/// <summary>
/// Appends an abbreviation to the given zscii text.
/// </summary>
/// <param name="zcharacter">
/// The zcharacter.
/// </param>
/// <param name="calledRecursively">
/// A value which indicates whether the method was called recursively.
/// </param>
/// <param name="zcharacters">
/// The zcharacters.
/// </param>
/// <param name="zsciiText">
/// The zscii text.
/// </param>
protected void AppendAbbreviation(byte zcharacter, bool calledRecursively, ref ImmutableStack<byte> zcharacters, ref ImmutableStack<Zscii> zsciiText)
{
if (calledRecursively)
{
this.FrontEnd.ErrorNotification(ErrorCondition.NestedAbbreviation, "Nested abbreviation detected.");
return;
}
if (zcharacters != null)
{
var abbreviationNumber = ((zcharacter - 1) * 32) + zcharacters.Top;
zcharacters = zcharacters.Tail;
var abbreviationsTableAddress = this.Memory.ReadWord(24);
var abbreviationAddress = 2 * this.Memory.ReadWord(abbreviationsTableAddress + (2 * abbreviationNumber));
var abbreviation = this.ZCharactersToZscii(true, this.EncodedTextToZCharacters(ref abbreviationAddress));
foreach (var zsciiCharacter in abbreviation.Enumerable())
{
zsciiText = zsciiText.Add(zsciiCharacter);
}
}
}
/// <summary>
/// Adds an alphabet shift to z-characters.
/// </summary>
/// <param name="neededAlphabet">
/// The needed alphabet.
/// </param>
/// <param name="zsciiText">
/// The zscii text following the alphabet shift.
/// </param>
/// <param name="lockedAlphabet">
/// The locked alphabet.
/// </param>
/// <param name="characters">
/// The z-characters.
/// </param>
protected override void AddAlphabetShiftToZCharacters(byte neededAlphabet, ImmutableStack<Zscii> zsciiText, ref byte lockedAlphabet, ref ImmutableStack<byte> characters)
{
characters = characters.Add((byte)(neededAlphabet + 3));
}
/// <summary>
/// Adds an alphabet shift to z-characters.
/// </summary>
/// <param name="neededAlphabet">
/// The needed alphabet.
/// </param>
/// <param name="zsciiText">
/// The zscii text following the alphabet shift.
/// </param>
/// <param name="lockedAlphabet">
/// The locked alphabet.
/// </param>
/// <param name="characters">
/// The z-characters.
/// </param>
protected virtual void AddAlphabetShiftToZCharacters(byte neededAlphabet, ImmutableStack<Zscii> zsciiText, ref byte lockedAlphabet, ref ImmutableStack<byte> characters)
{
// bug: if next character is newline, space, etc...
var shiftCharacter = (byte)(((3 + neededAlphabet - lockedAlphabet) % 3) + 1);
if (zsciiText != null)
{
var nextIndex = this.GetZsciiAlphabetIndex(zsciiText.Top);
var nextNeededAlphabet = (byte)((nextIndex == -1) ? 2 : nextIndex / 26);
if (nextNeededAlphabet == neededAlphabet)
{
shiftCharacter += 2;
lockedAlphabet = neededAlphabet;
}
}
characters = characters.Add(shiftCharacter);
}
/// <summary>
/// Converts a zscii character to z-characters.
/// </summary>
/// <param name="zsciiCharacter">
/// The zscii character.
/// </param>
/// <param name="zsciiText">
/// The zscii text following the zscii character.
/// </param>
/// <param name="lockedAlphabet">
/// The locked alphabet.
/// </param>
/// <param name="characters">
/// The z-characters to add the results to.
/// </param>
/// <remarks>
/// Newline is now part of the zscii alphabet.
/// </remarks>
protected virtual void ZsciiCharacterToZCharacters(Zscii zsciiCharacter, ImmutableStack<Zscii> zsciiText, ref byte lockedAlphabet, ref ImmutableStack<byte> characters)
{
switch (zsciiCharacter)
{
case Zscii.Null:
break;
case Zscii.Space:
characters = characters.Add((byte)0);
break;
case Zscii.NewLine:
characters = characters.Add((byte)1);
break;
default:
this.ZsciiAlphabetCharacterToZCharacters(zsciiCharacter, zsciiText, ref lockedAlphabet, ref characters);
break;
}
}
/// <summary>
/// Converts a zscii alphabet character to z-characters.
/// </summary>
/// <param name="zsciiCharacter">
/// The zscii character.
/// </param>
/// <param name="zsciiText">
/// The zscii text.
/// </param>
/// <param name="lockedAlphabet">
/// The locked alphabet.
/// </param>
/// <param name="characters">
/// The z-characters.
/// </param>
protected void ZsciiAlphabetCharacterToZCharacters(Zscii zsciiCharacter, ImmutableStack<Zscii> zsciiText, ref byte lockedAlphabet, ref ImmutableStack<byte> characters)
{
var zsciiAlphabetIndex = this.GetZsciiAlphabetIndex(zsciiCharacter);
var neededAlphabet = (byte)((zsciiAlphabetIndex == -1) ? 2 : zsciiAlphabetIndex / 26);
if (neededAlphabet != lockedAlphabet)
{
this.AddAlphabetShiftToZCharacters(neededAlphabet, zsciiText, ref lockedAlphabet, ref characters);
}
if (zsciiAlphabetIndex > -1)
{
characters = characters.Add((byte)((zsciiAlphabetIndex % 26) + 6));
}
else
{
characters = characters.Add((byte)6);
characters = characters.Add((byte)((ushort)zsciiCharacter / 32));
characters = characters.Add((byte)((ushort)zsciiCharacter & 31));
}
}
/// <summary>
/// Converts z-characters to zscii text.
/// </summary>
/// <param name="calledRecursively">
/// A value which indicates whether the method was called recursively.
/// </param>
/// <param name="zcharacter">
/// The zcharacter.
/// </param>
/// <param name="currentAlphabet">
/// The current alphabet.
/// </param>
/// <param name="nextAlphabet">
/// The next alphabet.
/// </param>
/// <param name="lockedAlphabet">
/// The locked alphabet.
/// </param>
/// <param name="zcharacters">
/// The zcharacters.
/// </param>
/// <param name="zsciiText">
/// The zscii text.
/// </param>
protected virtual void ZCharactersToZscii(bool calledRecursively, byte zcharacter, byte currentAlphabet, ref byte nextAlphabet, ref byte lockedAlphabet, ref ImmutableStack<byte> zcharacters, ref ImmutableStack<Zscii> zsciiText)
{
switch (zcharacter)
{
case 0:
zsciiText = zsciiText.Add(Zscii.Space);
break;
case 1:
zsciiText = zsciiText.Add(Zscii.NewLine);
break;
case 2:
case 3:
nextAlphabet = (byte)((lockedAlphabet + zcharacter - 1) % 3);
break;
case 4:
case 5:
nextAlphabet = lockedAlphabet = (byte)((lockedAlphabet + zcharacter) % 3);
break;
default:
if (zcharacter == 6 && currentAlphabet == 2)
{
if (zcharacters.Count() > 1)
{
zsciiText = zsciiText.Add((Zscii)((zcharacters.Top * 32) + zcharacters.Tail.Top));
zcharacters = zcharacters.Tail.Tail;
}
else
{
zcharacters = null;
}
break;
}
zsciiText = zsciiText.Add(this.GetZsciiAlphabetCharacter((byte)((currentAlphabet * 26) + zcharacter - 6)));
break;
}
}
