private int InternalRead()

in src/RecyclableMemoryStream.cs [1474:1507]

• 29 lines of code
• 4 McCabe index (conditional complexity)

        private int InternalRead(Span<byte> buffer, long fromPosition)
        {
            if (this.length - fromPosition <= 0)
            {
                return 0;
            }

            int amountToCopy;

            if (this.largeBuffer == null)
            {
                var blockAndOffset = this.GetBlockAndRelativeOffset(fromPosition);
                int bytesWritten = 0;
                int bytesRemaining = (int)Math.Min(buffer.Length, this.length - fromPosition);

                while (bytesRemaining > 0)
                {
                    amountToCopy = Math.Min(this.blocks[blockAndOffset.Block].Length - blockAndOffset.Offset,
                                            bytesRemaining);
                    this.blocks[blockAndOffset.Block].AsSpan(blockAndOffset.Offset, amountToCopy)
                        .CopyTo(buffer.Slice(bytesWritten));

                    bytesWritten += amountToCopy;
                    bytesRemaining -= amountToCopy;

                    ++blockAndOffset.Block;
                    blockAndOffset.Offset = 0;
                }
                return bytesWritten;
            }
            amountToCopy = (int)Math.Min((long)buffer.Length, this.length - fromPosition);
            this.largeBuffer.AsSpan((int)fromPosition, amountToCopy).CopyTo(buffer);
            return amountToCopy;
        }