private static void CopyStream(IEnumerator <Step> sourceWalker, IEnumerator <Step> targetWalker, CopyInfo copyInfo)
{
/* initialize source walker */
var sourceStream = default(Stream);
var lastSourceChunk = default(ulong[]);
/* initialize target walker */
var targetBuffer = default(Memory <byte>);
var lastTargetChunk = default(ulong[]);
var currentTarget = default(Memory <byte>);
/* walk until end */
while (sourceWalker.MoveNext())
{
/* load next source stream */
var sourceStep = sourceWalker.Current;
if (sourceStream is null /* if stream not assigned yet */ ||
!sourceStep.Chunk.SequenceEqual(lastSourceChunk) /* or the chunk has changed */)
{
sourceStream = copyInfo.GetSourceStream(sourceStep.Chunk);
lastSourceChunk = sourceStep.Chunk;
}
sourceStream?.Seek((int)sourceStep.Offset * copyInfo.TypeSize, SeekOrigin.Begin); // corresponds to
var currentLength = (int)sourceStep.Length * copyInfo.TypeSize; // sourceBuffer.Slice()
while (currentLength > 0)
{
/* load next target buffer */
if (currentTarget.Length == 0)
{
var success = targetWalker.MoveNext();
var targetStep = targetWalker.Current;
if (!success || targetStep.Length == 0)
{
throw new UriFormatException("The target walker stopped early.");
}
if (targetBuffer.Length == 0 /* if buffer not assigned yet */ ||
!targetStep.Chunk.SequenceEqual(lastTargetChunk) /* or the chunk has changed */)
{
targetBuffer = copyInfo.GetTargetBuffer(targetStep.Chunk);
lastTargetChunk = targetStep.Chunk;
}
currentTarget = targetBuffer.Slice(
(int)targetStep.Offset * copyInfo.TypeSize,
(int)targetStep.Length * copyInfo.TypeSize);
}
/* copy */
var length = Math.Min(currentLength, currentTarget.Length);
sourceStream?.Read(currentTarget.Slice(0, length).Span); // corresponds to span.CopyTo
sourceStream?.Seek((int)sourceStep.Offset * copyInfo.TypeSize, SeekOrigin.Begin); // corresponds to
currentLength -= (int)sourceStep.Length * copyInfo.TypeSize; // sourceBuffer.Slice()
currentTarget = currentTarget.Slice(length);
}
}
}
private static void CopyMemory(IEnumerator <Step> sourceWalker, IEnumerator <Step> targetWalker, CopyInfo copyInfo)
{
/* initialize source walker */
var sourceBuffer = default(Memory <byte>);
var lastSourceChunk = default(ulong[]);
/* initialize target walker */
var targetBuffer = default(Memory <byte>);
var lastTargetChunk = default(ulong[]);
var currentTarget = default(Memory <byte>);
/* walk until end */
while (sourceWalker.MoveNext())
{
/* load next source buffer */
var sourceStep = sourceWalker.Current;
if (sourceBuffer.Length == 0 /* if buffer not assigned yet */ ||
!sourceStep.Chunk.SequenceEqual(lastSourceChunk) /* or the chunk has changed */)
{
sourceBuffer = copyInfo.GetSourceBuffer(sourceStep.Chunk);
lastSourceChunk = sourceStep.Chunk;
}
var currentSource = sourceBuffer.Slice(
(int)sourceStep.Offset * copyInfo.TypeSize,
(int)sourceStep.Length * copyInfo.TypeSize);
while (currentSource.Length > 0)
{
/* load next target buffer */
if (currentTarget.Length == 0)
{
var success = targetWalker.MoveNext();
var targetStep = targetWalker.Current;
if (!success || targetStep.Length == 0)
{
throw new UriFormatException("The target walker stopped early.");
}
if (targetBuffer.Length == 0 /* if buffer not assigned yet */ ||
!targetStep.Chunk.SequenceEqual(lastTargetChunk) /* or the chunk has changed */)
{
targetBuffer = copyInfo.GetTargetBuffer(targetStep.Chunk);
lastTargetChunk = targetStep.Chunk;
}
currentTarget = targetBuffer.Slice(
(int)targetStep.Offset * copyInfo.TypeSize,
(int)targetStep.Length * copyInfo.TypeSize);
}
/* copy */
var length = Math.Min(currentSource.Length, currentTarget.Length);
currentSource
.Slice(0, length)
.CopyTo(currentTarget);
currentSource = currentSource.Slice(length);
currentTarget = currentTarget.Slice(length);
}
}
}