///////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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 for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
///////////////////////////////////////////////////////////////////////////////

package gnu.trove;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Random;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

/**
 * A resizable, array-backed list of int primitives.
 *
 * Created: Sat Dec 29 14:21:12 2001
 *
 * @author Eric D. Friedman
 * @version $Id: TIntArrayList.java,v 1.13 2003/11/09 09:22:22 ericdf Exp $
 */

public class TIntArrayList implements Serializable, Cloneable {

    /** the data of the list */
    protected transient int[] _data;

    /** the index after the last entry in the list */
    protected transient int _pos;

    /** the default capacity for new lists */
    protected static final int DEFAULT_CAPACITY = 10;

    /**
     * Creates a new TIntArrayList instance with the
     * default capacity.
     */
    public TIntArrayList() {
        this(DEFAULT_CAPACITY);
    }
    
    /**
     * Creates a new TIntArrayList instance with the
     * specified capacity.
     *
     * @param capacity an int value
     */
    public TIntArrayList(int capacity) {
        _data = new int[capacity];
        _pos = 0;
    }

    /**
     * Creates a new TIntArrayList instance whose
     * capacity is the greater of the length of values and
     * DEFAULT_CAPACITY and whose initial contents are the specified
     * values.
     *
     * @param values an int[] value
     */
    public TIntArrayList(int[] values) {
        this(Math.max(values.length, DEFAULT_CAPACITY));
        add(values);
    }

    // sizing
    
    /**
     * Grow the internal array as needed to accomodate the specified
     * number of elements.  The size of the array doubles on each
     * resize unless capacity requires more than twice the
     * current capacity.
     *
     * @param capacity an int value
     */
    public void ensureCapacity(int capacity) {
        if (capacity > _data.length) {
            int newCap = Math.max(_data.length << 1, capacity);
            int[] tmp = new int[newCap];
            System.arraycopy(_data, 0, tmp, 0, _data.length);
            _data = tmp;
        }
    }

    /**
     * Returns the number of values in the list.
     *
     * @return the number of values in the list.
     */
    public int size() {
        return _pos;
    }

    /**
     * Tests whether this list contains any values.
     *
     * @return true if the list is empty.
     */
    public boolean isEmpty() {
        return _pos == 0;
    }

    /**
     * Sheds any excess capacity above and beyond the current size of
     * the list.
     */
    public void trimToSize() {
        if (_data.length > size()) {
            int[] tmp = new int[size()];
            toNativeArray(tmp, 0, tmp.length);
            _data = tmp;
        }
    }

    // modifying

    /**
     * Adds val to the end of the list, growing as needed.
     *
     * @param val an int value
     */
    public void add(int val) {
        ensureCapacity(_pos + 1);
        _data[_pos++] = val;
    }

    /**
     * Adds the values in the array vals to the end of the
     * list, in order.
     *
     * @param vals an int[] value
     */
    public void add(int[] vals) {
        add(vals, 0, vals.length);
    }

    /**
     * Adds a subset of the values in the array vals to the
     * end of the list, in order.
     *
     * @param vals an int[] value
     * @param offset the offset at which to start copying
     * @param length the number of values to copy.
     */
    public void add(int[] vals, int offset, int length) {
        ensureCapacity(_pos + length);
        System.arraycopy(vals, offset, _data, _pos, length);
        _pos += length;
    }

    /**
     * Inserts value into the list at offset.  All
     * values including and to the right of offset are shifted
     * to the right.
     *
     * @param offset an int value
     * @param value an int value
     */
    public void insert(int offset, int value) {
        if (offset == _pos) {
            add(value);
            return;
        }
        ensureCapacity(_pos + 1);
        // shift right
        System.arraycopy(_data, offset, _data, offset + 1, _pos - offset);
        // insert
        _data[offset] = value;
        _pos++;
    }

    /**
     * Inserts the array of values into the list at
     * offset.  All values including and to the right of
     * offset are shifted to the right.
     *
     * @param offset an int value
     * @param values an int[] value
     */
    public void insert(int offset, int[] values) {
        insert(offset, values, 0, values.length);
    }

    /**
     * Inserts a slice of the array of values into the list
     * at offset.  All values including and to the right of
     * offset are shifted to the right.
     *
     * @param offset an int value
     * @param values an int[] value
     * @param valOffset the offset in the values array at which to
     * start copying.
     * @param len the number of values to copy from the values array
     */
    public void insert(int offset, int[] values, int valOffset, int len) {
        if (offset == _pos) {
            add(values, valOffset, len);
            return;
        }

        ensureCapacity(_pos + len);
        // shift right
        System.arraycopy(_data, offset, _data, offset + len, _pos - offset);
        // insert
        System.arraycopy(values, valOffset, _data, offset, len);
        _pos += len;
    }

    /**
     * Returns the value at the specified offset.
     *
     * @param offset an int value
     * @return an int value
     */
    public int get(int offset) {
        if (offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        return _data[offset];
    }

    /**
     * Returns the value at the specified offset without doing any
     * bounds checking.
     *
     * @param offset an int value
     * @return an int value
     */
    public int getQuick(int offset) {
        return _data[offset];
    }

    /**
     * Sets the value at the specified offset.
     *
     * @param offset an int value
     * @param val an int value
     */
    public void set(int offset, int val) {
        if (offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        _data[offset] = val;
    }

    /**
     * Sets the value at the specified offset and returns the
     * previously stored value.
     *
     * @param offset an int value
     * @param val an int value
     * @return the value previously stored at offset.
     */
    public int getSet(int offset, int val) {
        if (offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        int old = _data[offset];
        _data[offset] = val;
        return old;
    }

    /**
     * Replace the values in the list starting at offset with
     * the contents of the values array.
     *
     * @param offset the first offset to replace
     * @param values the source of the new values
     */
    public void set(int offset, int[] values) {
        set(offset, values, 0, values.length);
    }

    /**
     * Replace the values in the list starting at offset with
     * length values from the values array, starting
     * at valOffset.
     *
     * @param offset the first offset to replace
     * @param values the source of the new values
     * @param valOffset the first value to copy from the values array
     * @param length the number of values to copy
     */
    public void set(int offset, int[] values, int valOffset, int length) {
        if (offset < 0 || offset + length >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        System.arraycopy(values, valOffset, _data, offset, length);
    }

    /**
     * Sets the value at the specified offset without doing any bounds
     * checking.
     *
     * @param offset an int value
     * @param val an int value
     */
    public void setQuick(int offset, int val) {
        _data[offset] = val;
    }

    /**
     * Flushes the internal state of the list, resetting the capacity
     * to the default.
     */
    public void clear() {
        clear(DEFAULT_CAPACITY);
    }

    /**
     * Flushes the internal state of the list, setting the capacity of
     * the empty list to capacity.
     *
     * @param capacity an int value
     */
    public void clear(int capacity) {
        _data = new int[capacity];
        _pos = 0;
    }

    /**
     * Sets the size of the list to 0, but does not change its
     * capacity.  This method can be used as an alternative to the
     * {@link #clear clear} method if you want to recyle a list without
     * allocating new backing arrays.
     *
     * @see #clear
     */
    public void reset() {
        _pos = 0;
        fill(0);
    }

    /**
     * Sets the size of the list to 0, but does not change its
     * capacity.  This method can be used as an alternative to the
     * {@link #clear clear} method if you want to recyle a list
     * without allocating new backing arrays.  This method differs
     * from {@link #reset reset} in that it does not clear the old
     * values in the backing array.  Thus, it is possible for {@link
     * #getQuick getQuick} to return stale data if this method is used
     * and the caller is careless about bounds checking.
     *
     * @see #reset
     * @see #clear
     * @see #getQuick
     */
    public void resetQuick() {
        _pos = 0;
    }

    /**
     * Removes the value at offset from the list.
     *
     * @param offset an int value
     * @return the value previously stored at offset.
     */
    public int remove(int offset) {
        int old = get(offset);
        remove(offset, 1);
        return old;
    }

    /**
     * Removes length values from the list, starting at
     * offset
     *
     * @param offset an int value
     * @param length an int value
     */
    public void remove(int offset, int length) {
        if (offset < 0 || offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }

        if (offset == 0) {
            // data at the front
            System.arraycopy(_data, length, _data, 0, _pos - length);
        } else if (_pos - length == offset) {
            // no copy to make, decrementing pos "deletes" values at
            // the end
        } else {
            // data in the middle
            System.arraycopy(_data, offset + length,
                             _data, offset, _pos - (offset + length));
        }
        _pos -= length;
        // no need to clear old values beyond _pos, because this is a
        // primitive collection and 0 takes as much room as any other
        // value
    }

    /**
     * Transform each value in the list using the specified function.
     *
     * @param function a TIntFunction value
     */
    public void transformValues(TIntFunction function) {
        for (int i = _pos; i-- > 0;) {
            _data[i] = function.execute(_data[i]);
        }
    }

    /**
     * Reverse the order of the elements in the list.
     */
    public void reverse() {
        reverse(0, _pos);
    }

    /**
     * Reverse the order of the elements in the range of the list.
     *
     * @param from the inclusive index at which to start reversing
     * @param to the exclusive index at which to stop reversing
     */
    public void reverse(int from, int to) {
        if (from == to) {
            return;             // nothing to do
        }
        if (from > to) {
            throw new IllegalArgumentException("from cannot be greater than to");
        }
        for (int i = from, j = to - 1; i < j; i++, j--) {
            swap(i, j);
        }
    }

    /**
     * Shuffle the elements of the list using the specified random
     * number generator.
     *
     * @param rand a Random value
     */
    public void shuffle(Random rand) {
        for (int i = _pos; i-- > 1;) {
            swap(i, rand.nextInt(i));
        }
    }

    /**
     * Swap the values at offsets i and j.
     *
     * @param i an offset into the data array
     * @param j an offset into the data array
     */
    private final void swap(int i, int j) {
        int tmp = _data[i];
        _data[i] = _data[j];
        _data[j] = tmp;
    }

    // copying
    
    /**
     * Returns a clone of this list.  Since this is a primitive
     * collection, this will be a deep clone.
     *
     * @return a deep clone of the list.
     */
    public Object clone() {
        TIntArrayList clone = null;
        try {
            clone = (TIntArrayList)super.clone();
            clone._data = (int[])_data.clone();
        } catch (CloneNotSupportedException e) {
            // it's supported
        } // end of try-catch
        return clone;
    }

    /**
     * Copies the contents of the list into a native array.
     *
     * @return an int[] value
     */
    public int[] toNativeArray() {
        return toNativeArray(0, _pos);
    }

    /**
     * Copies a slice of the list into a native array.
     *
     * @param offset the offset at which to start copying
     * @param len the number of values to copy.
     * @return an int[] value
     */
    public int[] toNativeArray(int offset, int len) {
        int[] rv = new int[len];
        toNativeArray(rv, offset, len);
        return rv;
    }

    /**
     * Copies a slice of the list into a native array.
     *
     * @param dest the array to copy into.
     * @param offset the offset of the first value to copy
     * @param len the number of values to copy.
     */
    public void toNativeArray(int[] dest, int offset, int len) {
        if (len == 0) {
            return;             // nothing to copy
        }
        if (offset < 0 || offset >= _pos) {
            throw new ArrayIndexOutOfBoundsException(offset);
        }
        System.arraycopy(_data, offset, dest, 0, len);
    }

    // comparing
    
    /**
     * Compares this list to another list, value by value.
     *
     * @param other the object to compare against
     * @return true if other is a TIntArrayList and has exactly the
     * same values.
     */
    public boolean equals(Object other) {
        if (other == this) {
            return true;
        } else if (other instanceof TIntArrayList) {
            TIntArrayList that = (TIntArrayList)other;
            if (that.size() != this.size()) {
                return false;
            } else {
                for (int i = _pos; i-- > 0;) {
                    if (this._data[i] != that._data[i]) {
                        return false;
                    }
                }
                return true;
            }
        } else {
            return false;
        }
    }

    public int hashCode() {
        int h = 0;
        for (int i = _pos; i-- > 0;) {
            h += _data[i];
        }
        return h;
    }

    // procedures
    
    /**
     * Applies the procedure to each value in the list in ascending
     * (front to back) order.
     *
     * @param procedure a TIntProcedure value
     * @return true if the procedure did not terminate prematurely.
     */
    public boolean forEach(TIntProcedure procedure) {
        for (int i = 0; i < _pos; i++) {
            if (! procedure.execute(_data[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Applies the procedure to each value in the list in descending
     * (back to front) order.
     *
     * @param procedure a TIntProcedure value
     * @return true if the procedure did not terminate prematurely.
     */
    public boolean forEachDescending(TIntProcedure procedure) {
        for (int i = _pos; i-- > 0;) {
            if (! procedure.execute(_data[i])) {
                return false;
            }
        }
        return true;
    }

    // sorting
    
    /**
     * Sort the values in the list (ascending) using the Sun quicksort
     * implementation.
     *
     * @see java.util.Arrays#sort
     */
    public void sort() {
        Arrays.sort(_data, 0, _pos);
    }

    /**
     * Sort a slice of the list (ascending) using the Sun quicksort
     * implementation.
     *
     * @param fromIndex the index at which to start sorting (inclusive)
     * @param toIndex the index at which to stop sorting (exclusive)
     * @see java.util.Arrays#sort
     */
    public void sort(int fromIndex, int toIndex) {
        Arrays.sort(_data, fromIndex, toIndex);
    }

    // filling
    
    /**
     * Fills every slot in the list with the specified value.
     *
     * @param val the value to use when filling
     */
    public void fill(int val) {
        Arrays.fill(_data, 0, _pos, val);
    }

    /**
     * Fills a range in the list with the specified value.
     *
     * @param fromIndex the offset at which to start filling (inclusive)
     * @param toIndex the offset at which to stop filling (exclusive)
     * @param val the value to use when filling
     */
    public void fill(int fromIndex, int toIndex, int val) {
        if (toIndex > _pos) {
          ensureCapacity(toIndex);
          _pos = toIndex;
        }
        Arrays.fill(_data, fromIndex, toIndex, val);
    }

    // searching
    
    /**
     * Performs a binary search for value in the entire list.
     * Note that you must {@link #sort sort} the list before
     * doing a search.
     *
     * @param value the value to search for
     * @return the absolute offset in the list of the value, or its
     * negative insertion point into the sorted list.
     */
    public int binarySearch(int value) {
        return binarySearch(value, 0, _pos);
    }
    
    /**
     * Performs a binary search for value in the specified
     * range.  Note that you must {@link #sort sort} the list
     * or the range before doing a search.
     *
     * @param value the value to search for
     * @param fromIndex the lower boundary of the range (inclusive)
     * @param toIndex the upper boundary of the range (exclusive)
     * @return the absolute offset in the list of the value, or its
     * negative insertion point into the sorted list.
     */
    public int binarySearch(int value, int fromIndex, int toIndex) {
        if (fromIndex < 0) {
            throw new ArrayIndexOutOfBoundsException(fromIndex);
        }
        if (toIndex > _pos) {
            throw new ArrayIndexOutOfBoundsException(toIndex);
        }
        
        int low = fromIndex;
        int high = toIndex - 1;
        
        while (low <= high) {
            int mid = (low + high) >> 1;
            int midVal = _data[mid];

            if (midVal < value) {
                low = mid + 1;
            } else if (midVal > value) {
                high = mid - 1;
            } else {
                return mid; // value found
            }
        }
        return -(low + 1);  // value not found.
    }

    /**
     * Searches the list front to back for the index of
     * value.
     *
     * @param value an int value
     * @return the first offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int indexOf(int value) {
        return indexOf(0, value);
    }

    /**
     * Searches the list front to back for the index of
     * value, starting at offset.
     *
     * @param offset the offset at which to start the linear search
     * (inclusive)
     * @param value an int value
     * @return the first offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int indexOf(int offset, int value) {
        for (int i = offset; i < _pos; i++) {
            if (_data[i] == value) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Searches the list back to front for the last index of
     * value.
     *
     * @param value an int value
     * @return the last offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int lastIndexOf(int value) {
        return lastIndexOf(_pos, value);
    }

    /**
     * Searches the list back to front for the last index of
     * value, starting at offset.
     *
     * @param offset the offset at which to start the linear search
     * (exclusive)
     * @param value an int value
     * @return the last offset of the value, or -1 if it is not in
     * the list.
     * @see #binarySearch for faster searches on sorted lists
     */
    public int lastIndexOf(int offset, int value) {
        for (int i = offset; i-- > 0;) {
            if (_data[i] == value) {
                return i;
            }
        }
        return -1;
    }

    /**
     * Searches the list for value
     *
     * @param value an int value
     * @return true if value is in the list.
     */
    public boolean contains(int value) {
        return lastIndexOf(value) >= 0;
    }

    /**
     * Searches the list for values satisfying condition in
     * the manner of the *nix grep utility.
     *
     * @param condition a condition to apply to each element in the list
     * @return a list of values which match the condition.
     */
    public TIntArrayList grep(TIntProcedure condition) {
        TIntArrayList list = new TIntArrayList();
        for (int i = 0; i < _pos; i++) {
            if (condition.execute(_data[i])) {
                list.add(_data[i]);
            }
        }
        return list;
    }

    /**
     * Searches the list for values which do not satisfy
     * condition.  This is akin to *nix grep -v.
     *
     * @param condition a condition to apply to each element in the list
     * @return a list of values which do not match the condition.
     */
    public TIntArrayList inverseGrep(TIntProcedure condition) {
        TIntArrayList list = new TIntArrayList();
        for (int i = 0; i < _pos; i++) {
            if (! condition.execute(_data[i])) {
                list.add(_data[i]);
            }
        }
        return list;
    }

    /**
     * Finds the maximum value in the list.
     *
     * @return the largest value in the list.
     * @exception IllegalStateException if the list is empty
     */
    public int max() {
        if (size() == 0) {
            throw new IllegalStateException("cannot find maximum of an empty list");
        }
        int max = _data[_pos - 1];
        for (int i = _pos - 1; i-- > 0;) {
            if (_data[i] > max) {
                max = _data[i];
            }
        }
        return max;
    }

    /**
     * Finds the minimum value in the list.
     *
     * @return the smallest value in the list.
     * @exception IllegalStateException if the list is empty
     */
    public int min() {
        if (size() == 0) {
            throw new IllegalStateException("cannot find minimum of an empty list");
        }
        int min = _data[_pos - 1];
        for (int i = _pos - 1; i-- > 0;) {
            if (_data[i] < min) {
                min = _data[i];
            }
        }
        return min;
    }

    // stringification
    
    /**
     * Returns a String representation of the list, front to back.
     *
     * @return a String value
     */
    public String toString() {
        StringBuffer buf = new StringBuffer("{");
        for (int i = 0, end = _pos - 1; i < end; i++) {
            buf.append(_data[i]);
            buf.append(", ");
        }
        if (size() > 0) {
            buf.append(_data[_pos - 1]);
        }
        buf.append("}");
        return buf.toString();
    }

    private void writeObject(ObjectOutputStream stream)
        throws IOException {
        stream.defaultWriteObject();

        // number of entries
        stream.writeInt(size());

        SerializationProcedure writeProcedure = new SerializationProcedure(stream);
        if (! forEach(writeProcedure)) {
            throw writeProcedure.exception;
        }
    }

    private void readObject(ObjectInputStream stream)
        throws IOException, ClassNotFoundException {
        stream.defaultReadObject();

        int size = stream.readInt();
        _data = new int[size];
        while (size-- > 0) {
            int val = stream.readInt();
            add(val);
        }
    }
    
} // TIntArrayList