/// <summary>
/// Set the record to a FreeRecord
/// </summary>
public virtual void MarkAsFreeRecord()
{
var s = Ggpk.FileStream;
s.Seek(Offset, SeekOrigin.Begin);
var free = new FreeRecord(Length, Ggpk, 0, Offset);
free.Write();
var lastFree = Ggpk.FreeRecords.Last?.Value;
if (lastFree == null) // No FreeRecord
{
Ggpk.GgpkRecord.FirstFreeRecordOffset = Offset;
s.Seek(Ggpk.GgpkRecord.Offset + 20, SeekOrigin.Begin);
s.Write(Offset);
}
else
{
lastFree.NextFreeOffset = Offset;
s.Seek(lastFree.Offset + 8, SeekOrigin.Begin);
s.Write(Offset);
}
Ggpk.FreeRecords.AddLast(free);
}
/// <summary>
/// Replace the file content with a new content,
/// and move the record to the FreeRecord with most suitable size.
/// </summary>
public virtual void ReplaceContent(ReadOnlySpan <byte> NewContent)
{
var s = Ggpk.FileStream;
if (!Hash256.TryComputeHash(NewContent, Hash, out _))
{
throw new("Unable to compute hash of the content");
}
if (NewContent.Length == DataLength) // Replace in situ
{
s.Seek(DataOffset, SeekOrigin.Begin);
s.Write(NewContent);
}
else // Replace a FreeRecord
{
var oldOffset = Offset;
MarkAsFreeRecord();
DataLength = NewContent.Length;
Length = 44 + (Name.Length + 1) * 2 + DataLength; // (8 + (Name + "\0").Length * 2 + 32 + 4) + DataLength
LinkedListNode <FreeRecord>?bestNode = null; // Find the FreeRecord with most suitable size
var currentNode = Ggpk.FreeRecords.First !;
var space = int.MaxValue;
do
{
if (currentNode.Value.Length == Length)
{
bestNode = currentNode;
space = 0;
break;
}
var tmpSpace = currentNode.Value.Length - Length;
if (tmpSpace < space && tmpSpace >= 16)
{
bestNode = currentNode;
space = tmpSpace;
}
} while ((currentNode = currentNode.Next) != null);
if (bestNode == null)
{
s.Seek(0, SeekOrigin.End); // Write to the end of GGPK
Write();
s.Write(NewContent);
}
else
{
FreeRecord free = bestNode.Value;
s.Seek(free.Offset + free.Length - Length, SeekOrigin.Begin); // Write to the FreeRecord
Write();
s.Write(NewContent);
free.Length = space;
if (space >= 16) // Update offset of FreeRecord
{
s.Seek(free.Offset, SeekOrigin.Begin);
s.Write(free.Length);
}
else // Remove the FreeRecord
{
free.Remove(bestNode);
}
}
UpdateOffset(oldOffset); // Update the offset of FileRecord in Parent.Entries/>
}
s.Flush();
}
