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Android example source code file (PackedIntVector.java)

This example Android source code file (PackedIntVector.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, indexoutofboundsexception, packedintvector, util, utilities, utils

The PackedIntVector.java Android example source code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.text;

import com.android.internal.util.ArrayUtils;


/**
 * PackedIntVector stores a two-dimensional array of integers,
 * optimized for inserting and deleting rows and for
 * offsetting the values in segments of a given column.
 */
class PackedIntVector {
    private final int mColumns;
    private int mRows;

    private int mRowGapStart;
    private int mRowGapLength;

    private int[] mValues;
    private int[] mValueGap; // starts, followed by lengths

    /**
     * Creates a new PackedIntVector with the specified width and
     * a height of 0.
     *
     * @param columns the width of the PackedIntVector.
     */
    public PackedIntVector(int columns) {
        mColumns = columns;
        mRows = 0;

        mRowGapStart = 0;
        mRowGapLength = mRows;

        mValues = null;
        mValueGap = new int[2 * columns];
    }

    /**
     * Returns the value at the specified row and column.
     *
     * @param row the index of the row to return.
     * @param column the index of the column to return.
     *
     * @return the value stored at the specified position.
     *
     * @throws IndexOutOfBoundsException if the row is out of range
     *         (row < 0 || row >= size()) or the column is out of range
     *         (column < 0 || column >= width()).
     */
    public int getValue(int row, int column) {
        final int columns = mColumns;

        if (((row | column) < 0) || (row >= size()) || (column >= columns)) {
            throw new IndexOutOfBoundsException(row + ", " + column);
        }

        if (row >= mRowGapStart) {
            row += mRowGapLength;
        }

        int value = mValues[row * columns + column];

        int[] valuegap = mValueGap;
        if (row >= valuegap[column]) {
            value += valuegap[column + columns];
        }

        return value;
    }

    /**
     * Sets the value at the specified row and column.
     *
     * @param row the index of the row to set.
     * @param column the index of the column to set.
     *
     * @throws IndexOutOfBoundsException if the row is out of range
     *         (row < 0 || row >= size()) or the column is out of range
     *         (column < 0 || column >= width()).
     */
    public void setValue(int row, int column, int value) {
        if (((row | column) < 0) || (row >= size()) || (column >= mColumns)) {
            throw new IndexOutOfBoundsException(row + ", " + column);
        }

        if (row >= mRowGapStart) {
            row += mRowGapLength;
        }

        int[] valuegap = mValueGap;
        if (row >= valuegap[column]) {
            value -= valuegap[column + mColumns];
        }

        mValues[row * mColumns + column] = value;
    }

    /**
     * Sets the value at the specified row and column.
     * Private internal version: does not check args.
     *
     * @param row the index of the row to set.
     * @param column the index of the column to set.
     *
     */
    private void setValueInternal(int row, int column, int value) {
        if (row >= mRowGapStart) {
            row += mRowGapLength;
        }

        int[] valuegap = mValueGap;
        if (row >= valuegap[column]) {
            value -= valuegap[column + mColumns];
        }

        mValues[row * mColumns + column] = value;
    }


    /**
     * Increments all values in the specified column whose row >= the
     * specified row by the specified delta.
     *
     * @param startRow the row at which to begin incrementing.
     *        This may be == size(), which case there is no effect.
     * @param column the index of the column to set.
     *
     * @throws IndexOutOfBoundsException if the row is out of range
     *         (startRow < 0 || startRow > size()) or the column
     *         is out of range (column < 0 || column >= width()).
     */
    public void adjustValuesBelow(int startRow, int column, int delta) {
        if (((startRow | column) < 0) || (startRow > size()) ||
                (column >= width())) {
            throw new IndexOutOfBoundsException(startRow + ", " + column);
        }

        if (startRow >= mRowGapStart) {
            startRow += mRowGapLength;
        }

        moveValueGapTo(column, startRow);
        mValueGap[column + mColumns] += delta;
    }

    /**
     * Inserts a new row of values at the specified row offset.
     *
     * @param row the row above which to insert the new row.
     *        This may be == size(), which case the new row is added
     *        at the end.
     * @param values the new values to be added.  If this is null,
     *        a row of zeroes is added.
     *
     * @throws IndexOutOfBoundsException if the row is out of range
     *         (row < 0 || row > size()) or if the length of the
     *         values array is too small (values.length < width()).
     */
    public void insertAt(int row, int[] values) {
        if ((row < 0) || (row > size())) {
            throw new IndexOutOfBoundsException("row " + row);
        }

        if ((values != null) && (values.length < width())) {
            throw new IndexOutOfBoundsException("value count " + values.length);
        }

        moveRowGapTo(row);

        if (mRowGapLength == 0) {
            growBuffer();
        }

        mRowGapStart++;
        mRowGapLength--;

        if (values == null) {
            for (int i = mColumns - 1; i >= 0; i--) {
                setValueInternal(row, i, 0);
            }
        } else {
            for (int i = mColumns - 1; i >= 0; i--) {
                setValueInternal(row, i, values[i]);
            }
        }
    }

    /**
     * Deletes the specified number of rows starting with the specified
     * row.
     *
     * @param row the index of the first row to be deleted.
     * @param count the number of rows to delete.
     *
     * @throws IndexOutOfBoundsException if any of the rows to be deleted
     *         are out of range (row < 0 || count < 0 ||
     *         row + count > size()).
     */
    public void deleteAt(int row, int count) {
        if (((row | count) < 0) || (row + count > size())) {
            throw new IndexOutOfBoundsException(row + ", " + count);
        }

        moveRowGapTo(row + count);

        mRowGapStart -= count;
        mRowGapLength += count;

        // TODO: Reclaim memory when the new height is much smaller
        // than the allocated size.
    }

    /**
     * Returns the number of rows in the PackedIntVector.  This number
     * will change as rows are inserted and deleted.
     *
     * @return the number of rows.
     */
    public int size() {
        return mRows - mRowGapLength;
    }

    /**
     * Returns the width of the PackedIntVector.  This number is set
     * at construction and will not change.
     *
     * @return the number of columns.
     */
    public int width() {
        return mColumns;
    }

    /**
     * Grows the value and gap arrays to be large enough to store at least
     * one more than the current number of rows.
     */
    private final void growBuffer() {
        final int columns = mColumns;
        int newsize = size() + 1;
        newsize = ArrayUtils.idealIntArraySize(newsize * columns) / columns;
        int[] newvalues = new int[newsize * columns];

        final int[] valuegap = mValueGap;
        final int rowgapstart = mRowGapStart;

        int after = mRows - (rowgapstart + mRowGapLength);

        if (mValues != null) {
            System.arraycopy(mValues, 0, newvalues, 0, columns * rowgapstart);
            System.arraycopy(mValues, (mRows - after) * columns,
                             newvalues, (newsize - after) * columns,
                             after * columns);
        }

        for (int i = 0; i < columns; i++) {
            if (valuegap[i] >= rowgapstart) {
                valuegap[i] += newsize - mRows;

                if (valuegap[i] < rowgapstart) {
                    valuegap[i] = rowgapstart;
                }
            }
        }

        mRowGapLength += newsize - mRows;
        mRows = newsize;
        mValues = newvalues;
    }

    /**
     * Moves the gap in the values of the specified column to begin at
     * the specified row.
     */
    private final void moveValueGapTo(int column, int where) {
        final int[] valuegap = mValueGap;
        final int[] values = mValues;
        final int columns = mColumns;

        if (where == valuegap[column]) {
            return;
        } else if (where > valuegap[column]) {
            for (int i = valuegap[column]; i < where; i++) {
                values[i * columns + column] += valuegap[column + columns];
            }
        } else /* where < valuegap[column] */ {
            for (int i = where; i < valuegap[column]; i++) {
                values[i * columns + column] -= valuegap[column + columns];
            }
        }

        valuegap[column] = where;
    }

    /**
     * Moves the gap in the row indices to begin at the specified row.
     */
    private final void moveRowGapTo(int where) {
        if (where == mRowGapStart) {
            return;
        } else if (where > mRowGapStart) {
            int moving = where + mRowGapLength - (mRowGapStart + mRowGapLength);
            final int columns = mColumns;
            final int[] valuegap = mValueGap;
            final int[] values = mValues;
            final int gapend = mRowGapStart + mRowGapLength;

            for (int i = gapend; i < gapend + moving; i++) {
                int destrow = i - gapend + mRowGapStart;

                for (int j = 0; j < columns; j++) {
                    int val = values[i * columns+ j];

                    if (i >= valuegap[j]) {
                        val += valuegap[j + columns];
                    }

                    if (destrow >= valuegap[j]) {
                        val -= valuegap[j + columns];
                    }

                    values[destrow * columns + j] = val;
                }
            }
        } else /* where < mRowGapStart */ {
            int moving = mRowGapStart - where;
            final int columns = mColumns;
            final int[] valuegap = mValueGap;
            final int[] values = mValues;
            final int gapend = mRowGapStart + mRowGapLength;

            for (int i = where + moving - 1; i >= where; i--) {
                int destrow = i - where + gapend - moving;

                for (int j = 0; j < columns; j++) {
                    int val = values[i * columns+ j];

                    if (i >= valuegap[j]) {
                        val += valuegap[j + columns];
                    }

                    if (destrow >= valuegap[j]) {
                        val -= valuegap[j + columns];
                    }

                    values[destrow * columns + j] = val;
                }
            }
        }

        mRowGapStart = where;
    }
}

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