/// <summary>
/// Process state that has wildcard transition.
/// </summary>
/// <param name="state">State with wildcard transition</param>
/// <param name="sSearchIn">String to search in.</param>
/// <param name="nCurrIndex">Current index of the search</param>
/// <param name="nSearchUpTo">Index where to stop the search.</param>
private void ProcessWildCard(State state, string sSearchIn, ref int nCurrIndex, int nSearchUpTo)
{
State toState = null;
int nIndex = nCurrIndex;
while (nIndex <= nSearchUpTo)
{
char ch = sSearchIn[nIndex];
toState = state.GetSingleTransition(ch.ToString());
if (toState != null)
{
nCurrIndex = nIndex;
}
nIndex++;
}
}
/// <summary>
/// Determins if a state contains a wildcard transition.
/// i.e., A_*B
/// </summary>
/// <param name="state">State to check</param>
/// <returns>true if the state contains wildcard transition, otherwise false</returns>
private bool IsWildCard(State state)
{
return(state == state.GetSingleTransition(MetaSymbol.ANY_ONE_CHAR_TRANS));
}
/// <summary>
/// Search and finds a match for the compiled pattern.
/// One must call Compile method before calling this method.
/// </summary>
/// <param name="sSearchIn">String to search in.</param>
/// <param name="nSearchStartAt">Index at which to begin the search.</param>
/// <param name="nSearchEndAt">Index at which to end the search.</param>
/// <param name="nFoundBeginAt">If match found, recives the index where the match started, otherwise -1</param>
/// <param name="nFoundEndAt">If match found, recives the index where the match ended, otherwise -1</param>
/// <returns>true if match found, otherwise false.</returns>
public bool FindMatch(string sSearchIn,
int nSearchStartAt,
int nSearchEndAt,
ref int nFoundBeginAt,
ref int nFoundEndAt)
{
if (m_stateStartDfaM == null)
{
return(false);
}
if (nSearchStartAt < 0)
{
return(false);
}
State stateStart = m_stateStartDfaM;
nFoundBeginAt = -1;
nFoundEndAt = -1;
bool bAccepted = false;
State toState = null;
State stateCurr = stateStart;
int nIndex = nSearchStartAt;
int nSearchUpTo = nSearchEndAt;
//看不懂这个匹配
while (nIndex <= nSearchUpTo)
{
if (m_bGreedy && IsWildCard(stateCurr) == true)
{
if (nFoundBeginAt == -1)
{
nFoundBeginAt = nIndex;
}
ProcessWildCard(stateCurr, sSearchIn, ref nIndex, nSearchUpTo);
}
char chInputSymbol = sSearchIn[nIndex];
toState = stateCurr.GetSingleTransition(chInputSymbol.ToString());
if (toState == null)
{
//找不到就寻找是否有any符号
toState = stateCurr.GetSingleTransition(MetaSymbol.ANY_ONE_CHAR_TRANS);
}
if (toState != null)
{
if (nFoundBeginAt == -1)
{
nFoundBeginAt = nIndex;
}
if (toState.AcceptingState)
{
if (m_bMatchAtEnd && nIndex != nSearchUpTo) // then we ignore the accepting state
{
//toState = stateStart ;
}
else
{
bAccepted = true;
nFoundEndAt = nIndex;
if (m_bGreedy == false)
{
break;
}
}
}
stateCurr = toState;
nIndex++;
}
else
{
//找不到状态就重新开始
if (!m_bMatchAtStart && !bAccepted) // we reset everything
{
nIndex = (nFoundBeginAt != -1 ? nFoundBeginAt + 1 : nIndex + 1);
nFoundBeginAt = -1;
nFoundEndAt = -1;
//nIndex++;
stateCurr = stateStart; // start from begining
}
else
{
break;
}
}
} // end of while..loop
if (!bAccepted)
{
if (stateStart.AcceptingState == false)
{
return(false);
}
else // matched an empty string
{
nFoundBeginAt = nSearchStartAt;
nFoundEndAt = nFoundBeginAt - 1;
return(true);
}
}
return(true);
}
