using System;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Crypto.Digests;

public class Sha3Digest : KeccakDigest
{
	public override string AlgorithmName => "SHA3-" + fixedOutputLength;

	private static int CheckBitLength(int bitLength)
	{
		switch (bitLength)
		{
		case 224:
		case 256:
		case 384:
		case 512:
			return bitLength;
		default:
			throw new ArgumentException(bitLength + " not supported for SHA-3", "bitLength");
		}
	}

	public Sha3Digest()
		: this(256)
	{
	}

	public Sha3Digest(int bitLength)
		: base(CheckBitLength(bitLength))
	{
	}

	public Sha3Digest(Sha3Digest source)
		: base(source)
	{
	}

	public override int DoFinal(byte[] output, int outOff)
	{
		AbsorbBits(2, 2);
		return base.DoFinal(output, outOff);
	}

	protected override int DoFinal(byte[] output, int outOff, byte partialByte, int partialBits)
	{
		if (partialBits < 0 || partialBits > 7)
		{
			throw new ArgumentException("must be in the range [0,7]", "partialBits");
		}
		int num = (partialByte & ((1 << partialBits) - 1)) | (2 << partialBits);
		int num2 = partialBits + 2;
		if (num2 >= 8)
		{
			Absorb(new byte[1] { (byte)num }, 0, 1);
			num2 -= 8;
			num >>= 8;
		}
		return base.DoFinal(output, outOff, (byte)num, num2);
	}

	public override IMemoable Copy()
	{
		return new Sha3Digest(this);
	}
}