/**
    * Redistribution and use of this software and associated documentation ("Software"), with or
    * without modification, are permitted provided that the following conditions are met:
    *
    * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
    * must also contain a copy of this document.
    *
    * 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 name "Exolab" must not be used to endorse or promote products derived from this Software
   * without prior written permission of Intalio, Inc. For written permission, please contact
   * info@exolab.org.
   *
   * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
   * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
   * Intalio, Inc.
   *
   * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
   *
   * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``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 INTALIO, INC. 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.
   *
   * Copyright 2000 (C) Intalio Inc. All Rights Reserved.
   *
   * $Id$
   */
  
  package org.exolab.castor.xml.dtd.parser;
  
  /**
   * An implementation of interface {@link org.exolab.castor.xml.dtd.parser.CharStream CharStream}.
   * Implements input character stream that maintains line and column number positions of the
   * characters. It also has the capability to backup the stream to some extent.<br>
   * The object of this class is constructed using {@link java.io.Reader java.io.Reader}
   * <tt>reader</tt> and it is left to constructor of the <tt>reader</tt> to set up character encoding
   * correctly. This means that method <u><font color="blue">read</font></u> of the <tt>reader</tt> is
   * used to get next characters, assuming it returns appropriate values. It is recommended to use
   * class {@link java.io.InputStreamReader java.io.InputStreamReader} as a <tt>reader</tt>, which
   * allows to set desired character encoding. This class is an intermediate component between input
   * character reader and the parser.<br>
   * The code of this class is based on the class <b>ASCII_CharStream</b> - implementation of
   * interface {@link org.exolab.castor.xml.dtd.parser.CharStream CharStream}, that JavaCC would have
   * generated with the following options set in a JavaCC grammar file:
   * 
   * <pre>
   * JAVA_UNICODE_ESCAPE = false;
   * UNICODE_INPUT = false;
   * USER_CHAR_STREAM = false;
   * </pre>
   * 
   * Note that this class is not fully JavaCC generated.<br>
   * 
   * @author <b>JavaCC</b>, <a href="mailto:totok@intalio.com">Alexander Totok</a>
   * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
   */
  public final class InputCharStream implements CharStream {
  
    public static final boolean staticFlag = false;
    int bufsize;
    int available;
    int tokenBegin;
    public int bufpos = -1;
    private int bufline[];
    private int bufcolumn[];
  
    private int column = 0;
    private int line = 1;
  
    private boolean prevCharIsCR = false;
    private boolean prevCharIsLF = false;
  
    private java.io.Reader inputStream;
  
    private char[] buffer;
    private int maxNextCharInd = 0;
    private int inBuf = 0;
  
    private final void ExpandBuff(boolean wrapAround) {
  
      char[] newbuffer = new char[bufsize + 2048];
      int newbufline[] = new int[bufsize + 2048];
      int newbufcolumn[] = new int[bufsize + 2048];
  
      try {
        if (wrapAround) {
          System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
          System.arraycopy(buffer, 0, newbuffer, bufsize - tokenBegin, bufpos);
          buffer = newbuffer;
  
          System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
          System.arraycopy(bufline, 0, newbufline, bufsize - tokenBegin, bufpos);
         bufline = newbufline;
 
         System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
         System.arraycopy(bufcolumn, 0, newbufcolumn, bufsize - tokenBegin, bufpos);
         bufcolumn = newbufcolumn;
 
         maxNextCharInd = (bufpos += (bufsize - tokenBegin));
 
       } else {
 
         System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
         buffer = newbuffer;
 
         System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
         bufline = newbufline;
 
         System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
         bufcolumn = newbufcolumn;
 
         maxNextCharInd = (bufpos -= tokenBegin);
       }
     } catch (Throwable t) {
       throw new Error(t.getMessage());
     }
 
     bufsize += 2048;
     available = bufsize;
     tokenBegin = 0;
   }
 
   private final void FillBuff() throws java.io.IOException {
     if (maxNextCharInd == available) {
       if (available == bufsize) {
         if (tokenBegin > 2048) {
           bufpos = maxNextCharInd = 0;
           available = tokenBegin;
         } else if (tokenBegin < 0)
           bufpos = maxNextCharInd = 0;
         else
           ExpandBuff(false);
       } else if (available > tokenBegin)
         available = bufsize;
       else if ((tokenBegin - available) < 2048)
         ExpandBuff(true);
       else
         available = tokenBegin;
     }
 
     int i;
 
     try {
       if ((i = inputStream.read(buffer, maxNextCharInd, available - maxNextCharInd)) == -1) {
         inputStream.close();
         throw new java.io.IOException();
       }
       maxNextCharInd += i;
       return;
     } catch (java.io.IOException e) {
       --bufpos;
       backup(0);
       if (tokenBegin == -1)
         tokenBegin = bufpos;
       throw e;
     }
   }
 
   public final char BeginToken() throws java.io.IOException {
 
     tokenBegin = -1;
     char c = readChar();
     tokenBegin = bufpos;
     return c;
   }
 
   private final void UpdateLineColumn(char c) {
 
     column++;
     if (prevCharIsLF) {
       prevCharIsLF = false;
       line += (column = 1);
     } else if (prevCharIsCR) {
       prevCharIsCR = false;
       if (c == '\n')
         prevCharIsLF = true;
       else
         line += (column = 1);
     }
 
     switch (c) {
       case '\r':
         prevCharIsCR = true;
         break;
       case '\n':
         prevCharIsLF = true;
         break;
       case '\t':
         column--;
         column += (8 - (column & 07));
         break;
       default:
         break;
     }
 
     bufline[bufpos] = line;
     bufcolumn[bufpos] = column;
   }
 
   /**
    * Returns the next character from the input stream. The only method whose implementation is
    * different from its original in the ASCII_CharStream class.
    */
   public final char readChar() throws java.io.IOException {
 
     if (inBuf > 0) {
       --inBuf;
 
       // ----------------------------------------------------------------------
       // the next line was changed, the original line generated by JavaCC was:
       // return (char)((char)0xff & buffer[(bufpos == bufsize - 1) ? (bufpos = 0) : ++bufpos]);
       // ----------------------------------------------------------------------
       return buffer[(bufpos == bufsize - 1) ? (bufpos = 0) : ++bufpos];
     }
     if (++bufpos >= maxNextCharInd)
       FillBuff();
 
     // ----------------------------------------------------------------------
     // the next line was changed, the original line generated by JavaCC was:
     // char c = (char)((char)0xff & buffer[bufpos]);
     // ----------------------------------------------------------------------
     char c = buffer[bufpos];
 
     UpdateLineColumn(c);
     return (c);
   }
 
   /**
    * @deprecated
    * @see #getEndColumn
    */
   public final int getColumn() {
     return bufcolumn[bufpos];
   }
 
   /**
    * @deprecated
    * @see #getEndLine
    */
   public final int getLine() {
     return bufline[bufpos];
   }
 
   public final int getEndColumn() {
     return bufcolumn[bufpos];
   }
 
   public final int getEndLine() {
     return bufline[bufpos];
   }
 
   public final int getBeginColumn() {
     return bufcolumn[tokenBegin];
   }
 
   public final int getBeginLine() {
     return bufline[tokenBegin];
   }
 
   public final void backup(int amount) {
     inBuf += amount;
     if ((bufpos -= amount) < 0)
       bufpos += bufsize;
   }
 
   /**
    * Constructor, allowing to specify start line and start column of the char stream, and buffer
    * size as well.
    */
   public InputCharStream(java.io.Reader dstream, int startline, int startcolumn, int buffersize) {
     inputStream = dstream;
     line = startline;
     column = startcolumn - 1;
     available = bufsize = buffersize;
     buffer = new char[buffersize];
     bufline = new int[buffersize];
     bufcolumn = new int[buffersize];
   }
 
   /**
    * Constructor, allowing to specify start line and start column of the char stream.
    */
   public InputCharStream(java.io.Reader dstream, int startline, int startcolumn) {
     this(dstream, startline, startcolumn, 4096);
   }
 
   /**
    * Constructor, instantiating the char stream to begin at 1-st line and 1-st column of
    * <tt>dstream</tt>.
    */
   public InputCharStream(java.io.Reader dstream) {
     this(dstream, 1, 1);
   }
 
   /**
    * Reinitialization of the char stream, allowing to specify start line and start column of the
    * char stream, and buffer size as well.
    */
   public void ReInit(java.io.Reader dstream, int startline, int startcolumn, int buffersize) {
     inputStream = dstream;
     line = startline;
     column = startcolumn - 1;
 
     if (buffer == null || buffersize != buffer.length) {
       available = bufsize = buffersize;
       buffer = new char[buffersize];
       bufline = new int[buffersize];
       bufcolumn = new int[buffersize];
     }
     prevCharIsLF = prevCharIsCR = false;
     tokenBegin = inBuf = maxNextCharInd = 0;
     bufpos = -1;
   }
 
   /**
    * Reinitialization of the char stream, allowing to specify start line and start column of the
    * char stream.
    */
   public void ReInit(java.io.Reader dstream, int startline, int startcolumn) {
     ReInit(dstream, startline, startcolumn, 4096);
   }
 
   /**
    * Reinitialization of the char stream, instantiating the char stream to begin at 1-st line and
    * 1-st column of <tt>dstream</tt>.
    */
   public void ReInit(java.io.Reader dstream) {
     ReInit(dstream, 1, 1);
   }
 
   public final String GetImage() {
     if (bufpos >= tokenBegin) {
       return new String(buffer, tokenBegin, bufpos - tokenBegin + 1);
     }
     return new String(buffer, tokenBegin, bufsize - tokenBegin) + new String(buffer, 0, bufpos + 1);
   }
 
   public final char[] GetSuffix(int len) {
     char[] ret = new char[len];
 
     if ((bufpos + 1) >= len)
       System.arraycopy(buffer, bufpos - len + 1, ret, 0, len);
     else {
       System.arraycopy(buffer, bufsize - (len - bufpos - 1), ret, 0, len - bufpos - 1);
       System.arraycopy(buffer, 0, ret, len - bufpos - 1, bufpos + 1);
     }
     return ret;
   }
 
   public void Done() {
     buffer = null;
     bufline = null;
     bufcolumn = null;
   }
 
   /**
    * Method to adjust line and column numbers for the start of a token.
    */
   public void adjustBeginLineColumn(int newLine, int newCol) {
     int start = tokenBegin;
     int len;
 
     if (bufpos >= tokenBegin) {
       len = bufpos - tokenBegin + inBuf + 1;
     } else {
       len = bufsize - tokenBegin + bufpos + 1 + inBuf;
     }
 
     int i = 0, j = 0, k = 0;
     int nextColDiff = 0, columnDiff = 0;
 
     while (i < len && bufline[j = start % bufsize] == bufline[k = ++start % bufsize]) {
       bufline[j] = newLine;
       nextColDiff = columnDiff + bufcolumn[k] - bufcolumn[j];
       bufcolumn[j] = newCol + columnDiff;
       columnDiff = nextColDiff;
       i++;
     }
 
     if (i < len) {
       bufline[j] = newLine++;
       bufcolumn[j] = newCol + columnDiff;
 
       while (i++ < len) {
         if (bufline[j = start % bufsize] != bufline[++start % bufsize])
           bufline[j] = newLine++;
         else
           bufline[j] = newLine;
       }
     }
 
     line = bufline[j];
     column = bufcolumn[j];
   }
 }