BaseInputStream
{
private readonly Asn1StreamParser m_parser;
private readonly bool m_octetAligned;
private bool m_first = true;
private int m_padBits = 0;
private Asn1BitStringParser m_currentParser;
private Stream m_currentStream;
internal ConstructedBitStream(Asn1StreamParser parser, bool octetAligned)
{
m_parser = parser;
m_octetAligned = octetAligned;
}
internal int PadBits
{
get { return m_padBits; }
}
public override int Read(byte[] buffer, int offset, int count)
{
Streams.ValidateBufferArguments(buffer, offset, count);
if (count < 1)
return 0;
if (m_currentStream == null)
{
if (!m_first)
return 0;
m_currentParser = GetNextParser();
if (m_currentParser == null)
return 0;
m_first = false;
m_currentStream = m_currentParser.GetBitStream();
}
int totalRead = 0;
for (;;)
{
int numRead = m_currentStream.Read(buffer, offset + totalRead, count - totalRead);
if (numRead > 0)
{
totalRead += numRead;
if (totalRead == count)
return totalRead;
}
else
{
m_padBits = m_currentParser.PadBits;
m_currentParser = GetNextParser();
if (m_currentParser == null)
{
m_currentStream = null;
return totalRead;
}
m_currentStream = m_currentParser.GetBitStream();
}
}
}
public override int ReadByte()
{
if (m_currentStream == null)
{
if (!m_first)
return -1;
m_currentParser = GetNextParser();
if (m_currentParser == null)
return -1;
m_first = false;
m_currentStream = m_currentParser.GetBitStream();
}
for (;;)
{
int b = m_currentStream.ReadByte();
if (b >= 0)
return b;
m_padBits = m_currentParser.PadBits;
m_currentParser = GetNextParser();
if (m_currentParser == null)
{
m_currentStream = null;
return -1;
}
m_currentStream = m_currentParser.GetBitStream();
}
}
private Asn1BitStringParser GetNextParser()
{
IAsn1Convertible asn1Obj = m_parser.ReadObject();
if (asn1Obj == null)
{
if (m_octetAligned && m_padBits != 0)
throw new IOException("expected octet-aligned bitstring, but found padBits: " + m_padBits);
return null;
}
if (asn1Obj is Asn1BitStringParser)
{
if (m_padBits != 0)
throw new IOException("only the last nested bitstring can have padding");
return (Asn1BitStringParser)asn1Obj;
}
throw new IOException("unknown object encountered: " + Platform.GetTypeName(asn1Obj));
}
}
}
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