BasicHashtableImpl::rehash(minimumCapacity, loadFactor);
}
+ /* Determines whether there is room to add another entry without rehashing.
+ * When this returns true, a subsequent add() operation is guaranteed to
+ * complete without performing a rehash.
+ */
+ inline bool hasMoreRoom() const {
+ return mCapacity > mFilledBuckets;
+ }
+
protected:
static inline const TEntry& entryFor(const Bucket& bucket) {
return reinterpret_cast<const TEntry&>(bucket.entry);
--- /dev/null
+/*
+ * Copyright (C) 2012 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.
+ */
+
+/* Implementation of Jenkins one-at-a-time hash function. These choices are
+ * optimized for code size and portability, rather than raw speed. But speed
+ * should still be quite good.
+ **/
+
+#include <utils/TypeHelpers.h>
+
+namespace android {
+
+/* The Jenkins hash of a sequence of 32 bit words A, B, C is:
+ * Whiten(Mix(Mix(Mix(0, A), B), C)) */
+
+inline uint32_t JenkinsHashMix(uint32_t hash, uint32_t data) {
+ hash += data;
+ hash += (hash << 10);
+ hash ^= (hash >> 6);
+ return hash;
+}
+
+hash_t JenkinsHashWhiten(uint32_t hash);
+
+/* Helpful utility functions for hashing data in 32 bit chunks */
+uint32_t JenkinsHashMixBytes(uint32_t hash, const uint8_t* bytes, size_t size);
+
+uint32_t JenkinsHashMixShorts(uint32_t hash, const uint16_t* shorts, size_t size);
+
+}
+
--- /dev/null
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#include <utils/BasicHashtable.h>
+#include <utils/GenerationCache.h>
+#include <utils/UniquePtr.h>
+
+namespace android {
+
+// OnEntryRemoved is defined in GenerationCache.h, but maybe should move here.
+
+template <typename TKey, typename TValue>
+class LruCache {
+public:
+ explicit LruCache(uint32_t maxCapacity);
+
+ enum Capacity {
+ kUnlimitedCapacity,
+ };
+
+ void setOnEntryRemovedListener(OnEntryRemoved<TKey, TValue>* listener);
+ size_t size() const;
+ const TValue& get(const TKey& key);
+ bool put(const TKey& key, const TValue& value);
+ bool remove(const TKey& key);
+ bool removeOldest();
+ void clear();
+
+private:
+ LruCache(const LruCache& that); // disallow copy constructor
+
+ struct Entry {
+ TKey key;
+ TValue value;
+ Entry* parent;
+ Entry* child;
+
+ Entry(TKey key_, TValue value_) : key(key_), value(value_), parent(NULL), child(NULL) {
+ }
+ const TKey& getKey() const { return key; }
+ };
+
+ void attachToCache(Entry& entry);
+ void detachFromCache(Entry& entry);
+ void rehash(size_t newCapacity);
+
+ UniquePtr<BasicHashtable<TKey, Entry> > mTable;
+ OnEntryRemoved<TKey, TValue>* mListener;
+ Entry* mOldest;
+ Entry* mYoungest;
+ uint32_t mMaxCapacity;
+ TValue mNullValue;
+};
+
+// Implementation is here, because it's fully templated
+template <typename TKey, typename TValue>
+LruCache<TKey, TValue>::LruCache(uint32_t maxCapacity): mMaxCapacity(maxCapacity),
+ mNullValue(NULL), mTable(new BasicHashtable<TKey, Entry>), mYoungest(NULL), mOldest(NULL),
+ mListener(NULL) {
+};
+
+template<typename K, typename V>
+void LruCache<K, V>::setOnEntryRemovedListener(OnEntryRemoved<K, V>* listener) {
+ mListener = listener;
+}
+
+template <typename TKey, typename TValue>
+size_t LruCache<TKey, TValue>::size() const {
+ return mTable->size();
+}
+
+template <typename TKey, typename TValue>
+const TValue& LruCache<TKey, TValue>::get(const TKey& key) {
+ hash_t hash = hash_type(key);
+ ssize_t index = mTable->find(-1, hash, key);
+ if (index == -1) {
+ return mNullValue;
+ }
+ Entry& entry = mTable->editEntryAt(index);
+ detachFromCache(entry);
+ attachToCache(entry);
+ return entry.value;
+}
+
+template <typename TKey, typename TValue>
+bool LruCache<TKey, TValue>::put(const TKey& key, const TValue& value) {
+ if (mMaxCapacity != kUnlimitedCapacity && size() >= mMaxCapacity) {
+ removeOldest();
+ }
+
+ hash_t hash = hash_type(key);
+ ssize_t index = mTable->find(-1, hash, key);
+ if (index >= 0) {
+ return false;
+ }
+ if (!mTable->hasMoreRoom()) {
+ rehash(mTable->capacity() * 2);
+ }
+
+ // Would it be better to initialize a blank entry and assign key, value?
+ Entry initEntry(key, value);
+ index = mTable->add(hash, initEntry);
+ Entry& entry = mTable->editEntryAt(index);
+ attachToCache(entry);
+ return true;
+}
+
+template <typename TKey, typename TValue>
+bool LruCache<TKey, TValue>::remove(const TKey& key) {
+ hash_t hash = hash_type(key);
+ ssize_t index = mTable->find(-1, hash, key);
+ if (index < 0) {
+ return false;
+ }
+ Entry& entry = mTable->editEntryAt(index);
+ if (mListener) {
+ (*mListener)(entry.key, entry.value);
+ }
+ detachFromCache(entry);
+ mTable->removeAt(index);
+ return true;
+}
+
+template <typename TKey, typename TValue>
+bool LruCache<TKey, TValue>::removeOldest() {
+ if (mOldest != NULL) {
+ return remove(mOldest->key);
+ // TODO: should probably abort if false
+ }
+ return false;
+}
+
+template <typename TKey, typename TValue>
+void LruCache<TKey, TValue>::clear() {
+ if (mListener) {
+ for (Entry* p = mOldest; p != NULL; p = p->child) {
+ (*mListener)(p->key, p->value);
+ }
+ }
+ mYoungest = NULL;
+ mOldest = NULL;
+ mTable->clear();
+}
+
+template <typename TKey, typename TValue>
+void LruCache<TKey, TValue>::attachToCache(Entry& entry) {
+ if (mYoungest == NULL) {
+ mYoungest = mOldest = &entry;
+ } else {
+ entry.parent = mYoungest;
+ mYoungest->child = &entry;
+ mYoungest = &entry;
+ }
+}
+
+template <typename TKey, typename TValue>
+void LruCache<TKey, TValue>::detachFromCache(Entry& entry) {
+ if (entry.parent != NULL) {
+ entry.parent->child = entry.child;
+ } else {
+ mOldest = entry.child;
+ }
+ if (entry.child != NULL) {
+ entry.child->parent = entry.parent;
+ } else {
+ mYoungest = entry.parent;
+ }
+
+ entry.parent = NULL;
+ entry.child = NULL;
+}
+
+template <typename TKey, typename TValue>
+void LruCache<TKey, TValue>::rehash(size_t newCapacity) {
+ UniquePtr<BasicHashtable<TKey, Entry> > oldTable(mTable.release());
+ Entry* oldest = mOldest;
+
+ mOldest = NULL;
+ mYoungest = NULL;
+ mTable.reset(new BasicHashtable<TKey, Entry>(newCapacity));
+ for (Entry* p = oldest; p != NULL; p = p->child) {
+ put(p->key, p->value);
+ }
+}
+
+}
ANDROID_REINTERPRET_HASH(float, uint32_t)
ANDROID_REINTERPRET_HASH(double, uint64_t)
-template <typename T> inline hash_t hash_type(const T*& value) {
+template <typename T> inline hash_t hash_type(T* const & value) {
return hash_type(uintptr_t(value));
}
Debug.cpp \
FileMap.cpp \
Flattenable.cpp \
+ JenkinsHash.cpp \
LinearTransform.cpp \
Log.cpp \
PropertyMap.cpp \
SharedBuffer* sb = SharedBuffer::bufferFromData(mBuckets);
if (sb->onlyOwner()) {
destroyBuckets(mBuckets, mBucketCount);
- for (size_t i = 0; i < mSize; i++) {
+ for (size_t i = 0; i < mBucketCount; i++) {
Bucket& bucket = bucketAt(mBuckets, i);
bucket.cookie = 0;
}
--- /dev/null
+/*
+ * Copyright (C) 2012 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.
+ */
+
+/* Implementation of Jenkins one-at-a-time hash function. These choices are
+ * optimized for code size and portability, rather than raw speed. But speed
+ * should still be quite good.
+ **/
+
+#include <utils/JenkinsHash.h>
+
+namespace android {
+
+hash_t JenkinsHashWhiten(uint32_t hash) {
+ hash += (hash << 3);
+ hash ^= (hash >> 11);
+ hash += (hash << 15);
+ return hash;
+}
+
+uint32_t JenkinsHashMixBytes(uint32_t hash, const uint8_t* bytes, size_t size) {
+ hash = JenkinsHashMix(hash, (uint32_t)size);
+ size_t i;
+ for (i = 0; i < (size & -4); i += 4) {
+ uint32_t data = bytes[i] | (bytes[i+1] << 8) | (bytes[i+2] << 16) | (bytes[i+3] << 24);
+ hash = JenkinsHashMix(hash, data);
+ }
+ if (size & 3) {
+ uint32_t data = bytes[i];
+ data |= ((size & 3) > 1) ? (bytes[i+1] << 8) : 0;
+ data |= ((size & 3) > 2) ? (bytes[i+2] << 16) : 0;
+ hash = JenkinsHashMix(hash, data);
+ }
+ return hash;
+}
+
+uint32_t JenkinsHashMixShorts(uint32_t hash, const uint16_t* shorts, size_t size) {
+ hash = JenkinsHashMix(hash, (uint32_t)size);
+ size_t i;
+ for (i = 0; i < (size & -2); i += 2) {
+ uint32_t data = shorts[i] | (shorts[i+1] << 16);
+ hash = JenkinsHashMix(hash, data);
+ }
+ if (size & 1) {
+ uint32_t data = shorts[i];
+ hash = JenkinsHashMix(hash, data);
+ }
+ return hash;
+}
+
+}
+
BasicHashtable_test.cpp \
BlobCache_test.cpp \
Looper_test.cpp \
+ LruCache_test.cpp \
String8_test.cpp \
Unicode_test.cpp \
Vector_test.cpp \
--- /dev/null
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#include <stdlib.h>
+#include <utils/JenkinsHash.h>
+#include <utils/LruCache.h>
+#include <cutils/log.h>
+#include <gtest/gtest.h>
+
+namespace android {
+
+typedef int SimpleKey;
+typedef const char* StringValue;
+
+struct ComplexKey {
+ int k;
+
+ explicit ComplexKey(int k) : k(k) {
+ instanceCount += 1;
+ }
+
+ ComplexKey(const ComplexKey& other) : k(other.k) {
+ instanceCount += 1;
+ }
+
+ ~ComplexKey() {
+ instanceCount -= 1;
+ }
+
+ bool operator ==(const ComplexKey& other) const {
+ return k == other.k;
+ }
+
+ bool operator !=(const ComplexKey& other) const {
+ return k != other.k;
+ }
+
+ static ssize_t instanceCount;
+};
+
+ssize_t ComplexKey::instanceCount = 0;
+
+template<> inline hash_t hash_type(const ComplexKey& value) {
+ return hash_type(value.k);
+}
+
+struct ComplexValue {
+ int v;
+
+ explicit ComplexValue(int v) : v(v) {
+ instanceCount += 1;
+ }
+
+ ComplexValue(const ComplexValue& other) : v(other.v) {
+ instanceCount += 1;
+ }
+
+ ~ComplexValue() {
+ instanceCount -= 1;
+ }
+
+ static ssize_t instanceCount;
+};
+
+ssize_t ComplexValue::instanceCount = 0;
+
+typedef LruCache<ComplexKey, ComplexValue> ComplexCache;
+
+class EntryRemovedCallback : public OnEntryRemoved<SimpleKey, StringValue> {
+public:
+ EntryRemovedCallback() : callbackCount(0), lastKey(-1), lastValue(NULL) { }
+ ~EntryRemovedCallback() {}
+ void operator()(SimpleKey& k, StringValue& v) {
+ callbackCount += 1;
+ lastKey = k;
+ lastValue = v;
+ }
+ ssize_t callbackCount;
+ SimpleKey lastKey;
+ StringValue lastValue;
+};
+
+class LruCacheTest : public testing::Test {
+protected:
+ virtual void SetUp() {
+ ComplexKey::instanceCount = 0;
+ ComplexValue::instanceCount = 0;
+ }
+
+ virtual void TearDown() {
+ ASSERT_NO_FATAL_FAILURE(assertInstanceCount(0, 0));
+ }
+
+ void assertInstanceCount(ssize_t keys, ssize_t values) {
+ if (keys != ComplexKey::instanceCount || values != ComplexValue::instanceCount) {
+ FAIL() << "Expected " << keys << " keys and " << values << " values "
+ "but there were actually " << ComplexKey::instanceCount << " keys and "
+ << ComplexValue::instanceCount << " values";
+ }
+ }
+};
+
+TEST_F(LruCacheTest, Empty) {
+ LruCache<SimpleKey, StringValue> cache(100);
+
+ EXPECT_EQ(NULL, cache.get(0));
+ EXPECT_EQ(0u, cache.size());
+}
+
+TEST_F(LruCacheTest, Simple) {
+ LruCache<SimpleKey, StringValue> cache(100);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ EXPECT_STREQ("one", cache.get(1));
+ EXPECT_STREQ("two", cache.get(2));
+ EXPECT_STREQ("three", cache.get(3));
+ EXPECT_EQ(3u, cache.size());
+}
+
+TEST_F(LruCacheTest, MaxCapacity) {
+ LruCache<SimpleKey, StringValue> cache(2);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ EXPECT_EQ(NULL, cache.get(1));
+ EXPECT_STREQ("two", cache.get(2));
+ EXPECT_STREQ("three", cache.get(3));
+ EXPECT_EQ(2u, cache.size());
+}
+
+TEST_F(LruCacheTest, RemoveLru) {
+ LruCache<SimpleKey, StringValue> cache(100);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ cache.removeOldest();
+ EXPECT_EQ(NULL, cache.get(1));
+ EXPECT_STREQ("two", cache.get(2));
+ EXPECT_STREQ("three", cache.get(3));
+ EXPECT_EQ(2u, cache.size());
+}
+
+TEST_F(LruCacheTest, GetUpdatesLru) {
+ LruCache<SimpleKey, StringValue> cache(100);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ EXPECT_STREQ("one", cache.get(1));
+ cache.removeOldest();
+ EXPECT_STREQ("one", cache.get(1));
+ EXPECT_EQ(NULL, cache.get(2));
+ EXPECT_STREQ("three", cache.get(3));
+ EXPECT_EQ(2u, cache.size());
+}
+
+uint32_t hash_int(int x) {
+ return JenkinsHashWhiten(JenkinsHashMix(0, x));
+}
+
+TEST_F(LruCacheTest, StressTest) {
+ const size_t kCacheSize = 512;
+ LruCache<SimpleKey, StringValue> cache(512);
+ const size_t kNumKeys = 16 * 1024;
+ const size_t kNumIters = 100000;
+ char* strings[kNumKeys];
+
+ for (size_t i = 0; i < kNumKeys; i++) {
+ strings[i] = (char *)malloc(16);
+ sprintf(strings[i], "%d", i);
+ }
+
+ srandom(12345);
+ int hitCount = 0;
+ for (size_t i = 0; i < kNumIters; i++) {
+ int index = random() % kNumKeys;
+ uint32_t key = hash_int(index);
+ const char *val = cache.get(key);
+ if (val != NULL) {
+ EXPECT_EQ(strings[index], val);
+ hitCount++;
+ } else {
+ cache.put(key, strings[index]);
+ }
+ }
+ size_t expectedHitCount = kNumIters * kCacheSize / kNumKeys;
+ EXPECT_LT(int(expectedHitCount * 0.9), hitCount);
+ EXPECT_GT(int(expectedHitCount * 1.1), hitCount);
+ EXPECT_EQ(kCacheSize, cache.size());
+
+ for (size_t i = 0; i < kNumKeys; i++) {
+ free((void *)strings[i]);
+ }
+}
+
+TEST_F(LruCacheTest, NoLeak) {
+ ComplexCache cache(100);
+
+ cache.put(ComplexKey(0), ComplexValue(0));
+ cache.put(ComplexKey(1), ComplexValue(1));
+ EXPECT_EQ(2, cache.size());
+ assertInstanceCount(2, 3); // the null value counts as an instance
+}
+
+TEST_F(LruCacheTest, Clear) {
+ ComplexCache cache(100);
+
+ cache.put(ComplexKey(0), ComplexValue(0));
+ cache.put(ComplexKey(1), ComplexValue(1));
+ EXPECT_EQ(2, cache.size());
+ assertInstanceCount(2, 3);
+ cache.clear();
+ assertInstanceCount(0, 1);
+}
+
+TEST_F(LruCacheTest, ClearNoDoubleFree) {
+ {
+ ComplexCache cache(100);
+
+ cache.put(ComplexKey(0), ComplexValue(0));
+ cache.put(ComplexKey(1), ComplexValue(1));
+ EXPECT_EQ(2, cache.size());
+ assertInstanceCount(2, 3);
+ cache.removeOldest();
+ cache.clear();
+ assertInstanceCount(0, 1);
+ }
+ assertInstanceCount(0, 0);
+}
+
+TEST_F(LruCacheTest, ClearReuseOk) {
+ ComplexCache cache(100);
+
+ cache.put(ComplexKey(0), ComplexValue(0));
+ cache.put(ComplexKey(1), ComplexValue(1));
+ EXPECT_EQ(2, cache.size());
+ assertInstanceCount(2, 3);
+ cache.clear();
+ assertInstanceCount(0, 1);
+ cache.put(ComplexKey(0), ComplexValue(0));
+ cache.put(ComplexKey(1), ComplexValue(1));
+ EXPECT_EQ(2, cache.size());
+ assertInstanceCount(2, 3);
+}
+
+TEST_F(LruCacheTest, Callback) {
+ LruCache<SimpleKey, StringValue> cache(100);
+ EntryRemovedCallback callback;
+ cache.setOnEntryRemovedListener(&callback);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ EXPECT_EQ(3, cache.size());
+ cache.removeOldest();
+ EXPECT_EQ(1, callback.callbackCount);
+ EXPECT_EQ(1, callback.lastKey);
+ EXPECT_STREQ("one", callback.lastValue);
+}
+
+TEST_F(LruCacheTest, CallbackOnClear) {
+ LruCache<SimpleKey, StringValue> cache(100);
+ EntryRemovedCallback callback;
+ cache.setOnEntryRemovedListener(&callback);
+
+ cache.put(1, "one");
+ cache.put(2, "two");
+ cache.put(3, "three");
+ EXPECT_EQ(3, cache.size());
+ cache.clear();
+ EXPECT_EQ(3, callback.callbackCount);
+}
+
+}
OSDN Git Service
