it.unimi.dsi.fastutil.floats.FloatArrayList Maven / Gradle / Ivy
/*
* Copyright (C) 2002-2017 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.floats;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.RandomAccess;
import java.util.NoSuchElementException;
/** A type-specific array-based list; provides some additional methods that use polymorphism to avoid (un)boxing.
*
* This class implements a lightweight, fast, open, optimized,
* reuse-oriented version of array-based lists. Instances of this class
* represent a list with an array that is enlarged as needed when new entries
* are created (by doubling its current length), but is
* never made smaller (even on a {@link #clear()}). A family of
* {@linkplain #trim() trimming methods} lets you control the size of the
* backing array; this is particularly useful if you reuse instances of this class.
* Range checks are equivalent to those of {@link java.util}'s classes, but
* they are delayed as much as possible. The backing array is exposed by the
* {@link #elements()} method.
*
*
This class implements the bulk methods removeElements(),
* addElements() and getElements() using
* high-performance system calls (e.g., {@link
* System#arraycopy(Object,int,Object,int,int) System.arraycopy()} instead of
* expensive loops.
*
* @see java.util.ArrayList
*/
public class FloatArrayList extends AbstractFloatList implements RandomAccess, Cloneable, java.io.Serializable {
private static final long serialVersionUID = -7046029254386353130L;
/** The initial default capacity of an array list. */
public final static int DEFAULT_INITIAL_CAPACITY = 16;
/** The backing array. */
protected transient float a[];
/** The current actual size of the list (never greater than the backing-array length). */
protected int size;
private static final boolean ASSERTS = false;
/** Creates a new array list using a given array.
*
*
This constructor is only meant to be used by the wrapping methods.
*
* @param a the array that will be used to back this array list.
*/
protected FloatArrayList(final float a[], boolean dummy) {
this.a = a;
}
/** Creates a new array list with given capacity.
*
* @param capacity the initial capacity of the array list (may be 0).
*/
public FloatArrayList(final int capacity) {
if (capacity < 0) throw new IllegalArgumentException("Initial capacity (" + capacity + ") is negative");
a = new float[capacity];
}
/** Creates a new array list with {@link #DEFAULT_INITIAL_CAPACITY} capacity.
*/
public FloatArrayList() {
this(DEFAULT_INITIAL_CAPACITY);
}
/** Creates a new array list and fills it with a given collection.
*
* @param c a collection that will be used to fill the array list.
*/
public FloatArrayList(final Collection c) {
this(c.size());
size = FloatIterators.unwrap(FloatIterators.asFloatIterator(c.iterator()), a);
}
/** Creates a new array list and fills it with a given type-specific collection.
*
* @param c a type-specific collection that will be used to fill the array list.
*/
public FloatArrayList(final FloatCollection c) {
this(c.size());
size = FloatIterators.unwrap(c.iterator(), a);
}
/** Creates a new array list and fills it with a given type-specific list.
*
* @param l a type-specific list that will be used to fill the array list.
*/
public FloatArrayList(final FloatList l) {
this(l.size());
l.getElements(0, a, 0, size = l.size());
}
/** Creates a new array list and fills it with the elements of a given array.
*
* @param a an array whose elements will be used to fill the array list.
*/
public FloatArrayList(final float a[]) {
this(a, 0, a.length);
}
/** Creates a new array list and fills it with the elements of a given array.
*
* @param a an array whose elements will be used to fill the array list.
* @param offset the first element to use.
* @param length the number of elements to use.
*/
public FloatArrayList(final float a[], final int offset, final int length) {
this(length);
System.arraycopy(a, offset, this.a, 0, length);
size = length;
}
/** Creates a new array list and fills it with the elements returned by an iterator..
*
* @param i an iterator whose returned elements will fill the array list.
*/
public FloatArrayList(final Iterator i) {
this();
while(i.hasNext()) this.add(((i.next()).floatValue()));
}
/** Creates a new array list and fills it with the elements returned by a type-specific iterator..
*
* @param i a type-specific iterator whose returned elements will fill the array list.
*/
public FloatArrayList(final FloatIterator i) {
this();
while(i.hasNext()) this.add(i.nextFloat());
}
/** Returns the backing array of this list.
*
* @return the backing array.
*/
public float[] elements() {
return a;
}
/** Wraps a given array into an array list of given size.
*
*
Note it is guaranteed
* that the type of the array returned by {@link #elements()} will be the same
* (see the comments in the class documentation).
*
* @param a an array to wrap.
* @param length the length of the resulting array list.
* @return a new array list of the given size, wrapping the given array.
*/
public static FloatArrayList wrap(final float a[], final int length) {
if (length > a.length) throw new IllegalArgumentException("The specified length (" + length + ") is greater than the array size (" + a.length + ")");
final FloatArrayList l = new FloatArrayList (a, false);
l.size = length;
return l;
}
/** Wraps a given array into an array list.
*
*
Note it is guaranteed
* that the type of the array returned by {@link #elements()} will be the same
* (see the comments in the class documentation).
*
* @param a an array to wrap.
* @return a new array list wrapping the given array.
*/
public static FloatArrayList wrap(final float a[]) {
return wrap(a, a.length);
}
/** Ensures that this array list can contain the given number of entries without resizing.
*
* @param capacity the new minimum capacity for this array list.
*/
public void ensureCapacity(final int capacity) {
a = FloatArrays.ensureCapacity(a, capacity, size);
if (ASSERTS) assert size <= a.length;
}
/** Grows this array list, ensuring that it can contain the given number of entries without resizing,
* and in case enlarging it at least by a factor of two.
*
* @param capacity the new minimum capacity for this array list.
*/
private void grow(final int capacity) {
a = FloatArrays.grow(a, capacity, size);
if (ASSERTS) assert size <= a.length;
}
@Override
public void add(final int index, final float k) {
ensureIndex(index);
grow(size + 1);
if (index != size) System.arraycopy(a, index, a, index + 1, size - index);
a[index] = k;
size++;
if (ASSERTS) assert size <= a.length;
}
@Override
public boolean add(final float k) {
grow(size + 1);
a[size++] = k;
if (ASSERTS) assert size <= a.length;
return true;
}
@Override
public float getFloat(final int index) {
if (index >= size) throw new IndexOutOfBoundsException("Index (" + index + ") is greater than or equal to list size (" + size + ")");
return a[index];
}
@Override
public int indexOf(final float k) {
for(int i = 0; i < size; i++) if (( Float.floatToIntBits(k) == Float.floatToIntBits(a[i]) )) return i;
return -1;
}
@Override
public int lastIndexOf(final float k) {
for(int i = size; i-- != 0;) if (( Float.floatToIntBits(k) == Float.floatToIntBits(a[i]) )) return i;
return -1;
}
@Override
public float removeFloat(final int index) {
if (index >= size) throw new IndexOutOfBoundsException("Index (" + index + ") is greater than or equal to list size (" + size + ")");
final float old = a[index];
size--;
if (index != size) System.arraycopy(a, index + 1, a, index, size - index);
if (ASSERTS) assert size <= a.length;
return old;
}
@Override
public boolean rem(final float k) {
int index = indexOf(k);
if (index == -1) return false;
removeFloat(index);
if (ASSERTS) assert size <= a.length;
return true;
}
@Override
public float set(final int index, final float k) {
if (index >= size) throw new IndexOutOfBoundsException("Index (" + index + ") is greater than or equal to list size (" + size + ")");
float old = a[index];
a[index] = k;
return old;
}
@Override
public void clear() {
size = 0;
if (ASSERTS) assert size <= a.length;
}
@Override
public int size() {
return size;
}
@Override
public void size(final int size) {
if (size > a.length) ensureCapacity(size);
if (size > this.size) Arrays.fill(a, this.size, size, (0));
this.size = size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/** Trims this array list so that the capacity is equal to the size.
*
* @see java.util.ArrayList#trimToSize()
*/
public void trim() {
trim(0);
}
/** Trims the backing array if it is too large.
*
* If the current array length is smaller than or equal to
* n, this method does nothing. Otherwise, it trims the
* array length to the maximum between n and {@link #size()}.
*
*
This method is useful when reusing lists. {@linkplain #clear() Clearing a
* list} leaves the array length untouched. If you are reusing a list
* many times, you can call this method with a typical
* size to avoid keeping around a very large array just
* because of a few large transient lists.
*
* @param n the threshold for the trimming.
*/
public void trim(final int n) {
// TODO: use Arrays.trim() and preserve type only if necessary
if (n >= a.length || size == a.length) return;
final float t[] = new float[Math.max(n, size)];
System.arraycopy(a, 0, t, 0, size);
a = t;
if (ASSERTS) assert size <= a.length;
}
/** Copies element of this type-specific list into the given array using optimized system calls.
*
* @param from the start index (inclusive).
* @param a the destination array.
* @param offset the offset into the destination array where to store the first element copied.
* @param length the number of elements to be copied.
*/
@Override
public void getElements(final int from, final float[] a, final int offset, final int length) {
FloatArrays.ensureOffsetLength(a, offset, length);
System.arraycopy(this.a, from, a, offset, length);
}
/** Removes elements of this type-specific list using optimized system calls.
*
* @param from the start index (inclusive).
* @param to the end index (exclusive).
*/
@Override
public void removeElements(final int from, final int to) {
it.unimi.dsi.fastutil.Arrays.ensureFromTo(size, from, to);
System.arraycopy(a, to, a, from, size - to);
size -= (to - from);
}
/** Adds elements to this type-specific list using optimized system calls.
*
* @param index the index at which to add elements.
* @param a the array containing the elements.
* @param offset the offset of the first element to add.
* @param length the number of elements to add.
*/
@Override
public void addElements(final int index, final float a[], final int offset, final int length) {
ensureIndex(index);
FloatArrays.ensureOffsetLength(a, offset, length);
grow(size + length);
System.arraycopy(this.a, index, this.a, index + length, size - index);
System.arraycopy(a, offset, this.a, index, length);
size += length;
}
@Override
public float[] toArray(float a[]) {
if (a == null || a.length < size) a = new float[size];
System.arraycopy(this.a, 0, a, 0, size);
return a;
}
@Override
public boolean addAll(int index, final FloatCollection c) {
ensureIndex(index);
int n = c.size();
if (n == 0) return false;
grow(size + n);
if (index != size) System.arraycopy(a, index, a, index + n, size - index);
final FloatIterator i = c.iterator();
size += n;
while(n-- != 0) a[index++] = i.nextFloat();
if (ASSERTS) assert size <= a.length;
return true;
}
@Override
public boolean addAll(final int index, final FloatList l) {
ensureIndex(index);
final int n = l.size();
if (n == 0) return false;
grow(size + n);
if (index != size) System.arraycopy(a, index, a, index + n, size - index);
l.getElements(0, a, index, n);
size += n;
if (ASSERTS) assert size <= a.length;
return true;
}
@Override
public boolean removeAll(final FloatCollection c) {
final float[] a = this.a;
int j = 0;
for(int i = 0; i < size; i++)
if (! c.contains(a[i])) a[j++] = a[i];
final boolean modified = size != j;
size = j;
return modified;
}
@Override
public boolean removeAll(final Collection c) {
final float[] a = this.a;
int j = 0;
for(int i = 0; i < size; i++)
if (! c.contains((Float.valueOf(a[i])))) a[j++] = a[i];
final boolean modified = size != j;
size = j;
return modified;
}
@Override
public FloatListIterator listIterator(final int index) {
ensureIndex(index);
return new AbstractFloatListIterator () {
int pos = index, last = -1;
public boolean hasNext() { return pos < size; }
public boolean hasPrevious() { return pos > 0; }
public float nextFloat() { if (! hasNext()) throw new NoSuchElementException(); return a[last = pos++]; }
public float previousFloat() { if (! hasPrevious()) throw new NoSuchElementException(); return a[last = --pos]; }
public int nextIndex() { return pos; }
public int previousIndex() { return pos - 1; }
public void add(float k) {
FloatArrayList.this.add(pos++, k);
last = -1;
}
public void set(float k) {
if (last == -1) throw new IllegalStateException();
FloatArrayList.this.set(last, k);
}
public void remove() {
if (last == -1) throw new IllegalStateException();
FloatArrayList.this.removeFloat(last);
/* If the last operation was a next(), we are removing an element *before* us, and we must decrease pos correspondingly. */
if (last < pos) pos--;
last = -1;
}
};
}
@Override
public FloatArrayList clone() {
FloatArrayList c = new FloatArrayList (size);
System.arraycopy(a, 0, c.a, 0, size);
c.size = size;
return c;
}
/** Compares this type-specific array list to another one.
*
*
This method exists only for sake of efficiency. The implementation
* inherited from the abstract implementation would already work.
*
* @param l a type-specific array list.
* @return true if the argument contains the same elements of this type-specific array list.
*/
public boolean equals(final FloatArrayList l) {
if (l == this) return true;
int s = size();
if (s != l.size()) return false;
final float[] a1 = a;
final float[] a2 = l.a;
while(s-- != 0) if (a1[s] != a2[s]) return false;
return true;
}
/** Compares this array list to another array list.
*
*
This method exists only for sake of efficiency. The implementation
* inherited from the abstract implementation would already work.
*
* @param l an array list.
* @return a negative integer,
* zero, or a positive integer as this list is lexicographically less than, equal
* to, or greater than the argument.
*/
public int compareTo(final FloatArrayList l) {
final int s1 = size(), s2 = l.size();
final float a1[] = a, a2[] = l.a;
float e1, e2;
int r, i;
for(i = 0; i < s1 && i < s2; i++) {
e1 = a1[i];
e2 = a2[i];
if ((r = ( Float.compare((e1),(e2)) )) != 0) return r;
}
return i < s2 ? -1 : (i < s1 ? 1 : 0);
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
s.defaultWriteObject();
for(int i = 0; i < size; i++) s.writeFloat(a[i]);
}
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
a = new float[size];
for(int i = 0; i < size; i++) a[i] = s.readFloat();
}
}