/// <summary>
/// Writes file payload to the filesystem and mark the sectors as allocated.
/// </summary>
/// <param name="data">Data to write to the filesystem.</param>
/// <param name="extents">Information about extents to write the data to.</param>
internal void WriteFileData(byte[] data, DragonDosDirectoryEntry.Extent[] extents)
{
int dataOffset = 0;
foreach (var extent in extents)
{
int lsn = extent.Lsn;
int sectorCnt = extent.Length;
while (sectorCnt-- > 0)
{
int length = Math.Min(SectorSize, data.Length - dataOffset);
WriteSector(lsn, data, dataOffset, length);
SetSectorAllocated(lsn++, true);
dataOffset += length;
}
}
}
/// <summary>
/// Create a set of directory entries for a file.
/// </summary>
/// <param name="filename">Filename</param>
/// <param name="extents">Ordered list of extents containing the file payload data.</param>
/// <param name="dirInx">Orderes list of directory entry indexes to use.</param>
/// <returns>Orderes list of directory entries</returns>
private DragonDosDirectoryEntry[] CreateDirectoryEntries(string filename, DragonDosDirectoryEntry.Extent[] extents, int[] dirInx, int lastSectorSize)
{
var dirEntries = new DragonDosDirectoryEntry[dirInx.Length];
int maxExtents;
int extentOffset = 0;
for (int i = 0; i < dirInx.Length; i++ )
{
var dir = new DragonDosDirectoryEntry() {Flags = 0};
if (i == 0)
{
dir.Filename = filename;
dir.IsExtensionEntry = false;
maxExtents = 4;
}
else
{
dir.IsExtensionEntry = true;
maxExtents = 7;
}
if (i == dirInx.Length-1)
{
dir.LastSectorSize = lastSectorSize;
}
else
{
dir.NextEntry = dirInx[i + 1];
}
dir.Extents = new DragonDosDirectoryEntry.Extent[Math.Min(maxExtents, extents.Length - extentOffset)];
Array.Copy(extents, extentOffset, dir.Extents, 0, dir.Extents.Length);
extentOffset += dir.Extents.Length;
dirEntries[i] = dir;
}
return dirEntries;
}
/// <summary>
/// Sets the directory entry at a given index.
/// </summary>
/// <param name="index"></param>
/// <param name="entry"></param>
private void SetDirectoryEntry(int index, DragonDosDirectoryEntry entry)
{
int sector = index / DirectoryEntryCount + DirectoryEntryOffset;
int offset = index % DirectoryEntryCount * DirectoryEntrySize;
entry.Encode(directoryTrack[sector], offset);
}
