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/* Generated by: ParserGeneratorCC: Do not edit this line. AbstractCharStream.java Version 1.1 */
/* ParserGeneratorCCOptions:SUPPORT_CLASS_VISIBILITY_PUBLIC=true */
/*
 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
 * Copyright (C) 2011, 2013-2024 The JavaParser Team.
 *
 * This file is part of JavaParser.
 *
 * JavaParser can be used either under the terms of
 * a) the GNU Lesser General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 * b) the terms of the Apache License
 *
 * You should have received a copy of both licenses in LICENCE.LGPL and
 * LICENCE.APACHE. Please refer to those files for details.
 *
 * JavaParser 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.
 */
package com.github.javaparser;

/**
 * An implementation of interface CharStream, where the stream is assumed to
 * contain only ASCII characters (without unicode processing).
 */

public
abstract class AbstractCharStream
implements CharStream
{
  /** Default buffer size if nothing is specified */
  public static final int DEFAULT_BUF_SIZE = 4096;

  static final int hexval (final char c) throws java.io.IOException
  {
    switch (c)
    {
      case '0':
        return 0;
      case '1':
        return 1;
      case '2':
        return 2;
      case '3':
        return 3;
      case '4':
        return 4;
      case '5':
        return 5;
      case '6':
        return 6;
      case '7':
        return 7;
      case '8':
        return 8;
      case '9':
        return 9;
      case 'a':
      case 'A':
        return 10;
      case 'b':
      case 'B':
        return 11;
      case 'c':
      case 'C':
        return 12;
      case 'd':
      case 'D':
        return 13;
      case 'e':
      case 'E':
        return 14;
      case 'f':
      case 'F':
        return 15;
      default:  
        throw new java.io.IOException ("Invalid hex char '" + c + "' (=" + (int) c + ") provided!"); 
    }
  }

  /** Tab size for formatting. Usually in the range 1 to 8. */
  private int m_nTabSize = 1;

  /** Internal circular buffer */
  protected char[] buffer;

  /** Overall buffer size - same as buffer.length */
  protected int bufsize;

  /** Current read position in buffer. */
  protected int bufpos;
  
  /** The number of unoccupied buffer array positions */
  protected int available;
  
  /** The first array index (of `buffer`) that the current token starts */
  protected int tokenBegin;

  /** Characters in the backup/pushBack buffer */
  protected int inBuf;
  protected int maxNextCharInd;

  private int[] m_aBufLine;
  private int[] m_aBufColumn;

  // Current line number
  private int m_nLineNo;
  // Current column number
  private int m_nColumnNo;

  // Was the previous character a "\r" char?
  private boolean m_bPrevCharIsCR;
  // Was the previous character a "\n" char?
  private boolean m_bPrevCharIsLF;
  
  // Is line/column tracking enabled?
  private boolean m_bTrackLineColumn = true;


  /** Constructor. */
  public AbstractCharStream(final int nStartLine,
                            final int nStartColumn, 
                            final int nBufferSize)
  {
    reInit (nStartLine, nStartColumn, nBufferSize);
  }

  /** Reinitialise. */
  public final void reInit(final int nStartLine,
                           final int nStartColumn, 
                           final int nBufferSize)
  {
    m_nLineNo = nStartLine;
    m_nColumnNo = nStartColumn - 1;
    m_bPrevCharIsCR = false;
    m_bPrevCharIsLF = false;
    if (buffer == null || nBufferSize != buffer.length)
    {
      bufsize = nBufferSize;
      available = nBufferSize;
      buffer = new char[nBufferSize];
      m_aBufLine = new int[nBufferSize];
      m_aBufColumn = new int[nBufferSize];
    }
    maxNextCharInd = 0;
    inBuf = 0;
    tokenBegin = 0;
    bufpos = -1;
  }

  /**
   * Read from the underlying stream.
   * @param aBuf the buffer to be filled
   * @param nOfs The offset into the buffer. 0-based
   * @param nLen Number of chars to read.
   * @return Number of effective chars read, or -1 on error.
   */
  protected abstract int streamRead (char[] aBuf, int nOfs, int nLen) throws java.io.IOException;
  
  /**
   * Close the underlying stream.
   * @throws java.io.IOException If closing fails.
   */
  protected abstract void streamClose () throws java.io.IOException;
   
  // Override this method if you need more aggressive buffer size expansion
  protected int getBufSizeAfterExpansion ()
  {
    // Double the size by default
    return bufsize * 2;
  }

  protected void expandBuff (final boolean bWrapAround)
  {
    // Get the new buffer size
    final int nNewBufSize = getBufSizeAfterExpansion ();
    
    final char[] newbuffer = new char[nNewBufSize];
    final int[] newbufline = new int[nNewBufSize];
    final int[] newbufcolumn = new int[nNewBufSize];

    // Number of chars to be preserved
    final int nPreservedChars = bufsize - tokenBegin;
    
    if (bWrapAround)
    {
      // Move from offset "tokenBegin" to offset 0
      // arraycopy(src, srcPos, dest, destPos, length)

      // copy the "tail end" to the "start" (index 0) of the new buffer array 
      System.arraycopy(buffer, tokenBegin, newbuffer, 0, nPreservedChars);
      
      // copy the remaining "wrap around" content of the buffer from the start of the original buffer (starting at srcPos index 0) 
      System.arraycopy(buffer, 0, newbuffer, nPreservedChars, bufpos);
      
      // swap the new buffer in place of the old buffer
      buffer = newbuffer;
      
      System.arraycopy(m_aBufLine, tokenBegin, newbufline, 0, nPreservedChars);
      System.arraycopy(m_aBufLine, 0, newbufline, nPreservedChars, bufpos);
      m_aBufLine = newbufline;

      System.arraycopy(m_aBufColumn, tokenBegin, newbufcolumn, 0, nPreservedChars);
      System.arraycopy(m_aBufColumn, 0, newbufcolumn, nPreservedChars, bufpos);
      m_aBufColumn = newbufcolumn;

      bufpos += nPreservedChars;
      maxNextCharInd = bufpos;
    }
    else
    {
      // Move from offset "tokenBegin" to offset 0
      
      System.arraycopy(buffer, tokenBegin, newbuffer, 0, nPreservedChars);
      buffer = newbuffer;

      System.arraycopy(m_aBufLine, tokenBegin, newbufline, 0, nPreservedChars);
      m_aBufLine = newbufline;

      System.arraycopy(m_aBufColumn, tokenBegin, newbufcolumn, 0, nPreservedChars);
      m_aBufColumn = newbufcolumn;

      bufpos -= tokenBegin;
      maxNextCharInd = bufpos;
    }

    // Increase buffer size
    bufsize = nNewBufSize;
    available = nNewBufSize;
    tokenBegin = 0;
  }

  protected final void internalAdjustBuffSize()
  {
    final int nHalfBufferSize = bufsize / 2; 
    if (available == bufsize)
    {
      if (tokenBegin < 0)
      {
        // If this method is called from "beginToken()"
        // Just refill the buffer from the start
        bufpos = 0;
        maxNextCharInd = 0;
      }
      else
        if (tokenBegin > nHalfBufferSize)
        {
          // The token started in the second half - fill the front part 
          bufpos = 0;
          maxNextCharInd = 0;

          // Available bytes are > 50%
          available = tokenBegin;
        }
        else
        {
          // Token starts in the first half
          // just append to existing buffer
          expandBuff (false);
        }
    }
    else
    {
      // A token was read across array boundaries 
      if (available > tokenBegin)
      {
        available = bufsize;
      }
      else
        if ((tokenBegin - available) < nHalfBufferSize)
        {
          expandBuff (true);
        }
        else
        {
          available = tokenBegin;
        }
    }
  }

  protected void fillBuff() throws java.io.IOException
  {
    if (maxNextCharInd == available)
      internalAdjustBuffSize();

    try
    {
      // Read from underlying stream
      final int nCharsRead = streamRead (buffer, maxNextCharInd, available - maxNextCharInd);
      if (nCharsRead == -1) 
      {
        // We reached the end of the file
        streamClose ();
        
        // Caught down below and re-thrown
        throw new java.io.IOException("PGCC end of stream");
      }
      maxNextCharInd += nCharsRead;
    }
    catch (final java.io.IOException ex)
    {
      --bufpos;
      // ?What is the reason of this? Backup of 0 does nothing
      backup (0);
      if (tokenBegin == -1)
      {
        // Error occurred in "beginToken()"
        tokenBegin = bufpos;
      }
      throw ex;
    }
  }

  protected final void internalSetBufLineColumn (final int nLine, final int nColumn)
  {
    m_aBufLine[bufpos] = nLine;
    m_aBufColumn[bufpos] = nColumn;
  }

  protected final void internalUpdateLineColumn(final char c)
  {
    m_nColumnNo++;

    if (m_bPrevCharIsLF)
    {
      // It's a "\r\n" or "\n"
      // Start of a new line
      m_bPrevCharIsLF = false;
      m_nColumnNo = 1;
      m_nLineNo++;
    }
    else
      if (m_bPrevCharIsCR)
      {
        m_bPrevCharIsCR = false;
        if (c == '\n')
        {
          // It's a "\r\n"
          m_bPrevCharIsLF = true;
        }
        else
        {
          // It's only a "\r"
          m_nColumnNo = 1;
          m_nLineNo++;
        }
      }

    switch (c)
    {
      case '\r':
        m_bPrevCharIsCR = true;
        break;
      case '\n':
        m_bPrevCharIsLF = true;
        break;
      case '\t':
        m_nColumnNo--;
        m_nColumnNo += (m_nTabSize - (m_nColumnNo % m_nTabSize));
        break;
    }

    internalSetBufLineColumn (m_nLineNo, m_nColumnNo);
  }

  public char readChar() throws java.io.IOException
  {
    if (inBuf > 0)
    {
      // Something is left from last backup
      --inBuf;

      ++bufpos;
      if (bufpos == bufsize)
      {
        // Buffer overflow
        bufpos = 0;
      }

      return buffer[bufpos];
    }

    ++bufpos;
    if (bufpos >= maxNextCharInd)
      fillBuff();

    final char c = buffer[bufpos];

    if (m_bTrackLineColumn)
      internalUpdateLineColumn(c);
    return c;
  }

  public char beginToken() throws java.io.IOException
  {
    tokenBegin = -1;
    final char c = readChar();
    tokenBegin = bufpos;
    return c;
  }

  public int getBeginColumn ()
  {
    return m_aBufColumn[tokenBegin];
  }

  public int getBeginLine ()
  {
    return m_aBufLine[tokenBegin];
  }

  public int getEndColumn ()
  {
    return m_aBufColumn[bufpos];
  }

  public int getEndLine ()
  {
     return m_aBufLine[bufpos];
  }

  public void backup (final int nAmount)
  {
    if (nAmount > bufsize)
      throw new IllegalStateException ("Cannot back " + nAmount + " chars which is larger than the internal buffer size (" + bufsize + ")");
  
    inBuf += nAmount;
    bufpos -= nAmount;
    if (bufpos < 0)
    {
      // Buffer underflow (modulo)
      bufpos += bufsize;
    }
  }

  public String getImage()
  {
    if (bufpos >= tokenBegin)
    {
      // from tokenBegin to bufpos
      return new String (buffer, tokenBegin, bufpos - tokenBegin + 1);
    }

    // from tokenBegin to bufsize, and from 0 to bufpos
    return new String (buffer, tokenBegin, bufsize - tokenBegin) +
           new String (buffer, 0, bufpos + 1);
  }

  public char[] getSuffix (final int len)
  {
    char[] ret = new char[len];
    if ((bufpos + 1) >= len)
    {
      // one piece
      System.arraycopy(buffer, bufpos - len + 1, ret, 0, len);
    }
    else
    {
      // Wrap around
      final int nPart1 = len - bufpos - 1;
      System.arraycopy(buffer, bufsize - nPart1, ret, 0, nPart1);
      System.arraycopy(buffer, 0, ret, nPart1, bufpos + 1);
    }
    return ret;
  }

  public void done()
  {
    buffer = null;
    m_aBufLine = null;
    m_aBufColumn = null;
  }
 
  public final int getTabSize()
  { 
    return m_nTabSize;
  }

  public final void setTabSize (final int nTabSize)
  { 
    m_nTabSize = nTabSize;
  }

  /**
   * Method to adjust line and column numbers for the start of a token.
   * This is used internally to 
   */
  public final void adjustBeginLineColumn(final int nNewLine, final int newCol)
  {
    int start = tokenBegin;
    int newLine = nNewLine;
    
    int len;
    if (bufpos >= tokenBegin)
    {
      len = bufpos - tokenBegin + inBuf + 1;
    }
    else
    {
      len = bufsize - tokenBegin + bufpos + 1 + inBuf;
    }

    int i = 0;
    int j = 0;
    int k = 0;
    int nextColDiff = 0;
    int columnDiff = 0;

    // TODO disassemble meaning and split up
    while (i < len && m_aBufLine[j = start % bufsize] == m_aBufLine[k = ++start % bufsize])
    {
      m_aBufLine[j] = newLine;
      nextColDiff = columnDiff + m_aBufColumn[k] - m_aBufColumn[j];
      m_aBufColumn[j] = newCol + columnDiff;
      columnDiff = nextColDiff;
      i++;
    }

    if (i < len)
    {
      m_aBufLine[j] = newLine++;
      m_aBufColumn[j] = newCol + columnDiff;

      while (i++ < len)
      {
        // TODO disassemble meaning and split up
        if (m_aBufLine[j = start % bufsize] != m_aBufLine[++start % bufsize])
          m_aBufLine[j] = newLine++;
        else
          m_aBufLine[j] = newLine;
      }
    }

    m_nLineNo = m_aBufLine[j];
    m_nColumnNo = m_aBufColumn[j];
  }
  
  /**
   * @return the current line number. 0-based.
   */
  protected final int getLine ()
  { 
    return m_nLineNo;
  }
  
  /**
   * @return the current column number. 0-based.
   */
  protected final int getColumn ()
  { 
    return m_nColumnNo;
  }
  
  public final boolean isTrackLineColumn ()
  { 
    return m_bTrackLineColumn;
  }

  public final void setTrackLineColumn (final boolean bTrackLineColumn)
  { 
    m_bTrackLineColumn = bTrackLineColumn;
  }
}
/* ParserGeneratorCC - OriginalChecksum=32b0d611f4bd31c3255572c83e001828 (do not edit this line) */




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