// ChoiceFormat.java - Formatter for `switch'-like string substitution.

/* Copyright (C) 1999, 2000  Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.text;

import java.util.Vector;

/**
 * @author Tom Tromey <tromey@cygnus.com>
 * @date March 9, 1999
 */
/* Written using "Java Class Libraries", 2nd edition, plus online
 * API docs for JDK 1.2 from http://www.javasoft.com.
 * Status:  Believed complete and correct to 1.1.
 */

public class ChoiceFormat extends NumberFormat
{
  // Note: we assume the same kind of quoting rules apply here.
  // This isn't explicitly documented.  But for instance we accept
  // '#' as a literal hash in a format string.
  public void applyPattern (String newPattern)
    {
      int index = 0, max = newPattern.length();
      Vector stringVec = new Vector ();
      Vector limitVec = new Vector ();
      StringBuffer buf = new StringBuffer ();

      while (true)
	{
	  // Find end of double.
	  int dstart = index;
	  while (index < max)
	    {
	      char c = newPattern.charAt(index);
	      if (c == '#' || c == '\u2064' || c == '<')
		break;
	      ++index;
	    }

	  if (index == max)
	    throw new IllegalArgumentException ("unexpected end of text");
	  Double d = new Double (newPattern.substring(dstart, index));

	  if (newPattern.charAt(index) == '<')
	    d = new Double (nextDouble (d.doubleValue()));

	  limitVec.addElement(d);

	  // Scan text.
	  ++index;
	  buf.setLength(0);
	  while (index < max)
	    {
	      char c = newPattern.charAt(index);
	      if (c == '\'' && index < max + 1
		  && newPattern.charAt(index + 1) == '\'')
		{
		  buf.append(c);
		  ++index;
		}
	      else if (c == '\'' && index < max + 2)
		{
		  buf.append(newPattern.charAt(index + 1));
		  index += 2;
		}
	      else if (c == '|')
		break;
	      else
		buf.append(c);
	      ++index;
	    }

	  stringVec.addElement(buf.toString());
	  if (index == max)
	    break;
	  ++index;
	}

      choiceFormats = new String[stringVec.size()];
      stringVec.copyInto(choiceFormats);

      choiceLimits = new double[limitVec.size()];
      for (int i = 0; i < choiceLimits.length; ++i)
	{
	  Double d = (Double) limitVec.elementAt(i);
	  choiceLimits[i] = d.doubleValue();
	}
    }

  public ChoiceFormat (String newPattern)
    {
      super ();
      applyPattern (newPattern);
    }

  public ChoiceFormat (double[] choiceLimits, String[] choiceFormats)
    {
      super ();
      setChoices (choiceLimits, choiceFormats);
    }

  public Object clone ()
    {
      return new ChoiceFormat (choiceLimits, choiceFormats);
    }

  public boolean equals (Object obj)
    {
      if (! (obj instanceof ChoiceFormat))
	return false;
      ChoiceFormat cf = (ChoiceFormat) obj;
      if (choiceLimits.length != cf.choiceLimits.length)
	return false;
      for (int i = choiceLimits.length - 1; i >= 0; --i)
	{
	  if (choiceLimits[i] != cf.choiceLimits[i]
	      || !choiceFormats[i].equals(cf.choiceFormats[i]))
	    return false;
	}
      return true;
    }

  public StringBuffer format (long num, StringBuffer appendBuf,
			      FieldPosition pos)
    {
      return format ((double) num, appendBuf, pos);
    }

  public StringBuffer format (double num, StringBuffer appendBuf,
			      FieldPosition pos)
    {
      if (choiceLimits.length == 0)
	return appendBuf;

      int index =  0;
      if (! Double.isNaN(num) && num >= choiceLimits[0])
	{
	  for (; index < choiceLimits.length - 1; ++index)
	    {
	      if (choiceLimits[index] <= num
		  && index != choiceLimits.length - 2
		  && num < choiceLimits[index + 1])
		break;
	    }
	}

      return appendBuf.append(choiceFormats[index]);
    }

  public Object[] getFormats ()
    {
      return (Object[]) choiceFormats.clone();
    }

  public double[] getLimits ()
    {
      return (double[]) choiceLimits.clone();
    }

  public int hashCode ()
    {
      int hash = 0;
      for (int i = 0; i < choiceLimits.length; ++i)
	{
	  long v = Double.doubleToLongBits(choiceLimits[i]);
	  hash ^= (v ^ (v >>> 32));
	  hash ^= choiceFormats[i].hashCode();
	}
      return hash;
    }

  public static final double nextDouble (double d)
    {
      return nextDouble (d, true);
    }

  public static double nextDouble (double d, boolean next)
    {
      if (Double.isInfinite(d) || Double.isNaN(d))
	return d;

      long bits = Double.doubleToLongBits(d);

      long mantMask = (1L << mantissaBits) - 1;
      long mantissa = bits & mantMask;

      long expMask = (1L << exponentBits) - 1;
      long exponent = (bits >>> mantissaBits) & expMask;

      if (next ^ (bits < 0)) // Increment magnitude
	{
	  if (mantissa == (1L << mantissaBits) - 1)
	    {
	      mantissa = 0L;
	      exponent++;
	     
	      // Check for absolute overflow.
	      if (exponent >= (1L << mantissaBits))
		return (bits > 0) ? Double.POSITIVE_INFINITY 
		  : Double.NEGATIVE_INFINITY;		      
	    }
	  else
	    mantissa++;
	}
      else // Decrement magnitude
	{
	  if (exponent == 0L && mantissa == 0L)
	    {
	      // The only case where there is a change of sign
	      return next ? Double.MIN_VALUE : -Double.MIN_VALUE;
	    }
	  else
	    {
	      if (mantissa == 0L)
		{
		  mantissa = (1L << mantissaBits) - 1;
		  exponent--;
		}
	      else
		mantissa--;
	    }
	}

      long result = bits < 0 ? 1 : 0;
      result = (result << exponentBits) | exponent;
      result = (result << mantissaBits) | mantissa;
      return Double.longBitsToDouble(result);
    }

  public Number parse (String sourceStr, ParsePosition pos)
    {
      int index = pos.getIndex();
      for (int i = 0; i < choiceLimits.length; ++i)
	{
	  if (sourceStr.startsWith(choiceFormats[i], index))
	    {
	      pos.setIndex(index + choiceFormats[i].length());
	      return new Double (choiceLimits[i]);
	    }
	}
      pos.setErrorIndex(index);
      return new Double (Double.NaN);
    }

  public static final double previousDouble (double d)
    {
      return nextDouble (d, false);
    }

  public void setChoices (double[] choiceLimits, String[] choiceFormats)
    {
      if (choiceLimits == null || choiceFormats == null)
	throw new NullPointerException ();
      if (choiceLimits.length != choiceFormats.length)
	throw new IllegalArgumentException ();
      this.choiceFormats = (String[]) choiceFormats.clone();
      this.choiceLimits = (double[]) choiceLimits.clone();
    }

  private final void quoteString (StringBuffer dest, String text)
    {
      int max = text.length();
      for (int i = 0; i < max; ++i)
	{
	  char c = text.charAt(i);
	  if (c == '\'')
	    {
	      dest.append(c);
	      dest.append(c);
	    }
	  else if (c == '#' || c == '|' || c == '\u2064' || c == '<')
	    {
	      dest.append('\'');
	      dest.append(c);
	      dest.append('\'');
	    }
	  else
	    dest.append(c);
	}
    }

  public String toPattern ()
    {
      StringBuffer result = new StringBuffer ();
      for (int i = 0; i < choiceLimits.length; ++i)
	{
	  result.append(choiceLimits[i]);
	  result.append('#');
	  quoteString (result, choiceFormats[i]);
	}
      return result.toString();
    }

  // Formats and limits.
  private String[] choiceFormats;
  private double[] choiceLimits;

  // Number of mantissa bits in double.
  private static final int mantissaBits = 52;
  // Number of exponent bits in a double.
  private static final int exponentBits = 11;
}