using System;
using System.Collections;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Security.Certificates;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.IO;

namespace Org.BouncyCastle.X509;

public class X509CertPairParser
{
	private Stream currentStream;

	private X509CertificatePair ReadDerCrossCertificatePair(Stream inStream)
	{
		Asn1InputStream asn1InputStream = new Asn1InputStream(inStream);
		Asn1Sequence obj = (Asn1Sequence)asn1InputStream.ReadObject();
		CertificatePair instance = CertificatePair.GetInstance(obj);
		return new X509CertificatePair(instance);
	}

	public X509CertificatePair ReadCertPair(byte[] input)
	{
		return ReadCertPair(new MemoryStream(input, writable: false));
	}

	public ICollection ReadCertPairs(byte[] input)
	{
		return ReadCertPairs(new MemoryStream(input, writable: false));
	}

	public X509CertificatePair ReadCertPair(Stream inStream)
	{
		if (inStream == null)
		{
			throw new ArgumentNullException("inStream");
		}
		if (!inStream.CanRead)
		{
			throw new ArgumentException("inStream must be read-able", "inStream");
		}
		if (currentStream == null)
		{
			currentStream = inStream;
		}
		else if (currentStream != inStream)
		{
			currentStream = inStream;
		}
		try
		{
			PushbackStream pushbackStream = new PushbackStream(inStream);
			int num = pushbackStream.ReadByte();
			if (num < 0)
			{
				return null;
			}
			pushbackStream.Unread(num);
			return ReadDerCrossCertificatePair(pushbackStream);
		}
		catch (Exception ex)
		{
			throw new CertificateException(ex.ToString());
		}
	}

	public ICollection ReadCertPairs(Stream inStream)
	{
		IList list = Platform.CreateArrayList();
		X509CertificatePair value;
		while ((value = ReadCertPair(inStream)) != null)
		{
			list.Add(value);
		}
		return list;
	}
}