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

87 lines
1.4 KiB
C#

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 int _length;
internal DefiniteLengthInputStream(
Stream inStream,
int length)
: base(inStream)
{
if (length < 0)
throw new ArgumentException("negative lengths not allowed", "length");
this._length = length;
}
public override int ReadByte()
{
if (_length > 0)
{
int b = _in.ReadByte();
if (b < 0)
throw new EndOfStreamException();
--_length;
return b;
}
SetParentEofDetect(true);
return -1;
}
public override int Read(
byte[] buf,
int off,
int len)
{
if (_length > 0)
{
int toRead = System.Math.Min(len, _length);
int numRead = _in.Read(buf, off, toRead);
if (numRead < 1)
throw new EndOfStreamException();
_length -= numRead;
return numRead;
}
SetParentEofDetect(true);
return 0;
}
internal byte[] ToArray()
{
byte[] bytes;
if (_length > 0)
{
bytes = new byte[_length];
if (Streams.ReadFully(_in, bytes) < _length)
throw new EndOfStreamException();
_length = 0;
}
else
{
bytes = EmptyBytes;
}
SetParentEofDetect(true);
return bytes;
}
}
}