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// Protocol Buffers - Google's data interchange format
// Copyright 2014 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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package com.google.protobuf.nano;
/**
* A custom version of {@code android.util.SparseArray} with the minimal API
* for storing {@link FieldData} objects.
*
* This class is an internal implementation detail of nano and should not
* be called directly by clients.
*
* Based on {@code android.support.v4.util.SpareArrayCompat}.
*/
public final class FieldArray implements Cloneable {
private static final FieldData DELETED = new FieldData();
private boolean mGarbage = false;
private int[] mFieldNumbers;
private FieldData[] mData;
private int mSize;
/**
* Creates a new FieldArray containing no fields.
*/
FieldArray() {
this(10);
}
/**
* Creates a new FieldArray containing no mappings that will not
* require any additional memory allocation to store the specified
* number of mappings.
*/
FieldArray(int initialCapacity) {
initialCapacity = idealIntArraySize(initialCapacity);
mFieldNumbers = new int[initialCapacity];
mData = new FieldData[initialCapacity];
mSize = 0;
}
/**
* Gets the FieldData mapped from the specified fieldNumber, or null
* if no such mapping has been made.
*/
FieldData get(int fieldNumber) {
int i = binarySearch(fieldNumber);
if (i < 0 || mData[i] == DELETED) {
return null;
} else {
return mData[i];
}
}
/**
* Removes the data from the specified fieldNumber, if there was any.
*/
void remove(int fieldNumber) {
int i = binarySearch(fieldNumber);
if (i >= 0 && mData[i] != DELETED) {
mData[i] = DELETED;
mGarbage = true;
}
}
private void gc() {
int n = mSize;
int o = 0;
int[] keys = mFieldNumbers;
FieldData[] values = mData;
for (int i = 0; i < n; i++) {
FieldData val = values[i];
if (val != DELETED) {
if (i != o) {
keys[o] = keys[i];
values[o] = val;
values[i] = null;
}
o++;
}
}
mGarbage = false;
mSize = o;
}
/**
* Adds a mapping from the specified fieldNumber to the specified data,
* replacing the previous mapping if there was one.
*/
void put(int fieldNumber, FieldData data) {
int i = binarySearch(fieldNumber);
if (i >= 0) {
mData[i] = data;
} else {
i = ~i;
if (i < mSize && mData[i] == DELETED) {
mFieldNumbers[i] = fieldNumber;
mData[i] = data;
return;
}
if (mGarbage && mSize >= mFieldNumbers.length) {
gc();
// Search again because indices may have changed.
i = ~ binarySearch(fieldNumber);
}
if (mSize >= mFieldNumbers.length) {
int n = idealIntArraySize(mSize + 1);
int[] nkeys = new int[n];
FieldData[] nvalues = new FieldData[n];
System.arraycopy(mFieldNumbers, 0, nkeys, 0, mFieldNumbers.length);
System.arraycopy(mData, 0, nvalues, 0, mData.length);
mFieldNumbers = nkeys;
mData = nvalues;
}
if (mSize - i != 0) {
System.arraycopy(mFieldNumbers, i, mFieldNumbers, i + 1, mSize - i);
System.arraycopy(mData, i, mData, i + 1, mSize - i);
}
mFieldNumbers[i] = fieldNumber;
mData[i] = data;
mSize++;
}
}
/**
* Returns the number of key-value mappings that this FieldArray
* currently stores.
*/
int size() {
if (mGarbage) {
gc();
}
return mSize;
}
public boolean isEmpty() {
return size() == 0;
}
/**
* Given an index in the range 0...size()-1, returns
* the value from the indexth key-value mapping that this
* FieldArray stores.
*/
FieldData dataAt(int index) {
if (mGarbage) {
gc();
}
return mData[index];
}
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (!(o instanceof FieldArray)) {
return false;
}
FieldArray other = (FieldArray) o;
if (size() != other.size()) { // size() will call gc() if necessary.
return false;
}
return arrayEquals(mFieldNumbers, other.mFieldNumbers, mSize) &&
arrayEquals(mData, other.mData, mSize);
}
@Override
public int hashCode() {
if (mGarbage) {
gc();
}
int result = 17;
for (int i = 0; i < mSize; i++) {
result = 31 * result + mFieldNumbers[i];
result = 31 * result + mData[i].hashCode();
}
return result;
}
private int idealIntArraySize(int need) {
return idealByteArraySize(need * 4) / 4;
}
private int idealByteArraySize(int need) {
for (int i = 4; i < 32; i++)
if (need <= (1 << i) - 12)
return (1 << i) - 12;
return need;
}
private int binarySearch(int value) {
int lo = 0;
int hi = mSize - 1;
while (lo <= hi) {
int mid = (lo + hi) >>> 1;
int midVal = mFieldNumbers[mid];
if (midVal < value) {
lo = mid + 1;
} else if (midVal > value) {
hi = mid - 1;
} else {
return mid; // value found
}
}
return ~lo; // value not present
}
private boolean arrayEquals(int[] a, int[] b, int size) {
for (int i = 0; i < size; i++) {
if (a[i] != b[i]) {
return false;
}
}
return true;
}
private boolean arrayEquals(FieldData[] a, FieldData[] b, int size) {
for (int i = 0; i < size; i++) {
if (!a[i].equals(b[i])) {
return false;
}
}
return true;
}
@Override
public final FieldArray clone() {
// Trigger GC so we compact and don't copy DELETED elements.
int size = size();
FieldArray clone = new FieldArray(size);
System.arraycopy(mFieldNumbers, 0, clone.mFieldNumbers, 0, size);
for (int i = 0; i < size; i++) {
if (mData[i] != null) {
clone.mData[i] = mData[i].clone();
}
}
clone.mSize = size;
return clone;
}
}