AvxBase64Perf.cs

namespace Base64Benchmarks
{
    public class Base64EncodeBenchmarks
    {
        private const int N = 20 * 1024 * 1024;
        private readonly byte[] _data;

        public Base64EncodeBenchmarks()
        {
            _data = new byte[N];
            new Random(42).NextBytes(_data);
        }
        
        [Benchmark]
        public void System_Base64_EncodeToUtf8()
        {
            var output = new byte[4 * 1024];
            for (var i = 0; i < _data.Length;)
            {
                Base64.EncodeToUtf8(new ReadOnlySpan<byte>(_data, i, _data.Length - i), output, out var bytesConsumed,
                    out var bytesWritten);
                i += bytesConsumed;
            }
        }

        [Benchmark]
        public void NaiveLoad()
        {
            for (var i = 0; i < _data.Length; i++)
            {
                _ = _data[i];
            }
        }

        [Benchmark]
        public unsafe void AvxLoad()
        {
            fixed (byte* ptr = _data)
            {
                var pData = ptr;
                var pEnd = ptr + _data.Length;

                while (pData < pEnd)
                {
                    Avx.LoadVector256(pData);
                    pData += 8;
                }
            }
        }
    }
}