muparsertokenreader.cpp

Mathematical expressions parser library

				              m_iSynFlags  = noBO | noVAR | noVAL | noFUN | noINFIXOP | noSTR | noASSIGN;
				              break;
      	
		    default:      // The operator is listed in c_DefaultOprt, but not here. This is a bad thing...
                      Error(ecINTERNAL_ERROR);
	      } // switch operator id

        m_iPos += (int)len;
        a_Tok.Set( (ECmdCode)i, pOprtDef[i] );
        return true;
	    } // if operator string found
    } // end of for all operator strings
  
    return false;
  }

  //---------------------------------------------------------------------------
  /** \brief Check for End of Formula.

      \return true if an end of formula is found false otherwise.
      \param a_Tok [out] If an eof is found the corresponding token will be stored there.
      \throw nothrow
      \sa IsOprt, IsFunTok, IsStrFunTok, IsValTok, IsVarTok, IsString, IsInfixOpTok, IsPostOpTok
  */
  bool ParserTokenReader::IsEOF(token_type &a_Tok)
  {
    const char_type* szFormula = m_strFormula.c_str();

    // check for EOF
    if ( !szFormula[m_iPos] || szFormula[m_iPos] == '\n')
    {
      if ( m_iSynFlags & noEND )
        Error(ecUNEXPECTED_EOF, m_iPos);

      m_iSynFlags = 0;
      a_Tok.Set(cmEND);
      return true;
    }

    return false;
  }

  //---------------------------------------------------------------------------
  /** \brief Check if a string position contains a unary infix operator. 
      \return true if a function token has been found false otherwise.
  */
  bool ParserTokenReader::IsInfixOpTok(token_type &a_Tok)
  {
    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidInfixOprtChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    funmap_type::const_iterator item = m_pInfixOprtDef->find(strTok);
    if (item==m_pInfixOprtDef->end())
      return false;

    a_Tok.Set(item->second, strTok);
    m_iPos = (int)iEnd;

    if (m_iSynFlags & noINFIXOP) 
      Error(ecUNEXPECTED_OPERATOR, m_iPos, a_Tok.GetAsString());

    m_iSynFlags = noPOSTOP | noINFIXOP | noOPT | noBC | noSTR | noASSIGN; 
    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Check whether the token at a given position is a function token.
      \param a_Tok [out] If a value token is found it will be placed here.
      \throw ParserException if Syntaxflags do not allow a function at a_iPos
      \return true if a function token has been found false otherwise.
      \pre [assert] m_pParser!=0
  */
  bool ParserTokenReader::IsFunTok(token_type &a_Tok)
  {
    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidNameChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    funmap_type::const_iterator item = m_pFunDef->find(strTok);
    if (item==m_pFunDef->end())
        return false;

    a_Tok.Set(item->second, strTok);

    m_iPos = (int)iEnd;
    if (m_iSynFlags & noFUN)
      Error(ecUNEXPECTED_FUN, m_iPos-(int)a_Tok.GetAsString().length(), a_Tok.GetAsString());

    m_iSynFlags = noANY ^ noBO;
    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Check if a string position contains a unary post value operator. */
  bool ParserTokenReader::IsPostOpTok(token_type &a_Tok)
  {
    // Tricky problem with equations like "3m+5":
    //     m is a postfix operator, + is a valid sign for postfix operators and 
    //     for binary operators parser detects "m+" as operator string and 
    //     finds no matching postfix operator.
    // 
    // This is a special case so this routine slightly differs from the other
    // token readers.
    
    // Test if there could be a postfix operator
    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidOprtChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    // iteraterate over all postfix operator strings
    funmap_type::const_iterator item = m_pPostOprtDef->begin();
    for (item=m_pPostOprtDef->begin(); item!=m_pPostOprtDef->end(); ++item)
    {
      if (strTok.find(item->first)!=0)
        continue;

      a_Tok.Set(item->second, strTok);
  	  m_iPos += (int)item->first.length();

      if (m_iSynFlags & noPOSTOP)
        Error(ecUNEXPECTED_OPERATOR, m_iPos-(int)a_Tok.GetAsString().length(), a_Tok.GetAsString());

      m_iSynFlags = noVAL | noVAR | noFUN | noBO | noPOSTOP | noSTR | noASSIGN;
      return true;
    }

    return false;
  }

  //---------------------------------------------------------------------------
  /** \brief Check if a string position contains a binary operator.
      \param a_Tok  [out] Operator token if one is found. This can either be a binary operator or an infix operator token.
      \return true if an operator token has been found.
  */
  bool ParserTokenReader::IsOprt(token_type &a_Tok)
  {
    const char_type *szFormula = m_strFormula.c_str();
    int iVarEnd = (int)strspn(&szFormula[m_iPos], m_pParser->ValidOprtChars());
    if (!iVarEnd) return false;
    
    string_type strOprt(&szFormula[m_iPos], &szFormula[m_iPos+iVarEnd]);

    funmap_type::const_iterator item = m_pOprtDef->find(strOprt);
    if (item==m_pOprtDef->end())
      return false;

    a_Tok.Set(item->second, strOprt);

    if (m_iSynFlags & noOPT) 
    {
      // An operator was found but is not expected to occur at
      // this position of the formula, maybe it is an infix 
      // operator, not a binary operator. Both operator types
      // can share characters in their identifiers.
      if ( IsInfixOpTok(a_Tok) ) return true;
      // nope, no infix operator
      Error(ecUNEXPECTED_OPERATOR, m_iPos, a_Tok.GetAsString()); 
    }

	  m_iPos += iVarEnd;
    m_iSynFlags  = noBC | noOPT | noCOMMA | noPOSTOP | noEND | noBC | noASSIGN;
    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Check whether the token at a given position is a value token.

    Value tokens are either values or constants.

    \param a_Tok [out] If a value token is found it will be placed here.
    \return true if a value token has been found.
  */
  bool ParserTokenReader::IsValTok(token_type &a_Tok)
  {
    assert(m_pConstDef);
    assert(m_pParser);

    #if defined(_MSC_VER)
      #pragma warning( disable : 4244 )
    #endif


    stringstream_type stream(&m_strFormula[m_iPos]);
    string_type strTok;
    value_type fVal(0);
    int iEnd(0);
    
    // 2.) Check for user defined constant
    // Read everything that could be a constant name
    iEnd = ExtractToken(m_pParser->ValidNameChars(), strTok, m_iPos);
    if (iEnd!=m_iPos)
    {
      valmap_type::const_iterator item = m_pConstDef->find(strTok);
      if (item!=m_pConstDef->end())
      {
        m_iPos = iEnd;
        a_Tok.SetVal(item->second, strTok);

        if (m_iSynFlags & noVAL)
          Error(ecUNEXPECTED_VAL, m_iPos - (int)strTok.length(), strTok);

        m_iSynFlags = noVAL | noVAR | noFUN | noBO | noINFIXOP | noSTR | noASSIGN; 
        return true;
      }
    }

    // 3.call the value recognition functions provided by the user
    // Call user defined value recognition functions
    std::vector<identfun_type>::const_iterator item = m_vIdentFun.begin();
    for (item = m_vIdentFun.begin(); item!=m_vIdentFun.end(); ++item)
    {
      int iStart = m_iPos;
      if ( (*item)(m_strFormula.c_str() + m_iPos, m_iPos, fVal) )
      {
        strTok.assign(m_strFormula.c_str(), iStart, m_iPos);
        if (m_iSynFlags & noVAL)
          Error(ecUNEXPECTED_VAL, m_iPos - (int)strTok.length(), strTok);

        a_Tok.SetVal(fVal, strTok);
        m_iSynFlags = noVAL | noVAR | noFUN | noBO | noINFIXOP | noSTR | noASSIGN;
        return true;
      }
    }

    return false;

    #if defined(_MSC_VER)
      #pragma warning( default : 4244 )
    #endif
  }

  //---------------------------------------------------------------------------
  /** \brief Check wheter a token at a given position is a variable token. 
      \param a_Tok [out] If a variable token has been found it will be placed here.
	    \return true if a variable token has been found.
  */
  bool ParserTokenReader::IsVarTok(token_type &a_Tok)
  {
    if (!m_pVarDef->size())
      return false;

    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidNameChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    varmap_type::const_iterator item =  m_pVarDef->find(strTok);
    if (item==m_pVarDef->end())
      return false;

    if (m_iSynFlags & noVAR)
      Error(ecUNEXPECTED_VAR, m_iPos, strTok);

    m_iPos = iEnd;
    a_Tok.SetVar(item->second, strTok);
    m_UsedVar[item->first] = item->second;  // Add variable to used-var-list

    m_iSynFlags = noVAL | noVAR | noFUN | noBO | noPOSTOP | noINFIXOP | noSTR;
    return true;
  }

  //---------------------------------------------------------------------------
  bool ParserTokenReader::IsStrVarTok(token_type &a_Tok)
  {
    if (!m_pStrVarDef || !m_pStrVarDef->size())
      return false;

    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidNameChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    strmap_type::const_iterator item =  m_pStrVarDef->find(strTok);
    if (item==m_pStrVarDef->end())
      return false;

    if (m_iSynFlags & noSTR)
      Error(ecUNEXPECTED_VAR, m_iPos, strTok);

    m_iPos = iEnd;
    if (!m_pParser->m_vStringVarBuf.size())
      Error(ecINTERNAL_ERROR);

    a_Tok.SetString(m_pParser->m_vStringVarBuf[item->second], m_pParser->m_vStringVarBuf.size() );

    m_iSynFlags = m_iSynFlags = noANY ^ ( noBC | noOPT | noEND | noCOMMA);
    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Check wheter a token at a given position is an undefined variable. 

      \param a_Tok [out] If a variable tom_pParser->m_vStringBufken has been found it will be placed here.
	    \return true if a variable token has been found.
      \throw nothrow
  */
  bool ParserTokenReader::IsUndefVarTok(token_type &a_Tok)
  {
    string_type strTok;
    int iEnd = ExtractToken(m_pParser->ValidNameChars(), strTok, m_iPos);
    if (iEnd==m_iPos)
      return false;

    if (m_iSynFlags & noVAR)
      Error(ecUNEXPECTED_VAR, m_iPos - (int)a_Tok.GetAsString().length(), a_Tok.GetAsString());

    // If a factory is available implicitely create new variables
    if (m_pFactory)
    {
      value_type *fVar = m_pFactory(strTok.c_str());
      a_Tok.SetVar(fVar, strTok );

      // Do not use m_pParser->DefineVar( strTok, fVar );
      // in order to define the new variable, it will clear the
      // m_UsedVar array which will kill previousely defined variables
      // from the list
      // This is safe because the new variable can never override an existing one
      // because they are checked first!
      (*m_pVarDef)[strTok] = fVar;
      m_UsedVar[strTok] = fVar;  // Add variable to used-var-list
    }
    else
    {
      a_Tok.SetVar((value_type*)&m_fZero, strTok);
      m_UsedVar[strTok] = 0;  // Add variable to used-var-list
    }

    m_iPos = iEnd;

    // Call the variable factory in order to let it define a new parser variable
    m_iSynFlags = noVAL | noVAR | noFUN | noBO | noPOSTOP | noINFIXOP | noSTR;
    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Check wheter a token at a given position is a string.

      \param a_Tok [out] If a variable token has been found it will be placed here.
  	  \return true if a string token has been found.
      \sa IsOprt, IsFunTok, IsStrFunTok, IsValTok, IsVarTok, IsEOF, IsInfixOpTok, IsPostOpTok
      \throw nothrow
  */
  bool ParserTokenReader::IsString(token_type &a_Tok)
  {
    if (m_strFormula[m_iPos]!='"') 
      return false;

    string_type strBuf(&m_strFormula[m_iPos+1]);
    std::size_t iEnd(0), iSkip(0);

    // parser over escaped '\"' end replace them with '"'
    for(iEnd=(int)strBuf.find("\""); iEnd!=string_type::npos; iEnd=(int)strBuf.find("\"", iEnd))
    {
      if (strBuf[iEnd-1]!='\\') break;
      strBuf.replace(iEnd-1, 2, "\"");
      iSkip++;
    }

    if (iEnd==string_type::npos)
      Error(ecUNTERMINATED_STRING, m_iPos, "\"");

    string_type strTok(strBuf.begin(), strBuf.begin()+iEnd);

    if (m_iSynFlags & noSTR)
      Error(ecUNEXPECTED_STR, m_iPos, strTok);

		m_pParser->m_vStringBuf.push_back(strTok); // Store string in internal buffer
    a_Tok.SetString(strTok, m_pParser->m_vStringBuf.size());

    m_iPos += (int)strTok.length() + 2 + (int)iSkip;  // +2 wg Anf黨rungszeichen; +iSkip f黵 entfernte escape zeichen
    m_iSynFlags = m_iSynFlags = noANY ^ ( noBC | noOPT | noEND );

    return true;
  }

  //---------------------------------------------------------------------------
  /** \brief Create an error containing the parse error position.

    This function will create an Parser Exception object containing the error text and its position.

    \param a_iErrc [in] The error code of type #EErrorCodes.
    \param a_iPos [in] The position where the error was detected.
    \param a_strTok [in] The token string representation associated with the error.
    \throw ParserException always throws thats the only purpose of this function.
  */
  void  ParserTokenReader::Error( EErrorCodes a_iErrc, 
                                  int a_iPos, 
                                  const string_type &a_sTok) const
  {
    m_pParser->Error(a_iErrc, a_iPos, a_sTok);
  }
} // namespace mu