expproc.cpp

一个通讯管理机的源代码。比较好用。推荐

/***************************************************************************
                          expproc.cpp  -  description
                             -------------------
    begin                : Thu Jan 17 2002
    copyright            : (C) 2002 by 
    email                : 
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
/*  $Id: expproc.cpp,v 1.6 2001/01/13 20:20:53 dbryson Exp $

    Xbase project source code

    Copyright (C) 1997  Startech, Gary A. Kunkel   

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Contact:

      Mail:

        Technology Associates, Inc.
        XBase Project
        1455 Deming Way #11
        Sparks, NV 89434
        USA

      Email:

        [e-mail]

      See our website at:

        xdb.sourceforge.net


    V 1.0   10/10/97   - Initial release of software
    V 1.5   1/2/97     - Added memo field support
    V 1.6a  4/1/98     - Added expression support
    V 1.7.1 5/25/98    - Enhanced expression support
*/

#ifdef __WIN32__
#include "xbconfigw32.h"
#else
#include "xbconfig.h"
#endif

#include "xbase.h"

#ifdef XB_EXPRESSIONS

#include <ctype.h>
#include <math.h>
#include <string.h>

#include "xbexcept.h"

/*! \file expproc.cpp
*/

/*************************************************************************/
//! Short description
/*!
  \param e
*/
xbExpNode * xbExpn::GetFirstTreeNode( xbExpNode * e )
{
   xbExpNode * WorkNode;
   if( !e ) return e;
   WorkNode = e;
   while( WorkNode->Sibling1 )
      WorkNode = WorkNode->Sibling1;
   return WorkNode;
}
/*************************************************************************/
//! Short description
/*!
  \param Operand
  \param Op1
  \pamam Op2
*/
xbShort xbExpn::ValidOperation( char * Operand, char Op1, char Op2 )
{
   /*  Valid operation table

       operator  Field1   Field2          operator Field1   Field2

        **        N        N                 =        N        N
        *         N        N                 =        C        C
        /         N        N                 <>,#     N        N
        +         N        N                 <>,#     C        C
        +         C        C                 <=       N        N
        -         N        N                 <=       C        C
        -         C        C                 >=       N        N
        <         N        N                 >=       C        C
        <         C        C                 
        >         N        N
        >         C        C

    */


   if( Operand[0] == '*' && Operand[1] == '*' && Op1 == 'N' && Op2 == 'N' )
      return 1;

   switch( Operand[0] ) {
      case '*': 
      case '/':
         if( Op1 == 'N' && Op2 == 'N' ) 
            return 1; 
         else 
            return 0;

      case '+':
      case '-':
      case '<':
      case '>':
      case '=':
      case '#':
      case '$': // added 3/26/00 dtb
         if(( Op1 == 'N' && Op2 == 'N' ) || ( Op1 == 'C' && Op2 == 'C' ))
             return 1;
         else
             return 0;
             
      case '.' : // logical operators, added 3/26/00 dtb
         if((Operand[1] == 'A' || Operand[1] == 'N' || Operand[1] == 'O')) /* &&
            (Op1 == 'N' && Op2 == 'N')) */
            return 1;
      return 0;

      default:
         return 0;
   }
}
/*************************************************************************/
//! Short description
/*!
  \param e
*/
xbExpNode * xbExpn::GetNextTreeNode( xbExpNode * e )
{
   if( !e->Node ) return NULL;

   /* sibling 1 && sibling 2 exists */
   if( e == e->Node->Sibling1 && e->Node->Sibling2 )
      return GetFirstTreeNode( e->Node->Sibling2 );

   /* sibling2 && sibling3 exists */
   else if( e == e->Node->Sibling2 && e->Node->Sibling3 )
      return GetFirstTreeNode( e->Node->Sibling3 );

   else
      return e->Node;
}
/*************************************************************************/
//! Short description
/*!
  \param e
*/
xbShort xbExpn::ProcessExpression( xbExpNode * e )
{
   return ProcessExpression( e, 0 );
}
/*************************************************************************/
//! Short description
/*!
  \param Wtree
  \param RecBufSw
*/
xbShort xbExpn::ProcessExpression( xbExpNode * Wtree, xbShort RecBufSw )
{
   xbExpNode * WorkNode;
   xbShort rc = 0;
   if( Wtree == 0 )
      Wtree = Tree;
   memset(WorkBuf, 0x00, WorkBufMaxLen+1 );
   /* initialize the stack - free any expnodes */
   while( GetStackDepth() > 0 ) {
      WorkNode = (xbExpNode *) Pop();
      if( !WorkNode->InTree )
         delete WorkNode;
   }   
   if(( WorkNode = GetFirstTreeNode( Wtree )) == NULL )
     xb_error(XB_NO_DATA);

   while( WorkNode ) {
      Push( (void *) WorkNode );
      if( WorkNode->Type == 'D' && WorkNode->dbf ) {
         WorkNode->dbf->GetField( WorkNode->FieldNo, WorkNode->StringResult, RecBufSw );
         if( WorkNode->dbf->GetFieldType( WorkNode->FieldNo ) == 'N' || 
            WorkNode->dbf->GetFieldType( WorkNode->FieldNo ) == 'F' )
            WorkNode->DoubResult = WorkNode->dbf->GetDoubleField( WorkNode->FieldNo, RecBufSw );
      }
      else if( WorkNode->Type == 'O' ) {
         if(( rc = ProcessOperator( RecBufSw )) != XB_NO_ERROR )
           return rc;
      }
      else if( WorkNode->Type == 'F' )
         if(( rc = ProcessFunction( WorkNode->NodeText )) != XB_NO_ERROR )
            return rc;
      WorkNode = GetNextTreeNode( WorkNode );
   }
   if( GetStackDepth() != 1 )    /* should only have result left in stack */
     xb_error(XB_PARSE_ERROR);
   return XB_NO_ERROR;
}
/*************************************************************************/
//! Short description
/*!
  \param e
*/
char xbExpn::GetOperandType( xbExpNode * e )
{
   /* this routine returns
         L - logical
         N - Numeric
         C - Character
         0 - error
   */
   char WorkType;
   if( e->Type == 'd' || e->Type == 'N' || e->Type == 'i' ) return 'N';
   if( e->Type == 'l' ) return 'L';
   if( e->Type == 's' ) return 'C';
   if( e->Type == 'C' ) {
      if(e->NodeText[0]=='-' || e->NodeText[0]=='+' || 
         (isdigit(e->NodeText[0]) &&
     !(e->NodeText[e->DataLen] == '\'' || e->NodeText[e->DataLen] == '"'))
    )
        return 'N';
      else
        return 'C';
   }
   else if( e->Type == 'D' && e->dbf ) {
      WorkType = e->dbf->GetFieldType( e->FieldNo );
      if( WorkType == 'C' ) return 'C';
      else if( WorkType == 'F' || WorkType == 'N' ) return 'N';
      else if( WorkType == 'L' ) return 'L';
      else return 0;
   }
   else
      return 0;
}
/*************************************************************************/
//! Short description
/*!
  \param RecBufSw
*/
xbShort xbExpn::ProcessOperator( xbShort RecBufSw )
{
   xbExpNode * WorkNode;
   char Operator[6 /*3*/];  // changed for logical ops 3/26/00 dtb
   char t;
   if( GetStackDepth() < 3 ) 
     xb_error(XB_PARSE_ERROR);
   WorkNode = (xbExpNode *) Pop();
   if( WorkNode->Len > 5 /*2*/) // changed for logical ops 3/26/00 dtb
{
//printf("WorkNode->Len = %d\n", WorkNode->Len);