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/* XLogo4Schools - A Logo Interpreter specialized for use in schools, based on XLogo by Loic Le Coq
* Copyright (C) 2013 Marko Zivkovic
*
* Contact Information: marko88zivkovic at gmail dot com
*
* 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. This program 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 General
* Public License for more details. You should have received a copy of the
* GNU General Public License along with this program; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
*
* This Java source code belongs to XLogo4Schools, written by Marko Zivkovic
* during his Bachelor thesis at the computer science department of ETH Zurich,
* in the year 2013 and/or during future work.
*
* It is a reengineered version of XLogo written by Loic Le Coq, published
* under the GPL License at http://xlogo.tuxfamily.org/
*
* Contents of this file were initially written by Loic Le Coq,
* modifications, extensions, refactorings might have been applied by Marko Zivkovic
*/
package xlogo.kernel;
public class InstructionBuffer {
/**
* This integer represents the max Characters in the StringBuffer
*/
private final static int MAX_CHARACTERS=15000;
/**
* The main StringBuffer containing instruction
*/
private StringBuffer mainBuffer;
/**
* If the main StringBuffer is very large, Xlogo could become very slow. If main StringBuffer should contain more than MAX_CHARACTERS, those characters are saved in this StringBuffer
*/
private StringBuffer stock;
InstructionBuffer(){
clear();
}
InstructionBuffer(String s){
mainBuffer=new StringBuffer(s);
stock=new StringBuffer();
}
/**
* Inserts some instructions at the beginning of the StringBuffer mainBuffer
* @param sb: The code to insert
*/
void insertCode(StringBuffer sb){
if (sb.length()>InstructionBuffer.MAX_CHARACTERS) {
// insert current mainBuffer to stock
if (mainBuffer.length()!=0) stock.insert(0,mainBuffer);
// Copy MAX_CHARACTERS into mainBuffer
mainBuffer=new StringBuffer(sb.substring(0, InstructionBuffer.MAX_CHARACTERS));
// All remaining characters into stock
stock.insert(0,sb.substring(InstructionBuffer.MAX_CHARACTERS));
}
else {
mainBuffer.insert(0, sb);
}
}
/**
* returns the total length of the two Buffer
*/
protected int getLength(){
return mainBuffer.length()+stock.length();
}
/**
* Inserts the String s at the beginning of the mainBuffer
* @param s
*/
protected void insert(String s){
mainBuffer.insert(0, s);
}
/**
* Search for the String s , first in mainBuffer and then in stock
* if it isn't found in any buffer returns -1
* @param s: The String to search
*/
protected int indexOf(String s){
int index=mainBuffer.indexOf(s);
if (index==-1){
index=stock.indexOf(s);
if (index==-1) return -1;
else return index+mainBuffer.length();
}
return index;
}
/**
* Search for the String s , first in mainBuffer and then in stock
* if not found in any buffer returns -1
* @param s: The String to search
*/
protected int indexOf(String s, int fromIndex){
int index=-1;
if (fromIndex<mainBuffer.length()) index=mainBuffer.indexOf(s,fromIndex);
if (index==-1){
int from=0;
if (fromIndex>=mainBuffer.length()) from=fromIndex-mainBuffer.length();
index=stock.indexOf(s,from);
if (index==-1) return -1;
else return index+mainBuffer.length();
}
return index;
}
/**
* Delete all code from offset start to offset end
* @param start Start offset
* @param end End offset
*/
protected void delete(int start, int end){
if (end<=mainBuffer.length()) mainBuffer.delete(start, end);
else {
stock.delete(0, end-mainBuffer.length());
mainBuffer=new StringBuffer();
transferStock();
}
if (mainBuffer.length()==0){
// if there are instruction in stock yet
if (stock.length()!=0) transferStock();
}
}
/**
* Transfers MAX_CHARCATERS from the buffer stock to mainBuffer
*/
private void transferStock(){
if (stock.length()>InstructionBuffer.MAX_CHARACTERS){
mainBuffer.append(stock.substring(0, InstructionBuffer.MAX_CHARACTERS));
stock.delete(0, InstructionBuffer.MAX_CHARACTERS);
}
else {
mainBuffer.append(stock);
stock=new StringBuffer();
}
}
/**
* Returns next Word
* @return a String which represents the next word
*/
protected String getNextWord() {
StringBuffer mot = new StringBuffer();
char caractere;
for (int i = 0; i < mainBuffer.length(); i++) {
caractere = mainBuffer.charAt(i);
if (caractere == ' ') {
return mot.toString();
} else
mot.append(caractere);
if (i==mainBuffer.length()-1&& stock.length()!=0){
transferStock();
}
}
// System.out.println("mot: "+mot);
return mot.toString();
}
/**
* Deletes the String mot from the mainBuffer instructions
* @param mot The string to delete
*/
protected void deleteFirstWord(String mot) {
if (mainBuffer.length() > mot.length())
mainBuffer = mainBuffer.delete(0, mot.length() + 1);
else
mainBuffer = new StringBuffer();
if (mainBuffer.length()==0){
// if there are instruction in stock yet
if (stock.length()!=0) transferStock();
}
}
/**
* Return Character at the chosen index. this methos search first in mainBuffer and then in stock
* @param index The chosen index
* @return A character
*/
protected char charAt(int index){
if (index<mainBuffer.length()) return mainBuffer.charAt(index);
return stock.charAt(index-mainBuffer.length());
}
/**
* Clear the both buffers
*/
public void clear(){
mainBuffer=new StringBuffer();
stock=new StringBuffer();
}
public String toString(){
return mainBuffer.toString()+stock.toString();
// return "MainBuffer:"+mainBuffer.toString()+":stock:"+stock.toString();
}
}
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