package speiger.src.collections.PACKAGE.lists;

import java.util.Arrays;
#if TYPE_OBJECT
import java.util.Comparator;
#endif
import java.util.Collection;
import java.util.Iterator;
import java.util.Objects;
#if TYPE_OBJECT
import java.util.function.Consumer;
#endif
import java.util.function.Predicate;
import java.util.function.UnaryOperator;
#if PRIMITIVES
import java.util.function.JAVA_PREDICATE;
import java.util.function.JAVA_UNARY_OPERATOR;
#endif

import speiger.src.collections.PACKAGE.collections.COLLECTION;
#if !TYPE_OBJECT
import speiger.src.collections.PACKAGE.collections.STACK;
#endif
import speiger.src.collections.PACKAGE.collections.ITERATOR;
#if !TYPE_OBJECT
import speiger.src.collections.PACKAGE.functions.COMPARATOR;
import speiger.src.collections.PACKAGE.functions.CONSUMER;
#endif
import speiger.src.collections.PACKAGE.utils.ARRAYS;
import speiger.src.collections.PACKAGE.utils.ITERATORS;
#if TYPE_OBJECT
import speiger.src.collections.utils.Stack;
#else
import speiger.src.collections.objects.utils.ObjectArrays;
#endif
import speiger.src.collections.PACKAGE.utils.IARRAY;
import speiger.src.collections.utils.SanityChecks;

#if TYPE_OBJECT
/**
 * A Type-Specific Array-based implementation of list that is written to reduce (un)boxing
 * 
 * <p>This implementation is optimized to improve how data is processed with interfaces like {@link IARRAY}, {@link Stack}
 * and with optimized functions that use type-specific implementations for primitives and optimized logic for bulkactions.
 */
public class ARRAY_LIST KEY_GENERIC_TYPE extends ABSTRACT_LIST KEY_GENERIC_TYPE implements IARRAY<KEY_TYPE>, Stack<KEY_TYPE>
#else
/**
 * A Type-Specific Array-based implementation of list that is written to reduce (un)boxing
 * 
 * <p>This implementation is optimized to improve how data is processed with interfaces like {@link IARRAY}, {@link STACK}
 * and with optimized functions that use type-specific implementations for primitives and optimized logic for bulkactions.
 */
public class ARRAY_LIST KEY_GENERIC_TYPE extends ABSTRACT_LIST KEY_GENERIC_TYPE implements IARRAY, STACK
#endif
{
	static final int DEFAULT_ARRAY_SIZE = 10;
	
	/** The backing array */
	protected transient KEY_TYPE[] data;
	/** The current size of the elements stored in the backing array */
	protected int size = 0;
	
	/**
	 * Creates a new ArrayList with a Empty array.
	 */
	public ARRAY_LIST() {
		data = EMPTY_KEY_ARRAY;
	}
	
	/**
	 * Creates a new ArrayList with the specific requested size
	 */
	public ARRAY_LIST(int size) {
		data = NEW_KEY_ARRAY(size);
	}
	
	/**
	 * Creates a new ArrayList a copy with the contents of the Collection.
	 */
	public ARRAY_LIST(Collection<? extends CLASS_TYPE> c) {
		this(c.size());
		size = ITERATORS.unwrap(data, c.iterator());
	}
	
	/**
	 * Creates a new ArrayList a copy with the contents of the Collection.
	 */
	public ARRAY_LIST(COLLECTION KEY_GENERIC_TYPE c) {
		this(c.size());
		size = ITERATORS.unwrap(data, c.iterator());
	}
	
	/**
	 * Creates a new ArrayList a copy with the contents of the List.
	 */
	public ARRAY_LIST(LIST KEY_GENERIC_TYPE l) {
		this(l.size());
		size = l.size();
		l.getElements(0, data, 0, size);
	}
	
	/**
	 * Creates a new ArrayList with a Copy of the array
	 */
	public ARRAY_LIST(KEY_TYPE[] a)	{
		this(a, 0, a.length);
	}
	
	/**
	 * Creates a new ArrayList with a Copy of the array with a custom length
	 */
	public ARRAY_LIST(KEY_TYPE[] a, int length) {
		this(a, 0, length);
	}
	
	/**
	 * Creates a new ArrayList with a Copy of the array with in the custom range.
	 */
	public ARRAY_LIST(KEY_TYPE[] a, int offset, int length) {
		this(length);
		SanityChecks.checkArrayCapacity(a.length, offset, length);
		System.arraycopy(a, offset, data, 0, length);
		size = length;
	}
	
	/**
	 * Creates a wrapped arraylist that uses the array as backing array
	 * @param a elements that should be wrapped
	 * @return a Wrapped list using the input array
	 */
	public static GENERIC_KEY_BRACES ARRAY_LIST KEY_GENERIC_TYPE wrap(KEY_TYPE... a) {
		return wrap(a, a.length);
	}
	
	/**
	 * Creates a wrapped arraylist that uses the array as backing array and a custom fillsize
	 * @param a elements that should be wrapped
	 * @param length the size of the elements within the array
 	 * @return a Wrapped list using the input array
	 */
	public static GENERIC_KEY_BRACES ARRAY_LIST KEY_GENERIC_TYPE wrap(KEY_TYPE[] a, int length) {
		SanityChecks.checkArrayCapacity(a.length, 0, length);
		ARRAY_LIST KEY_GENERIC_TYPE list = new ARRAY_LISTBRACES();
		list.data = a;
		list.size = length;
		return list;
	}
	
#if TYPE_OBJECT
	/**
	 * Creates a new ArrayList with a EmptyObject array of the Type requested
	 * @param c the type of the array
	 * @return a typed List
	 */
	public static GENERIC_KEY_BRACES ARRAY_LIST KEY_GENERIC_TYPE of(Class<KEY_TYPE> c) {
		ARRAY_LIST KEY_GENERIC_TYPE list = new ARRAY_LISTBRACES();
		list.data = (KEY_TYPE[])ObjectArrays.newArray(c.getClass().getComponentType(), 0);
		return list;
	}
	
#endif
	/**
	 * Appends the specified element to the end of this list.
	 *
	 * @param e element to be appended to this list
	 * @return <tt>true</tt> (as specified by {@link Collection#add})
	 */
	@Override
	public boolean add(KEY_TYPE e) {
		grow(size + 1);
		data[size++] = e;
		return true;
	}
	
	/**
	 * Appends the specified element to the end of this Stack.
	 * @param e element to be appended to this Stack
	 */
	@Override
	public void PUSH(KEY_TYPE e) {
		add(e);
	}
	
	/**
	 * Appends the specified element to the index of the list
	 * @param index the index where to append the element to
	 * @param e the element to append to the list
	 * @throws IndexOutOfBoundsException if index is outside of the lists range
	 */
	@Override
	public void add(int index, KEY_TYPE e) {
		checkAddRange(index);
		grow(size + 1);
		if(index != size) System.arraycopy(data, index, data, index+1, size - index);
		data[index] = e;
		size++;
	}
	
	/**
	 * Appends the specified elements to the index of the list.
	 * This function may delegate to more appropiate function if nessesary
	 * @param index the index where to append the elements to
	 * @param c the elements to append to the list
	 * @throws IndexOutOfBoundsException if index is outside of the lists range
	 * @deprecated if type is primitive
	 */
	@Override
	@Primitive
	public boolean addAll(int index, Collection<? extends CLASS_TYPE> c) {
		if(c instanceof COLLECTION) return addAll(index, (COLLECTION KEY_GENERIC_TYPE)c);
		int add = c.size();
		if(add <= 0) return false;
		grow(size + add);
		if(index != size) System.arraycopy(data, index, data, index+add, size - index);
		size+=add;
		Iterator<? extends CLASS_TYPE> iter = c.iterator();
		while(add != 0) data[index++] = OBJ_TO_KEY(iter.next());
		return true;
	}
	
	/**
	 * Appends the specified elements to the index of the list.
	 * This function may delegate to more appropiate function if nessesary
	 * @param index the index where to append the elements to
	 * @param c the elements to append to the list
	 * @throws IndexOutOfBoundsException if index is outside of the lists range
	 * @deprecated if type is primitive
	 */
	@Override
	public boolean addAll(int index, COLLECTION KEY_GENERIC_TYPE c) {
		if(c instanceof LIST) return addAll(index, (LIST KEY_GENERIC_TYPE)c);
		int add = c.size();
		if(add <= 0) return false;
		grow(size + add);
		if(index != size) System.arraycopy(data, index, data, index+add, size - index);
		size+=add;
		ITERATOR KEY_GENERIC_TYPE iter = c.iterator();
		while(add-- != 0) data[index++] = iter.NEXT();
		return true;
	}
	
	/**
	 * Appends the specified elements to the index of the list.
	 * @param index the index where to append the elements to
	 * @param c the elements to append to the list
	 * @throws IndexOutOfBoundsException if index is outside of the lists range
	 * @deprecated if type is primitive
	 */
	@Override
	public boolean addAll(int index, LIST KEY_GENERIC_TYPE c) {
		int add = c.size();
		if(add <= 0) return false;
		checkAddRange(index);
		grow(size + add);
		if(index != size) System.arraycopy(data, index, data, index+add, size - index);
		size+=add;
		c.getElements(0, data, index, c.size());
		return true;
	}
	
	/**
	 * Appends the specified array elements to the index of the list.
	 * @param from the index where to append the elements to
	 * @param a the elements to append to the list
	 * @param offset where to start ino the array
	 * @param length the amount of elements to insert
	 * @throws IndexOutOfBoundsException if index is outside of the lists range
	 * @deprecated if type is primitive
	 */
	@Override
	public void addElements(int from, KEY_TYPE[] a, int offset, int length) {
		if(length <= 0) return;
		checkAddRange(from);
		grow(size + length);
		if(from != size) System.arraycopy(data, from, data, from+length, size - length);
		size+=length;
		System.arraycopy(a, offset, data, from, length);
	}
	
	/**
	 * A function to fast fetch elements from the list
	 * @param from index where the list should be fetching elements from
	 * @param a the array where the values should be inserted to
	 * @param offset the startIndex of where the array should be written to
	 * @param length the number of elements the values should be fetched from
	 * @return the inputArray
	 * @throws NullPointerException if the array is null
	 * @throws IndexOutOfBoundsException if from is outside of the lists range
	 * @throws IllegalStateException if offset or length are smaller then 0 or exceed the array length
	 */
	@Override
	public KEY_TYPE[] getElements(int from, KEY_TYPE[] a, int offset, int length) {
		SanityChecks.checkArrayCapacity(size, offset, length);
		System.arraycopy(data, from, a, offset, length);
		return a;
	}
	
	/**
	 * a function to fast remove elements from the list.
	 * @param from the start index of where the elements should be removed from (inclusive)
	 * @param to the end index of where the elements should be removed to (exclusive)
	 */
	@Override
	public void removeElements(int from, int to) {
		checkRange(from);
		checkAddRange(to);
		int length = to - from;
		if(length <= 0) return;
		if(to != size) System.arraycopy(data, to, data, from, size - to);
#if TYPE_OBJECT
		for(int i = 0;i<length;i++)
			data[i+to] = null;
#endif
		size -= length;
	}
	
#if TYPE_OBJECT
	/**
	 * A function to fast extract elements out of the list, this removes the elements that were fetched.
	 * @param from the start index of where the elements should be fetched from (inclusive)
	 * @param to the end index of where the elements should be fetched to (exclusive)
	 * @param type the type of the OutputArray
	 * @return a array of the elements that were fetched
	 */
	@Override
	public <K> K[] extractElements(int from, int to, Class<K> type) {
		checkRange(from);
		checkAddRange(to);
		int length = to - from;
		K[] a = ARRAYS.newArray(type, length);
		if(length <= 0) return a;
		System.arraycopy(data, from, a, 0, length);
		if(to != size) System.arraycopy(data, to, data, from, size - to);
		for(int i = 0;i<length;i++)
			data[i+to] = null;
		size -= length;		
		return a;
	}
	
#else
	/**
	 * A function to fast extract elements out of the list, this removes the elements that were fetched.
	 * @param from the start index of where the elements should be fetched from (inclusive)
	 * @param to the end index of where the elements should be fetched to (exclusive)
	 * @return a array of the elements that were fetched
	 */
	@Override
	public KEY_TYPE[] extractElements(int from, int to) {
		int length = to - from;
		if(length <= 0) return ARRAYS.EMPTY_ARRAY;
		KEY_TYPE[] a = new KEY_TYPE[length];
		System.arraycopy(data, from, a, 0, length);
		if(to != size) System.arraycopy(data, to, data, from, size - to);
		size -= length;		
		return a;
	}
	
#endif
	
	/**
	 * A function to find if the Element is present in this list.
	 * @param o the element that is searched for
	 * @return if the element was found.
	 * @deprecated if type-specific but still supported because of special edgecase Object-Comparason features
	 */
	@Override
	@Primitive
	public boolean contains(Object o) {
		return indexOf(o) != -1;
	}
	
	/**
	 * A function to find the index of a given element
	 * @param o the element that is searched for
	 * @return the index of the element if found. (if not found then -1)
	 * @deprecated if type-specific but still supported because of special edgecase Object-Comparason features
	 */
	@Override
	@Primitive
	public int indexOf(Object o) {
#if TYPE_OBJECT
		if(o == null) {
			for(int i = 0;i<size;i++)
				if(data[i] == null) return i;
			return -1;
		}
#else
		if(o == null) return -1;
#endif
		for(int i = 0;i<size;i++) {
			if(EQUALS_KEY_TYPE(data[i], o)) return i;
		}
		return -1;
	}
	
	/**
	 * A function to find the last index of a given element
	 * @param o the element that is searched for
	 * @return the last index of the element if found. (if not found then -1)
	 * @deprecated if type-specific but still supported because of special edgecase Object-Comparason features
	 */
	@Override
	@Primitive
	public int lastIndexOf(Object o) {
#if TYPE_OBJECT
		if(o == null) {
			for(int i = size - 1;i>=0;i--)
				if(data[i] == null) return i;
			return -1;
		}
#else
		if(o == null) return -1;
#endif
		for(int i = size - 1;i>=0;i--) {
			if(EQUALS_KEY_TYPE(data[i], o)) return i;
		}
		return -1;
	}
	
#if TYPE_OBJECT
	/**
	 * Sorts the elements specified by the Natural order either by using the Comparator or the elements
	 * @param c the sorter of the elements, can be null
	 * @see List#sort(Comparator)
	 * @see ARRAYS#stableSort(KEY_TYPE[], Comparator)
	 */
	@Override
	public void sort(Comparator<? super CLASS_TYPE> c) {
		if(c != null) ARRAYS.stableSort(data, size, c);
		else ARRAYS.stableSort((Comparable[])data, size);
	}
	
	/**
	 * Sorts the elements specified by the Natural order either by using the Comparator or the elements using a unstable sort
	 * @param c the sorter of the elements, can be null
	 * @see List#sort(Comparator)
	 * @see ARRAYS#unstableSort(KEY_TYPE[], Comparator)
	 */
	@Override
	public void unstableSort(Comparator<? super CLASS_TYPE> c) {
		if(c != null) ARRAYS.unstableSort(data, size, c);
		else ARRAYS.unstableSort((Comparable[])data, size);
	}
	
#else
	/**
	 * A Type Specific implementation of the Collection#contains function.
	 * @param e the element that is searched for.
	 * @return if the element was found
	 */
	@Override
	public boolean contains(KEY_TYPE e) {
		return indexOf(e) != -1;
	}
	
	/**
	 * A Type-Specific function to find the index of a given element
	 * @param e the element that is searched for
	 * @return the index of the element if found. (if not found then -1)
	 */
	@Override
	public int indexOf(KEY_TYPE e) {
		for(int i = 0;i<size;i++) {
			if(KEY_EQUALS(data[i], e)) return i;
		}
		return -1;
	}
	
	/**
	 * A Type-Specific function to find the last index of a given element
	 * @param e the element that is searched for
	 * @return the last index of the element if found. (if not found then -1)
	 */
	@Override
	public int lastIndexOf(KEY_TYPE e) {
		for(int i = size - 1;i>=0;i--) {
			if(KEY_EQUALS(data[i], e)) return i;
		}
		return -1;
	}
	
	/**
	 * Sorts the elements specified by the Natural order either by using the Comparator or the elements
	 * @param c the sorter of the elements, can be null
	 * @see List#sort(Comparator)
	 * @see ARRAYS#stableSort(KEY_TYPE[], COMPARATOR)
	 */
	@Override
	public void sort(COMPARATOR c) {
		if(c != null) ARRAYS.stableSort(data, size, c);
		else ARRAYS.stableSort(data, size);
	}
	
	/**
	 * Sorts the elements specified by the Natural order either by using the Comparator or the elements using a unstable sort
	 * @param c the sorter of the elements, can be null
	 * @see List#sort(Comparator)
	 * @see ARRAYS#unstableSort(KEY_TYPE[], COMPARATOR)
	 */
	@Override
	public void unstableSort(COMPARATOR c) {
		if(c != null) ARRAYS.unstableSort(data, size, c);
		else ARRAYS.unstableSort(data, size);		
	}
	
#endif
	/**
	 * A Type-Specific get function to reduce (un)boxing
	 * @param index the index of the element to fetch
	 * @return the value of the requested index
	 * @throws IndexOutOfBoundsException if the index is out of range
	 */
	@Override
	public KEY_TYPE GET_KEY(int index) {
		checkRange(index);
		return data[index];
	}
	
	/**
	 * Provides the Selected Object from the stack.
	 * Top to bottom
	 * @param index of the element that should be provided
	 * @return the element that was requested
	 * @throws ArrayIndexOutOfBoundsException if the index is out of bounds
	 * @see Stack#peek(int)
	 */
	@Override
	public KEY_TYPE PEEK(int index) {
		checkRange((size() - 1) - index);
		return data[(size() - 1) - index];
	}
	
	/**
	 * Provides the Underlying Array in the Implementation
	 * @return underlying Array
	 * @throws ClassCastException if the return type does not match the underlying array. (Only for Object Implementations)
	 */
	@Override
	public KEY_TYPE[] elements() {
		return data;
	}
	
	/**
	 * A Type Specific foreach function that reduces (un)boxing
	 * 
     * @implSpec
     * <p>The default implementation behaves as if:
     * <pre>{@code
     *     for(int i = 0;i<size;i++)
     *     		action.accept(data[i]);
     * }</pre>
     *
     * @param action The action to be performed for each element
     * @throws java.util.NullPointerException if the specified action is null
     * @see Iterable#forEach(Consumer)
     */
	@Override
	public void forEach(CONSUMER KEY_SUPER_GENERIC_TYPE action) {
		Objects.requireNonNull(action);
		for(int i = 0;i<size;i++)
			action.accept(data[i]);
	}
	
	/**
	 * A Type-Specific set function to reduce (un)boxing
	 * @param index the index of the element to set
	 * @param e the value that should be set
	 * @return the previous element
	 * @throws IndexOutOfBoundsException if the index is out of range
	 */
	@Override
	public KEY_TYPE set(int index, KEY_TYPE e) {
		checkRange(index);
		KEY_TYPE old = data[index];
		data[index] = e;
		return old;
	}
	
	/**
	 * A function to replace all values in the list
	 * @param o the action to replace the values
	 * @throws NullPointerException if o is null
	 */
	@Override
	@Primitive
	public void replaceAll(UnaryOperator<CLASS_TYPE> o) {
#if PRIMITIVES
		Objects.requireNonNull(o);
#if TYPE_BYTE || TYPE_SHORT || TYPE_CHAR || TYPE_FLOAT
		REPLACE(T -> OBJ_TO_KEY(o.apply(KEY_TO_OBJ(SanityChecks.SANITY_CAST(T)))));
#else
		REPLACE(T -> OBJ_TO_KEY(o.apply(KEY_TO_OBJ(T))));
#endif
#else
		Objects.requireNonNull(o);
		for(int i = 0;i<size;i++)
			data[i] = OBJ_TO_KEY(o.apply(KEY_TO_OBJ(data[i])));
#endif
	}
	
#if PRIMITIVES
	/**
	 * A Type-Specific replace function to reduce (un)boxing
	 * @param o the action to replace the values
	 * @throws NullPointerException if o is null
	 */
	@Override
	public void REPLACE(JAVA_UNARY_OPERATOR o) {
		for(int i = 0;i<size;i++)
#if TYPE_BYTE || TYPE_SHORT || TYPE_CHAR || TYPE_FLOAT
			data[i] = SanityChecks.SANITY_CAST(o.APPLY_CAST(data[i]));
#else
	data[i] = o.APPLY(data[i]);
#endif
	}
	
#endif
	/**
	 * A Type-Specific remove function to reduce (un)boxing
	 * @param index the index of the element to fetch
	 * @return the value of the requested index
	 * @throws IndexOutOfBoundsException if the index is out of range
	 */
	@Override
	public KEY_TYPE REMOVE(int index) {
		checkRange(index);
		KEY_TYPE old = data[index];
		size--;
		if(index != size) System.arraycopy(data, index+1, data, index, size - index);
#if TYPE_OBJECT
		data[size] = null;
#endif
		return old;
	}
	
#if !TYPE_OBJECT
	/**
	 * A Type-Specific implementation of remove. This implementation iterates over the elements until it finds the element that is searched for or it runs out of elements.
	 * It stops after finding the first element
	 * @param e the element that is searched for
	 * @return true if the element was found and removed.
	 */
	@Override
	public boolean REMOVE_KEY(KEY_TYPE type) {
		int index = indexOf(type);
		if(index == -1) return false;
		REMOVE(index);
		return true;
	}
	
#endif
	/**
	 * A Type-Specific pop function to reduce (un)boxing
	 * @param index the index of the element to fetch
	 * @return the value of the requested index
	 * @throws IndexOutOfBoundsException if the index is out of range
	 */
	@Override
	public KEY_TYPE POP() {
		return REMOVE(size() - 1);
	}
	
	/**
	 * A function to remove all elements that were provided in the other collection
	 * This function might delegate to a more appropiate function if nessesary
	 * @param c the elements that should be removed
	 * @return true if the collection was modified
	 * @throws NullPointerException if the collection is null
	 * @deprecated if the collection is type-specific
	 */
	@Override
	@Primitive
	public boolean removeAll(Collection<?> c) {
		if(c.isEmpty()) return false;
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(!c.contains(KEY_TO_OBJ(data[i]))) data[j++] = data[i];
			else modified = true;
		}
#if TYPE_OBJECT
		Arrays.fill(data, j, size, null);
#endif
		size = j;
		return modified;
	}
	
	/**
	 * A function to retain all elements that were provided in the other collection
	 * This function might delegate to a more appropiate function if nessesary
	 * @param c the elements that should be kept. If empty, ARRAY_LIST#clear is called.
	 * @return true if the collection was modified
	 * @throws NullPointerException if the collection is null
	 * @deprecated if the collection is type-specific
	 */
	@Override
	@Primitive
	public boolean retainAll(Collection<?> c) {
		if(c.isEmpty()) {
			boolean modifed = size > 0;
			clear();
			return modifed;
		}
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(c.contains(KEY_TO_OBJ(data[i]))) data[j++] = data[i];
			else modified = true;
		}
#if TYPE_OBJECT
		Arrays.fill(data, j, size, null);
#endif
		size = j;
		return modified;
	}
	
	/**
	 * A optimized List#removeIf(Predicate) that more quickly removes elements from the list then the ArrayList implementation
	 * @param filter the filter to remove elements
	 * @return true if the list was modified
	 * @deprecated if Type-Specific, use #remIf instead
	 */
	@Override
	@Primitive
	public boolean removeIf(Predicate<? super CLASS_TYPE> filter) {
		Objects.requireNonNull(filter);
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(!filter.test(KEY_TO_OBJ(data[i]))) data[j++] = data[i];
			else modified = true;
		}
#if TYPE_OBJECT
		Arrays.fill(data, j, size, null);
#endif
		size = j;
		return modified;
	}
	
	/**
	 * A function to remove all elements that were provided in the other collection
	 * @param c the elements that should be removed
	 * @return true if the collection was modified
	 * @throws NullPointerException if the collection is null
	 */
	@Override
	public boolean removeAll(COLLECTION KEY_GENERIC_TYPE c) {
		if(c.isEmpty()) return false;
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(!c.contains(data[i])) data[j++] = data[i];
			else modified = true;
		}
#if TYPE_OBJECT
		Arrays.fill(data, j, size, null);
#endif		
		size = j;
		return modified;
	}
	
	/**
	 * A function to retain all elements that were provided in the other collection
	 * This function might delegate to a more appropiate function if nessesary
	 * @param c the elements that should be kept. If empty, ARRAY_LIST#clear is called.
	 * @return true if the collection was modified
	 * @throws NullPointerException if the collection is null
	 */
	@Override
	public boolean retainAll(COLLECTION KEY_GENERIC_TYPE c) {
		if(c.isEmpty()) {
			boolean modifed = size > 0;
			clear();
			return modifed;
		}
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(c.contains(data[i])) data[j++] = data[i];
			else modified = true;
		}
#if TYPE_OBJECT
		Arrays.fill(data, j, size, null);
#endif
		size = j;
		return modified;
	}
	
#if PRIMITIVES
	/**
	 * A optimized List#removeIf(Predicate) that more quickly removes elements from the list then the ArrayList implementation
	 * @param filter the filter to remove elements
	 * @return true if the list was modified
	 */
	@Override
	public boolean remIf(JAVA_PREDICATE filter) {
		Objects.requireNonNull(filter);
		boolean modified = false;
		int j = 0;
		for(int i = 0;i<size;i++) {
			if(!filter.test(data[i])) data[j++] = data[i];
			else modified = true;
		}
		size = j;
		return modified;
	}
	
#endif
	/**
	 * A toArray implementation that ensures the Array itself is a Object.
	 * @return a Array of the elements in the list
	 */
	@Override
	@Primitive
	public Object[] toArray() {
		Object[] obj = new Object[size];
		for(int i = 0;i<size;i++)
			obj[i] = KEY_TO_OBJ(data[i]);
		return obj;
	}
	
	/**
	 * A toArray implementation that ensures the Array itself is a Object.
	 * @param a original array. If null a Object array with the right size is created. If to small the Array of the same type is created with the right size
	 * @return a Array of the elements in the list
	 */
	@Override
	@Primitive
	public <E> E[] toArray(E[] a) {
		if(a == null) a = (E[])new Object[size];
		else if(a.length < size) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size);
		for(int i = 0;i<size;i++)
			a[i] = (E)KEY_TO_OBJ(data[i]);
		return a;
	}
	
#if !TYPE_OBJECT
	@Override
	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
		if(a.length < size) a = new KEY_TYPE[size];
		System.arraycopy(data, 0, a, 0, size);
		return a;
	}
	
#endif
	/**
	 * A function to return the size of the list
	 * @return the size of elements in the list
	 */
	@Override
	public int size() {
		return size;
	}
	
	/**
	 * A function to ensure the elements are within the requested size.
	 * If smaller then the stored elements they get removed as needed.
	 * If bigger it is ensured that enough room is provided depending on the implementation
	 * @param size the requested amount of elements/room for elements
	 */
	@Override
	public void size(int size) {
		if(size > data.length)
			data = Arrays.copyOf(data, size);
		else if(size < size() && size >= 0)
			Arrays.fill(data, size, size(), EMPTY_KEY_VALUE);
		this.size = size;
	}
	
	/**
	 * A function to clear all elements in the list.
	 */
	@Override
	public void clear() {
#if TYPE_OBJECT
		for(int i = 0;i<size;data[i] = null,i++);
#endif
		size = 0;
	}
	
	/**
	 * Trims the original collection down to the size of the current elements or the requested size depending which is bigger
	 * @param size the requested trim size.
	 */
	@Override
	public boolean trim(int size) {
		if(size > size() || size() == data.length) return false;
		int value = Math.max(size, size());
		data = value == 0 ? EMPTY_KEY_ARRAY : Arrays.copyOf(data, value);
		return true;
	}
	
	/**
	 * Increases the capacity of this implementation instance, if necessary,
	 * to ensure that it can hold at least the number of elements specified by
	 * the minimum capacity argument.
	 *
	 * @param size the desired minimum capacity
	 */
	@Override
	public void ensureCapacity(int size) {
		grow(size);
	}
	
	protected void grow(int capacity) {
		if(capacity < data.length) return;
		data = Arrays.copyOf(data, data == ARRAYS.EMPTY_ARRAY ? DEFAULT_ARRAY_SIZE : (int)Math.max(Math.min((long)data.length + (data.length >> 1), SanityChecks.MAX_ARRAY_SIZE), capacity));		
	}
	
	protected void checkRange(int index) {
		if (index < 0 || index >= size)
			throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
	}
	
	protected void checkAddRange(int index) {
		if (index < 0 || index > size)
			throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size);
	}
}