org.eclipse.jdt.internal.compiler.util.HashtableOfObjectToIntArray.java Source code

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Here is the source code for org.eclipse.jdt.internal.compiler.util.HashtableOfObjectToIntArray.java

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/*******************************************************************************
 * Copyright (c) 2000, 2009 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.util;

/**
 * Hashtable of {Object --> int[] }
 */
public final class HashtableOfObjectToIntArray implements Cloneable {

    // to avoid using Enumerations, walk the individual tables skipping nulls
    public Object[] keyTable;
    public int[][] valueTable;

    public int elementSize; // number of elements in the table
    int threshold;

    public HashtableOfObjectToIntArray() {
        this(13);
    }

    public HashtableOfObjectToIntArray(int size) {

        this.elementSize = 0;
        this.threshold = size; // size represents the expected number of elements
        int extraRoom = (int) (size * 1.75f);
        if (this.threshold == extraRoom)
            extraRoom++;
        this.keyTable = new Object[extraRoom];
        this.valueTable = new int[extraRoom][];
    }

    @Override
    public Object clone() throws CloneNotSupportedException {
        HashtableOfObjectToIntArray result = (HashtableOfObjectToIntArray) super.clone();
        result.elementSize = this.elementSize;
        result.threshold = this.threshold;

        int length = this.keyTable.length;
        result.keyTable = new Object[length];
        System.arraycopy(this.keyTable, 0, result.keyTable, 0, length);

        length = this.valueTable.length;
        result.valueTable = new int[length][];
        System.arraycopy(this.valueTable, 0, result.valueTable, 0, length);
        return result;
    }

    public boolean containsKey(Object key) {
        int length = this.keyTable.length, index = (key.hashCode() & 0x7FFFFFFF) % length;
        Object currentKey;
        while ((currentKey = this.keyTable[index]) != null) {
            if (currentKey.equals(key))
                return true;
            if (++index == length) {
                index = 0;
            }
        }
        return false;
    }

    public int[] get(Object key) {
        int length = this.keyTable.length, index = (key.hashCode() & 0x7FFFFFFF) % length;
        Object currentKey;
        while ((currentKey = this.keyTable[index]) != null) {
            if (currentKey.equals(key))
                return this.valueTable[index];
            if (++index == length) {
                index = 0;
            }
        }
        return null;
    }

    public void keysToArray(Object[] array) {
        int index = 0;
        for (int i = 0, length = this.keyTable.length; i < length; i++) {
            if (this.keyTable[i] != null)
                array[index++] = this.keyTable[i];
        }
    }

    public int[] put(Object key, int[] value) {
        int length = this.keyTable.length, index = (key.hashCode() & 0x7FFFFFFF) % length;
        Object currentKey;
        while ((currentKey = this.keyTable[index]) != null) {
            if (currentKey.equals(key))
                return this.valueTable[index] = value;
            if (++index == length) {
                index = 0;
            }
        }
        this.keyTable[index] = key;
        this.valueTable[index] = value;

        // assumes the threshold is never equal to the size of the table
        if (++this.elementSize > this.threshold)
            rehash();
        return value;
    }

    public int[] removeKey(Object key) {
        int length = this.keyTable.length, index = (key.hashCode() & 0x7FFFFFFF) % length;
        Object currentKey;
        while ((currentKey = this.keyTable[index]) != null) {
            if (currentKey.equals(key)) {
                int[] value = this.valueTable[index];
                this.elementSize--;
                this.keyTable[index] = null;
                rehash();
                return value;
            }
            if (++index == length) {
                index = 0;
            }
        }
        return null;
    }

    private void rehash() {

        HashtableOfObjectToIntArray newHashtable = new HashtableOfObjectToIntArray(this.elementSize * 2); // double the number of expected elements
        Object currentKey;
        for (int i = this.keyTable.length; --i >= 0;)
            if ((currentKey = this.keyTable[i]) != null)
                newHashtable.put(currentKey, this.valueTable[i]);

        this.keyTable = newHashtable.keyTable;
        this.valueTable = newHashtable.valueTable;
        this.threshold = newHashtable.threshold;
    }

    public int size() {
        return this.elementSize;
    }

    @Override
    public String toString() {
        StringBuffer buffer = new StringBuffer();
        Object key;
        for (int i = 0, length = this.keyTable.length; i < length; i++) {
            if ((key = this.keyTable[i]) != null) {
                buffer.append(key).append(" -> "); //$NON-NLS-1$
                int[] ints = this.valueTable[i];
                buffer.append('[');
                if (ints != null) {
                    for (int j = 0, max = ints.length; j < max; j++) {
                        if (j > 0) {
                            buffer.append(',');
                        }
                        buffer.append(ints[j]);
                    }
                }
                buffer.append("]\n"); //$NON-NLS-1$
            }
        }
        return String.valueOf(buffer);
    }
}