icldataq.java

SRI international 发布的OAA框架软件

package com.sri.oaa2.icl;

import java.util.zip.CRC32;

/**
 * IclTerm representing binary data.
 */
public final class IclDataQ extends IclAtomic
{
  /// The functor
  protected byte[] data = null;
  int rawLen = -1;
  int numQuotes = -1;

  /**
   * Create an empty IclDataQ.  Use setData() to set the binary data.
   */
  public IclDataQ() 
  {
    setType(OaaPrologVocabTokenTypes.ICLDATAQ);
    setData(new byte[0]);
  }

  /**
   * Construct an IclDataQ from a byte array.
   * This constructor assumes that the given array does not have quotes
   * escaped.
   *
   * @param byte[] d: the byte array data
   */
  public IclDataQ(byte[] d) 
  {
    setType(OaaPrologVocabTokenTypes.ICLDATAQ);
    setData(d);
  }

  /**
   * Doubles (escapes) double quotes in the data.
   */
  public void fixQuotes() 
  {
    byte[] d = getData();
    if(getNumQuotes() == 0) {
      return;
    }

    int realDataIndex = 0;
    for(int i = 1;
        i < d.length - 1; 
        ++i, ++realDataIndex) {
      if(d[i] == ((byte)'"')) {
        d[realDataIndex] = '"';
        ++i;
      }
      else {
        d[realDataIndex] = d[i];
      }
    }
    byte[] newData = new byte[realDataIndex];
    System.arraycopy(d, 0, newData, 0, realDataIndex);
    setData(newData);
  }

  /**
   * Doubles (escapes) double quotes in a String.
   *
   * @param String s: the String to escape
   * @return byte[]: a byte array representing the data.
   */
  public static byte[] fixQuotes(String s) 
  {
    IclDataQ d = new IclDataQ();
    byte[] b = s.getBytes();
    d.setData(b);
    d.fixQuotes();
    return d.getData();
  }

  /**
   * Return the data; the length of the returned array is the length of
   * the data.
   */
  public byte[] getData()
  {
    return this.data;
  }

  /**
   * The length of this array should be the length of the raw (quotes not
   * doubled) data.  This data should not be escaped.  This automatically
   * sets the raw length.
   */
  public void setData(byte[] d)
  {
    if(this.data == d) {
      return;
    }
    this.data = d;
    this.setRawLen(d.length);

    CRC32 computedCrc = new CRC32();
    computedCrc.update(d);
    this.setCrc(computedCrc.getValue());
  }

  /**
   * Raw length of the data.  This is the number of bytes of unescaped data.
   */
  public int getRawLen()
  {
    return this.rawLen;
  }

  /**
   * Set the raw length of the data.  Not needed if setData(byte[]) has been
   * used.
   */
  public void setRawLen(int r)
  {
    this.rawLen = r;
  }
  
  /**
   * Get the number of double quotes in the data.
   *
   * @return int: -1 if unknown, or the number of quotes
   */
  public int getNumQuotes()
  {
    return this.numQuotes;
  }

  /**
   * Set the number of double quotes in the data.
   */
  public void setNumQuotes(int n)
  {
    this.numQuotes = n;
  }

  /**
   * For parser.
   */
  protected IclDataQ(int id) {
    super(OaaPrologVocabTokenTypes.ICLDATAQ);
  }

  /** Accept the visitor. **/
  protected Object accept(OaaPrologVisitor visitor, Object d) {
    return visitor.visit(this, d);
  }

  /**
   * Return data as icldataq("<data>"), where <data> is the data with
   * quote characters doubled
   */
  public String getQuotedData() 
  {
    StringBuffer b = new StringBuffer();
    
    b.append("icldataq(\"");
    byte[] unquoted = getData();
    int start = 0;
    for(int i = 0; i < getRawLen(); ++i) {
      if(unquoted[i] == ((byte)'"')) {
        // append all the stuff that wasn't a quote character
        if((i - start) > 0) {
          b.append(new String(unquoted, start, i - start));
        }
        b.append("\"\"");
        start = i + 1;
      }
    }
    // might not have added stuff at the end of the unquoted data
    if(start < getRawLen()) {
      b.append(new String(unquoted, start, getRawLen() - start));
    }
    b.append("\")");
    return b.toString();
  }

  /**
   * Get a String representing the data.  This String consists
   * of an octal representation of the String: \010\012.
   *
   * @return String: an octal representation of the data
   */
  public String toHumanReadableString() 
  {
    StringBuffer b = new StringBuffer("");
    byte[] d = getData();
    Byte aByte;
    String s;
    for(int i = 0; i < d.length; ++i) {
      aByte = new Byte(d[i]);
      s = Integer.toOctalString(aByte.intValue());
      b.append("\\");
      if(s.length() < 2) {
        b.append("0");
      }
      b.append(s);
    }
    return b.toString();
  }

  /**
   * Returns icldataq.
   */
  public String toIdentifyingString() 
  {
    return toHumanReadableString();
  }

  public boolean equals(Object o) 
  {
    if(o == this) {
      return true;
    }
    
    if(!(o instanceof IclDataQ)) {
      return false;
    }
    
    IclDataQ t = (IclDataQ)o;
    if(t.getData().length != this.getData().length) {
      return false;
    }
    
    if(t.getCrc() != this.getCrc()) {
      return false;
    }
    
    for(int i = 0; i < t.getData().length; ++i) {
      if((t.getData())[i] != (this.getData())[i]) {
        return false;
      }
    }

    return true;
  }

  long getCrc() 
  {
    CRC32 computedCrc = new CRC32();
    computedCrc.update(this.data);
    return computedCrc.getValue();
  }
}