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Diffstat (limited to 'platform/android/viewer/src/com/artifex/mupdfdemo/ArrayDeque.java')
| -rw-r--r-- | platform/android/viewer/src/com/artifex/mupdfdemo/ArrayDeque.java | 855 |
1 files changed, 0 insertions, 855 deletions
diff --git a/platform/android/viewer/src/com/artifex/mupdfdemo/ArrayDeque.java b/platform/android/viewer/src/com/artifex/mupdfdemo/ArrayDeque.java deleted file mode 100644 index c8549058..00000000 --- a/platform/android/viewer/src/com/artifex/mupdfdemo/ArrayDeque.java +++ /dev/null @@ -1,855 +0,0 @@ -/* - * Written by Josh Bloch of Google Inc. and released to the public domain, - * as explained at http://creativecommons.org/publicdomain/zero/1.0/. - */ - -package com.artifex.mupdfdemo; - -import java.util.AbstractCollection; -import java.util.Arrays; -import java.util.Collection; -import java.util.ConcurrentModificationException; -import java.util.Iterator; -import java.util.LinkedList; -import java.util.List; -import java.util.NoSuchElementException; -import java.util.Queue; -import java.util.Stack; - -// BEGIN android-note -// removed link to collections framework docs -// END android-note - -/** - * Resizable-array implementation of the {@link Deque} interface. Array - * deques have no capacity restrictions; they grow as necessary to support - * usage. They are not thread-safe; in the absence of external - * synchronization, they do not support concurrent access by multiple threads. - * Null elements are prohibited. This class is likely to be faster than - * {@link Stack} when used as a stack, and faster than {@link LinkedList} - * when used as a queue. - * - * <p>Most <tt>ArrayDeque</tt> operations run in amortized constant time. - * Exceptions include {@link #remove(Object) remove}, {@link - * #removeFirstOccurrence removeFirstOccurrence}, {@link #removeLastOccurrence - * removeLastOccurrence}, {@link #contains contains}, {@link #iterator - * iterator.remove()}, and the bulk operations, all of which run in linear - * time. - * - * <p>The iterators returned by this class's <tt>iterator</tt> method are - * <i>fail-fast</i>: If the deque is modified at any time after the iterator - * is created, in any way except through the iterator's own <tt>remove</tt> - * method, the iterator will generally throw a {@link - * ConcurrentModificationException}. Thus, in the face of concurrent - * modification, the iterator fails quickly and cleanly, rather than risking - * arbitrary, non-deterministic behavior at an undetermined time in the - * future. - * - * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed - * as it is, generally speaking, impossible to make any hard guarantees in the - * presence of unsynchronized concurrent modification. Fail-fast iterators - * throw <tt>ConcurrentModificationException</tt> on a best-effort basis. - * Therefore, it would be wrong to write a program that depended on this - * exception for its correctness: <i>the fail-fast behavior of iterators - * should be used only to detect bugs.</i> - * - * <p>This class and its iterator implement all of the - * <em>optional</em> methods of the {@link Collection} and {@link - * Iterator} interfaces. - * - * @author Josh Bloch and Doug Lea - * @since 1.6 - * @param <E> the type of elements held in this collection - */ -public class ArrayDeque<E> extends AbstractCollection<E> - implements Deque<E>, Cloneable, java.io.Serializable -{ - /** - * The array in which the elements of the deque are stored. - * The capacity of the deque is the length of this array, which is - * always a power of two. The array is never allowed to become - * full, except transiently within an addX method where it is - * resized (see doubleCapacity) immediately upon becoming full, - * thus avoiding head and tail wrapping around to equal each - * other. We also guarantee that all array cells not holding - * deque elements are always null. - */ - private transient Object[] elements; - - /** - * The index of the element at the head of the deque (which is the - * element that would be removed by remove() or pop()); or an - * arbitrary number equal to tail if the deque is empty. - */ - private transient int head; - - /** - * The index at which the next element would be added to the tail - * of the deque (via addLast(E), add(E), or push(E)). - */ - private transient int tail; - - /** - * The minimum capacity that we'll use for a newly created deque. - * Must be a power of 2. - */ - private static final int MIN_INITIAL_CAPACITY = 8; - - // ****** Array allocation and resizing utilities ****** - - /** - * Allocate empty array to hold the given number of elements. - * - * @param numElements the number of elements to hold - */ - private void allocateElements(int numElements) { - int initialCapacity = MIN_INITIAL_CAPACITY; - // Find the best power of two to hold elements. - // Tests "<=" because arrays aren't kept full. - if (numElements >= initialCapacity) { - initialCapacity = numElements; - initialCapacity |= (initialCapacity >>> 1); - initialCapacity |= (initialCapacity >>> 2); - initialCapacity |= (initialCapacity >>> 4); - initialCapacity |= (initialCapacity >>> 8); - initialCapacity |= (initialCapacity >>> 16); - initialCapacity++; - - if (initialCapacity < 0) // Too many elements, must back off - initialCapacity >>>= 1; // Good luck allocating 2 ^ 30 elements - } - elements = new Object[initialCapacity]; - } - - /** - * Double the capacity of this deque. Call only when full, i.e., - * when head and tail have wrapped around to become equal. - */ - private void doubleCapacity() { - // assert head == tail; - int p = head; - int n = elements.length; - int r = n - p; // number of elements to the right of p - int newCapacity = n << 1; - if (newCapacity < 0) - throw new IllegalStateException("Sorry, deque too big"); - Object[] a = new Object[newCapacity]; - System.arraycopy(elements, p, a, 0, r); - System.arraycopy(elements, 0, a, r, p); - elements = a; - head = 0; - tail = n; - } - - /** - * Copies the elements from our element array into the specified array, - * in order (from first to last element in the deque). It is assumed - * that the array is large enough to hold all elements in the deque. - * - * @return its argument - */ - private <T> T[] copyElements(T[] a) { - if (head < tail) { - System.arraycopy(elements, head, a, 0, size()); - } else if (head > tail) { - int headPortionLen = elements.length - head; - System.arraycopy(elements, head, a, 0, headPortionLen); - System.arraycopy(elements, 0, a, headPortionLen, tail); - } - return a; - } - - /** - * Constructs an empty array deque with an initial capacity - * sufficient to hold 16 elements. - */ - public ArrayDeque() { - elements = new Object[16]; - } - - /** - * Constructs an empty array deque with an initial capacity - * sufficient to hold the specified number of elements. - * - * @param numElements lower bound on initial capacity of the deque - */ - public ArrayDeque(int numElements) { - allocateElements(numElements); - } - - /** - * Constructs a deque containing the elements of the specified - * collection, in the order they are returned by the collection's - * iterator. (The first element returned by the collection's - * iterator becomes the first element, or <i>front</i> of the - * deque.) - * - * @param c the collection whose elements are to be placed into the deque - * @throws NullPointerException if the specified collection is null - */ - public ArrayDeque(Collection<? extends E> c) { - allocateElements(c.size()); - addAll(c); - } - - // The main insertion and extraction methods are addFirst, - // addLast, pollFirst, pollLast. The other methods are defined in - // terms of these. - - /** - * Inserts the specified element at the front of this deque. - * - * @param e the element to add - * @throws NullPointerException if the specified element is null - */ - public void addFirst(E e) { - if (e == null) - throw new NullPointerException("e == null"); - elements[head = (head - 1) & (elements.length - 1)] = e; - if (head == tail) - doubleCapacity(); - } - - /** - * Inserts the specified element at the end of this deque. - * - * <p>This method is equivalent to {@link #add}. - * - * @param e the element to add - * @throws NullPointerException if the specified element is null - */ - public void addLast(E e) { - if (e == null) - throw new NullPointerException("e == null"); - elements[tail] = e; - if ( (tail = (tail + 1) & (elements.length - 1)) == head) - doubleCapacity(); - } - - /** - * Inserts the specified element at the front of this deque. - * - * @param e the element to add - * @return <tt>true</tt> (as specified by {@link Deque#offerFirst}) - * @throws NullPointerException if the specified element is null - */ - public boolean offerFirst(E e) { - addFirst(e); - return true; - } - - /** - * Inserts the specified element at the end of this deque. - * - * @param e the element to add - * @return <tt>true</tt> (as specified by {@link Deque#offerLast}) - * @throws NullPointerException if the specified element is null - */ - public boolean offerLast(E e) { - addLast(e); - return true; - } - - /** - * @throws NoSuchElementException {@inheritDoc} - */ - public E removeFirst() { - E x = pollFirst(); - if (x == null) - throw new NoSuchElementException(); - return x; - } - - /** - * @throws NoSuchElementException {@inheritDoc} - */ - public E removeLast() { - E x = pollLast(); - if (x == null) - throw new NoSuchElementException(); - return x; - } - - public E pollFirst() { - int h = head; - @SuppressWarnings("unchecked") E result = (E) elements[h]; - // Element is null if deque empty - if (result == null) - return null; - elements[h] = null; // Must null out slot - head = (h + 1) & (elements.length - 1); - return result; - } - - public E pollLast() { - int t = (tail - 1) & (elements.length - 1); - @SuppressWarnings("unchecked") E result = (E) elements[t]; - if (result == null) - return null; - elements[t] = null; - tail = t; - return result; - } - - /** - * @throws NoSuchElementException {@inheritDoc} - */ - public E getFirst() { - @SuppressWarnings("unchecked") E result = (E) elements[head]; - if (result == null) - throw new NoSuchElementException(); - return result; - } - - /** - * @throws NoSuchElementException {@inheritDoc} - */ - public E getLast() { - @SuppressWarnings("unchecked") - E result = (E) elements[(tail - 1) & (elements.length - 1)]; - if (result == null) - throw new NoSuchElementException(); - return result; - } - - public E peekFirst() { - @SuppressWarnings("unchecked") E result = (E) elements[head]; - // elements[head] is null if deque empty - return result; - } - - public E peekLast() { - @SuppressWarnings("unchecked") - E result = (E) elements[(tail - 1) & (elements.length - 1)]; - return result; - } - - /** - * Removes the first occurrence of the specified element in this - * deque (when traversing the deque from head to tail). - * If the deque does not contain the element, it is unchanged. - * More formally, removes the first element <tt>e</tt> such that - * <tt>o.equals(e)</tt> (if such an element exists). - * Returns <tt>true</tt> if this deque contained the specified element - * (or equivalently, if this deque changed as a result of the call). - * - * @param o element to be removed from this deque, if present - * @return <tt>true</tt> if the deque contained the specified element - */ - public boolean removeFirstOccurrence(Object o) { - if (o == null) - return false; - int mask = elements.length - 1; - int i = head; - Object x; - while ( (x = elements[i]) != null) { - if (o.equals(x)) { - delete(i); - return true; - } - i = (i + 1) & mask; - } - return false; - } - - /** - * Removes the last occurrence of the specified element in this - * deque (when traversing the deque from head to tail). - * If the deque does not contain the element, it is unchanged. - * More formally, removes the last element <tt>e</tt> such that - * <tt>o.equals(e)</tt> (if such an element exists). - * Returns <tt>true</tt> if this deque contained the specified element - * (or equivalently, if this deque changed as a result of the call). - * - * @param o element to be removed from this deque, if present - * @return <tt>true</tt> if the deque contained the specified element - */ - public boolean removeLastOccurrence(Object o) { - if (o == null) - return false; - int mask = elements.length - 1; - int i = (tail - 1) & mask; - Object x; - while ( (x = elements[i]) != null) { - if (o.equals(x)) { - delete(i); - return true; - } - i = (i - 1) & mask; - } - return false; - } - - // *** Queue methods *** - - /** - * Inserts the specified element at the end of this deque. - * - * <p>This method is equivalent to {@link #addLast}. - * - * @param e the element to add - * @return <tt>true</tt> (as specified by {@link Collection#add}) - * @throws NullPointerException if the specified element is null - */ - public boolean add(E e) { - addLast(e); - return true; - } - - /** - * Inserts the specified element at the end of this deque. - * - * <p>This method is equivalent to {@link #offerLast}. - * - * @param e the element to add - * @return <tt>true</tt> (as specified by {@link Queue#offer}) - * @throws NullPointerException if the specified element is null - */ - public boolean offer(E e) { - return offerLast(e); - } - - /** - * Retrieves and removes the head of the queue represented by this deque. - * - * This method differs from {@link #poll poll} only in that it throws an - * exception if this deque is empty. - * - * <p>This method is equivalent to {@link #removeFirst}. - * - * @return the head of the queue represented by this deque - * @throws NoSuchElementException {@inheritDoc} - */ - public E remove() { - return removeFirst(); - } - - /** - * Retrieves and removes the head of the queue represented by this deque - * (in other words, the first element of this deque), or returns - * <tt>null</tt> if this deque is empty. - * - * <p>This method is equivalent to {@link #pollFirst}. - * - * @return the head of the queue represented by this deque, or - * <tt>null</tt> if this deque is empty - */ - public E poll() { - return pollFirst(); - } - - /** - * Retrieves, but does not remove, the head of the queue represented by - * this deque. This method differs from {@link #peek peek} only in - * that it throws an exception if this deque is empty. - * - * <p>This method is equivalent to {@link #getFirst}. - * - * @return the head of the queue represented by this deque - * @throws NoSuchElementException {@inheritDoc} - */ - public E element() { - return getFirst(); - } - - /** - * Retrieves, but does not remove, the head of the queue represented by - * this deque, or returns <tt>null</tt> if this deque is empty. - * - * <p>This method is equivalent to {@link #peekFirst}. - * - * @return the head of the queue represented by this deque, or - * <tt>null</tt> if this deque is empty - */ - public E peek() { - return peekFirst(); - } - - // *** Stack methods *** - - /** - * Pushes an element onto the stack represented by this deque. In other - * words, inserts the element at the front of this deque. - * - * <p>This method is equivalent to {@link #addFirst}. - * - * @param e the element to push - * @throws NullPointerException if the specified element is null - */ - public void push(E e) { - addFirst(e); - } - - /** - * Pops an element from the stack represented by this deque. In other - * words, removes and returns the first element of this deque. - * - * <p>This method is equivalent to {@link #removeFirst()}. - * - * @return the element at the front of this deque (which is the top - * of the stack represented by this deque) - * @throws NoSuchElementException {@inheritDoc} - */ - public E pop() { - return removeFirst(); - } - - private void checkInvariants() { - // assert elements[tail] == null; - // assert head == tail ? elements[head] == null : - // (elements[head] != null && - // elements[(tail - 1) & (elements.length - 1)] != null); - // assert elements[(head - 1) & (elements.length - 1)] == null; - } - - /** - * Removes the element at the specified position in the elements array, - * adjusting head and tail as necessary. This can result in motion of - * elements backwards or forwards in the array. - * - * <p>This method is called delete rather than remove to emphasize - * that its semantics differ from those of {@link List#remove(int)}. - * - * @return true if elements moved backwards - */ - private boolean delete(int i) { - //checkInvariants(); - final Object[] elements = this.elements; - final int mask = elements.length - 1; - final int h = head; - final int t = tail; - final int front = (i - h) & mask; - final int back = (t - i) & mask; - - // Invariant: head <= i < tail mod circularity - if (front >= ((t - h) & mask)) - throw new ConcurrentModificationException(); - - // Optimize for least element motion - if (front < back) { - if (h <= i) { - System.arraycopy(elements, h, elements, h + 1, front); - } else { // Wrap around - System.arraycopy(elements, 0, elements, 1, i); - elements[0] = elements[mask]; - System.arraycopy(elements, h, elements, h + 1, mask - h); - } - elements[h] = null; - head = (h + 1) & mask; - return false; - } else { - if (i < t) { // Copy the null tail as well - System.arraycopy(elements, i + 1, elements, i, back); - tail = t - 1; - } else { // Wrap around - System.arraycopy(elements, i + 1, elements, i, mask - i); - elements[mask] = elements[0]; - System.arraycopy(elements, 1, elements, 0, t); - tail = (t - 1) & mask; - } - return true; - } - } - - // *** Collection Methods *** - - /** - * Returns the number of elements in this deque. - * - * @return the number of elements in this deque - */ - public int size() { - return (tail - head) & (elements.length - 1); - } - - /** - * Returns <tt>true</tt> if this deque contains no elements. - * - * @return <tt>true</tt> if this deque contains no elements - */ - public boolean isEmpty() { - return head == tail; - } - - /** - * Returns an iterator over the elements in this deque. The elements - * will be ordered from first (head) to last (tail). This is the same - * order that elements would be dequeued (via successive calls to - * {@link #remove} or popped (via successive calls to {@link #pop}). - * - * @return an iterator over the elements in this deque - */ - public Iterator<E> iterator() { - return new DeqIterator(); - } - - public Iterator<E> descendingIterator() { - return new DescendingIterator(); - } - - private class DeqIterator implements Iterator<E> { - /** - * Index of element to be returned by subsequent call to next. - */ - private int cursor = head; - - /** - * Tail recorded at construction (also in remove), to stop - * iterator and also to check for comodification. - */ - private int fence = tail; - - /** - * Index of element returned by most recent call to next. - * Reset to -1 if element is deleted by a call to remove. - */ - private int lastRet = -1; - - public boolean hasNext() { - return cursor != fence; - } - - public E next() { - if (cursor == fence) - throw new NoSuchElementException(); - @SuppressWarnings("unchecked") E result = (E) elements[cursor]; - // This check doesn't catch all possible comodifications, - // but does catch the ones that corrupt traversal - if (tail != fence || result == null) - throw new ConcurrentModificationException(); - lastRet = cursor; - cursor = (cursor + 1) & (elements.length - 1); - return result; - } - - public void remove() { - if (lastRet < 0) - throw new IllegalStateException(); - if (delete(lastRet)) { // if left-shifted, undo increment in next() - cursor = (cursor - 1) & (elements.length - 1); - fence = tail; - } - lastRet = -1; - } - } - - private class DescendingIterator implements Iterator<E> { - /* - * This class is nearly a mirror-image of DeqIterator, using - * tail instead of head for initial cursor, and head instead of - * tail for fence. - */ - private int cursor = tail; - private int fence = head; - private int lastRet = -1; - - public boolean hasNext() { - return cursor != fence; - } - - public E next() { - if (cursor == fence) - throw new NoSuchElementException(); - cursor = (cursor - 1) & (elements.length - 1); - @SuppressWarnings("unchecked") E result = (E) elements[cursor]; - if (head != fence || result == null) - throw new ConcurrentModificationException(); - lastRet = cursor; - return result; - } - - public void remove() { - if (lastRet < 0) - throw new IllegalStateException(); - if (!delete(lastRet)) { - cursor = (cursor + 1) & (elements.length - 1); - fence = head; - } - lastRet = -1; - } - } - - /** - * Returns <tt>true</tt> if this deque contains the specified element. - * More formally, returns <tt>true</tt> if and only if this deque contains - * at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>. - * - * @param o object to be checked for containment in this deque - * @return <tt>true</tt> if this deque contains the specified element - */ - public boolean contains(Object o) { - if (o == null) - return false; - int mask = elements.length - 1; - int i = head; - Object x; - while ( (x = elements[i]) != null) { - if (o.equals(x)) - return true; - i = (i + 1) & mask; - } - return false; - } - - /** - * Removes a single instance of the specified element from this deque. - * If the deque does not contain the element, it is unchanged. - * More formally, removes the first element <tt>e</tt> such that - * <tt>o.equals(e)</tt> (if such an element exists). - * Returns <tt>true</tt> if this deque contained the specified element - * (or equivalently, if this deque changed as a result of the call). - * - * <p>This method is equivalent to {@link #removeFirstOccurrence}. - * - * @param o element to be removed from this deque, if present - * @return <tt>true</tt> if this deque contained the specified element - */ - public boolean remove(Object o) { - return removeFirstOccurrence(o); - } - - /** - * Removes all of the elements from this deque. - * The deque will be empty after this call returns. - */ - public void clear() { - int h = head; - int t = tail; - if (h != t) { // clear all cells - head = tail = 0; - int i = h; - int mask = elements.length - 1; - do { - elements[i] = null; - i = (i + 1) & mask; - } while (i != t); - } - } - - /** - * Returns an array containing all of the elements in this deque - * in proper sequence (from first to last element). - * - * <p>The returned array will be "safe" in that no references to it are - * maintained by this deque. (In other words, this method must allocate - * a new array). The caller is thus free to modify the returned array. - * - * <p>This method acts as bridge between array-based and collection-based - * APIs. - * - * @return an array containing all of the elements in this deque - */ - public Object[] toArray() { - return copyElements(new Object[size()]); - } - - /** - * Returns an array containing all of the elements in this deque in - * proper sequence (from first to last element); the runtime type of the - * returned array is that of the specified array. If the deque fits in - * the specified array, it is returned therein. Otherwise, a new array - * is allocated with the runtime type of the specified array and the - * size of this deque. - * - * <p>If this deque fits in the specified array with room to spare - * (i.e., the array has more elements than this deque), the element in - * the array immediately following the end of the deque is set to - * <tt>null</tt>. - * - * <p>Like the {@link #toArray()} method, this method acts as bridge between - * array-based and collection-based APIs. Further, this method allows - * precise control over the runtime type of the output array, and may, - * under certain circumstances, be used to save allocation costs. - * - * <p>Suppose <tt>x</tt> is a deque known to contain only strings. - * The following code can be used to dump the deque into a newly - * allocated array of <tt>String</tt>: - * - * <pre> {@code String[] y = x.toArray(new String[0]);}</pre> - * - * Note that <tt>toArray(new Object[0])</tt> is identical in function to - * <tt>toArray()</tt>. - * - * @param a the array into which the elements of the deque are to - * be stored, if it is big enough; otherwise, a new array of the - * same runtime type is allocated for this purpose - * @return an array containing all of the elements in this deque - * @throws ArrayStoreException if the runtime type of the specified array - * is not a supertype of the runtime type of every element in - * this deque - * @throws NullPointerException if the specified array is null - */ - @SuppressWarnings("unchecked") - public <T> T[] toArray(T[] a) { - int size = size(); - if (a.length < size) - a = (T[])java.lang.reflect.Array.newInstance( - a.getClass().getComponentType(), size); - copyElements(a); - if (a.length > size) - a[size] = null; - return a; - } - - // *** Object methods *** - - /** - * Returns a copy of this deque. - * - * @return a copy of this deque - */ - public ArrayDeque<E> clone() { - try { - @SuppressWarnings("unchecked") - ArrayDeque<E> result = (ArrayDeque<E>) super.clone(); - result.elements = Arrays.copyOf(elements, elements.length); - return result; - - } catch (CloneNotSupportedException e) { - throw new AssertionError(); - } - } - - /** - * Appease the serialization gods. - */ - private static final long serialVersionUID = 2340985798034038923L; - - /** - * Serialize this deque. - * - * @serialData The current size (<tt>int</tt>) of the deque, - * followed by all of its elements (each an object reference) in - * first-to-last order. - */ - private void writeObject(java.io.ObjectOutputStream s) - throws java.io.IOException { - s.defaultWriteObject(); - - // Write out size - s.writeInt(size()); - - // Write out elements in order. - int mask = elements.length - 1; - for (int i = head; i != tail; i = (i + 1) & mask) - s.writeObject(elements[i]); - } - - /** - * Deserialize this deque. - */ - private void readObject(java.io.ObjectInputStream s) - throws java.io.IOException, ClassNotFoundException { - s.defaultReadObject(); - - // Read in size and allocate array - int size = s.readInt(); - allocateElements(size); - head = 0; - tail = size; - - // Read in all elements in the proper order. - for (int i = 0; i < size; i++) - elements[i] = s.readObject(); - } -} |