code: /*
   * Copyright (C) 2013 The Android Open Source Project
   *
   * 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 com.lody.virtual.helper.collection;
  
  import android.util.Log;
  
  import java.util.Map;
  
  /**
   * Base implementation of {@link ArrayMap} that doesn't include any standard Java
   * container API interoperability.  These features are generally heavier-weight ways
   * to interact with the container, so discouraged, but they can be useful to make it
   * easier to use as a drop-in replacement for HashMap.  If you don't need them, this
   * class can be preferrable since it doesn't bring in any of the implementation of those
   * APIs, allowing that code to be stripped by ProGuard.
   */
  public class SimpleArrayMap<K, V> {
      private static final boolean DEBUG = false;
      private static final String TAG = "ArrayMap";
  
      /**
       * The minimum amount by which the capacity of a ArrayMap will increase.
       * This is tuned to be relatively space-efficient.
       */
      private static final int BASE_SIZE = 4;
  
      /**
       * Maximum number of entries to have in array caches.
       */
      private static final int CACHE_SIZE = 10;
  
      /**
       * Caches of small array objects to avoid spamming garbage.  The cache
       * Object[] variable is a pointer to a linked list of array objects.
       * The first entry in the array is a pointer to the next array in the
       * list; the second entry is a pointer to the int[] hash code array for it.
       */
      static Object[] mBaseCache;
      static int mBaseCacheSize;
      static Object[] mTwiceBaseCache;
      static int mTwiceBaseCacheSize;
  
      int[] mHashes;
      Object[] mArray;
      int mSize;
  
      /**
       * Create a new empty ArrayMap.  The default capacity of an array map is 0, and
       * will grow once items are added to it.
       */
      public SimpleArrayMap() {
          mHashes = ContainerHelpers.EMPTY_INTS;
          mArray = ContainerHelpers.EMPTY_OBJECTS;
          mSize = 0;
      }
  
      /**
       * Create a new ArrayMap with a given initial capacity.
       */
      public SimpleArrayMap(int capacity) {
          if (capacity == 0) {
              mHashes = ContainerHelpers.EMPTY_INTS;
              mArray = ContainerHelpers.EMPTY_OBJECTS;
          } else {
              allocArrays(capacity);
          }
          mSize = 0;
      }
  
      /**
       * Create a new ArrayMap with the mappings from the given ArrayMap.
       */
      public SimpleArrayMap(SimpleArrayMap map) {
          this();
          if (map != null) {
              putAll(map);
          }
      }
  
      private static void freeArrays(final int[] hashes, final Object[] array, final int size) {
          if (hashes.length == (BASE_SIZE*2)) {
              synchronized (ArrayMap.class) {
                  if (mTwiceBaseCacheSize < CACHE_SIZE) {
                      array[0] = mTwiceBaseCache;
                      array[1] = hashes;
                      for (int i=(size<<1)-1; i>=2; i--) {
                          array[i] = null;
                      }
                      mTwiceBaseCache = array;
                      mTwiceBaseCacheSize++;
                      if (DEBUG) Log.d(TAG, "Storing 2x cache " + array
                              + " now have " + mTwiceBaseCacheSize + " entries");
                  }
              }
          } else if (hashes.length == BASE_SIZE) {
              synchronized (ArrayMap.class) {
                  if (mBaseCacheSize < CACHE_SIZE) {
                      array[0] = mBaseCache;
                      array[1] = hashes;
                      for (int i=(size<<1)-1; i>=2; i--) {
                          array[i] = null;
                      }
                      mBaseCache = array;
                      mBaseCacheSize++;
                      if (DEBUG) Log.d(TAG, "Storing 1x cache " + array
                              + " now have " + mBaseCacheSize + " entries");
                  }
              }
          }
      }
  
      int indexOf(Object key, int hash) {
          final int N = mSize;
  
          // Important fast case: if nothing is in here, nothing to look for.
          if (N == 0) {
              return ~0;
          }
  
          int index = ContainerHelpers.binarySearch(mHashes, N, hash);
  
          // If the hash code wasn't found, then we have no entry for this key.
          if (index < 0) {
              return index;
          }
  
          // If the key at the returned index matches, that's what we want.
          if (key.equals(mArray[index<<1])) {
              return index;
          }
  
          // Search for a matching key after the index.
          int end;
          for (end = index + 1; end < N && mHashes[end] == hash; end++) {
              if (key.equals(mArray[end << 1])) return end;
          }
  
          // Search for a matching key before the index.
          for (int i = index - 1; i >= 0 && mHashes[i] == hash; i--) {
              if (key.equals(mArray[i << 1])) return i;
          }
  
          // Key not found -- return negative value indicating where a
          // new entry for this key should go.  We use the end of the
          // hash chain to reduce the number of array entries that will
          // need to be copied when inserting.
          return ~end;
      }
  
      int indexOfNull() {
          final int N = mSize;
  
          // Important fast case: if nothing is in here, nothing to look for.
          if (N == 0) {
              return ~0;
          }
  
          int index = ContainerHelpers.binarySearch(mHashes, N, 0);
  
          // If the hash code wasn't found, then we have no entry for this key.
          if (index < 0) {
              return index;
          }
  
          // If the key at the returned index matches, that's what we want.
          if (null == mArray[index<<1]) {
              return index;
          }
  
          // Search for a matching key after the index.
          int end;
          for (end = index + 1; end < N && mHashes[end] == 0; end++) {
              if (null == mArray[end << 1]) return end;
          }
  
          // Search for a matching key before the index.
          for (int i = index - 1; i >= 0 && mHashes[i] == 0; i--) {
              if (null == mArray[i << 1]) return i;
          }
  
          // Key not found -- return negative value indicating where a
          // new entry for this key should go.  We use the end of the
          // hash chain to reduce the number of array entries that will
          // need to be copied when inserting.
          return ~end;
      }
  
      private void allocArrays(final int size) {
          if (size == (BASE_SIZE*2)) {
              synchronized (ArrayMap.class) {
                  if (mTwiceBaseCache != null) {
                      final Object[] array = mTwiceBaseCache;
                      mArray = array;
                      mTwiceBaseCache = (Object[])array[0];
                      mHashes = (int[])array[1];
                      array[0] = array[1] = null;
                      mTwiceBaseCacheSize--;
                      if (DEBUG) Log.d(TAG, "Retrieving 2x cache " + mHashes
                              + " now have " + mTwiceBaseCacheSize + " entries");
                      return;
                  }
              }
          } else if (size == BASE_SIZE) {
              synchronized (ArrayMap.class) {
                  if (mBaseCache != null) {
                      final Object[] array = mBaseCache;
                      mArray = array;
                      mBaseCache = (Object[])array[0];
                      mHashes = (int[])array[1];
                      array[0] = array[1] = null;
                      mBaseCacheSize--;
                      if (DEBUG) Log.d(TAG, "Retrieving 1x cache " + mHashes
                              + " now have " + mBaseCacheSize + " entries");
                      return;
                  }
              }
          }
  
          mHashes = new int[size];
          mArray = new Object[size<<1];
      }
  
      /**
       * Make the array map empty.  All storage is released.
       */
      public void clear() {
          if (mSize != 0) {
              freeArrays(mHashes, mArray, mSize);
              mHashes = ContainerHelpers.EMPTY_INTS;
              mArray = ContainerHelpers.EMPTY_OBJECTS;
              mSize = 0;
          }
      }
  
      /**
       * Ensure the array map can hold at least <var>minimumCapacity</var>
       * items.
       */
      public void ensureCapacity(int minimumCapacity) {
          if (mHashes.length < minimumCapacity) {
              final int[] ohashes = mHashes;
              final Object[] oarray = mArray;
              allocArrays(minimumCapacity);
              if (mSize > 0) {
                  System.arraycopy(ohashes, 0, mHashes, 0, mSize);
                  System.arraycopy(oarray, 0, mArray, 0, mSize<<1);
              }
              freeArrays(ohashes, oarray, mSize);
          }
      }
  
      /**
       * Check whether a key exists in the array.
       *
       * @param key The key to search for.
       * @return Returns true if the key exists, else false.
       */
      public boolean containsKey(Object key) {
          return indexOfKey(key) >= 0;
      }
  
      /**
       * Returns the index of a key in the set.
       *
       * @param key The key to search for.
       * @return Returns the index of the key if it exists, else a negative integer.
       */
      public int indexOfKey(Object key) {
          return key == null ? indexOfNull() : indexOf(key, key.hashCode());
      }
  
      int indexOfValue(Object value) {
          final int N = mSize*2;
          final Object[] array = mArray;
          if (value == null) {
              for (int i=1; i<N; i+=2) {
                  if (array[i] == null) {
                      return i>>1;
                  }
              }
          } else {
              for (int i=1; i<N; i+=2) {
                  if (value.equals(array[i])) {
                      return i>>1;
                  }
              }
          }
          return -1;
      }
  
      /**
       * Check whether a value exists in the array.  This requires a linear search
       * through the entire array.
       *
       * @param value The value to search for.
       * @return Returns true if the value exists, else false.
       */
      public boolean containsValue(Object value) {
          return indexOfValue(value) >= 0;
      }
  
      /**
       * Retrieve a value from the array.
       * @param key The key of the value to retrieve.
       * @return Returns the value associated with the given key,
       * or null if there is no such key.
       */
      public V get(Object key) {
          final int index = indexOfKey(key);
          return index >= 0 ? (V)mArray[(index<<1)+1] : null;
      }
  
      /**
       * Return the key at the given index in the array.
       * @param index The desired index, must be between 0 and {@link #size()}-1.
       * @return Returns the key stored at the given index.
       */
      public K keyAt(int index) {
          return (K)mArray[index << 1];
      }
  
      /**
       * Return the value at the given index in the array.
       * @param index The desired index, must be between 0 and {@link #size()}-1.
       * @return Returns the value stored at the given index.
       */
      public V valueAt(int index) {
          return (V)mArray[(index << 1) + 1];
      }
  
      /**
       * Set the value at a given index in the array.
       * @param index The desired index, must be between 0 and {@link #size()}-1.
       * @param value The new value to store at this index.
       * @return Returns the previous value at the given index.
       */
      public V setValueAt(int index, V value) {
          index = (index << 1) + 1;
          V old = (V)mArray[index];
          mArray[index] = value;
          return old;
      }
  
      /**
       * Return true if the array map contains no items.
       */
      public boolean isEmpty() {
          return mSize <= 0;
      }
  
      /**
       * Add a new value to the array map.
       * @param key The key under which to store the value.  <b>Must not be null.</b>  If
       * this key already exists in the array, its value will be replaced.
       * @param value The value to store for the given key.
       * @return Returns the old value that was stored for the given key, or null if there
       * was no such key.
       */
      public V put(K key, V value) {
          final int hash;
          int index;
          if (key == null) {
              hash = 0;
              index = indexOfNull();
          } else {
              hash = key.hashCode();
              index = indexOf(key, hash);
          }
          if (index >= 0) {
              index = (index<<1) + 1;
              final V old = (V)mArray[index];
              mArray[index] = value;
              return old;
          }
  
          index = ~index;
          if (mSize >= mHashes.length) {
              final int n = mSize >= (BASE_SIZE*2) ? (mSize+(mSize>>1))
                      : (mSize >= BASE_SIZE ? (BASE_SIZE*2) : BASE_SIZE);
  
              if (DEBUG) Log.d(TAG, "put: grow from " + mHashes.length + " to " + n);
  
              final int[] ohashes = mHashes;
              final Object[] oarray = mArray;
              allocArrays(n);
  
              if (mHashes.length > 0) {
                  if (DEBUG) Log.d(TAG, "put: copy 0-" + mSize + " to 0");
                  System.arraycopy(ohashes, 0, mHashes, 0, ohashes.length);
                  System.arraycopy(oarray, 0, mArray, 0, oarray.length);
              }
  
              freeArrays(ohashes, oarray, mSize);
          }
  
          if (index < mSize) {
              if (DEBUG) Log.d(TAG, "put: move " + index + "-" + (mSize-index)
                      + " to " + (index+1));
              System.arraycopy(mHashes, index, mHashes, index + 1, mSize - index);
              System.arraycopy(mArray, index << 1, mArray, (index + 1) << 1, (mSize - index) << 1);
          }
  
          mHashes[index] = hash;
          mArray[index<<1] = key;
          mArray[(index<<1)+1] = value;
          mSize++;
          return null;
      }
  
      /**
       * Perform a {@link #put(Object, Object)} of all key/value pairs in <var>array</var>
       * @param array The array whose contents are to be retrieved.
       */
      public void putAll(SimpleArrayMap<? extends K, ? extends V> array) {
          final int N = array.mSize;
          ensureCapacity(mSize + N);
          if (mSize == 0) {
              if (N > 0) {
                  System.arraycopy(array.mHashes, 0, mHashes, 0, N);
                  System.arraycopy(array.mArray, 0, mArray, 0, N<<1);
                  mSize = N;
              }
          } else {
              for (int i=0; i<N; i++) {
                  put(array.keyAt(i), array.valueAt(i));
              }
          }
      }
  
      /**
       * Remove an existing key from the array map.
       * @param key The key of the mapping to remove.
       * @return Returns the value that was stored under the key, or null if there
       * was no such key.
       */
      public V remove(Object key) {
          final int index = indexOfKey(key);
          if (index >= 0) {
              return removeAt(index);
          }
  
          return null;
      }
  
      /**
       * Remove the key/value mapping at the given index.
       * @param index The desired index, must be between 0 and {@link #size()}-1.
       * @return Returns the value that was stored at this index.
       */
      public V removeAt(int index) {
          final Object old = mArray[(index << 1) + 1];
          if (mSize <= 1) {
              // Now empty.
              if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to 0");
              freeArrays(mHashes, mArray, mSize);
              mHashes = ContainerHelpers.EMPTY_INTS;
              mArray = ContainerHelpers.EMPTY_OBJECTS;
              mSize = 0;
          } else {
              if (mHashes.length > (BASE_SIZE*2) && mSize < mHashes.length/3) {
                  // Shrunk enough to reduce size of arrays.  We don't allow it to
                  // shrink smaller than (BASE_SIZE*2) to avoid flapping between
                  // that and BASE_SIZE.
                  final int n = mSize > (BASE_SIZE*2) ? (mSize + (mSize>>1)) : (BASE_SIZE*2);
  
                  if (DEBUG) Log.d(TAG, "remove: shrink from " + mHashes.length + " to " + n);
  
                  final int[] ohashes = mHashes;
                  final Object[] oarray = mArray;
                  allocArrays(n);
  
                  mSize--;
                  if (index > 0) {
                      if (DEBUG) Log.d(TAG, "remove: copy from 0-" + index + " to 0");
                      System.arraycopy(ohashes, 0, mHashes, 0, index);
                      System.arraycopy(oarray, 0, mArray, 0, index << 1);
                  }
                  if (index < mSize) {
                      if (DEBUG) Log.d(TAG, "remove: copy from " + (index+1) + "-" + mSize
                              + " to " + index);
                      System.arraycopy(ohashes, index + 1, mHashes, index, mSize - index);
                      System.arraycopy(oarray, (index + 1) << 1, mArray, index << 1,
                              (mSize - index) << 1);
                  }
              } else {
                  mSize--;
                  if (index < mSize) {
                      if (DEBUG) Log.d(TAG, "remove: move " + (index+1) + "-" + mSize
                              + " to " + index);
                      System.arraycopy(mHashes, index + 1, mHashes, index, mSize - index);
                      System.arraycopy(mArray, (index + 1) << 1, mArray, index << 1,
                              (mSize - index) << 1);
                  }
                  mArray[mSize << 1] = null;
                  mArray[(mSize << 1) + 1] = null;
              }
          }
          return (V)old;
      }
  
      /**
       * Return the number of items in this array map.
       */
      public int size() {
          return mSize;
      }
  
      /**
       * {@inheritDoc}
       *
       * <p>This implementation returns false if the object is not a map, or
       * if the maps have different sizes. Otherwise, for each key in this map,
       * values of both maps are compared. If the values for any key are not
       * equal, the method returns false, otherwise it returns true.
       */
      @Override
      public boolean equals(Object object) {
          if (this == object) {
              return true;
          }
          if (object instanceof Map) {
              Map<?, ?> map = (Map<?, ?>) object;
              if (size() != map.size()) {
                  return false;
              }
  
              try {
                  for (int i=0; i<mSize; i++) {
                      K key = keyAt(i);
                      V mine = valueAt(i);
                      Object theirs = map.get(key);
                      if (mine == null) {
                          if (theirs != null || !map.containsKey(key)) {
                              return false;
                          }
                      } else if (!mine.equals(theirs)) {
                          return false;
                      }
                  }
              } catch (NullPointerException ignored) {
                  return false;
              } catch (ClassCastException ignored) {
                  return false;
              }
              return true;
          }
          return false;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public int hashCode() {
          final int[] hashes = mHashes;
          final Object[] array = mArray;
          int result = 0;
          for (int i = 0, v = 1, s = mSize; i < s; i++, v+=2) {
              Object value = array[v];
              result += hashes[i] ^ (value == null ? 0 : value.hashCode());
          }
          return result;
      }
  
      /**
       * {@inheritDoc}
       *
       * <p>This implementation composes a string by iterating over its mappings. If
       * this map contains itself as a key or a value, the string "(this Map)"
       * will appear in its place.
       */
      @Override
      public String toString() {
          if (isEmpty()) {
              return "{}";
          }
  
          StringBuilder buffer = new StringBuilder(mSize * 28);
          buffer.append('{');
          for (int i=0; i<mSize; i++) {
              if (i > 0) {
                  buffer.append(", ");
              }
              Object key = keyAt(i);
              if (key != this) {
                  buffer.append(key);
              } else {
                  buffer.append("(this Map)");
              }
              buffer.append('=');
              Object value = valueAt(i);
              if (value != this) {
                  buffer.append(value);
              } else {
                  buffer.append("(this Map)");
              }
          }
          buffer.append('}');
          return buffer.toString();
      }
  }
  