/*
	* Copyright (C) 2007-2019 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.objects;
import java.util.Map;
import java.util.NoSuchElementException;
import it.unimi.dsi.fastutil.objects.AbstractObjectSet;
import it.unimi.dsi.fastutil.objects.ObjectIterator;
import it.unimi.dsi.fastutil.chars.CharCollection;
import it.unimi.dsi.fastutil.chars.AbstractCharCollection;
import it.unimi.dsi.fastutil.chars.CharArrays;
A simple, brute-force implementation of a map based on two parallel backing
arrays.

The main purpose of this implementation is that of wrapping cleanly the
brute-force approach to the storage of a very small number of pairs: just put
them into two parallel arrays and scan linearly to find an item.
/**
 * A simple, brute-force implementation of a map based on two parallel backing
 * arrays.
 *
 * <p>
 * The main purpose of this implementation is that of wrapping cleanly the
 * brute-force approach to the storage of a very small number of pairs: just put
 * them into two parallel arrays and scan linearly to find an item.
 */
public class Object2CharArrayMap<K> extends AbstractObject2CharMap<K> implements java.io.Serializable, Cloneable {
	private static final long serialVersionUID = 1L;
	
The keys (valid up to Object2CharArrayMap<K>.size, excluded). /** The keys (valid up to {@link #size}, excluded). */
	private transient Object[] key;
	
The values (parallel to Object2CharArrayMap<K>.key). /** The values (parallel to {@link #key}). */
	private transient char[] value;
	
The number of valid entries in Object2CharArrayMap<K>.key and Object2CharArrayMap<K>.value. /** The number of valid entries in {@link #key} and {@link #value}. */
	private int size;
	
Creates a new empty array map with given key and value backing arrays. The
resulting map will have as many entries as the given arrays.
 It is responsibility of the caller that the elements of key are distinct. 
Params:
key – 
           the key array.
value – 
           the value array (it must have the same length as key)./**
	 * Creates a new empty array map with given key and value backing arrays. The
	 * resulting map will have as many entries as the given arrays.
	 *
	 * <p>
	 * It is responsibility of the caller that the elements of {@code key} are
	 * distinct.
	 *
	 * @param key
	 *            the key array.
	 * @param value
	 *            the value array (it <em>must</em> have the same length as
	 *            {@code key}).
	 */
	public Object2CharArrayMap(final Object[] key, final char[] value) {
		this.key = key;
		this.value = value;
		size = key.length;
		if (key.length != value.length)
			throw new IllegalArgumentException(
					"Keys and values have different lengths (" + key.length + ", " + value.length + ")");
	}
	
Creates a new empty array map.
/**
	 * Creates a new empty array map.
	 */
	public Object2CharArrayMap() {
		this.key = ObjectArrays.EMPTY_ARRAY;
		this.value = CharArrays.EMPTY_ARRAY;
	}
	
Creates a new empty array map of given capacity.
Params:
capacity – 
           the initial capacity./**
	 * Creates a new empty array map of given capacity.
	 *
	 * @param capacity
	 *            the initial capacity.
	 */
	public Object2CharArrayMap(final int capacity) {
		this.key = new Object[capacity];
		this.value = new char[capacity];
	}
	
Creates a new empty array map copying the entries of a given map.
Params:
m – 
           a map./**
	 * Creates a new empty array map copying the entries of a given map.
	 *
	 * @param m
	 *            a map.
	 */
	public Object2CharArrayMap(final Object2CharMap<K> m) {
		this(m.size());
		putAll(m);
	}
	
Creates a new empty array map copying the entries of a given map.
Params:
m – 
           a map./**
	 * Creates a new empty array map copying the entries of a given map.
	 *
	 * @param m
	 *            a map.
	 */
	public Object2CharArrayMap(final Map<? extends K, ? extends Character> m) {
		this(m.size());
		putAll(m);
	}
	
Creates a new array map with given key and value backing arrays, using the
given number of elements.
 It is responsibility of the caller that the first size elements of key are distinct. 
Params:
key – 
           the key array.
value – 
           the value array (it must have the same length as key).
size –  the number of valid elements in key and value./**
	 * Creates a new array map with given key and value backing arrays, using the
	 * given number of elements.
	 *
	 * <p>
	 * It is responsibility of the caller that the first {@code size} elements of
	 * {@code key} are distinct.
	 *
	 * @param key
	 *            the key array.
	 * @param value
	 *            the value array (it <em>must</em> have the same length as
	 *            {@code key}).
	 * @param size
	 *            the number of valid elements in {@code key} and {@code value}.
	 */
	public Object2CharArrayMap(final Object[] key, final char[] value, final int size) {
		this.key = key;
		this.value = value;
		this.size = size;
		if (key.length != value.length)
			throw new IllegalArgumentException(
					"Keys and values have different lengths (" + key.length + ", " + value.length + ")");
		if (size > key.length)
			throw new IllegalArgumentException("The provided size (" + size
					+ ") is larger than or equal to the backing-arrays size (" + key.length + ")");
	}
	private final class EntrySet extends AbstractObjectSet<Object2CharMap.Entry<K>> implements FastEntrySet<K> {
		@Override
		public ObjectIterator<Object2CharMap.Entry<K>> iterator() {
			return new ObjectIterator<Object2CharMap.Entry<K>>() {
				int curr = -1, next = 0;
				@Override
				public boolean hasNext() {
					return next < size;
				}
				@Override
				@SuppressWarnings("unchecked")
				public Entry<K> next() {
					if (!hasNext())
						throw new NoSuchElementException();
					return new AbstractObject2CharMap.BasicEntry<>((K) key[curr = next], value[next++]);
				}
				@Override
				public void remove() {
					if (curr == -1)
						throw new IllegalStateException();
					curr = -1;
					final int tail = size-- - next--;
					System.arraycopy(key, next + 1, key, next, tail);
					System.arraycopy(value, next + 1, value, next, tail);
					key[size] = null;
				}
			};
		}
		@Override
		public ObjectIterator<Object2CharMap.Entry<K>> fastIterator() {
			return new ObjectIterator<Object2CharMap.Entry<K>>() {
				int next = 0, curr = -1;
				final BasicEntry<K> entry = new BasicEntry<>();
				@Override
				public boolean hasNext() {
					return next < size;
				}
				@Override
				@SuppressWarnings("unchecked")
				public Entry<K> next() {
					if (!hasNext())
						throw new NoSuchElementException();
					entry.key = (K) key[curr = next];
					entry.value = value[next++];
					return entry;
				}
				@Override
				public void remove() {
					if (curr == -1)
						throw new IllegalStateException();
					curr = -1;
					final int tail = size-- - next--;
					System.arraycopy(key, next + 1, key, next, tail);
					System.arraycopy(value, next + 1, value, next, tail);
					key[size] = null;
				}
			};
		}
		@Override
		public int size() {
			return size;
		}
		@Override
		@SuppressWarnings("unchecked")
		public boolean contains(Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
			if (e.getValue() == null || !(e.getValue() instanceof Character))
				return false;
			final K k = ((K) e.getKey());
			return Object2CharArrayMap.this.containsKey(k)
					&& ((Object2CharArrayMap.this.getChar(k)) == (((Character) (e.getValue())).charValue()));
		}
		@Override
		@SuppressWarnings("unchecked")
		public boolean remove(final Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
			if (e.getValue() == null || !(e.getValue() instanceof Character))
				return false;
			final K k = ((K) e.getKey());
			final char v = ((Character) (e.getValue())).charValue();
			final int oldPos = Object2CharArrayMap.this.findKey(k);
			if (oldPos == -1 || !((v) == (Object2CharArrayMap.this.value[oldPos])))
				return false;
			final int tail = size - oldPos - 1;
			System.arraycopy(Object2CharArrayMap.this.key, oldPos + 1, Object2CharArrayMap.this.key, oldPos, tail);
			System.arraycopy(Object2CharArrayMap.this.value, oldPos + 1, Object2CharArrayMap.this.value, oldPos, tail);
			Object2CharArrayMap.this.size--;
			Object2CharArrayMap.this.key[size] = null;
			return true;
		}
	}
	@Override
	public FastEntrySet<K> object2CharEntrySet() {
		return new EntrySet();
	}
	private int findKey(final Object k) {
		final Object[] key = this.key;
		for (int i = size; i-- != 0;)
			if (java.util.Objects.equals(key[i], k))
				return i;
		return -1;
	}
	@Override

	public char getChar(final Object k) {
		final Object[] key = this.key;
		for (int i = size; i-- != 0;)
			if (java.util.Objects.equals(key[i], k))
				return value[i];
		return defRetValue;
	}
	@Override
	public int size() {
		return size;
	}
	@Override
	public void clear() {
		for (int i = size; i-- != 0;) {
			key[i] = null;
		}
		size = 0;
	}
	@Override
	public boolean containsKey(final Object k) {
		return findKey(k) != -1;
	}
	@Override
	public boolean containsValue(char v) {
		for (int i = size; i-- != 0;)
			if (((value[i]) == (v)))
				return true;
		return false;
	}
	@Override
	public boolean isEmpty() {
		return size == 0;
	}
	@Override

	public char put(K k, char v) {
		final int oldKey = findKey(k);
		if (oldKey != -1) {
			final char oldValue = value[oldKey];
			value[oldKey] = v;
			return oldValue;
		}
		if (size == key.length) {
			final Object[] newKey = new Object[size == 0 ? 2 : size * 2];
			final char[] newValue = new char[size == 0 ? 2 : size * 2];
			for (int i = size; i-- != 0;) {
				newKey[i] = key[i];
				newValue[i] = value[i];
			}
			key = newKey;
			value = newValue;
		}
		key[size] = k;
		value[size] = v;
		size++;
		return defRetValue;
	}
	@Override

	public char removeChar(final Object k) {
		final int oldPos = findKey(k);
		if (oldPos == -1)
			return defRetValue;
		final char oldValue = value[oldPos];
		final int tail = size - oldPos - 1;
		System.arraycopy(key, oldPos + 1, key, oldPos, tail);
		System.arraycopy(value, oldPos + 1, value, oldPos, tail);
		size--;
		key[size] = null;
		return oldValue;
	}
	@Override
	public ObjectSet<K> keySet() {
		return new AbstractObjectSet<K>() {
			@Override
			public boolean contains(final Object k) {
				return findKey(k) != -1;
			}
			@Override
			public boolean remove(final Object k) {
				final int oldPos = findKey(k);
				if (oldPos == -1)
					return false;
				final int tail = size - oldPos - 1;
				System.arraycopy(key, oldPos + 1, key, oldPos, tail);
				System.arraycopy(value, oldPos + 1, value, oldPos, tail);
				size--;
				return true;
			}
			@Override
			public ObjectIterator<K> iterator() {
				return new ObjectIterator<K>() {
					int pos = 0;
					@Override
					public boolean hasNext() {
						return pos < size;
					}
					@Override
					@SuppressWarnings("unchecked")
					public K next() {
						if (!hasNext())
							throw new NoSuchElementException();
						return (K) key[pos++];
					}
					@Override
					public void remove() {
						if (pos == 0)
							throw new IllegalStateException();
						final int tail = size - pos;
						System.arraycopy(key, pos, key, pos - 1, tail);
						System.arraycopy(value, pos, value, pos - 1, tail);
						size--;
					}
				};
			}
			@Override
			public int size() {
				return size;
			}
			@Override
			public void clear() {
				Object2CharArrayMap.this.clear();
			}
		};
	}
	@Override
	public CharCollection values() {
		return new AbstractCharCollection() {
			@Override
			public boolean contains(final char v) {
				return containsValue(v);
			}
			@Override
			public it.unimi.dsi.fastutil.chars.CharIterator iterator() {
				return new it.unimi.dsi.fastutil.chars.CharIterator() {
					int pos = 0;
					@Override
					public boolean hasNext() {
						return pos < size;
					}
					@Override

					public char nextChar() {
						if (!hasNext())
							throw new NoSuchElementException();
						return value[pos++];
					}
					@Override
					public void remove() {
						if (pos == 0)
							throw new IllegalStateException();
						final int tail = size - pos;
						System.arraycopy(key, pos, key, pos - 1, tail);
						System.arraycopy(value, pos, value, pos - 1, tail);
						size--;
					}
				};
			}
			@Override
			public int size() {
				return size;
			}
			@Override
			public void clear() {
				Object2CharArrayMap.this.clear();
			}
		};
	}
	
Returns a deep copy of this map.

This method performs a deep copy of this hash map; the data stored in the
map, however, is not cloned. Note that this makes a difference only for
object keys.
Returns:
a deep copy of this map./**
	 * Returns a deep copy of this map.
	 *
	 * <p>
	 * This method performs a deep copy of this hash map; the data stored in the
	 * map, however, is not cloned. Note that this makes a difference only for
	 * object keys.
	 *
	 * @return a deep copy of this map.
	 */
	@Override
	@SuppressWarnings("unchecked")
	public Object2CharArrayMap<K> clone() {
		Object2CharArrayMap<K> c;
		try {
			c = (Object2CharArrayMap<K>) super.clone();
		} catch (CloneNotSupportedException cantHappen) {
			throw new InternalError();
		}
		c.key = key.clone();
		c.value = value.clone();
		return c;
	}
	private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
		s.defaultWriteObject();
		for (int i = 0; i < size; i++) {
			s.writeObject(key[i]);
			s.writeChar(value[i]);
		}
	}
	private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();
		key = new Object[size];
		value = new char[size];
		for (int i = 0; i < size; i++) {
			key[i] = s.readObject();
			value[i] = s.readChar();
		}
	}
}