AlignedMemoryReader.cs

using System;
using System.Diagnostics;
using System.IO;
using Ara3D.Buffers;

namespace Ara3D.StepParser
{
    public static class AlignedMemoryReader
    {
        public static unsafe AlignedMemory ReadAllBytes(string path, int bufferSize = 1024 * 1024)
        {
            using var fs = new FileStream(path,
                FileMode.Open,
                FileAccess.Read,
                FileShare.Read,
                bufferSize,
                false);
            var fileLength = fs.Length;
            if (fileLength > int.MaxValue)
                throw new IOException("File too big: > 2GB");

            var count = (int)fileLength;
            var r = new AlignedMemory(count);
            var pBytes = r.BytePtr;
            while (count > 0)
            {
                var span = new Span<byte>(pBytes, count);
                var n = fs.Read(span);
                if (n == 0)
                    break;
                pBytes += n;
                count -= n;
            }

            Debug.Assert(count == 0);
            return r;
        }
    }
}