/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.

 */

package com.oracle.solaris.vp.util.misc;

import java.text.DecimalFormat;

import com.oracle.solaris.vp.util.misc.finder.Finder;

public class DataSizeUtil {

    //

    // Inner classes

    //

    public static class DataSize {

	public double value;

	public int unitsIndex;

	public DataSize(double value, int unitsIndex) {

	    this.value = value;

	    this.unitsIndex = unitsIndex;

	}

    }

    //

    // Static methods

    //

    public static String[] getDefaultUnits() {

	return new String[] {

	    Finder.getString("constants.bytes.short"),

	    Finder.getString("constants.kilobytes.short"),

	    Finder.getString("constants.megabytes.short"),

	    Finder.getString("constants.gigabytes.short"),

	    Finder.getString("constants.terabytes.short"),

	    Finder.getString("constants.petabytes.short"),

	    Finder.getString("constants.exabytes.short"),

	};

    }

    /**

     * Gets a DataSize object that represents the most displayable

     * form of the given data size.

     *

     * @param	    bytes

     *		    the size of the data in bytes

     *

     * @param	    precision

     *		    the number of digits to appear after the decimal

     *		    separator

     *

     * @param	    units

     *		    a String array of the units to be shown after the

     *		    size, in the following order:

     *		    <pre>

     *		    index  unit

     *		    ---------------------------

     *		    0	   byte unit string

     *		    1	   kilobyte unit string

     *		    2	   megabyte unit string

     *		    3	   gigabyte unit string

     *		    4	   terabyte unit string

     *		    5	   petabyte unit string

     *		    6	   exabyte unit string

     *		    </pre>

     *		    If null, the default units will be used.

     *

     * @param	    unit

     *		    a string from the units array to force the use of

     *		    a particular unit, or {@code null} to use the

     *		    most appropriate unit for the given size

     *

     * @return	    a DataSize object that represents the most

     *		    displayable form of the given data size.

     */

    public static DataSize getDataSize(

	long bytes, int precision, String[] units, String unit) {

	if (units == null) {

	    units = getDefaultUnits();

	}

	// Handle negative values

	double factor = 1;

	if (bytes < 0) {

	    bytes = -bytes;

	    factor = -1;

	}

	double adjusted;

	long bytesPerUnit = 1;

	int i;

	if (unit == null) {

	    // Determine which units to use

	    double slop = precision > 0 ? .5 : 0;

	    for (i = 0; i < precision; i++) {

		slop /= 10;

	    }

	    adjusted = bytes;

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

		adjusted = (double)bytes / (double)bytesPerUnit;

		if (i == units.length - 1 || adjusted + slop < 1024) {

		    break;

		}

		bytesPerUnit <<= 10;

	    }

	} else {

	    for (i = 0; i < units.length - 1 && ! units[i].equals(unit); i++) {

		bytesPerUnit <<= 10;

	    }

	    adjusted = (double)bytes / (double)bytesPerUnit;

	}

	return new DataSize(factor * adjusted, i);

    }

    /**

     * Gets the given data size in a human-readable format.

     *

     * @param	    bytes

     *		    the size of the data in bytes

     *

     * @param	    precision

     *		    the number of digits to appear after the decimal

     *		    separator

     *

     * @param	    forcePrecision

     *		    whether to keep the decimal portion of the

     *		    output if all digits after the decimal separator

     *		    are 0.  If units are in bytes, the decimal portion

     *		    is never included in the output.

     *

     * @param	    units

     *		    a String array of the units to be shown after the

     *		    size, in the following order:

     *		    <pre>

     *		    index  unit

     *		    ---------------------------

     *		    0	   byte unit string

     *		    1	   kilobyte unit string

     *		    2	   megabyte unit string

     *		    3	   gigabyte unit string

     *		    4	   terabyte unit string

     *		    5	   petabyte unit string

     *		    6	   exabyte unit string

     *		    </pre>

     *		    If null, the default units will be used.

     *

     * @param	    unit

     *		    a string from the units array to force the use of

     *		    a particular unit, or {@code null} to use the

     *		    most appropriate unit for the given size

     *

     * @param	    addSpace

     *		    whether to add a space between the numerical value

     *		    and the units text

     *

     * @param	    useCommas

     *		    whether to separate every third digit with a comma

     *

     * @return	    a data size string in human-readable format

     */

    public static String getHumanReadableDataSize(

	long bytes, int precision, boolean forcePrecision,

	String[] units, String unit, boolean addSpace, boolean useCommas) {

	if (units == null) {

	    units = getDefaultUnits();

	}

	DataSize dataSize = getDataSize(bytes, precision, units, unit);

	// Build format string

	StringBuilder pattern = new StringBuilder();

	pattern.append(useCommas ? "#,##0" : "###0");

	char formatChar =

	    (forcePrecision && dataSize.unitsIndex != 0) ? '0' : '#';

	for (int j = 0; j < precision; j++) {

	    if (j == 0) {

		pattern.append('.');

	    }

	    pattern.append(formatChar);

	}

	DecimalFormat format = new DecimalFormat(pattern.toString());

	String space = addSpace ? " " : "";

	return format.format(dataSize.value) + space +

	    units[dataSize.unitsIndex];

    }

    /**

     * Tries to parse the given string as a human-readable expression

     * of size.  Only enough of the unit string must appear in the

     * given string to uniquely distinguish a single unit string.

     * Parsing is case-insensitive.

     *

     * @param	    text

     *		    the text to parse

     *

     * @param	    units

     *		    a String array of valid units that may appear

     *		    after the size.

     *		    <pre>

     *		    index  unit

     *		    ---------------------------

     *		    0	   byte unit string

     *		    1	   kilobyte unit string

     *		    2	   megabyte unit string

     *		    3	   gigabyte unit string

     *		    4	   terabyte unit string

     *		    5	   petabyte unit string

     *		    6	   exabyte unit string

     *		    </pre>

     *		    If null, the default units will be used.

     *

     * @param	    defaultUnitIndex

     *		    the default units (specified as an index of the

     *		    {@code units} array) to use if no unit text

     *		    is specified as part of the given string

     *

     * @return	    the size in bytes that the given string represents

     *

     * @exception   NumberFormatException

     *		    if the given text does not represent a valid size

     */

    public static long parseHumanReadableDataSize(

	String text, String[] units, int defaultUnitIndex) {

	if (units == null) {

	    units = getDefaultUnits();

	}

	String[] groups = TextUtil.match(

	    text, "^\\s*(\\d+(\\.\\d+)?)\\s*(\\S*)\\s*$");

	if (groups == null) {

	    throw new NumberFormatException(Finder.getString(

		"error.invalidsize", text));

	}

	double value = Double.parseDouble(groups[1]);

	long multiplier = 1;

	// Was a units string specified?

	if (groups[3].isEmpty()) {

	    // No, use default

	    multiplier <<= 10 * defaultUnitIndex;

	} else {

	    // Yes, search for matching units string

	    String matchingUnit = null;

	    String unitText = groups[3].toLowerCase();

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

		if (units[i].toLowerCase().startsWith(unitText)) {

		    // If we've already found a match, then the given

		    // units text is ambiguous

		    if (matchingUnit != null) {

			throw new NumberFormatException(Finder.getString(

			    "error.ambiguousunits",

			    unitText, matchingUnit, units[i]));

		    }

		    matchingUnit = units[i];

		}

		if (matchingUnit == null) {

		    multiplier <<= 10;

		}

	    }

	    if (matchingUnit == null) {

		throw new NumberFormatException(Finder.getString(

		    "error.invalidunits", unitText));

	    }

	}

	return (long)(value * multiplier);

    }

}