Function BuildExpressionTree

mapogcsld.c:5045–5347

/ BuildExpressionTree */ / Build a filter expression node based on mapserver's class */ expression. This is limited to simple expressions like : */ A = B, A < B, A <= B, A > B, A >= B, A != B */ It also handles one level of logical expressions : */ A AND B */ A OR B

/*        NOT A                                                         */
/************************************************************************/
FilterEncodingNode *BuildExpressionTree(char *pszExpression, 
                                        FilterEncodingNode *psNode)
{
    char *apszExpression[20]; 
    int nLength = 0;
    /* int bInsideExpression = 0; */
    int i =0, nOperators=0;
    char *pszFinalExpression = NULL;
    int iFinal = 0, iIndiceExp=0, nOpeningBrackets=0;/* nIndice=0; */
    /* char szTmp[6]; */
    int iExpression = 0;
    /* char *pszSimplifiedExpression = NULL; */
    char *pszComparionValue=NULL, *pszAttibuteName=NULL;
    char *pszAttibuteValue=NULL;
    char *pszLeftExpression=NULL, *pszRightExpression=NULL, *pszOperator=NULL;

    if (!pszExpression || (nLength = strlen(pszExpression)) <=0)
      return NULL;

    for (i=0; i<20; i++)
      apszExpression[i] = (char *)malloc(sizeof(char)*(nLength+1));

    pszFinalExpression = (char *)malloc(sizeof(char)*(nLength+1));
    pszFinalExpression[0] = '\0';

    iExpression = -1; /* first incremnt will put it to 0; */
    iFinal = 0;
    iIndiceExp = 0;
    nOpeningBrackets = 0;

/* -------------------------------------------------------------------- */
/*      First we check how many logical operators are there :           */
/*       - if none : It means It is a comparision operator (like =,      */
/*      >, >= .... We get the comparison value as well as the           */
/*      attribute and the attribut's value and assign it to the node    */
/*      passed in argument.                                             */
/*       - if there is one operator, we assign the operator to the      */
/*      node and adds the expressions into the left and right nodes.    */
/* -------------------------------------------------------------------- */
    nOperators = msSLDNumberOfLogicalOperators(pszExpression);
    if (nOperators == 0)
    {
        if (!psNode)
          psNode = FLTCreateFilterEncodingNode();

        pszComparionValue = msSLDGetComparisonValue(pszExpression);
        pszAttibuteName = msSLDGetAttributeName(pszExpression, pszComparionValue);
        pszAttibuteValue = msSLDGetAttributeValue(pszExpression, pszComparionValue);
        if (pszComparionValue && pszAttibuteName && pszAttibuteValue)
        {
            psNode->eType = FILTER_NODE_TYPE_COMPARISON;
            psNode->pszValue = msStrdup(pszComparionValue);

            psNode->psLeftNode = FLTCreateFilterEncodingNode();
            psNode->psLeftNode->eType = FILTER_NODE_TYPE_PROPERTYNAME;
            psNode->psLeftNode->pszValue = msStrdup(pszAttibuteName);

            psNode->psRightNode = FLTCreateFilterEncodingNode();