DefiniteLengthInputStream.cs
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using System;
using System.IO;
using Org.BouncyCastle.Utilities.IO;
namespace Org.BouncyCastle.Asn1
{
class DefiniteLengthInputStream
: LimitedInputStream
{
private static readonly byte[] EmptyBytes = new byte[0];
private readonly int _originalLength;
private int _remaining;
internal DefiniteLengthInputStream(
Stream inStream,
int length)
: base(inStream, length)
{
if (length < 0)
throw new ArgumentException("negative lengths not allowed", "length");
this._originalLength = length;
this._remaining = length;
if (length == 0)
{
SetParentEofDetect(true);
}
}
internal int Remaining
{
get { return _remaining; }
}
public override int ReadByte()
{
if (_remaining == 0)
return -1;
int b = _in.ReadByte();
if (b < 0)
throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
if (--_remaining == 0)
{
SetParentEofDetect(true);
}
return b;
}
public override int Read(
byte[] buf,
int off,
int len)
{
if (_remaining == 0)
return 0;
int toRead = System.Math.Min(len, _remaining);
int numRead = _in.Read(buf, off, toRead);
if (numRead < 1)
throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
if ((_remaining -= numRead) == 0)
{
SetParentEofDetect(true);
}
return numRead;
}
internal void ReadAllIntoByteArray(byte[] buf)
{
if (_remaining != buf.Length)
throw new ArgumentException("buffer length not right for data");
if ((_remaining -= Streams.ReadFully(_in, buf)) != 0)
throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
SetParentEofDetect(true);
}
internal byte[] ToArray()
{
if (_remaining == 0)
return EmptyBytes;
byte[] bytes = new byte[_remaining];
if ((_remaining -= Streams.ReadFully(_in, bytes)) != 0)
throw new EndOfStreamException("DEF length " + _originalLength + " object truncated by " + _remaining);
SetParentEofDetect(true);
return bytes;
}
}
}