alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

What this is

This file is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Other links

The source code

/* Generated By:JavaCC: Do not edit this line. JavaCharStream.java Version 3.0 */
package bsh;

/**
 * An implementation of interface CharStream, where the stream is assumed to
 * contain only ASCII characters (with java-like unicode escape processing).
 */

public class JavaCharStream
{
  public static final boolean staticFlag = false;
  static final int hexval(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;
    }

    throw new java.io.IOException(); // Should never come here
  }

  public int bufpos = -1;
  int bufsize;
  int available;
  int tokenBegin;
  protected int bufline[];
  protected int bufcolumn[];

  protected int column = 0;
  protected int line = 1;

  protected boolean prevCharIsCR = false;
  protected boolean prevCharIsLF = false;

  protected java.io.Reader inputStream;

  protected char[] nextCharBuf;
  protected char[] buffer;
  protected int maxNextCharInd = 0;
  protected int nextCharInd = -1;
  protected int inBuf = 0;

  protected 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;

           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;

           bufpos -= tokenBegin;
        }
     }
     catch (Throwable t)
     {
        throw new Error(t.getMessage());
     }

     available = (bufsize += 2048);
     tokenBegin = 0;
  }

  protected void FillBuff() throws java.io.IOException
  {
     int i;
     if (maxNextCharInd == 4096)
        maxNextCharInd = nextCharInd = 0;

     try {
        if ((i = inputStream.read(nextCharBuf, maxNextCharInd,
                                            4096 - maxNextCharInd)) == -1)
        {
           inputStream.close();
           throw new java.io.IOException();
        }
        else
           maxNextCharInd += i;
        return;
     }
     catch(java.io.IOException e) {
        if (bufpos != 0)
        {
           --bufpos;
           backup(0);
        }
        else
        {
           bufline[bufpos] = line;
           bufcolumn[bufpos] = column;
        }
        throw e;
     }
  }

  protected char ReadByte() throws java.io.IOException
  {
     if (++nextCharInd >= maxNextCharInd)
        FillBuff();

     return nextCharBuf[nextCharInd];
  }

  public char BeginToken() throws java.io.IOException
  {     
     if (inBuf > 0)
     {
        --inBuf;

        if (++bufpos == bufsize)
           bufpos = 0;

        tokenBegin = bufpos;
        return buffer[bufpos];
     }

     tokenBegin = 0;
     bufpos = -1;

     return readChar();
  }     

  protected void AdjustBuffSize()
  {
     if (available == bufsize)
     {
        if (tokenBegin > 2048)
        {
           bufpos = 0;
           available = tokenBegin;
        }
        else
           ExpandBuff(false);
     }
     else if (available > tokenBegin)
        available = bufsize;
     else if ((tokenBegin - available) < 2048)
        ExpandBuff(true);
     else
        available = tokenBegin;
  }

  protected 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;
  }

  public char readChar() throws java.io.IOException
  {
     if (inBuf > 0)
     {
        --inBuf;

        if (++bufpos == bufsize)
           bufpos = 0;

        return buffer[bufpos];
     }

     char c;

     if (++bufpos == available)
        AdjustBuffSize();

     if ((buffer[bufpos] = c = ReadByte()) == '\\')
     {
        UpdateLineColumn(c);

        int backSlashCnt = 1;

        for (;;) // Read all the backslashes
        {
           if (++bufpos == available)
              AdjustBuffSize();

           try
           {
              if ((buffer[bufpos] = c = ReadByte()) != '\\')
              {
                 UpdateLineColumn(c);
                 // found a non-backslash char.
                 if ((c == 'u') && ((backSlashCnt & 1) == 1))
                 {
                    if (--bufpos < 0)
                       bufpos = bufsize - 1;

                    break;
                 }

                 backup(backSlashCnt);
                 return '\\';
              }
           }
           catch(java.io.IOException e)
           {
              if (backSlashCnt > 1)
                 backup(backSlashCnt);

              return '\\';
           }

           UpdateLineColumn(c);
           backSlashCnt++;
        }

        // Here, we have seen an odd number of backslash's followed by a 'u'
        try
        {
           while ((c = ReadByte()) == 'u')
              ++column;

           buffer[bufpos] = c = (char)(hexval(c) << 12 |
                                       hexval(ReadByte()) << 8 |
                                       hexval(ReadByte()) << 4 |
                                       hexval(ReadByte()));

           column += 4;
        }
        catch(java.io.IOException e)
        {
           throw new Error("Invalid escape character at line " + line +
                                         " column " + column + ".");
        }

        if (backSlashCnt == 1)
           return c;
        else
        {
           backup(backSlashCnt - 1);
           return '\\';
        }
     }
     else
     {
        UpdateLineColumn(c);
        return (c);
     }
  }

  /**
   * @deprecated 
   * @see #getEndColumn
   */

  public int getColumn() {
     return bufcolumn[bufpos];
  }

  /**
   * @deprecated 
   * @see #getEndLine
   */

  public int getLine() {
     return bufline[bufpos];
  }

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

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

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

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

  public void backup(int amount) {

    inBuf += amount;
    if ((bufpos -= amount) < 0)
       bufpos += bufsize;
  }

  public JavaCharStream(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];
    nextCharBuf = new char[4096];
  }

  public JavaCharStream(java.io.Reader dstream,
                                        int startline, int startcolumn)
  {
     this(dstream, startline, startcolumn, 4096);
  }

  public JavaCharStream(java.io.Reader dstream)
  {
     this(dstream, 1, 1, 4096);
  }
  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];
      nextCharBuf = new char[4096];
    }
    prevCharIsLF = prevCharIsCR = false;
    tokenBegin = inBuf = maxNextCharInd = 0;
    nextCharInd = bufpos = -1;
  }

  public void ReInit(java.io.Reader dstream,
                                        int startline, int startcolumn)
  {
     ReInit(dstream, startline, startcolumn, 4096);
  }

  public void ReInit(java.io.Reader dstream)
  {
     ReInit(dstream, 1, 1, 4096);
  }
  public JavaCharStream(java.io.InputStream dstream, int startline,
  int startcolumn, int buffersize)
  {
     this(new java.io.InputStreamReader(dstream), startline, startcolumn, 4096);
  }

  public JavaCharStream(java.io.InputStream dstream, int startline,
                                                           int startcolumn)
  {
     this(dstream, startline, startcolumn, 4096);
  }

  public JavaCharStream(java.io.InputStream dstream)
  {
     this(dstream, 1, 1, 4096);
  }

  public void ReInit(java.io.InputStream dstream, int startline,
  int startcolumn, int buffersize)
  {
     ReInit(new java.io.InputStreamReader(dstream), startline, startcolumn, 4096);
  }
  public void ReInit(java.io.InputStream dstream, int startline,
                                                           int startcolumn)
  {
     ReInit(dstream, startline, startcolumn, 4096);
  }
  public void ReInit(java.io.InputStream dstream)
  {
     ReInit(dstream, 1, 1, 4096);
  }

  public String GetImage()
  {
     if (bufpos >= tokenBegin)
        return new String(buffer, tokenBegin, bufpos - tokenBegin + 1);
     else
        return new String(buffer, tokenBegin, bufsize - tokenBegin) +
                              new String(buffer, 0, bufpos + 1);
  }

  public 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()
  {
     nextCharBuf = null;
     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]; } }
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.