zlib.java

Java实现的各种数学算法

  /**
   * if path has no extension, add the given one;
   * ext should include the period.
   * TODO this does not work properly if the path is  abc.0120
   */
  public static String addExtensionIfMissing(String path, String ext)
  {
    String hasext = getExtension(path);
    if (hasext == null)
      path = path + ext;
    return path;
  } 


  /**
   * Java link detection:
   * <p>
   * For a link that actually points to something (either a file or
   * a directory), the absolute path is the path through the link,
   * whereas the canonical path is the path the link references.
   * <p>
   * Dangling links appear as files of size zero - 
   * no way to distinguish dangling links from non-existent files
   * other than by consulting the parent directory.
   */
  public static boolean isLink(File file)
  {
    try {
      if (!file.exists())
	return true;
      else

      {
	String cnnpath = file.getCanonicalPath();
	String abspath = file.getAbsolutePath();
	//System.out.println(abspath+" <-> "+cnnpath);
	return !abspath.equals(cnnpath);
      }
    }
    catch (java.io.FileNotFoundException ex) {
      return true;	      // a dangling link.
    }
    catch (IOException ex) { /*ignore other errors*/ }

    return false;
  } //isLink


  /**
   * launch JFileChooser to select a file
   */
  public static String chooseFile(Component parent)
  {
    String wdir = System.getProperty("user.dir");
    JFileChooser chooser = new JFileChooser(wdir);
    int retval = chooser.showOpenDialog(parent);
    if (retval != JFileChooser.APPROVE_OPTION) return null;
    File f = chooser.getSelectedFile();
    if (f == null || f.isDirectory()) return null;
    return f.getPath();
  }

  /**
   * launch JFileChooser to select a directory
   */
  public static String chooseDir(Component parent)
  {
    String wdir = System.getProperty("user.dir");
    JFileChooser chooser = new JFileChooser(wdir);
    chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    int retval = chooser.showOpenDialog(parent);
    if (retval != JFileChooser.APPROVE_OPTION) return null;
    File f = chooser.getSelectedFile();
    if (f == null) return null;
    return f.getPath();
  } //chooseDir


  /** pop up a GUI to ask the user to pick one of a couple choices
   * choces are passed like: Object[] values = { "draw mode", "paint mode" };
   */
  public static Object getUIInput(Object[] values)
  {
    Object selected
      = JOptionPane.showInputDialog(null, "Choose one", "Input",
				    JOptionPane.INFORMATION_MESSAGE, null,
				    values, values[0]);
    return selected;
  } //getUIInput

  //----------------------------------------------------------------

  /**
   * load properties from file
   */
  public static java.util.Properties readProps(String path)
    throws IOException
  {
    java.util.Properties props = new java.util.Properties();
    InputStream f = new FileInputStream(path);
    props.load(f);
    f.close();
    return props;
  } //readProps


  /**
   * go over cmdline, for any arg that looks like an -option,
   * add the next arg as its value unless it too begins with a hypen,
   * in that case add True as its value.
   */
  public static void addCmdlineProps(java.util.Properties props,
				     String[] cmdline)
  {
    for( int i=0; i < cmdline.length; i++ ) {
      if (cmdline[i].startsWith("-")) {
	String key = cmdline[i];
	Object val = Boolean.TRUE;
	if (i < (cmdline.length-1) &&
	    !cmdline[i+1].startsWith("-"))
	  val = cmdline[i+1];
	props.put(key, val);  // relying on the fact that props is a hashtable
      }
    }
  } //addCmdlineProps

  //----------------------------------------------------------------

  /**
   * return a string with any characters c removed
   */
  public static String stripchar(String tok, char c)
  {
    if (tok.indexOf(c) < 0)
      return tok;

    StringBuffer sb = new StringBuffer();
    int len = tok.length();
    for( int i = 0; i < len; i++ ) {
      char c1 = tok.charAt(i);
      if (c1 != c) sb.append(c1);
    }

    return sb.toString();
  } //stripchars


  /**
   */
  public static void sleepfor(int msecs)
  {
    //System.out.println("sleeping for " + msecs);
    System.out.print(".");
    try { Thread.sleep(msecs); } catch(Exception x) {}
  }

  /**
   * Print --more--, wait for user to hit enter to continue.
   */
  public static void more()
  {
    //if (verbose == 0) return;
    System.out.println("--more--");
    try { System.in.read(); }
    catch(Exception x) {}
  }

  /**
   * substitute becomes for was in str, return new string
   */
  public static String stringsubst(String str, String was, String becomes)
  {
    int idx = str.indexOf(was);
    if (idx < 0) return str;
    String start = str.substring(0, idx);
    String end = str.substring(idx+was.length(), str.length());
    return start + becomes + end;
  }

  /**
   * Split string at delimiters, like python string.split.
   * NOTE There is a jdk1.4 String.split routine
   * TODO: could probably speed this up by coding without the stringtokenizer
   */
  public static ArrayList stringSplit(String s, String delim)
  {
    ArrayList l = null;
    StringTokenizer st = new StringTokenizer(s, delim, false);
    while( st.hasMoreTokens() ) {
      String tok = st.nextToken();
      if (l == null) l = new ArrayList(5);
      l.add(tok);
    }
    return l;
  } //stringSplit

  //----------------------------------------------------------------

  /**
   * full clone of a 2d int array
   * @deprecated moved to zlib.array
   */
  public static int[][] cloneArray(int[][] arr)
  {
    int[][] rarr = (int[][])arr.clone();
    int nr = arr.length;
    for( int r=0; r < nr; r++ ) {
      rarr[r] = (int[])(arr[r]).clone();
    }

    return rarr;
  } //cloneArray

  /**
   * full clone of a 2d float array
   * @deprecated moved to zlib.array
   */
  public static float[][] cloneArray(float[][] arr)
  {
    float[][] rarr = (float[][])arr.clone();
    int nr = arr.length;
    for( int r=0; r < nr; r++ ) {
      rarr[r] = (float[])(arr[r]).clone();
    }

    return rarr;
  } //cloneArray

  /**
   * full clone of a 2d double array
   * @deprecated moved to zlib.array
   */
  public static double[][] cloneArray(double[][] arr)
  {
    double[][] rarr = (double[][])arr.clone();
    int nr = arr.length;
    for( int r=0; r < nr; r++ ) {
      rarr[r] = (double[])(arr[r]).clone();
    }

    return rarr;
  } //cloneArray

  //----------------------------------------------------------------

  /**
   * copy float[][] to double[][]
   */
  public static double[] toDouble(float[] arr)
  {
    int len = arr.length;
    double[] d = new double[len];
    for( int i=0; i < len; i++ ) {
      d[i] = arr[i];
    }
    return d;
  } //toDouble


  /**
   * copy float[][] to double[][]
   * @deprecated moved to zlib.array
   */
  public static double[][] toDouble(float[][] arr)
  {
    int nr = arr.length;
    int nc = arr[0].length;
    double[][] darr = new double[nr][nc];

    for( int r=0; r < nr; r++ ) {
      for( int c=0; c < nc; c++ ) {
	darr[r][c] = arr[r][c];
      }
    }

    return darr;
  } //toDouble


  /**
   * copy double[][] to float[][]
   * @deprecated moved to zlib.array
   */
  public static float[] toFloat(double[] arr)
  {
    int len = arr.length;
    float[] d = new float[len];
    for( int i=0; i < len; i++ ) {
      d[i] = (float)arr[i];
    }
    return d;
  } //toFloat


  /**
   * copy double[][] to float[][]
   * @deprecated moved to zlib.array
   */
  public static float[][] toFloat(double[][] arr)
  {
    int nr = arr.length;
    int nc = arr[0].length;
    float[][] farr = new float[nr][nc];

    for( int r=0; r < nr; r++ ) {
      // TODO: row access to speed up
      for( int c=0; c < nc; c++ ) {
	farr[r][c] = (float)arr[r][c];
      }
    }

    return farr;
  } //toFloat


  //----------------------------------------------------------------

  /**
   * this is in java.util.Arrays
   * @deprecated
   */
  public static boolean equals(double[] arr1, double[] arr2)
  {
    int len = arr1.length;
    if (len != arr2.length) return false;

    for( int i=0; i < len; i++ ) {
      if (arr1[i] != arr2[i]) return false;
    }

    return true;
  } //equals(double[],double[])


  /**
   * this is in java.util.Arrays
   * @deprecated
   */
  public static boolean equals(float[] arr1, float[] arr2)
  {
    int len = arr1.length;
    if (len != arr2.length) return false;

    for( int i=0; i < len; i++ ) {
      if (arr1[i] != arr2[i]) return false;
    }

    return true;
  } //equals(float[],float[])

  //----------------------------------------------------------------

  /**
   * @deprecated moved to zlib.array
   */
  public static int max(int[] arr)
  {
    int len = arr.length;
    int max = Integer.MIN_VALUE;

    for( int i=0; i < len; i++ ) {
      if (arr[i] > max) max = arr[i];
    }

    return max;
  } //max


  /**
   * @deprecated moved to zlib.array
   */
  public static int min(int[] arr)
  {
    int len = arr.length;
    int min = Integer.MAX_VALUE;

    for( int i=0; i < len; i++ ) {
      if (arr[i] < min) min = arr[i];
    }

    return min;
  } //min


  /**
   * @deprecated moved to zlib.array
   */
  public static float max(float[] arr)
  {
    int len = arr.length;
    float max = Float.NEGATIVE_INFINITY;

    for( int i=0; i < len; i++ ) {
      if (arr[i] > max) max = arr[i];
    }

    return max;
  } //max


  /**
   * @deprecated moved to zlib.array
   */
  public static float min(float[] arr)
  {
    int len = arr.length;
    float min = Float.POSITIVE_INFINITY;

    for( int i=0; i < len; i++ ) {
      if (arr[i] < min) min = arr[i];
    }

    return min;
  } //min

  //----------------------------------------------------------------

  public static int atoi(String s)
  {
    return Integer.parseInt(s);
  }

  public static double atof(String s)
  {
    return Double.valueOf(s).doubleValue();
  }

  //----------------------------------------------------------------

  /** test the InputStreamReadLine
   */
  public static void main(String[] args)
  {
    try {
      InputStream f = new FileInputStream("zlib/zlib.java");
      String s = InputStreamReadLine(f);
      System.out.println("line :"+s+":");
      f.close();
    }
    catch(Exception ex) { System.err.println(ex); }
  }

} //zlib