public BufferReader ReadBuffer(int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}
if (length > endIndex - index)
{
throw new EndOfStreamException();
}
BufferReader subReader = new BufferReader(buffer, index, length, encoding);
index += length;
return(subReader);
}
// TODO: compression is topic/database independent, so move them
// into a separate namespace/class.
static HelpTopic DecompileTopic(byte[] buffer, char controlCharacter)
{
HelpTopic topic = new HelpTopic();
BufferReader reader = new BufferReader(buffer, Graphic437);
while (!reader.IsEOF)
{
HelpLine line = null;
try
{
DecodeLine(reader, out line);
}
catch (Exception)
{
if (line != null)
{
topic.Lines.Add(line);
}
throw;
}
bool isCommand = true;
try
{
isCommand = HelpCommandConverter.ProcessCommand(
line.Text, controlCharacter, topic);
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(string.Format(
"Unable to process command '{0}': {1}",
line.Text, ex.Message));
}
if (!isCommand)
{
topic.Lines.Add(line);
}
}
return(topic);
}
internal static void DecodeLine(BufferReader reader, out HelpLine line)
{
line = null;
// Read text length in bytes.
int textLength = reader.ReadByte();
string text = reader.ReadFixedLengthString(textLength - 1);
line = new HelpLine(text);
// Read byte count of attributes.
int attrLength = reader.ReadByte();
BufferReader attrReader = reader.ReadBuffer(attrLength - 1);
DecodeLineAttributes(line, attrReader);
// Read hyperlinks.
while (!attrReader.IsEOF)
{
DecodeLineHyperlink(line, attrReader);
}
}
private static void DecodeLineHyperlink(HelpLine line, BufferReader reader)
{
// Read link location.
int linkStartIndex = reader.ReadByte(); // one-base, inclusive
int linkEndIndex = reader.ReadByte(); // one-base, inclusive
if (linkStartIndex == 0 || linkStartIndex > linkEndIndex)
{
throw new InvalidDataException("Invalid link location.");
}
if (linkEndIndex > line.Length)
{
System.Diagnostics.Debug.WriteLine(string.Format(
"WARNING: Link end {0} is past line end {1}.",
linkEndIndex, line.Length));
linkEndIndex = line.Length;
}
//if (linkStartIndex
// Read NULL-terminated context string.
string context = reader.ReadNullTerminatedString();
if (context == "") // link is WORD topic index
{
int numContext = reader.ReadUInt16(); // 0x8000 | topicIndex
context = "@L" + numContext.ToString("X4");
}
// Add hyperlink to the line.
HelpUri link = new HelpUri(context);
for (int j = linkStartIndex; j <= linkEndIndex; j++)
{
line.Attributes[j - 1] = new TextAttribute(line.Attributes[j - 1].Style, link);
}
}