LatinIME/native/jni/src/dictionary/structure/pt_common/dynamic_pt_reading_helper.h

283 lines
11 KiB
C++

/*
* 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.
*/
#ifndef LATINIME_DYNAMIC_PT_READING_HELPER_H
#define LATINIME_DYNAMIC_PT_READING_HELPER_H
#include <cstddef>
#include <vector>
#include "defines.h"
#include "dictionary/structure/pt_common/pt_node_params.h"
#include "dictionary/structure/pt_common/pt_node_reader.h"
namespace latinime {
class DictionaryShortcutsStructurePolicy;
class PtNodeArrayReader;
/*
* This class is used for traversing dynamic patricia trie. This class supports iterating nodes and
* dealing with additional buffer. This class counts nodes and node arrays to avoid infinite loop.
*/
class DynamicPtReadingHelper {
public:
class TraversingEventListener {
public:
virtual ~TraversingEventListener() {};
// Returns whether the event handling was succeeded or not.
virtual bool onAscend() = 0;
// Returns whether the event handling was succeeded or not.
virtual bool onDescend(const int ptNodeArrayPos) = 0;
// Returns whether the event handling was succeeded or not.
virtual bool onReadingPtNodeArrayTail() = 0;
// Returns whether the event handling was succeeded or not.
virtual bool onVisitingPtNode(const PtNodeParams *const node) = 0;
protected:
TraversingEventListener() {};
private:
DISALLOW_COPY_AND_ASSIGN(TraversingEventListener);
};
class TraversePolicyToGetAllTerminalPtNodePositions : public TraversingEventListener {
public:
TraversePolicyToGetAllTerminalPtNodePositions(std::vector<int> *const terminalPositions)
: mTerminalPositions(terminalPositions) {}
bool onAscend() { return true; }
bool onDescend(const int ptNodeArrayPos) { return true; }
bool onReadingPtNodeArrayTail() { return true; }
bool onVisitingPtNode(const PtNodeParams *const ptNodeParams);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(TraversePolicyToGetAllTerminalPtNodePositions);
std::vector<int> *const mTerminalPositions;
};
DynamicPtReadingHelper(const PtNodeReader *const ptNodeReader,
const PtNodeArrayReader *const ptNodeArrayReader)
: mIsError(false), mReadingState(), mPtNodeReader(ptNodeReader),
mPtNodeArrayReader(ptNodeArrayReader), mReadingStateStack() {}
~DynamicPtReadingHelper() {}
AK_FORCE_INLINE bool isError() const {
return mIsError;
}
AK_FORCE_INLINE bool isEnd() const {
return mReadingState.mPos == NOT_A_DICT_POS;
}
// Initialize reading state with the head position of a PtNode array.
AK_FORCE_INLINE void initWithPtNodeArrayPos(const int ptNodeArrayPos) {
if (ptNodeArrayPos == NOT_A_DICT_POS) {
mReadingState.mPos = NOT_A_DICT_POS;
} else {
mIsError = false;
mReadingState.mPos = ptNodeArrayPos;
mReadingState.mTotalCodePointCountSinceInitialization = 0;
mReadingState.mTotalPtNodeIndexInThisArrayChain = 0;
mReadingState.mPtNodeArrayIndexInThisArrayChain = 0;
mReadingState.mPosOfLastForwardLinkField = NOT_A_DICT_POS;
mReadingStateStack.clear();
nextPtNodeArray();
}
}
// Initialize reading state with the head position of a node.
AK_FORCE_INLINE void initWithPtNodePos(const int ptNodePos) {
if (ptNodePos == NOT_A_DICT_POS) {
mReadingState.mPos = NOT_A_DICT_POS;
} else {
mIsError = false;
mReadingState.mPos = ptNodePos;
mReadingState.mRemainingPtNodeCountInThisArray = 1;
mReadingState.mTotalCodePointCountSinceInitialization = 0;
mReadingState.mTotalPtNodeIndexInThisArrayChain = 1;
mReadingState.mPtNodeArrayIndexInThisArrayChain = 1;
mReadingState.mPosOfLastForwardLinkField = NOT_A_DICT_POS;
mReadingState.mPosOfThisPtNodeArrayHead = NOT_A_DICT_POS;
mReadingStateStack.clear();
}
}
AK_FORCE_INLINE const PtNodeParams getPtNodeParams() const {
if (isEnd()) {
return PtNodeParams();
}
return mPtNodeReader->fetchPtNodeParamsInBufferFromPtNodePos(mReadingState.mPos);
}
AK_FORCE_INLINE bool isValidTerminalNode(const PtNodeParams &ptNodeParams) const {
return !isEnd() && !ptNodeParams.isDeleted() && ptNodeParams.isTerminal();
}
AK_FORCE_INLINE bool isMatchedCodePoint(const PtNodeParams &ptNodeParams, const int index,
const int codePoint) const {
return ptNodeParams.getCodePoints()[index] == codePoint;
}
// Return code point count exclude the last read node's code points.
AK_FORCE_INLINE size_t getPrevTotalCodePointCount() const {
return mReadingState.mTotalCodePointCountSinceInitialization;
}
// Return code point count include the last read node's code points.
AK_FORCE_INLINE size_t getTotalCodePointCount(const PtNodeParams &ptNodeParams) const {
return mReadingState.mTotalCodePointCountSinceInitialization
+ ptNodeParams.getCodePointCount();
}
AK_FORCE_INLINE void fetchMergedNodeCodePointsInReverseOrder(const PtNodeParams &ptNodeParams,
const int index, int *const outCodePoints) const {
const int nodeCodePointCount = ptNodeParams.getCodePointCount();
const int *const nodeCodePoints = ptNodeParams.getCodePoints();
for (int i = 0; i < nodeCodePointCount; ++i) {
outCodePoints[index + i] = nodeCodePoints[nodeCodePointCount - 1 - i];
}
}
AK_FORCE_INLINE void readNextSiblingNode(const PtNodeParams &ptNodeParams) {
mReadingState.mRemainingPtNodeCountInThisArray -= 1;
mReadingState.mPos = ptNodeParams.getSiblingNodePos();
if (mReadingState.mRemainingPtNodeCountInThisArray <= 0) {
// All nodes in the current node array have been read.
followForwardLink();
}
}
// Read the first child node of the current node.
AK_FORCE_INLINE void readChildNode(const PtNodeParams &ptNodeParams) {
if (ptNodeParams.hasChildren()) {
mReadingState.mTotalCodePointCountSinceInitialization +=
ptNodeParams.getCodePointCount();
mReadingState.mTotalPtNodeIndexInThisArrayChain = 0;
mReadingState.mPtNodeArrayIndexInThisArrayChain = 0;
mReadingState.mPos = ptNodeParams.getChildrenPos();
mReadingState.mPosOfLastForwardLinkField = NOT_A_DICT_POS;
// Read children node array.
nextPtNodeArray();
} else {
mReadingState.mPos = NOT_A_DICT_POS;
}
}
// Read the parent node of the current node.
AK_FORCE_INLINE void readParentNode(const PtNodeParams &ptNodeParams) {
if (ptNodeParams.getParentPos() != NOT_A_DICT_POS) {
mReadingState.mTotalCodePointCountSinceInitialization +=
ptNodeParams.getCodePointCount();
mReadingState.mTotalPtNodeIndexInThisArrayChain = 1;
mReadingState.mPtNodeArrayIndexInThisArrayChain = 1;
mReadingState.mRemainingPtNodeCountInThisArray = 1;
mReadingState.mPos = ptNodeParams.getParentPos();
mReadingState.mPosOfLastForwardLinkField = NOT_A_DICT_POS;
mReadingState.mPosOfThisPtNodeArrayHead = NOT_A_DICT_POS;
} else {
mReadingState.mPos = NOT_A_DICT_POS;
}
}
AK_FORCE_INLINE int getPosOfLastForwardLinkField() const {
return mReadingState.mPosOfLastForwardLinkField;
}
AK_FORCE_INLINE int getPosOfLastPtNodeArrayHead() const {
return mReadingState.mPosOfThisPtNodeArrayHead;
}
bool traverseAllPtNodesInPostorderDepthFirstManner(TraversingEventListener *const listener);
bool traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
TraversingEventListener *const listener);
int getCodePointsAndReturnCodePointCount(const int maxCodePointCount, int *const outCodePoints);
int getTerminalPtNodePositionOfWord(const int *const inWord, const size_t length,
const bool forceLowerCaseSearch);
private:
DISALLOW_COPY_AND_ASSIGN(DynamicPtReadingHelper);
// This class encapsulates the reading state of a position in the dictionary. It points at a
// specific PtNode in the dictionary.
class PtNodeReadingState {
public:
// Note that copy constructor and assignment operator are used for this class to use
// std::vector.
PtNodeReadingState() : mPos(NOT_A_DICT_POS), mRemainingPtNodeCountInThisArray(0),
mTotalCodePointCountSinceInitialization(0), mTotalPtNodeIndexInThisArrayChain(0),
mPtNodeArrayIndexInThisArrayChain(0), mPosOfLastForwardLinkField(NOT_A_DICT_POS),
mPosOfThisPtNodeArrayHead(NOT_A_DICT_POS) {}
int mPos;
// Remaining node count in the current array.
int mRemainingPtNodeCountInThisArray;
size_t mTotalCodePointCountSinceInitialization;
// Counter of PtNodes used to avoid infinite loops caused by broken or malicious links.
int mTotalPtNodeIndexInThisArrayChain;
// Counter of PtNode arrays used to avoid infinite loops caused by cyclic links of empty
// PtNode arrays.
int mPtNodeArrayIndexInThisArrayChain;
int mPosOfLastForwardLinkField;
int mPosOfThisPtNodeArrayHead;
};
static const int MAX_CHILD_COUNT_TO_AVOID_INFINITE_LOOP;
static const int MAX_PT_NODE_ARRAY_COUNT_TO_AVOID_INFINITE_LOOP;
static const size_t MAX_READING_STATE_STACK_SIZE;
// TODO: Introduce error code to track what caused the error.
bool mIsError;
PtNodeReadingState mReadingState;
const PtNodeReader *const mPtNodeReader;
const PtNodeArrayReader *const mPtNodeArrayReader;
std::vector<PtNodeReadingState> mReadingStateStack;
void nextPtNodeArray();
void followForwardLink();
AK_FORCE_INLINE void pushReadingStateToStack() {
if (mReadingStateStack.size() > MAX_READING_STATE_STACK_SIZE) {
AKLOGI("Reading state stack overflow. Max size: %zd", MAX_READING_STATE_STACK_SIZE);
ASSERT(false);
mIsError = true;
mReadingState.mPos = NOT_A_DICT_POS;
} else {
mReadingStateStack.push_back(mReadingState);
}
}
AK_FORCE_INLINE void popReadingStateFromStack() {
if (mReadingStateStack.empty()) {
mReadingState.mPos = NOT_A_DICT_POS;
} else {
mReadingState = mReadingStateStack.back();
mReadingStateStack.pop_back();
}
}
};
} // namespace latinime
#endif /* LATINIME_DYNAMIC_PT_READING_HELPER_H */