/*

 * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved

 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved

 *

 *   The original version of this source code and documentation is copyrighted

 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These

 * materials are provided under terms of a License Agreement between Taligent

 * and Sun. This technology is protected by multiple US and International

 * patents. This notice and attribution to Taligent may not be removed.

 *   Taligent is a registered trademark of Taligent, Inc.

 *

 */

package java.text;

import java.io.InvalidObjectException;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.util.Arrays;

/**

 * A <code>ChoiceFormat</code> allows you to attach a format to a range of numbers.

 * It is generally used in a <code>MessageFormat</code> for handling plurals.

 * The choice is specified with an ascending list of doubles, where each item

 * specifies a half-open interval up to the next item:

 * <blockquote>

 * <pre>

 * X matches j if and only if limit[j] <= X < limit[j+1]

 * </pre>

 * </blockquote>

 * If there is no match, then either the first or last index is used, depending

 * on whether the number (X) is too low or too high.  If the limit array is not

 * in ascending order, the results of formatting will be incorrect.  ChoiceFormat

 * also accepts <code>&#92;u221E</code> as equivalent to infinity(INF).

 *

 * <p>

 * <strong>Note:</strong>

 * <code>ChoiceFormat</code> differs from the other <code>Format</code>

 * classes in that you create a <code>ChoiceFormat</code> object with a

 * constructor (not with a <code>getInstance</code> style factory

 * method). The factory methods aren't necessary because <code>ChoiceFormat</code>

 * doesn't require any complex setup for a given locale. In fact,

 * <code>ChoiceFormat</code> doesn't implement any locale specific behavior.

 *

 * <p>

 * When creating a <code>ChoiceFormat</code>, you must specify an array of formats

 * and an array of limits. The length of these arrays must be the same.

 * For example,

 * <ul>

 * <li>

 *     <em>limits</em> = {1,2,3,4,5,6,7}<br>

 *     <em>formats</em> = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}

 * <li>

 *     <em>limits</em> = {0, 1, ChoiceFormat.nextDouble(1)}<br>

 *     <em>formats</em> = {"no files", "one file", "many files"}<br>

 *     (<code>nextDouble</code> can be used to get the next higher double, to

 *     make the half-open interval.)

 * </ul>

 *

 * <p>

 * Here is a simple example that shows formatting and parsing:

 * <blockquote>

 * <pre>

 * double[] limits = {1,2,3,4,5,6,7};

 * String[] dayOfWeekNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"};

 * ChoiceFormat form = new ChoiceFormat(limits, dayOfWeekNames);

 * ParsePosition status = new ParsePosition(0);

 * for (double i = 0.0; i <= 8.0; ++i) {

 *     status.setIndex(0);

 *     System.out.println(i + " -> " + form.format(i) + " -> "

 *                              + form.parse(form.format(i),status));

 * }

 * </pre>

 * </blockquote>

 * Here is a more complex example, with a pattern format:

 * <blockquote>

 * <pre>

 * double[] filelimits = {0,1,2};

 * String[] filepart = {"are no files","is one file","are {2} files"};

 * ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);

 * Format[] testFormats = {fileform, null, NumberFormat.getInstance()};

 * MessageFormat pattform = new MessageFormat("There {0} on {1}");

 * pattform.setFormats(testFormats);

 * Object[] testArgs = {null, "ADisk", null};

 * for (int i = 0; i < 4; ++i) {

 *     testArgs[0] = new Integer(i);

 *     testArgs[2] = testArgs[0];

 *     System.out.println(pattform.format(testArgs));

 * }

 * </pre>

 * </blockquote>

 * <p>

 * Specifying a pattern for ChoiceFormat objects is fairly straightforward.

 * For example:

 * <blockquote>

 * <pre>

 * ChoiceFormat fmt = new ChoiceFormat(

 *      "-1#is negative| 0#is zero or fraction | 1#is one |1.0<is 1+ |2#is two |2<is more than 2.");

 * System.out.println("Formatter Pattern : " + fmt.toPattern());

 *

 * System.out.println("Format with -INF : " + fmt.format(Double.NEGATIVE_INFINITY));

 * System.out.println("Format with -1.0 : " + fmt.format(-1.0));

 * System.out.println("Format with 0 : " + fmt.format(0));

 * System.out.println("Format with 0.9 : " + fmt.format(0.9));

 * System.out.println("Format with 1.0 : " + fmt.format(1));

 * System.out.println("Format with 1.5 : " + fmt.format(1.5));

 * System.out.println("Format with 2 : " + fmt.format(2));

 * System.out.println("Format with 2.1 : " + fmt.format(2.1));

 * System.out.println("Format with NaN : " + fmt.format(Double.NaN));

 * System.out.println("Format with +INF : " + fmt.format(Double.POSITIVE_INFINITY));

 * </pre>

 * </blockquote>

 * And the output result would be like the following:

 * <blockquote>

 * <pre>

 *   Format with -INF : is negative

 *   Format with -1.0 : is negative

 *   Format with 0 : is zero or fraction

 *   Format with 0.9 : is zero or fraction

 *   Format with 1.0 : is one

 *   Format with 1.5 : is 1+

 *   Format with 2 : is two

 *   Format with 2.1 : is more than 2.

 *   Format with NaN : is negative

 *   Format with +INF : is more than 2.

 * </pre>

 * </blockquote>

 *

 * <h4><a name="synchronization">Synchronization</a></h4>

 *

 * <p>

 * Choice formats are not synchronized.

 * It is recommended to create separate format instances for each thread.

 * If multiple threads access a format concurrently, it must be synchronized

 * externally.

 *

 *

 * @see          DecimalFormat

 * @see          MessageFormat

 * @author       Mark Davis

 */

public class ChoiceFormat extends NumberFormat {

    // Proclaim serial compatibility with 1.1 FCS

    private static final long serialVersionUID = 1795184449645032964L;

    /**

     * Sets the pattern.

     * @param newPattern See the class description.

     */

    public void applyPattern(String newPattern) {

        StringBuffer[] segments = new StringBuffer[2];

        for (int i = 0; i < segments.length; ++i) {

            segments[i] = new StringBuffer();

        }

        double[] newChoiceLimits = new double[30];

        String[] newChoiceFormats = new String[30];

        int count = 0;

        int part = 0;

        double startValue = 0;

        double oldStartValue = Double.NaN;

        boolean inQuote = false;

        for (int i = 0; i < newPattern.length(); ++i) {

            char ch = newPattern.charAt(i);

            if (ch=='\'') {

                // Check for "''" indicating a literal quote

                if ((i+1)<newPattern.length() && newPattern.charAt(i+1)==ch) {

                    segments[part].append(ch);

                    ++i;

                } else {

                    inQuote = !inQuote;

                }

            } else if (inQuote) {

                segments[part].append(ch);

            } else if (ch == '<' || ch == '#' || ch == '\u2264') {

                if (segments[0].length() == 0) {

                    throw new IllegalArgumentException();

                }

                try {

                    String tempBuffer = segments[0].toString();

                    if (tempBuffer.equals("\u221E")) {

                        startValue = Double.POSITIVE_INFINITY;

                    } else if (tempBuffer.equals("-\u221E")) {

                        startValue = Double.NEGATIVE_INFINITY;

                    } else {

                        startValue = Double.valueOf(segments[0].toString()).doubleValue();

                    }

                } catch (Exception e) {

                    throw new IllegalArgumentException();

                }

                if (ch == '<' && startValue != Double.POSITIVE_INFINITY &&

                        startValue != Double.NEGATIVE_INFINITY) {

                    startValue = nextDouble(startValue);

                }

                if (startValue <= oldStartValue) {

                    throw new IllegalArgumentException();

                }

                segments[0].setLength(0);

                part = 1;

            } else if (ch == '|') {

                if (count == newChoiceLimits.length) {

                    newChoiceLimits = doubleArraySize(newChoiceLimits);

                    newChoiceFormats = doubleArraySize(newChoiceFormats);

                }

                newChoiceLimits[count] = startValue;

                newChoiceFormats[count] = segments[1].toString();

                ++count;

                oldStartValue = startValue;

                segments[1].setLength(0);

                part = 0;

            } else {

                segments[part].append(ch);

            }

        }

        // clean up last one

        if (part == 1) {

            if (count == newChoiceLimits.length) {

                newChoiceLimits = doubleArraySize(newChoiceLimits);

                newChoiceFormats = doubleArraySize(newChoiceFormats);

            }

            newChoiceLimits[count] = startValue;

            newChoiceFormats[count] = segments[1].toString();

            ++count;

        }

        choiceLimits = new double[count];

        System.arraycopy(newChoiceLimits, 0, choiceLimits, 0, count);

        choiceFormats = new String[count];

        System.arraycopy(newChoiceFormats, 0, choiceFormats, 0, count);

    }

    /**

     * Gets the pattern.

     */

    public String toPattern() {

        StringBuffer result = new StringBuffer();

        for (int i = 0; i < choiceLimits.length; ++i) {

            if (i != 0) {

                result.append('|');

            }

            // choose based upon which has less precision

            // approximate that by choosing the closest one to an integer.

            // could do better, but it's not worth it.

            double less = previousDouble(choiceLimits[i]);

            double tryLessOrEqual = Math.abs(Math.IEEEremainder(choiceLimits[i], 1.0d));

            double tryLess = Math.abs(Math.IEEEremainder(less, 1.0d));

            if (tryLessOrEqual < tryLess) {

                result.append(""+choiceLimits[i]);

                result.append('#');

            } else {

                if (choiceLimits[i] == Double.POSITIVE_INFINITY) {

                    result.append("\u221E");

                } else if (choiceLimits[i] == Double.NEGATIVE_INFINITY) {

                    result.append("-\u221E");

                } else {

                    result.append(""+less);

                }

                result.append('<');

            }

            // Append choiceFormats[i], using quotes if there are special characters.

            // Single quotes themselves must be escaped in either case.

            String text = choiceFormats[i];

            boolean needQuote = text.indexOf('<') >= 0

                || text.indexOf('#') >= 0

                || text.indexOf('\u2264') >= 0

                || text.indexOf('|') >= 0;

            if (needQuote) result.append('\'');

            if (text.indexOf('\'') < 0) result.append(text);

            else {

                for (int j=0; j<text.length(); ++j) {

                    char c = text.charAt(j);

                    result.append(c);

                    if (c == '\'') result.append(c);

                }

            }

            if (needQuote) result.append('\'');

        }

        return result.toString();

    }

    /**

     * Constructs with limits and corresponding formats based on the pattern.

     * @see #applyPattern

     */

    public ChoiceFormat(String newPattern)  {

        applyPattern(newPattern);

    }

    /**

     * Constructs with the limits and the corresponding formats.

     * @see #setChoices

     */

    public ChoiceFormat(double[] limits, String[] formats) {

        setChoices(limits, formats);

    }

    /**

     * Set the choices to be used in formatting.

     * @param limits contains the top value that you want

     * parsed with that format,and should be in ascending sorted order. When

     * formatting X, the choice will be the i, where

     * limit[i] <= X < limit[i+1].

     * If the limit array is not in ascending order, the results of formatting

     * will be incorrect.

     * @param formats are the formats you want to use for each limit.

     * They can be either Format objects or Strings.

     * When formatting with object Y,

     * if the object is a NumberFormat, then ((NumberFormat) Y).format(X)

     * is called. Otherwise Y.toString() is called.

     */

    public void setChoices(double[] limits, String formats[]) {

        if (limits.length != formats.length) {

            throw new IllegalArgumentException(

                "Array and limit arrays must be of the same length.");

        }

        choiceLimits = limits;

        choiceFormats = formats;

    }

    /**

     * Get the limits passed in the constructor.

     * @return the limits.

     */

    public double[] getLimits() {

        return choiceLimits;

    }

    /**

     * Get the formats passed in the constructor.

     * @return the formats.

     */

    public Object[] getFormats() {

        return choiceFormats;

    }

    // Overrides

    /**

     * Specialization of format. This method really calls

     * <code>format(double, StringBuffer, FieldPosition)</code>

     * thus the range of longs that are supported is only equal to

     * the range that can be stored by double. This will never be

     * a practical limitation.

     */

    public StringBuffer format(long number, StringBuffer toAppendTo,

                               FieldPosition status) {

        return format((double)number, toAppendTo, status);

    }

    /**

     * Returns pattern with formatted double.

     * @param number number to be formatted & substituted.

     * @param toAppendTo where text is appended.

     * @param status ignore no useful status is returned.

     */

   public StringBuffer format(double number, StringBuffer toAppendTo,

                               FieldPosition status) {

        // find the number

        int i;

        for (i = 0; i < choiceLimits.length; ++i) {

            if (!(number >= choiceLimits[i])) {

                // same as number < choiceLimits, except catchs NaN

                break;

            }

        }

        --i;

        if (i < 0) i = 0;

        // return either a formatted number, or a string

        return toAppendTo.append(choiceFormats[i]);

    }

    /**

     * Parses a Number from the input text.

     * @param text the source text.

     * @param status an input-output parameter.  On input, the

     * status.index field indicates the first character of the

     * source text that should be parsed.  On exit, if no error

     * occured, status.index is set to the first unparsed character

     * in the source text.  On exit, if an error did occur,

     * status.index is unchanged and status.errorIndex is set to the

     * first index of the character that caused the parse to fail.

     * @return A Number representing the value of the number parsed.

     */

    public Number parse(String text, ParsePosition status) {

        // find the best number (defined as the one with the longest parse)

        int start = status.index;

        int furthest = start;

        double bestNumber = Double.NaN;

        double tempNumber = 0.0;

        for (int i = 0; i < choiceFormats.length; ++i) {

            String tempString = choiceFormats[i];

            if (text.regionMatches(start, tempString, 0, tempString.length())) {

                status.index = start + tempString.length();

                tempNumber = choiceLimits[i];

                if (status.index > furthest) {

                    furthest = status.index;

                    bestNumber = tempNumber;

                    if (furthest == text.length()) break;

                }

            }

        }

        status.index = furthest;

        if (status.index == start) {

            status.errorIndex = furthest;

        }

        return new Double(bestNumber);

    }

    /**

     * Finds the least double greater than d.

     * If NaN, returns same value.

     * <p>Used to make half-open intervals.

     * @see #previousDouble

     */

    public static final double nextDouble (double d) {

        return nextDouble(d,true);

    }

    /**

     * Finds the greatest double less than d.

     * If NaN, returns same value.

     * @see #nextDouble

     */

    public static final double previousDouble (double d) {

        return nextDouble(d,false);

    }

    /**

     * Overrides Cloneable

     */

    public Object clone()

    {

        ChoiceFormat other = (ChoiceFormat) super.clone();

        // for primitives or immutables, shallow clone is enough

        other.choiceLimits = (double[]) choiceLimits.clone();

        other.choiceFormats = (String[]) choiceFormats.clone();

        return other;

    }

    /**

     * Generates a hash code for the message format object.

     */

    public int hashCode() {

        int result = choiceLimits.length;

        if (choiceFormats.length > 0) {

            // enough for reasonable distribution

            result ^= choiceFormats[choiceFormats.length-1].hashCode();

        }

        return result;

    }

    /**

     * Equality comparision between two

     */

    public boolean equals(Object obj) {

        if (obj == null) return false;

        if (this == obj)                      // quick check

            return true;

        if (getClass() != obj.getClass())

            return false;

        ChoiceFormat other = (ChoiceFormat) obj;

        return (Arrays.equals(choiceLimits, other.choiceLimits)

             && Arrays.equals(choiceFormats, other.choiceFormats));

    }

    /**

     * After reading an object from the input stream, do a simple verification

     * to maintain class invariants.

     * @throws InvalidObjectException if the objects read from the stream is invalid.

     */

    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {

        in.defaultReadObject();

        if (choiceLimits.length != choiceFormats.length) {

            throw new InvalidObjectException(

                    "limits and format arrays of different length.");

        }

    }

    // ===============privates===========================

    /**

     * A list of lower bounds for the choices.  The formatter will return

     * <code>choiceFormats[i]</code> if the number being formatted is greater than or equal to

     * <code>choiceLimits[i]</code> and less than <code>choiceLimits[i+1]</code>.

     * @serial

     */

    private double[] choiceLimits;

    /**

     * A list of choice strings.  The formatter will return

     * <code>choiceFormats[i]</code> if the number being formatted is greater than or equal to

     * <code>choiceLimits[i]</code> and less than <code>choiceLimits[i+1]</code>.

     * @serial

     */

    private String[] choiceFormats;

    /*

    static final long SIGN          = 0x8000000000000000L;

    static final long EXPONENT      = 0x7FF0000000000000L;

    static final long SIGNIFICAND   = 0x000FFFFFFFFFFFFFL;

    private static double nextDouble (double d, boolean positive) {

        if (Double.isNaN(d) || Double.isInfinite(d)) {

                return d;

            }

        long bits = Double.doubleToLongBits(d);

        long significand = bits & SIGNIFICAND;

        if (bits < 0) {

            significand |= (SIGN | EXPONENT);

        }

        long exponent = bits & EXPONENT;

        if (positive) {

            significand += 1;

            // FIXME fix overflow & underflow

        } else {

            significand -= 1;

            // FIXME fix overflow & underflow

        }

        bits = exponent | (significand & ~EXPONENT);

        return Double.longBitsToDouble(bits);

    }

    */

    static final long SIGN                = 0x8000000000000000L;

    static final long EXPONENT            = 0x7FF0000000000000L;

    static final long POSITIVEINFINITY    = 0x7FF0000000000000L;

    /**

     * Finds the least double greater than d (if positive == true),

     * or the greatest double less than d (if positive == false).

     * If NaN, returns same value.

     *

     * Does not affect floating-point flags,

     * provided these member functions do not:

     *          Double.longBitsToDouble(long)

     *          Double.doubleToLongBits(double)

     *          Double.isNaN(double)

     */

    public static double nextDouble (double d, boolean positive) {

        /* filter out NaN's */

        if (Double.isNaN(d)) {

            return d;

        }

        /* zero's are also a special case */

        if (d == 0.0) {

            double smallestPositiveDouble = Double.longBitsToDouble(1L);

            if (positive) {

                return smallestPositiveDouble;

            } else {

                return -smallestPositiveDouble;

            }

        }

        /* if entering here, d is a nonzero value */

        /* hold all bits in a long for later use */

        long bits = Double.doubleToLongBits(d);

        /* strip off the sign bit */

        long magnitude = bits & ~SIGN;

        /* if next double away from zero, increase magnitude */

        if ((bits > 0) == positive) {

            if (magnitude != POSITIVEINFINITY) {

                magnitude += 1;

            }

        }

        /* else decrease magnitude */

        else {

            magnitude -= 1;

        }

        /* restore sign bit and return */

        long signbit = bits & SIGN;

        return Double.longBitsToDouble (magnitude | signbit);

    }

    private static double[] doubleArraySize(double[] array) {

        int oldSize = array.length;

        double[] newArray = new double[oldSize * 2];

        System.arraycopy(array, 0, newArray, 0, oldSize);

        return newArray;

    }

    private String[] doubleArraySize(String[] array) {

        int oldSize = array.length;

        String[] newArray = new String[oldSize * 2];

        System.arraycopy(array, 0, newArray, 0, oldSize);

        return newArray;

    }

}