/*
* Copyright (C) 2014, 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 "dictionary/utils/trie_map.h"
#include "dictionary/utils/dict_file_writing_utils.h"
namespace latinime {
const int TrieMap::INVALID_INDEX = -1;
const int TrieMap::FIELD0_SIZE = 4;
const int TrieMap::FIELD1_SIZE = 3;
const int TrieMap::ENTRY_SIZE = FIELD0_SIZE + FIELD1_SIZE;
const uint32_t TrieMap::VALUE_FLAG = 0x400000;
const uint32_t TrieMap::VALUE_MASK = 0x3FFFFF;
const uint32_t TrieMap::INVALID_VALUE_IN_KEY_VALUE_ENTRY = VALUE_MASK;
const uint32_t TrieMap::TERMINAL_LINK_FLAG = 0x800000;
const uint32_t TrieMap::TERMINAL_LINK_MASK = 0x7FFFFF;
const int TrieMap::NUM_OF_BITS_USED_FOR_ONE_LEVEL = 5;
const uint32_t TrieMap::LABEL_MASK = 0x1F;
const int TrieMap::MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL = 1 << NUM_OF_BITS_USED_FOR_ONE_LEVEL;
const int TrieMap::ROOT_BITMAP_ENTRY_INDEX = 0;
const int TrieMap::ROOT_BITMAP_ENTRY_POS = MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL * FIELD0_SIZE;
const TrieMap::Entry TrieMap::EMPTY_BITMAP_ENTRY = TrieMap::Entry(0, 0);
const int TrieMap::TERMINAL_LINKED_ENTRY_COUNT = 2; // Value entry and bitmap entry.
const uint64_t TrieMap::MAX_VALUE =
(static_cast<uint64_t>(1) << ((FIELD0_SIZE + FIELD1_SIZE) * CHAR_BIT)) - 1;
const int TrieMap::MAX_BUFFER_SIZE = TERMINAL_LINK_MASK * ENTRY_SIZE;
TrieMap::TrieMap() : mBuffer(MAX_BUFFER_SIZE) {
mBuffer.extend(ROOT_BITMAP_ENTRY_POS);
writeEntry(EMPTY_BITMAP_ENTRY, ROOT_BITMAP_ENTRY_INDEX);
}
TrieMap::TrieMap(const ReadWriteByteArrayView buffer)
: mBuffer(buffer, BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE) {}
void TrieMap::dump(const int from, const int to) const {
AKLOGI("BufSize: %d", mBuffer.getTailPosition());
for (int i = from; i < to; ++i) {
AKLOGI("Entry[%d]: %x, %x", i, readField0(i), readField1(i));
}
int unusedRegionSize = 0;
for (int i = 1; i <= MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL; ++i) {
int index = readEmptyTableLink(i);
while (index != ROOT_BITMAP_ENTRY_INDEX) {
index = readField0(index);
unusedRegionSize += i;
}
}
AKLOGI("Unused Size: %d", unusedRegionSize);
}
int TrieMap::getNextLevelBitmapEntryIndex(const int key, const int bitmapEntryIndex) {
const Entry bitmapEntry = readEntry(bitmapEntryIndex);
const uint32_t unsignedKey = static_cast<uint32_t>(key);
const int terminalEntryIndex = getTerminalEntryIndex(
unsignedKey, getBitShuffledKey(unsignedKey), bitmapEntry, 0 /* level */);
if (terminalEntryIndex == INVALID_INDEX) {
// Not found.
return INVALID_INDEX;
}
const Entry terminalEntry = readEntry(terminalEntryIndex);
if (terminalEntry.hasTerminalLink()) {
return terminalEntry.getValueEntryIndex() + 1;
}
// Create a value entry and a bitmap entry.
const int valueEntryIndex = allocateTable(TERMINAL_LINKED_ENTRY_COUNT);
if (valueEntryIndex == INVALID_INDEX) {
return INVALID_INDEX;
}
if (!writeEntry(Entry(0, terminalEntry.getValue()), valueEntryIndex)) {
return INVALID_INDEX;
}
if (!writeEntry(EMPTY_BITMAP_ENTRY, valueEntryIndex + 1)) {
return INVALID_INDEX;
}
if (!writeField1(valueEntryIndex | TERMINAL_LINK_FLAG, terminalEntryIndex)) {
return INVALID_INDEX;
}
return valueEntryIndex + 1;
}
const TrieMap::Result TrieMap::get(const int key, const int bitmapEntryIndex) const {
const uint32_t unsignedKey = static_cast<uint32_t>(key);
return getInternal(unsignedKey, getBitShuffledKey(unsignedKey), bitmapEntryIndex,
0 /* level */);
}
bool TrieMap::put(const int key, const uint64_t value, const int bitmapEntryIndex) {
if (value > MAX_VALUE) {
return false;
}
const uint32_t unsignedKey = static_cast<uint32_t>(key);
return putInternal(unsignedKey, value, getBitShuffledKey(unsignedKey), bitmapEntryIndex,
readEntry(bitmapEntryIndex), 0 /* level */);
}
bool TrieMap::save(FILE *const file) const {
return DictFileWritingUtils::writeBufferToFileTail(file, &mBuffer);
}
bool TrieMap::remove(const int key, const int bitmapEntryIndex) {
const Entry bitmapEntry = readEntry(bitmapEntryIndex);
const uint32_t unsignedKey = static_cast<uint32_t>(key);
const int terminalEntryIndex = getTerminalEntryIndex(
unsignedKey, getBitShuffledKey(unsignedKey), bitmapEntry, 0 /* level */);
if (terminalEntryIndex == INVALID_INDEX) {
// Not found.
return false;
}
const Entry terminalEntry = readEntry(terminalEntryIndex);
if (!writeField1(VALUE_FLAG ^ INVALID_VALUE_IN_KEY_VALUE_ENTRY , terminalEntryIndex)) {
return false;
}
if (terminalEntry.hasTerminalLink()) {
const Entry nextLevelBitmapEntry = readEntry(terminalEntry.getValueEntryIndex() + 1);
if (!freeTable(terminalEntry.getValueEntryIndex(), TERMINAL_LINKED_ENTRY_COUNT)) {
return false;
}
if (!removeInner(nextLevelBitmapEntry)){
return false;
}
}
return true;
}
/**
* Iterate next entry in a certain level.
*
* @param iterationState the iteration state that will be read and updated in this method.
* @param outKey the output key
* @return Result instance. mIsValid is false when all entries are iterated.
*/
const TrieMap::Result TrieMap::iterateNext(std::vector<TableIterationState> *const iterationState,
int *const outKey) const {
while (!iterationState->empty()) {
TableIterationState &state = iterationState->back();
if (state.mTableSize <= state.mCurrentIndex) {
// Move to parent.
iterationState->pop_back();
} else {
const int entryIndex = state.mTableIndex + state.mCurrentIndex;
state.mCurrentIndex += 1;
const Entry entry = readEntry(entryIndex);
if (entry.isBitmapEntry()) {
// Move to child.
iterationState->emplace_back(popCount(entry.getBitmap()), entry.getTableIndex());
} else if (entry.isValidTerminalEntry()) {
if (outKey) {
*outKey = entry.getKey();
}
if (!entry.hasTerminalLink()) {
return Result(entry.getValue(), true, INVALID_INDEX);
}
const int valueEntryIndex = entry.getValueEntryIndex();
const Entry valueEntry = readEntry(valueEntryIndex);
return Result(valueEntry.getValueOfValueEntry(), true, valueEntryIndex + 1);
}
}
}
// Visited all entries.
return Result(0, false, INVALID_INDEX);
}
/**
* Shuffle bits of the key in the fixed order.
*
* This method is used as a hash function. This returns different values for different inputs.
*/
uint32_t TrieMap::getBitShuffledKey(const uint32_t key) const {
uint32_t shuffledKey = 0;
for (int i = 0; i < 4; ++i) {
const uint32_t keyPiece = (key >> (i * 8)) & 0xFF;
shuffledKey ^= ((keyPiece ^ (keyPiece << 7) ^ (keyPiece << 14) ^ (keyPiece << 21))
& 0x11111111) << i;
}
return shuffledKey;
}
bool TrieMap::writeValue(const uint64_t value, const int terminalEntryIndex) {
if (value < VALUE_MASK) {
// Write value into the terminal entry.
return writeField1(value | VALUE_FLAG, terminalEntryIndex);
}
// Create value entry and write value.
const int valueEntryIndex = allocateTable(TERMINAL_LINKED_ENTRY_COUNT);
if (valueEntryIndex == INVALID_INDEX) {
return false;
}
if (!writeEntry(Entry(value >> (FIELD1_SIZE * CHAR_BIT), value), valueEntryIndex)) {
return false;
}
if (!writeEntry(EMPTY_BITMAP_ENTRY, valueEntryIndex + 1)) {
return false;
}
return writeField1(valueEntryIndex | TERMINAL_LINK_FLAG, terminalEntryIndex);
}
bool TrieMap::updateValue(const Entry &terminalEntry, const uint64_t value,
const int terminalEntryIndex) {
if (!terminalEntry.hasTerminalLink()) {
return writeValue(value, terminalEntryIndex);
}
const int valueEntryIndex = terminalEntry.getValueEntryIndex();
return writeEntry(Entry(value >> (FIELD1_SIZE * CHAR_BIT), value), valueEntryIndex);
}
bool TrieMap::freeTable(const int tableIndex, const int entryCount) {
if (!writeField0(readEmptyTableLink(entryCount), tableIndex)) {
return false;
}
return writeEmptyTableLink(tableIndex, entryCount);
}
/**
* Allocate table with entryCount-entries. Reuse freed table if possible.
*/
int TrieMap::allocateTable(const int entryCount) {
if (entryCount > 0 && entryCount <= MAX_NUM_OF_ENTRIES_IN_ONE_LEVEL) {
const int tableIndex = readEmptyTableLink(entryCount);
if (tableIndex > 0) {
if (!writeEmptyTableLink(readField0(tableIndex), entryCount)) {
return INVALID_INDEX;
}
// Reuse the table.
return tableIndex;
}
}
// Allocate memory space at tail position of the buffer.
const int mapIndex = getTailEntryIndex();
if (!mBuffer.extend(entryCount * ENTRY_SIZE)) {
return INVALID_INDEX;
}
return mapIndex;
}
int TrieMap::getTerminalEntryIndex(const uint32_t key, const uint32_t hashedKey,
const Entry &bitmapEntry, const int level) const {
const int label = getLabel(hashedKey, level);
if (!exists(bitmapEntry.getBitmap(), label)) {
return INVALID_INDEX;
}
const int entryIndex = bitmapEntry.getTableIndex() + popCount(bitmapEntry.getBitmap(), label);
const Entry entry = readEntry(entryIndex);
if (entry.isBitmapEntry()) {
// Move to the next level.
return getTerminalEntryIndex(key, hashedKey, entry, level + 1);
}
if (!entry.isValidTerminalEntry()) {
return INVALID_INDEX;
}
if (entry.getKey() == key) {
// Terminal entry is found.
return entryIndex;
}
return INVALID_INDEX;
}
/**
* Get Result corresponding to the key.
*
* @param key the key.
* @param hashedKey the hashed key.
* @param bitmapEntryIndex the index of bitmap entry
* @param level current level
* @return Result instance corresponding to the key. mIsValid indicates whether the key is in the
* map.
*/
const TrieMap::Result TrieMap::getInternal(const uint32_t key, const uint32_t hashedKey,
const int bitmapEntryIndex, const int level) const {
const int terminalEntryIndex = getTerminalEntryIndex(key, hashedKey,
readEntry(bitmapEntryIndex), level);
if (terminalEntryIndex == INVALID_INDEX) {
// Not found.
return Result(0, false, INVALID_INDEX);
}
const Entry terminalEntry = readEntry(terminalEntryIndex);
if (!terminalEntry.hasTerminalLink()) {
return Result(terminalEntry.getValue(), true, INVALID_INDEX);
}
const int valueEntryIndex = terminalEntry.getValueEntryIndex();
const Entry valueEntry = readEntry(valueEntryIndex);
return Result(valueEntry.getValueOfValueEntry(), true, valueEntryIndex + 1);
}
/**
* Put key to value mapping to the map.
*
* @param key the key.
* @param value the value
* @param hashedKey the hashed key.
* @param bitmapEntryIndex the index of bitmap entry
* @param bitmapEntry the bitmap entry
* @param level current level
* @return whether the key-value has been correctly inserted to the map or not.
*/
bool TrieMap::putInternal(const uint32_t key, const uint64_t value, const uint32_t hashedKey,
const int bitmapEntryIndex, const Entry &bitmapEntry, const int level) {
const int label = getLabel(hashedKey, level);
const uint32_t bitmap = bitmapEntry.getBitmap();
const int mapIndex = bitmapEntry.getTableIndex();
if (!exists(bitmap, label)) {
// Current map doesn't contain the label.
return addNewEntryByExpandingTable(key, value, mapIndex, bitmap, bitmapEntryIndex, label);
}
const int entryIndex = mapIndex + popCount(bitmap, label);
const Entry entry = readEntry(entryIndex);
if (entry.isBitmapEntry()) {
// Bitmap entry is found. Go to the next level.
return putInternal(key, value, hashedKey, entryIndex, entry, level + 1);
}
if (!entry.isValidTerminalEntry()) {
// Overwrite invalid terminal entry.
return writeTerminalEntry(key, value, entryIndex);
}
if (entry.getKey() == key) {
// Terminal entry for the key is found. Update the value.
return updateValue(entry, value, entryIndex);
}
// Conflict with the existing key.
return addNewEntryByResolvingConflict(key, value, hashedKey, entry, entryIndex, level);
}
/**
* Resolve a conflict in the current level and add new entry.
*
* @param key the key
* @param value the value
* @param hashedKey the hashed key
* @param conflictedEntry the existing conflicted entry
* @param conflictedEntryIndex the index of existing conflicted entry
* @param level current level
* @return whether the key-value has been correctly inserted to the map or not.
*/
bool TrieMap::addNewEntryByResolvingConflict(const uint32_t key, const uint64_t value,
const uint32_t hashedKey, const Entry &conflictedEntry, const int conflictedEntryIndex,
const int level) {
const int conflictedKeyNextLabel =
getLabel(getBitShuffledKey(conflictedEntry.getKey()), level + 1);
const int nextLabel = getLabel(hashedKey, level + 1);
if (conflictedKeyNextLabel == nextLabel) {
// Conflicted again in the next level.
const int newTableIndex = allocateTable(1 /* entryCount */);
if (newTableIndex == INVALID_INDEX) {
return false;
}
if (!writeEntry(conflictedEntry, newTableIndex)) {
return false;
}
const Entry newBitmapEntry(setExist(0 /* bitmap */, nextLabel), newTableIndex);
if (!writeEntry(newBitmapEntry, conflictedEntryIndex)) {
return false;
}
return putInternal(key, value, hashedKey, conflictedEntryIndex, newBitmapEntry, level + 1);
}
// The conflict has been resolved. Create a table that contains 2 entries.
const int newTableIndex = allocateTable(2 /* entryCount */);
if (newTableIndex == INVALID_INDEX) {
return false;
}
if (nextLabel < conflictedKeyNextLabel) {
if (!writeTerminalEntry(key, value, newTableIndex)) {
return false;
}
if (!writeEntry(conflictedEntry, newTableIndex + 1)) {
return false;
}
} else { // nextLabel > conflictedKeyNextLabel
if (!writeEntry(conflictedEntry, newTableIndex)) {
return false;
}
if (!writeTerminalEntry(key, value, newTableIndex + 1)) {
return false;
}
}
const uint32_t updatedBitmap =
setExist(setExist(0 /* bitmap */, nextLabel), conflictedKeyNextLabel);
return writeEntry(Entry(updatedBitmap, newTableIndex), conflictedEntryIndex);
}
/**
* Add new entry to the existing table.
*/
bool TrieMap::addNewEntryByExpandingTable(const uint32_t key, const uint64_t value,
const int tableIndex, const uint32_t bitmap, const int bitmapEntryIndex, const int label) {
// Current map doesn't contain the label.
const int entryCount = popCount(bitmap);
const int newTableIndex = allocateTable(entryCount + 1);
if (newTableIndex == INVALID_INDEX) {
return false;
}
const int newEntryIndexInTable = popCount(bitmap, label);
// Copy from existing table to the new table.
for (int i = 0; i < entryCount; ++i) {
if (!copyEntry(tableIndex + i, newTableIndex + i + (i >= newEntryIndexInTable ? 1 : 0))) {
return false;
}
}
// Write new terminal entry.
if (!writeTerminalEntry(key, value, newTableIndex + newEntryIndexInTable)) {
return false;
}
// Update bitmap.
if (!writeEntry(Entry(setExist(bitmap, label), newTableIndex), bitmapEntryIndex)) {
return false;
}
if (entryCount > 0) {
return freeTable(tableIndex, entryCount);
}
return true;
}
bool TrieMap::removeInner(const Entry &bitmapEntry) {
const int tableSize = popCount(bitmapEntry.getBitmap());
if (tableSize <= 0) {
// The table is empty. No need to remove any entries.
return true;
}
for (int i = 0; i < tableSize; ++i) {
const int entryIndex = bitmapEntry.getTableIndex() + i;
const Entry entry = readEntry(entryIndex);
if (entry.isBitmapEntry()) {
// Delete next bitmap entry recursively.
if (!removeInner(entry)) {
return false;
}
} else {
// Invalidate terminal entry just in case.
if (!writeField1(VALUE_FLAG ^ INVALID_VALUE_IN_KEY_VALUE_ENTRY , entryIndex)) {
return false;
}
if (entry.hasTerminalLink()) {
const Entry nextLevelBitmapEntry = readEntry(entry.getValueEntryIndex() + 1);
if (!freeTable(entry.getValueEntryIndex(), TERMINAL_LINKED_ENTRY_COUNT)) {
return false;
}
if (!removeInner(nextLevelBitmapEntry)) {
return false;
}
}
}
}
return true;
}
} // namespace latinime