private void AddDfaState(int p_index, FAState p_fastate)
{
if (!m_initialized)
{
throw new ParserException("Table sizes not initialized");
}
m_DfaStates[p_index] = p_fastate;
}
/// This method implements the DFA algorithm and returns a token
/// to the LALR state machine.
private Token RetrieveToken()
{
Token result;
int currentPos = 0;
int lastAcceptState = -1;
int lastAcceptPos = -1;
FAState currentState = m_DfaStates[m_initDfaState];
try
{
while (true)
{
// This code searches all the branches of the current DFA state for the next
// character in the input LookaheadStream. If found the target state is returned.
// The InStr() function searches the string pCharacterSetTable.Member(CharSetIndex)
// starting at position 1 for ch. The pCompareMode variable determines whether
// the search is case sensitive.
int target = -1;
char ch = FixCase(m_source.LookAhead(currentPos));
foreach (FAEdge edge in currentState.Edges)
{
String chars = edge.Characters;
if (chars.IndexOf(ch) != -1)
{
target = edge.TargetIndex;
break;
}
}
// This block-if statement checks whether an edge was found from the current state.
// If so, the state and current position advance. Otherwise it is time to exit the main loop
// and report the token found (if there was it fact one). If the LastAcceptState is -1,
// then we never found a match and the Error Token is created. Otherwise, a new token
// is created using the Symbol in the Accept State and all the characters that
// comprise it.
if (target != -1)
{
// This code checks whether the target state accepts a token. If so, it sets the
// appropiate variables so when the algorithm is done, it can return the proper
// token and number of characters.
if (m_DfaStates[target].AcceptSymbol != -1)
{
lastAcceptState = target;
lastAcceptPos = currentPos;
}
currentState = m_DfaStates[target];
currentPos++;
}
else
{
if (lastAcceptState == -1)
{
result = new Token(m_errorSymbol);
result.Data = m_source.Read(1);
}
else
{
Symbol symbol = m_symbols[m_DfaStates[lastAcceptState].AcceptSymbol];
result = new Token(symbol);
result.Data = m_source.Read(lastAcceptPos + 1);
}
break;
}
}
}
catch (EndOfStreamException)
{
result = new Token(m_endSymbol);
result.Data = "";
}
UpdateLineNumber((String)result.Data);
return(result);
}
private void LoadTables(GrammarReader reader)
{
Object obj; Int16 index;
while (reader.MoveNext())
{
byte id = (byte)reader.RetrieveNext();
switch ((RecordId)id)
{
case RecordId.Parameters:
m_parameters["Name"] = (String)reader.RetrieveNext();
m_parameters["Version"] = (String)reader.RetrieveNext();
m_parameters["Author"] = (String)reader.RetrieveNext();
m_parameters["About"] = (String)reader.RetrieveNext();
m_caseSensitive = (Boolean)reader.RetrieveNext();
m_startSymbol = (Int16)reader.RetrieveNext();
break;
case RecordId.TableCounts:
m_symbols = new Symbol[(Int16)reader.RetrieveNext()];
m_charsets = new String[(Int16)reader.RetrieveNext()];
m_rules = new Rule[(Int16)reader.RetrieveNext()];
m_DfaStates = new FAState[(Int16)reader.RetrieveNext()];
m_LalrTables = new LRActionTable[(Int16)reader.RetrieveNext()];
m_initialized = true;
break;
case RecordId.Initial:
m_initDfaState = (Int16)reader.RetrieveNext();
m_initLalrState = (Int16)reader.RetrieveNext();
break;
case RecordId.Symbols:
index = (Int16)reader.RetrieveNext();
String name = (String)reader.RetrieveNext();
SymbolType kind = (SymbolType)(Int16)reader.RetrieveNext();
Symbol symbol = new Symbol(index, name, kind);
AddSymbol(symbol);
break;
case RecordId.CharSets:
index = (Int16)reader.RetrieveNext();
String charset = (String)reader.RetrieveNext();
AddCharset(index, charset);
break;
case RecordId.Rules:
index = (Int16)reader.RetrieveNext();
Symbol head = m_symbols[(Int16)reader.RetrieveNext()];
Rule rule = new Rule(index, head);
reader.RetrieveNext(); // reserved
while ((obj = reader.RetrieveNext()) != null)
{
rule.AddItem(m_symbols[(Int16)obj]);
}
AddRule(rule);
break;
case RecordId.DFAStates:
FAState fastate = new FAState();
index = (Int16)reader.RetrieveNext();
if ((bool)reader.RetrieveNext())
{
fastate.AcceptSymbol = (Int16)reader.RetrieveNext();
}
else
{
reader.RetrieveNext();
}
reader.RetrieveNext(); // reserverd
while (!reader.RetrieveDone())
{
Int16 ci = (Int16)reader.RetrieveNext();
Int16 ti = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
fastate.AddEdge(m_charsets[ci], ti);
}
AddDfaState(index, fastate);
break;
case RecordId.LRTables:
LRActionTable table = new LRActionTable();
index = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserverd
while (!reader.RetrieveDone())
{
Int16 sid = (Int16)reader.RetrieveNext();
Int16 action = (Int16)reader.RetrieveNext();
Int16 tid = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
table.AddItem(m_symbols[sid], (Action)action, tid);
}
AddLalrTable(index, table);
break;
case RecordId.Comment:
Console.WriteLine("Comment record encountered");
break;
default:
throw new ParserException("Wrong id for record");
}
}
}
private void LoadTables(GrammarReader reader)
{
Object obj; Int16 index;
while (reader.MoveNext())
{
byte id = (byte)reader.RetrieveNext();
switch ((RecordId)id)
{
case RecordId.Parameters:
m_parameters["Name"] = (String)reader.RetrieveNext();
m_parameters["Version"] = (String)reader.RetrieveNext();
m_parameters["Author"] = (String)reader.RetrieveNext();
m_parameters["About"] = (String)reader.RetrieveNext();
m_caseSensitive = (Boolean)reader.RetrieveNext();
m_startSymbol = (Int16)reader.RetrieveNext();
break;
case RecordId.TableCounts:
m_symbols = new Symbol[(Int16)reader.RetrieveNext()];
m_charsets = new String[(Int16)reader.RetrieveNext()];
m_rules = new Rule[(Int16)reader.RetrieveNext()];
m_DfaStates = new FAState[(Int16)reader.RetrieveNext()];
m_LalrTables = new LRActionTable[(Int16)reader.RetrieveNext()];
m_initialized = true;
break;
case RecordId.Initial:
m_initDfaState = (Int16)reader.RetrieveNext();
m_initLalrState = (Int16)reader.RetrieveNext();
break;
case RecordId.Symbols:
index = (Int16)reader.RetrieveNext();
String name = (String)reader.RetrieveNext();
SymbolType kind = (SymbolType)(Int16)reader.RetrieveNext();
Symbol symbol = new Symbol(index, name, kind);
AddSymbol(symbol);
break;
case RecordId.CharSets:
index = (Int16)reader.RetrieveNext();
String charset = (String)reader.RetrieveNext();
AddCharset(index, charset);
break;
case RecordId.Rules:
index = (Int16)reader.RetrieveNext();
Symbol head = m_symbols[(Int16)reader.RetrieveNext()];
Rule rule = new Rule(index, head);
reader.RetrieveNext(); // reserved
while ((obj = reader.RetrieveNext()) != null)
rule.AddItem(m_symbols[(Int16)obj]);
AddRule(rule);
break;
case RecordId.DFAStates:
FAState fastate = new FAState();
index = (Int16)reader.RetrieveNext();
if ((bool)reader.RetrieveNext())
fastate.AcceptSymbol = (Int16)reader.RetrieveNext();
else
reader.RetrieveNext();
reader.RetrieveNext(); // reserverd
while (! reader.RetrieveDone())
{
Int16 ci = (Int16)reader.RetrieveNext();
Int16 ti = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
fastate.AddEdge(m_charsets[ci], ti);
}
AddDfaState(index, fastate);
break;
case RecordId.LRTables:
LRActionTable table = new LRActionTable();
index = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserverd
while (! reader.RetrieveDone())
{
Int16 sid = (Int16)reader.RetrieveNext();
Int16 action = (Int16)reader.RetrieveNext();
Int16 tid = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
table.AddItem(m_symbols[sid], (Action)action, tid);
}
AddLalrTable(index, table);
break;
case RecordId.Comment:
Console.WriteLine("Comment record encountered");
break;
default:
throw new ParserException("Wrong id for record");
}
}
}
private void AddDfaState(int p_index, FAState p_fastate)
{
if (! m_initialized)
throw new ParserException("Table sizes not initialized");
m_DfaStates[p_index] = p_fastate;
}