Removing/inserting bytes to a hex editor

[kb-1000]

CanRemove and RemoveBytes exist, but appear to be unused.

[kb-1000]

Inserting also seems to behave quite weirdly in general - so currently more or less everything but viewing and editing existing bytes appears to be broken. Unfortunately there's also no builtin resizable IBinaryDocument, though currently there wouldn't be much of a point anyways. I created my own using a List<byte>, could PR it if this gets fixed.
This screenshot shows some (but not all) of the weirdness, created by repeatedly typing A in varying locations:

It only really lets you edit one of the two half-bytes in insert mode. It also doesn't let you place the caret behind the last half-byte, so you can't append bytes.

DynamicBinaryDocument

        public class DynamicBinaryDocument : IBinaryDocument
        {
            private readonly List<byte> _data;

            public event EventHandler<BinaryDocumentChange>? Changed;

            public DynamicBinaryDocument(byte[] data)
            {
                _data = [..data];
                _validRanges = new BitRangeUnion([new BitRange(0UL, Length)]);
            }
    
            public ulong Length => (ulong)_data.Count;
            public bool IsReadOnly => false;
            public bool CanInsert => true;
            public bool CanRemove => true;
            private readonly BitRangeUnion _validRanges;
            public IReadOnlyBitRangeUnion ValidRanges => _validRanges;

            public void ReadBytes(ulong offset, Span<byte> buffer)
            {
                CollectionsMarshal.AsSpan(_data).Slice((int)offset, buffer.Length).CopyTo(buffer);
            }

            public void WriteBytes(ulong offset, ReadOnlySpan<byte> buffer)
            {
                buffer.CopyTo(CollectionsMarshal.AsSpan(_data).Slice((int)offset, buffer.Length));
                OnChanged(new BinaryDocumentChange(BinaryDocumentChangeType.Modify, new BitRange(offset, offset + (ulong) buffer.Length)));
            }

            public void InsertBytes(ulong offset, ReadOnlySpan<byte> buffer)
            {
                _data.InsertRange((int)offset, buffer);
                _validRanges.Add(new BitRange(Length - (ulong)buffer.Length, Length));
                OnChanged(new BinaryDocumentChange(BinaryDocumentChangeType.Insert, new BitRange(offset, offset + (ulong) buffer.Length)));
            }

            public void RemoveBytes(ulong offset, ulong length)
            {
                _data.RemoveRange((int)offset, (int)length);
                _validRanges.Remove(new BitRange(Length, Length + length));
                OnChanged(new BinaryDocumentChange(BinaryDocumentChangeType.Insert, new BitRange(offset, offset + length)));
            }

            protected virtual void OnChanged(BinaryDocumentChange e)
            {
                Changed?.Invoke(this, e);
            }
        }

[Washi1337]

This is correct. Currently the control only fully supports viewing and editing existing bytes. This is also one of the reasons there is no dynamically resizable binary document implementation yet. The interface methods are currently there as a WIP / future work.

Ideally, for a dynamically resizable document we should not use List<byte>, as this would result in insert and remove becoming O(n) operations, which is really bad for large documents of several 100s of megabytes to gigabytes.

[Washi1337]

Status update: Initial implementation of dynamic sized documents can be found in #11.