Source code
package android.support.v7.widget;
import java.util.ArrayList;
class PositionMap<E> implements Cloneable {
private static final Object DELETED = new Object();
private boolean mGarbage;
private int[] mKeys;
private int mSize;
private Object[] mValues;
static class ContainerHelpers {
static final boolean[] EMPTY_BOOLEANS = new boolean[0];
static final int[] EMPTY_INTS = new int[0];
static final long[] EMPTY_LONGS = new long[0];
static final Object[] EMPTY_OBJECTS = new Object[0];
ContainerHelpers() {
}
static int binarySearch(int[] array, int size, int value) {
int lo = 0;
int hi = size - 1;
while (lo <= hi) {
int i = (lo + hi) >>> 1;
int midVal = array[i];
if (midVal < value) {
lo = i + 1;
} else if (midVal <= value) {
return i;
} else {
hi = i - 1;
}
}
return lo ^ -1;
}
}
public PositionMap() {
this(10);
}
public PositionMap(int initialCapacity) {
this.mGarbage = false;
if (initialCapacity == 0) {
this.mKeys = ContainerHelpers.EMPTY_INTS;
this.mValues = ContainerHelpers.EMPTY_OBJECTS;
} else {
initialCapacity = idealIntArraySize(initialCapacity);
this.mKeys = new int[initialCapacity];
this.mValues = new Object[initialCapacity];
}
this.mSize = 0;
}
public PositionMap<E> clone() {
PositionMap<E> clone = null;
try {
clone = (PositionMap) super.clone();
clone.mKeys = (int[]) this.mKeys.clone();
clone.mValues = (Object[]) this.mValues.clone();
return clone;
} catch (CloneNotSupportedException e) {
return clone;
}
}
public E get(int key) {
return get(key, null);
}
public E get(int key, E valueIfKeyNotFound) {
int i = ContainerHelpers.binarySearch(this.mKeys, this.mSize, key);
return (i < 0 || this.mValues[i] == DELETED) ? valueIfKeyNotFound : this.mValues[i];
}
public void delete(int key) {
int i = ContainerHelpers.binarySearch(this.mKeys, this.mSize, key);
if (i >= 0 && this.mValues[i] != DELETED) {
this.mValues[i] = DELETED;
this.mGarbage = true;
}
}
public void remove(int key) {
delete(key);
}
public void removeAt(int index) {
if (this.mValues[index] != DELETED) {
this.mValues[index] = DELETED;
this.mGarbage = true;
}
}
public void removeAtRange(int index, int size) {
int end = Math.min(this.mSize, index + size);
for (int i = index; i < end; i++) {
removeAt(i);
}
}
public void insertKeyRange(int keyStart, int count) {
}
public void removeKeyRange(ArrayList<E> arrayList, int keyStart, int count) {
}
private void gc() {
int n = this.mSize;
int o = 0;
int[] keys = this.mKeys;
Object[] values = this.mValues;
for (int i = 0; i < n; i++) {
Object val = values[i];
if (val != DELETED) {
if (i != o) {
keys[o] = keys[i];
values[o] = val;
values[i] = null;
}
o++;
}
}
this.mGarbage = false;
this.mSize = o;
}
public void put(int key, E value) {
int i = ContainerHelpers.binarySearch(this.mKeys, this.mSize, key);
if (i >= 0) {
this.mValues[i] = value;
return;
}
i ^= -1;
if (i >= this.mSize || this.mValues[i] != DELETED) {
if (this.mGarbage && this.mSize >= this.mKeys.length) {
gc();
i = ContainerHelpers.binarySearch(this.mKeys, this.mSize, key) ^ -1;
}
if (this.mSize >= this.mKeys.length) {
int n = idealIntArraySize(this.mSize + 1);
int[] nkeys = new int[n];
Object[] nvalues = new Object[n];
System.arraycopy(this.mKeys, 0, nkeys, 0, this.mKeys.length);
System.arraycopy(this.mValues, 0, nvalues, 0, this.mValues.length);
this.mKeys = nkeys;
this.mValues = nvalues;
}
if (this.mSize - i != 0) {
System.arraycopy(this.mKeys, i, this.mKeys, i + 1, this.mSize - i);
System.arraycopy(this.mValues, i, this.mValues, i + 1, this.mSize - i);
}
this.mKeys[i] = key;
this.mValues[i] = value;
this.mSize++;
return;
}
this.mKeys[i] = key;
this.mValues[i] = value;
}
public int size() {
if (this.mGarbage) {
gc();
}
return this.mSize;
}
public int keyAt(int index) {
if (this.mGarbage) {
gc();
}
return this.mKeys[index];
}
public E valueAt(int index) {
if (this.mGarbage) {
gc();
}
return this.mValues[index];
}
public void setValueAt(int index, E value) {
if (this.mGarbage) {
gc();
}
this.mValues[index] = value;
}
public int indexOfKey(int key) {
if (this.mGarbage) {
gc();
}
return ContainerHelpers.binarySearch(this.mKeys, this.mSize, key);
}
public int indexOfValue(E value) {
if (this.mGarbage) {
gc();
}
for (int i = 0; i < this.mSize; i++) {
if (this.mValues[i] == value) {
return i;
}
}
return -1;
}
public void clear() {
int n = this.mSize;
Object[] values = this.mValues;
for (int i = 0; i < n; i++) {
values[i] = null;
}
this.mSize = 0;
this.mGarbage = false;
}
public void append(int key, E value) {
if (this.mSize == 0 || key > this.mKeys[this.mSize - 1]) {
if (this.mGarbage && this.mSize >= this.mKeys.length) {
gc();
}
int pos = this.mSize;
if (pos >= this.mKeys.length) {
int n = idealIntArraySize(pos + 1);
int[] nkeys = new int[n];
Object[] nvalues = new Object[n];
System.arraycopy(this.mKeys, 0, nkeys, 0, this.mKeys.length);
System.arraycopy(this.mValues, 0, nvalues, 0, this.mValues.length);
this.mKeys = nkeys;
this.mValues = nvalues;
}
this.mKeys[pos] = key;
this.mValues[pos] = value;
this.mSize = pos + 1;
return;
}
put(key, value);
}
public String toString() {
if (size() <= 0) {
return "{}";
}
StringBuilder buffer = new StringBuilder(this.mSize * 28);
buffer.append('{');
for (int i = 0; i < this.mSize; i++) {
if (i > 0) {
buffer.append(", ");
}
buffer.append(keyAt(i));
buffer.append('=');
PositionMap value = valueAt(i);
if (value != this) {
buffer.append(value);
} else {
buffer.append("(this Map)");
}
}
buffer.append('}');
return buffer.toString();
}
static int idealByteArraySize(int need) {
for (int i = 4; i < 32; i++) {
if (need <= (1 << i) - 12) {
return (1 << i) - 12;
}
}
return need;
}
static int idealBooleanArraySize(int need) {
return idealByteArraySize(need);
}
static int idealShortArraySize(int need) {
return idealByteArraySize(need * 2) / 2;
}
static int idealCharArraySize(int need) {
return idealByteArraySize(need * 2) / 2;
}
static int idealIntArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
static int idealFloatArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
static int idealObjectArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
static int idealLongArraySize(int need) {
return idealByteArraySize(need * 8) / 8;
}
}