/// <summary>
/// Creates a new z machine character encoder
/// </summary>
/// <param name="buf">game memory buffer</param>
public ZTextEncoder(MemoryBuffer buf)
{
//Store buffer
this.buf = buf;
//Get version
this.machineVersion = buf.GetByte(0);
//Find unicode table address
int unicodeTable = 0;
if (machineVersion >= 5)
{
//Search the extension header table
ushort extensionHdr = buf.GetUShort(0x36);
if (extensionHdr != 0 && buf.GetUShort(extensionHdr) >= 3)
{
unicodeTable = buf.GetUShort(extensionHdr + 6);
}
}
//Create unicode cache
this.unicodeCache = CreateUnicodeCache(unicodeTable);
//Create reverse cache
// Go in reverse so that ASCII takes priority over custom unicode
for(int i = 255; i > 0; i--)
{
//Add character
if (unicodeCache[i] != InvalidChar)
{
reverseUnicodeCache[unicodeCache[i]] = (byte) i;
}
}
//Create alphabet cache
if (machineVersion >= 5 && buf.GetUShort(0x34) != 0)
{
this.alphabetCache = CreateAlphabetCache(buf.GetUShort(0x34));
}
else
{
//Use default alphabet
this.alphabetCache = machineVersion == 1 ? DEFAULT_ALPHABET_TABLE_V1 : DEFAULT_ALPHABET_TABLE;
}
//Create reverse alphabet cache
for (int i = 0; i < 78; i++)
{
reverseAlphabetCache[reverseUnicodeCache[alphabetCache[i]]] = (byte) (i + 1);
}
//Create abbreviation cache
if (machineVersion >= 2 && buf.GetUShort(0x18) != 0)
{
this.abbreviationCache = CreateAbbreviationCache(buf.GetUShort(0x18));
}
//Cache dictionary information
mainDictionaryAddress = buf.GetUShort(0x8);
mainDictionary = GetDictionaryInfo(mainDictionaryAddress);
}
