/// <summary>
/// Parses the pice table and creates a list of PieceDescriptors.
/// </summary>
/// <param name="fib">The FIB</param>
/// <param name="tableStream">The 0Table or 1Table stream</param>
public PieceTable(FileInformationBlock fib, VirtualStream tableStream)
{
//Read the bytes of complex file information
byte[] bytes = new byte[fib.lcbClx];
tableStream.Read(bytes, 0, (int)fib.lcbClx, (int)fib.fcClx);
this.Pieces = new List <PieceDescriptor>();
this.FileCharacterPositions = new Dictionary <int, int>();
this.CharacterPositions = new Dictionary <int, int>();
int pos = 0;
bool goon = true;
while (goon)
{
try
{
byte type = bytes[pos];
//check if the type of the entry is a piece table
if (type == 2)
{
Int32 lcb = System.BitConverter.ToInt32(bytes, pos + 1);
//read the piece table
byte[] piecetable = new byte[lcb];
Array.Copy(bytes, pos + 5, piecetable, 0, piecetable.Length);
//count of PCD _entries
int n = (lcb - 4) / 12;
//and n piece descriptors
for (int i = 0; i < n; i++)
{
//read the CP
int indexCp = i * 4;
Int32 cp = System.BitConverter.ToInt32(piecetable, indexCp);
//read the next CP
int indexCpNext = (i + 1) * 4;
Int32 cpNext = System.BitConverter.ToInt32(piecetable, indexCpNext);
//read the PCD
int indexPcd = ((n + 1) * 4) + (i * 8);
byte[] pcdBytes = new byte[8];
Array.Copy(piecetable, indexPcd, pcdBytes, 0, 8);
PieceDescriptor pcd = new PieceDescriptor(pcdBytes);
pcd.cpStart = cp;
pcd.cpEnd = cpNext;
//add pcd
this.Pieces.Add(pcd);
//add positions
Int32 f = (Int32)pcd.fc;
Int32 multi = 1;
if (pcd.encoding == Encoding.Unicode)
{
multi = 2;
}
for (int c = pcd.cpStart; c < pcd.cpEnd; c++)
{
if (!this.FileCharacterPositions.ContainsKey(c))
{
this.FileCharacterPositions.Add(c, f);
}
if (!this.CharacterPositions.ContainsKey(f))
{
this.CharacterPositions.Add(f, c);
}
f += multi;
}
}
int maxCp = this.FileCharacterPositions.Count;
this.FileCharacterPositions.Add(maxCp, fib.fcMac);
this.CharacterPositions.Add(fib.fcMac, maxCp);
//piecetable was found
goon = false;
}
//entry is no piecetable so goon
else if (type == 1)
{
Int16 cb = System.BitConverter.ToInt16(bytes, pos + 1);
pos = pos + 1 + 2 + cb;
}
else
{
goon = false;
}
}
catch (Exception)
{
goon = false;
}
}
}
public List <char> GetChars(Int32 fcStart, Int32 fcEnd, VirtualStream wordStream)
{
List <char> chars = new List <char>();
for (int i = 0; i < this.Pieces.Count; i++)
{
PieceDescriptor pcd = this.Pieces[i];
//get the FC end of this piece
Int32 pcdFcEnd = pcd.cpEnd - pcd.cpStart;
if (pcd.encoding == Encoding.Unicode)
{
pcdFcEnd *= 2;
}
pcdFcEnd += (Int32)pcd.fc;
if (pcdFcEnd < fcStart)
{
//this piece is before the requested range
continue;
}
else if (fcStart >= pcd.fc && fcEnd > pcdFcEnd)
{
//requested char range starts at this piece
//read from fcStart to pcdFcEnd
//get count of bytes
int cb = pcdFcEnd - fcStart;
byte[] bytes = new byte[cb];
//read all bytes
wordStream.Read(bytes, 0, cb, (Int32)fcStart);
//get the chars
char[] plainChars = pcd.encoding.GetString(bytes).ToCharArray();
//add to list
foreach (char c in plainChars)
{
chars.Add(c);
}
}
else if (fcStart <= pcd.fc && fcEnd >= pcdFcEnd)
{
//the full piece is part of the requested range
//read from pc.fc to pcdFcEnd
//get count of bytes
int cb = pcdFcEnd - (Int32)pcd.fc;
byte[] bytes = new byte[cb];
//read all bytes
wordStream.Read(bytes, 0, cb, (Int32)pcd.fc);
//get the chars
char[] plainChars = pcd.encoding.GetString(bytes).ToCharArray();
//add to list
foreach (char c in plainChars)
{
chars.Add(c);
}
}
else if (fcStart < pcd.fc && fcEnd >= pcd.fc && fcEnd <= pcdFcEnd)
{
//requested char range ends at this piece
//read from pcd.fc to fcEnd
//get count of bytes
int cb = fcEnd - (Int32)pcd.fc;
byte[] bytes = new byte[cb];
//read all bytes
wordStream.Read(bytes, 0, cb, (Int32)pcd.fc);
//get the chars
char[] plainChars = pcd.encoding.GetString(bytes).ToCharArray();
//add to list
foreach (char c in plainChars)
{
chars.Add(c);
}
break;
}
else if (fcStart >= pcd.fc && fcEnd <= pcdFcEnd)
{
//requested chars are completly in this piece
//read from fcStart to fcEnd
//get count of bytes
int cb = fcEnd - fcStart;
byte[] bytes = new byte[cb];
//read all bytes
wordStream.Read(bytes, 0, cb, (Int32)fcStart);
//get the chars
char[] plainChars = pcd.encoding.GetString(bytes).ToCharArray();
//set the list
chars = new List <char>(plainChars);
break;
}
else if (fcEnd < pcd.fc)
{
//this piece is beyond the requested range
break;
}
}
return(chars);
}