parse.h File Reference

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Functions
ABC_NAMESPACE_HEADER_START DdNode *	Parse_FormulaParser (FILE *pOutput, char *pFormula, int nVars, int nRanks, char *ppVarNames[], DdManager *dd, DdNode *pbVars[])
	INCLUDES ///. More...

Function Documentation

ABC_NAMESPACE_HEADER_START DdNode* Parse_FormulaParser	(	FILE *	pOutput,
		char *	pFormulaInit,
		int	nVars,
		int	nRanks,
		char *	ppVarNames[],
		DdManager *	dd,
		DdNode *	pbVars[]
	)

INCLUDES ///.

CFile****************************************************************

FileName [parse.h]

PackageName [MVSIS 2.0: Multi-valued logic synthesis system.]

Synopsis [Parsing symbolic Boolean formulas into BDDs.]

Author [MVSIS Group]

Affiliation [UC Berkeley]

Date [Ver. 1.0. Started - September 8, 2003.]

Revision [

Id:

parse.h,v 1.0 2003/09/08 00:00:00 alanmi Exp

]PARAMETERS ///STRUCTURE DEFINITIONS ///GLOBAL VARIABLES ///MACRO DEFINITIONS ///FUNCTION DEFINITIONS ///

INCLUDES ///.

Function*************************************************************

Synopsis [Derives the BDD corresponding to the formula in language L.]

Description [Takes the stream to output messages, the formula, the number variables and the rank in the formula. The array of variable names is also given. The BDD manager and the elementary 0-rank variable are the last two arguments. The manager should have at least as many variables as nVars * (nRanks + 1). The 0-rank variables should have numbers larger than the variables of other ranks.]

SideEffects []

SeeAlso []

Definition at line 116 of file parseCore.c.

{
    char * pFormula;
    Parse_StackFn_t * pStackFn;
    Parse_StackOp_t * pStackOp;
    DdNode * bFunc, * bTemp;
    char * pTemp;
    int nParans, fFound, Flag;
    int Oper, Oper1, Oper2;
    int i, fLower;
    int v = -1; // Suppress "might be used uninitialized"

    // make sure that the number of vars and ranks is correct
    if ( nVars * (nRanks + 1) > dd->size )
    {
        printf( "Parse_FormulaParser(): The BDD manager does not have enough variables.\n" );
        return NULL;
    }

    // make sure that the number of opening and closing parantheses is the same
    nParans = 0;
    for ( pTemp = pFormulaInit; *pTemp; pTemp++ )
        if ( *pTemp == '(' )
            nParans++;
        else if ( *pTemp == ')' )
            nParans--;
    if ( nParans != 0 )
    {
        fprintf( pOutput, "Parse_FormulaParser(): Different number of opening and closing parantheses ().\n" );
        return NULL;
    }

    nParans = 0;
    for ( pTemp = pFormulaInit; *pTemp; pTemp++ )
        if ( *pTemp == '[' )
            nParans++;
        else if ( *pTemp == ']' )
            nParans--;
    if ( nParans != 0 )
    {
        fprintf( pOutput, "Parse_FormulaParser(): Different number of opening and closing brackets [].\n" );
        return NULL;
    }

    // copy the formula
    pFormula = ABC_ALLOC( char, strlen(pFormulaInit) + 3 );
    sprintf( pFormula, "(%s)", pFormulaInit );

    // start the stacks
    pStackFn = Parse_StackFnStart( STACKSIZE );
    pStackOp = Parse_StackOpStart( STACKSIZE );

    Flag = PARSE_FLAG_START;
    fLower = 0;
    for ( pTemp = pFormula; *pTemp; pTemp++ )
    {
        switch ( *pTemp )
        {
        // skip all spaces, tabs, and end-of-lines
        case ' ':
        case '\t':
        case '\r':
        case '\n':
            continue;

        // treat Constant 0 as a variable
        case PARSE_SYM_CONST0:
            Parse_StackFnPush( pStackFn, b0 );   Cudd_Ref( b0 );
            if ( Flag == PARSE_FLAG_VAR )
            {
                fprintf( pOutput, "Parse_FormulaParser(): No operation symbol before constant 0.\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            Flag = PARSE_FLAG_VAR; 
            break;

        // the same for Constant 1
        case PARSE_SYM_CONST1:
            Parse_StackFnPush( pStackFn, b1 );    Cudd_Ref( b1 );
            if ( Flag == PARSE_FLAG_VAR )
            {
                fprintf( pOutput, "Parse_FormulaParser(): No operation symbol before constant 1.\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            Flag = PARSE_FLAG_VAR; 
            break;

        case PARSE_SYM_NEGBEF1:
        case PARSE_SYM_NEGBEF2:
            if ( Flag == PARSE_FLAG_VAR )
            {// if NEGBEF follows a variable, AND is assumed
                Parse_StackOpPush( pStackOp, PARSE_OPER_AND );
                Flag = PARSE_FLAG_OPER;
            }
            Parse_StackOpPush( pStackOp, PARSE_OPER_NEG );
            break;

        case PARSE_SYM_NEGAFT:
            if ( Flag != PARSE_FLAG_VAR )
            {// if there is no variable before NEGAFT, it is an error
                fprintf( pOutput, "Parse_FormulaParser(): No variable is specified before the negation suffix.\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            else // if ( Flag == PARSE_FLAG_VAR )
                Parse_StackFnPush( pStackFn, Cudd_Not( Parse_StackFnPop(pStackFn) ) );
            break;

        case PARSE_SYM_AND1:
        case PARSE_SYM_AND2:
        case PARSE_SYM_OR1:
        case PARSE_SYM_OR2:
        case PARSE_SYM_XOR:
            if ( Flag != PARSE_FLAG_VAR )
            {
                fprintf( pOutput, "Parse_FormulaParser(): There is no variable before AND, EXOR, or OR.\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            if ( *pTemp == PARSE_SYM_AND1 || *pTemp == PARSE_SYM_AND2 )
                Parse_StackOpPush( pStackOp, PARSE_OPER_AND );
            else if ( *pTemp == PARSE_SYM_OR1 || *pTemp == PARSE_SYM_OR2 )
                Parse_StackOpPush( pStackOp, PARSE_OPER_OR );
            else //if ( Str[Pos] == PARSE_SYM_XOR )
                Parse_StackOpPush( pStackOp, PARSE_OPER_XOR );
            Flag = PARSE_FLAG_OPER; 
            break;

        case PARSE_SYM_EQU1:
            if ( Flag != PARSE_FLAG_VAR )
            { 
                fprintf( pOutput, "Parse_FormulaParser(): There is no variable before Equivalence or Implication\n" );
                Flag = PARSE_FLAG_ERROR; break;
            }
            if ( pTemp[1] == PARSE_SYM_EQU2 )
            { // check what is the next symbol in the string
                pTemp++; 
                if ( pTemp[1] == PARSE_SYM_EQU3 )
                {   
                    pTemp++; 
                    Parse_StackOpPush( pStackOp, PARSE_OPER_EQU ); 
                }
                else
                {   
                    Parse_StackOpPush( pStackOp, PARSE_OPER_FLL ); 
                }
            }
            else if ( pTemp[1] == PARSE_SYM_XOR2 )
            {
                pTemp++; 
                if ( pTemp[1] == PARSE_SYM_XOR3 )
                {   
                    pTemp++; 
                    Parse_StackOpPush( pStackOp, PARSE_OPER_XOR ); 
                }
                else
                {   
                    fprintf( pOutput, "Parse_FormulaParser(): Wrong symbol after \"%c%c\"\n", PARSE_SYM_EQU1, PARSE_SYM_XOR2 );
                    Flag = PARSE_FLAG_ERROR; 
                    break;
                }
            }
            else
            {
                fprintf( pOutput, "Parse_FormulaParser(): Wrong symbol after \"%c\"\n", PARSE_SYM_EQU1 );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            Flag = PARSE_FLAG_OPER; 
            break;

        case PARSE_SYM_EQU2:
            if ( Flag != PARSE_FLAG_VAR )
            {
                fprintf( pOutput, "Parse_FormulaParser(): There is no variable before Reverse Implication\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            if ( pTemp[1] == PARSE_SYM_EQU3 )
            {   
                pTemp++; 
                Parse_StackOpPush( pStackOp, PARSE_OPER_FLR ); 
            }
            else
            {
                fprintf( pOutput, "Parse_FormulaParser(): Wrong symbol after \"%c\"\n", PARSE_SYM_EQU2 );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            Flag = PARSE_FLAG_OPER; 
            break;

        case PARSE_SYM_LOWER:
        case PARSE_SYM_OPEN:
            if ( Flag == PARSE_FLAG_VAR )
                Parse_StackOpPush( pStackOp, PARSE_OPER_AND );
            Parse_StackOpPush( pStackOp, PARSE_OPER_MARK );
            // after an opening bracket, it feels like starting over again
            Flag = PARSE_FLAG_START; 
            break;

        case PARSE_SYM_RAISE:
            fLower = 1;
        case PARSE_SYM_CLOSE:
            if ( !Parse_StackOpIsEmpty( pStackOp ) )
            {
                while ( 1 )
                {
                    if ( Parse_StackOpIsEmpty( pStackOp ) )
                    {
                        fprintf( pOutput, "Parse_FormulaParser(): There is no opening paranthesis\n" );
                        Flag = PARSE_FLAG_ERROR; 
                        break;
                    }
                    Oper = Parse_StackOpPop( pStackOp );
                    if ( Oper == PARSE_OPER_MARK )
                        break;

                    // perform the given operation
                    if ( Parse_ParserPerformTopOp( dd, pStackFn, Oper ) == NULL )
                    {
                        fprintf( pOutput, "Parse_FormulaParser(): Unknown operation\n" );
                        ABC_FREE( pFormula );
                        return NULL;
                    }
                }

                if ( fLower )
                {
                    bFunc = (DdNode *)Parse_StackFnPop( pStackFn );
                    bFunc = Extra_bddMove( dd, bTemp = bFunc, -nVars );   Cudd_Ref( bFunc );
                    Cudd_RecursiveDeref( dd, bTemp );
                    Parse_StackFnPush( pStackFn, bFunc );
                }
            }
            else
            {
                fprintf( pOutput, "Parse_FormulaParser(): There is no opening paranthesis\n" );
                Flag = PARSE_FLAG_ERROR; 
                break;
            }
            if ( Flag != PARSE_FLAG_ERROR )
                Flag = PARSE_FLAG_VAR; 
            fLower = 0;
            break;


        default:
            // scan the next name
/*
            fFound = 0;
            for ( i = 0; pTemp[i] && pTemp[i] != ' ' && pTemp[i] != '\t' && pTemp[i] != '\r' && pTemp[i] != '\n'; i++ )
            {
                for ( v = 0; v < nVars; v++ )
                    if ( strncmp( pTemp, ppVarNames[v], i+1 ) == 0 && strlen(ppVarNames[v]) == (unsigned)(i+1) )
                    {
                        pTemp += i;
                        fFound = 1;
                        break;
                    }
                if ( fFound )
                    break;
            }
*/ 
            // bug fix by SV (9/11/08)
            fFound = 0;
            for ( i = 0; pTemp[i] && pTemp[i] != ' ' && pTemp[i] != '\t' && pTemp[i] != '\r' && pTemp[i] != '\n' && 
                         pTemp[i] != PARSE_SYM_AND1 && pTemp[i] != PARSE_SYM_AND2 && pTemp[i] != PARSE_SYM_XOR1 &&
                         pTemp[i] != PARSE_SYM_XOR2 && pTemp[i] != PARSE_SYM_XOR3 && pTemp[i] != PARSE_SYM_XOR  &&
                         pTemp[i] != PARSE_SYM_OR1  && pTemp[i] != PARSE_SYM_OR2  && pTemp[i] != PARSE_SYM_CLOSE &&
                         pTemp[i] != PARSE_SYM_NEGAFT;
                  i++ )
            {}
            for ( v = 0; v < nVars; v++ ) 
            {
                if ( strncmp( pTemp, ppVarNames[v], i ) == 0 && strlen(ppVarNames[v]) == (unsigned)(i) )
                {
                    pTemp += i-1;
                    fFound = 1;
                    break;
                }
            }

            if ( !fFound )
            { 
                fprintf( pOutput, "Parse_FormulaParser(): The parser cannot find var \"%s\" in the input var list.\n", pTemp ); 
                Flag = PARSE_FLAG_ERROR; 
                break; 
            }
            // assume operation AND, if vars follow one another
            if ( Flag == PARSE_FLAG_VAR )
                Parse_StackOpPush( pStackOp, PARSE_OPER_AND );
            Parse_StackFnPush( pStackFn, pbVars[v] );  Cudd_Ref( pbVars[v] );
            Flag = PARSE_FLAG_VAR; 
            break;
        }

        if ( Flag == PARSE_FLAG_ERROR )
            break;      // error exit
        else if ( Flag == PARSE_FLAG_START )
            continue;  //  go on parsing
        else if ( Flag == PARSE_FLAG_VAR )
            while ( 1 )
            {  // check if there are negations in the OpStack     
                if ( Parse_StackOpIsEmpty(pStackOp) )
                    break;
                Oper = Parse_StackOpPop( pStackOp );
                if ( Oper != PARSE_OPER_NEG )
                {
                    Parse_StackOpPush( pStackOp, Oper );
                    break;
                }
                else
                {
                    Parse_StackFnPush( pStackFn, Cudd_Not(Parse_StackFnPop(pStackFn)) );
                }
            }
        else // if ( Flag == PARSE_FLAG_OPER )
            while ( 1 )
            {  // execute all the operations in the OpStack
               // with precedence higher or equal than the last one
                Oper1 = Parse_StackOpPop( pStackOp ); // the last operation
                if ( Parse_StackOpIsEmpty(pStackOp) ) 
                {  // if it is the only operation, push it back
                    Parse_StackOpPush( pStackOp, Oper1 );
                    break;
                }
                Oper2 = Parse_StackOpPop( pStackOp ); // the operation before the last one
                if ( Oper2 >= Oper1 )  
                {  // if Oper2 precedence is higher or equal, execute it
//                  Parse_StackPush( pStackFn,  Operation( FunStack.Pop(), FunStack.Pop(), Oper2 ) );
                    if ( Parse_ParserPerformTopOp( dd, pStackFn, Oper2 ) == NULL )
                    {
                        fprintf( pOutput, "Parse_FormulaParser(): Unknown operation\n" );
                        ABC_FREE( pFormula );
                        return NULL;
                    }
                    Parse_StackOpPush( pStackOp,  Oper1 );     // push the last operation back
                }
                else
                {  // if Oper2 precedence is lower, push them back and done
                    Parse_StackOpPush( pStackOp, Oper2 );
                    Parse_StackOpPush( pStackOp, Oper1 );
                    break;
                }
            }
    }

    if ( Flag != PARSE_FLAG_ERROR )
    {
        if ( !Parse_StackFnIsEmpty(pStackFn) )
        {   
            bFunc = (DdNode *)Parse_StackFnPop(pStackFn);
            if ( Parse_StackFnIsEmpty(pStackFn) )
                if ( Parse_StackOpIsEmpty(pStackOp) )
                {
                    Parse_StackFnFree(pStackFn);
                    Parse_StackOpFree(pStackOp);
                    Cudd_Deref( bFunc );
                    ABC_FREE( pFormula );
                    return bFunc;
                }
                else
                    fprintf( pOutput, "Parse_FormulaParser(): Something is left in the operation stack\n" );
            else
                fprintf( pOutput, "Parse_FormulaParser(): Something is left in the function stack\n" );
        }
        else
            fprintf( pOutput, "Parse_FormulaParser(): The input string is empty\n" );
    }
    ABC_FREE( pFormula );
    return NULL;
}