[patch] Patch for FormulaParser

FormulaParser.java (text/plain), 14.59 KB, created by Werner Froidevaux on 2002-05-26 01:24:14 UTC

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Description: Patch for FormulaParser

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Creator: Werner Froidevaux

Created: 2002-05-26 01:24:14 UTC

Size: 14.59 KB

patch

obsolete

> >/* ==================================================================== > * The Apache Software License, Version 1.1 > * > * Copyright (c) 2002 The Apache Software Foundation. All rights > * reserved. > * > * Redistribution and use in source and binary forms, with or without > * modification, are permitted provided that the following conditions > * are met: > * > * 1. Redistributions of source code must retain the above copyright > * notice, this list of conditions and the following disclaimer. > * > * 2. Redistributions in binary form must reproduce the above copyright > * notice, this list of conditions and the following disclaimer in > * the documentation and/or other materials provided with the > * distribution. > * > * 3. The end-user documentation included with the redistribution, > * if any, must include the following acknowledgment: > * "This product includes software developed by the > * Apache Software Foundation (http://www.apache.org/)." > * Alternately, this acknowledgment may appear in the software itself, > * if and wherever such third-party acknowledgments normally appear. > * > * 4. The names "Apache" and "Apache Software Foundation" and > * "Apache POI" must not be used to endorse or promote products > * derived from this software without prior written permission. For > * written permission, please contact apache@apache.org. > * > * 5. Products derived from this software may not be called "Apache", > * "Apache POI", nor may "Apache" appear in their name, without > * prior written permission of the Apache Software Foundation. > * > * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED > * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES > * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE > * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR > * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, > * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT > * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF > * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND > * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, > * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT > * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF > * SUCH DAMAGE. > * ==================================================================== > * > * This software consists of voluntary contributions made by many > * individuals on behalf of the Apache Software Foundation. For more > * information on the Apache Software Foundation, please see > * <http://www.apache.org/>. > */ > > >package org.apache.poi.hssf.record.formula; > >import java.util.List; >import java.util.ArrayList; >import java.util.Stack; > >import java.io.FileOutputStream; >import java.io.File; > > >/** > * This class parses a formula string into a List of tokens in RPN order > * Inspired by > * Lets Build a Compiler, by Jack Crenshaw > * BNF for the formula expression is : > * <expression> ::= <term> [<addop> <term>]* > * <term> ::= <factor> [ <mulop> <factor> ]* > * <factor> ::= <number> | (<expression>) | <cellRef> | <function> > * <function> ::= <functionName> ([expression [, expression]*]) > * > * @author Avik Sengupta <avik AT Avik Sengupta DOT com> > * @author Andrew C. oliver (acoliver at apache dot org) > */ >public class FormulaParser { > > private String formulaString; > private int pointer=0; > > private List tokens = new java.util.Stack(); > //private Stack tokens = new java.util.Stack(); > private List result = new ArrayList(); > private int numParen; > > private static char TAB = '\t'; > private static char CR = '\n'; > > private char Look; // Lookahead Character > > > /** create the parser with the string that is to be parsed > * later call the parse() method to return ptg list in rpn order > * then call the getRPNPtg() to retrive the parse results > * This class is recommended only for single threaded use > * The parse and getPRNPtg are internally synchronized for safety, thus > * while it is safe to use in a multithreaded environment, you will get long lock waits. > */ > public FormulaParser(String formula){ > formulaString = formula; > pointer=0; > } > > > /** Read New Character From Input Stream */ > private void GetChar() { > Look=formulaString.charAt(pointer++); > //System.out.println("Got char: "+Look); > } > > > /** Report an Error */ > private void Error(String s) { > System.out.println("Error: "+s); > } > > > > /** Report Error and Halt */ > private void Abort(String s) { > Error(s); > //System.exit(1); //throw exception?? > throw new RuntimeException("Cannot Parse, sorry"); > } > > > > /** Report What Was Expected */ > private void Expected(String s) { > Abort(s + " Expected"); > } > > > > /** Recognize an Alpha Character */ > private boolean IsAlpha(char c) { > return Character.isLetter(c) || c == '$'; > } > > > > /** Recognize a Decimal Digit */ > private boolean IsDigit(char c) { > //System.out.println("Checking digit for"+c); > return Character.isDigit(c); > } > > > > /** Recognize an Alphanumeric */ > private boolean IsAlNum(char c) { > return (IsAlpha(c) || IsDigit(c)); > } > > > > /** Recognize an Addop */ > private boolean IsAddop( char c) { > return (c =='+' || c =='-'); > } > > > /** Recognize White Space */ > private boolean IsWhite( char c) { > return (c ==' ' || c== TAB); > } > > > > /** Skip Over Leading White Space */ > private void SkipWhite() { > while (IsWhite(Look)) { > GetChar(); > } > } > > > > /** Match a Specific Input Character */ > private void Match(char x) { > if (Look != x) { > Expected("" + x + ""); > }else { > GetChar(); > SkipWhite(); > } > } > > > /** Get an Identifier */ > private String GetName() { > String Token; > Token = ""; > if (!IsAlpha(Look)) { > Expected("Name"); > } > while (IsAlNum(Look)) { > Token = Token + Character.toUpperCase(Look); > GetChar(); > } > > SkipWhite(); > return Token; > } > > > /** Get a Number */ > private String GetNum() { > String Value =""; > if (!IsDigit(Look)) Expected("Integer"); > while (IsDigit(Look)){ > Value = Value + Look; > GetChar(); > } > SkipWhite(); > return Value; > } > > /** Output a String with Tab */ > private void Emit(String s){ > System.out.print(TAB+s); > } > > /** Output a String with Tab and CRLF */ > private void EmitLn(String s) { > Emit(s); > System.out.println();; > } > > /** Parse and Translate a Identifier */ > private void Ident() { > String name; > name = GetName(); > if (Look == '('){ > //This is a function > Match('('); > int numArgs = Arguments(); > Match(')'); > //this is the end of the function > tokens.add(function(name,(byte)numArgs)); > } else if (Look == ':') { // this is a AreaReference > String first = name; > Match(':'); > String second = GetName(); > tokens.add(new AreaPtg(first+":"+second)); > } else { > //this can be either a cell ref or a named range !! > boolean cellRef = true ; //we should probably do it with reg exp?? > if (cellRef) { > tokens.add(new ReferencePtg(name)); > }else { > //handle after named range is integrated!! > } > } > } > > private Ptg function(String name,byte numArgs) { > Ptg retval = null; > > if (numArgs == 1 && name.equals("SUM")) { > AttrPtg ptg = new AttrPtg(); > ptg.setData((short)1); //sums don't care but this is what excel does. > ptg.setSum(true); > retval = ptg; > } else { > FunctionPtg ptg = new FunctionPtg(name,numArgs); > retval = ptg; > } > > return retval; > } > > /** get arguments to a function */ > private int Arguments() { > int numArgs = 0; > if (Look != ')') { > numArgs++; > Expression(); > } > while (Look == ',' || Look == ';') { //TODO handle EmptyArgs > if(Look == ',') { > Match(','); > } > else { > Match(';'); > } > Expression(); > numArgs++; > } > return numArgs; > } > > /** Parse and Translate a Math Factor */ > private void Factor() { > if (Look == '(' ) { > Match('('); > Expression(); > Match(')'); > tokens.add(new ParenthesisPtg()); > return; > } else if (IsAlpha(Look)){ > Ident(); > }else{ > String number = GetNum(); > if (Look=='.') { > Match('.'); > String decimalPart = null; > if (IsDigit(Look)) number = number +"."+ GetNum(); //this also takes care of someone entering "1234." > tokens.add(new NumberPtg(number)); > } else { > tokens.add(new IntPtg(number)); //TODO:what if the number is too big to be a short? ..add factory to return Int or Number! > } > } > } > > > /** Recognize and Translate a Multiply */ > private void Multiply(){ > Match('*'); > Factor(); > tokens.add(new MultiplyPtg()); > > } > > > /** Recognize and Translate a Divide */ > private void Divide() { > Match('/'); > Factor(); > tokens.add(new DividePtg()); > > } > > > /** Parse and Translate a Math Term */ > private void Term(){ > Factor(); > while (Look == '*' || Look == '/' || Look == '^' || Look == '&') { > ///TODO do we need to do anything here?? > if (Look == '*') Multiply(); > if (Look == '/') Divide(); > if (Look == '^') Power(); > if (Look == '&') Concat(); > } > } > > /** Recognize and Translate an Add */ > private void Add() { > Match('+'); > Term(); > tokens.add(new AddPtg()); > } > > /** Recognize and Translate an Add */ > private void Concat() { > Match('&'); > Term(); > tokens.add(new ConcatPtg()); > } > > > > /** Recognize and Translate a Subtract */ > private void Subtract() { > Match('-'); > Term(); > tokens.add(new SubtractPtg()); > } > > private void Power() { > Match('^'); > Term(); > tokens.add(new PowerPtg()); > } > > > /** Parse and Translate an Expression */ > private void Expression() { > if (IsAddop(Look)) { > EmitLn("CLR D0"); //unaryAdd ptg??? > } else { > Term(); > } > while (IsAddop(Look)) { > if ( Look == '+' ) Add(); > if (Look == '-') Subtract(); > // if (Look == '*') Multiply(); > // if (Look == '/') Divide(); > } > } > > > //{--------------------------------------------------------------} > //{ Parse and Translate an Assignment Statement } > /** >procedure Assignment; >var Name: string[8]; >begin > Name := GetName; > Match('='); > Expression; > >end; > **/ > > > /** Initialize */ > > private void init() { > GetChar(); > SkipWhite(); > } > > /** API call to execute the parsing of the formula > * > */ > public void parse() { > synchronized (tokens) { > init(); > Expression(); > } > } > > /** API call to retrive the array of Ptgs created as > * a result of the parsing > */ > public Ptg[] getRPNPtg() { > synchronized (tokens) { > if (tokens == null) throw new IllegalStateException("Please parse a string before trying to access the parse result"); > Ptg[] retval = new Ptg[tokens.size()]; > return (Ptg[]) tokens.toArray(retval); > } > } > > /** > * Convience method which takes in a list then passes it to the other toFormulaString > * signature > */ > public static String toFormulaString(List lptgs) { > String retval = null; > Ptg[] ptgs = new Ptg[lptgs.size()]; > ptgs = (Ptg[])lptgs.toArray(ptgs); > retval = toFormulaString(ptgs); > return retval; > } > > /** Static method to convert an array of Ptgs in RPN order > * to a human readable string format in infix mode > */ > public static String toFormulaString(Ptg[] ptgs) { > java.util.Stack stack = new java.util.Stack(); > int numPtgs = ptgs.length; > OperationPtg o; > int numOperands; > String[] operands; > for (int i=0;i<numPtgs;i++) { > if (ptgs[i] instanceof OperationPtg) { > // Excel allows to have AttrPtg at position 0 (such as Blanks) which > // do not have any operands. Skip them. > if(i > 0) { > o = (OperationPtg) ptgs[i]; > numOperands = o.getNumberOfOperands(); > operands = new String[numOperands]; > for (int j=0;j<numOperands;j++) { > operands[numOperands-j-1] = (String) stack.pop(); //TODO: catch stack underflow and throw parse exception. > > } > String result = o.toFormulaString(operands); > stack.push(result); > } > } else { > stack.push(ptgs[i].toFormulaString()); > } > } > return (String) stack.pop(); //TODO: catch stack underflow and throw parse exception. > } > > /** toString on the parser instance returns the RPN ordered list of tokens > * Useful for testing > */ > public String toString() { > StringBuffer buf = new StringBuffer(); > for (int i=0;i<tokens.size();i++) { > buf.append( ( (Ptg)tokens.get(i)).toFormulaString()); > buf.append(' '); > } > return buf.toString(); > } > > >} View Attachment As Diff View Attachment As Raw

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