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am 2c67361c: Merge "Move methods in BinaryFormat to PatriciaTriePolicy."

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* commit '2c67361c165cf5f8be106d04aad038b48a08790e':
  Move methods in BinaryFormat to PatriciaTriePolicy.
This commit is contained in:
Keisuke Kuroyanagi 2013-08-16 00:59:04 -07:00 committed by Android Git Automerger
commit d694477c3c
2 changed files with 260 additions and 475 deletions
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470
native/jni/src/suggest/policyimpl/dictionary/binary_format.h
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@ -1,470 +0,0 @@
/*
* Copyright (C) 2011 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_BINARY_FORMAT_H
#define LATINIME_BINARY_FORMAT_H
#include <stdint.h>
#include "suggest/core/dictionary/probability_utils.h"
#include "utils/char_utils.h"
namespace latinime {
class BinaryFormat {
public:
// Mask and flags for children address type selection.
static const int MASK_GROUP_ADDRESS_TYPE = 0xC0;
// Flag for single/multiple char group
static const int FLAG_HAS_MULTIPLE_CHARS = 0x20;
// Flag for terminal groups
static const int FLAG_IS_TERMINAL = 0x10;
// Flag for shortcut targets presence
static const int FLAG_HAS_SHORTCUT_TARGETS = 0x08;
// Flag for bigram presence
static const int FLAG_HAS_BIGRAMS = 0x04;
// Flag for non-words (typically, shortcut only entries)
static const int FLAG_IS_NOT_A_WORD = 0x02;
// Flag for blacklist
static const int FLAG_IS_BLACKLISTED = 0x01;
// Attribute (bigram/shortcut) related flags:
// Flag for presence of more attributes
static const int FLAG_ATTRIBUTE_HAS_NEXT = 0x80;
// Flag for sign of offset. If this flag is set, the offset value must be negated.
static const int FLAG_ATTRIBUTE_OFFSET_NEGATIVE = 0x40;
// Mask for attribute probability, stored on 4 bits inside the flags byte.
static const int MASK_ATTRIBUTE_PROBABILITY = 0x0F;
// Mask and flags for attribute address type selection.
static const int MASK_ATTRIBUTE_ADDRESS_TYPE = 0x30;
static int getGroupCountAndForwardPointer(const uint8_t *const dict, int *pos);
static uint8_t getFlagsAndForwardPointer(const uint8_t *const dict, int *pos);
static int getCodePointAndForwardPointer(const uint8_t *const dict, int *pos);
static int readProbabilityWithoutMovingPointer(const uint8_t *const dict, const int pos);
static int skipOtherCharacters(const uint8_t *const dict, const int pos);
static int skipChildrenPosition(const uint8_t flags, const int pos);
static int skipProbability(const uint8_t flags, const int pos);
static int skipShortcuts(const uint8_t *const dict, const uint8_t flags, const int pos);
static int skipChildrenPosAndAttributes(const uint8_t *const dict, const uint8_t flags,
const int pos);
static int readChildrenPosition(const uint8_t *const dict, const uint8_t flags, const int pos);
static bool hasChildrenInFlags(const uint8_t flags);
static int getTerminalPosition(const uint8_t *const root, const int *const inWord,
const int length, const bool forceLowerCaseSearch);
static int getCodePointsAndProbabilityAndReturnCodePointCount(
const uint8_t *const root, const int nodePos, const int maxCodePointCount,
int *const outCodePoints, int *const outUnigramProbability);
private:
DISALLOW_IMPLICIT_CONSTRUCTORS(BinaryFormat);
static const int FLAG_GROUP_ADDRESS_TYPE_NOADDRESS = 0x00;
static const int FLAG_GROUP_ADDRESS_TYPE_ONEBYTE = 0x40;
static const int FLAG_GROUP_ADDRESS_TYPE_TWOBYTES = 0x80;
static const int FLAG_GROUP_ADDRESS_TYPE_THREEBYTES = 0xC0;
static const int FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE = 0x10;
static const int FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES = 0x20;
static const int FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES = 0x30;
static const int CHARACTER_ARRAY_TERMINATOR_SIZE = 1;
static const int MINIMAL_ONE_BYTE_CHARACTER_VALUE = 0x20;
static const int CHARACTER_ARRAY_TERMINATOR = 0x1F;
static const int MULTIPLE_BYTE_CHARACTER_ADDITIONAL_SIZE = 2;
static const int NO_FLAGS = 0;
static int skipAllAttributes(const uint8_t *const dict, const uint8_t flags, const int pos);
static int skipBigrams(const uint8_t *const dict, const uint8_t flags, const int pos);
};
AK_FORCE_INLINE int BinaryFormat::getGroupCountAndForwardPointer(const uint8_t *const dict,
int *pos) {
const int msb = dict[(*pos)++];
if (msb < 0x80) return msb;
return ((msb & 0x7F) << 8) | dict[(*pos)++];
}
inline uint8_t BinaryFormat::getFlagsAndForwardPointer(const uint8_t *const dict, int *pos) {
return dict[(*pos)++];
}
AK_FORCE_INLINE int BinaryFormat::getCodePointAndForwardPointer(const uint8_t *const dict,
int *pos) {
const int origin = *pos;
const int codePoint = dict[origin];
if (codePoint < MINIMAL_ONE_BYTE_CHARACTER_VALUE) {
if (codePoint == CHARACTER_ARRAY_TERMINATOR) {
*pos = origin + 1;
return NOT_A_CODE_POINT;
} else {
*pos = origin + 3;
const int char_1 = codePoint << 16;
const int char_2 = char_1 + (dict[origin + 1] << 8);
return char_2 + dict[origin + 2];
}
} else {
*pos = origin + 1;
return codePoint;
}
}
inline int BinaryFormat::readProbabilityWithoutMovingPointer(const uint8_t *const dict,
const int pos) {
return dict[pos];
}
AK_FORCE_INLINE int BinaryFormat::skipOtherCharacters(const uint8_t *const dict, const int pos) {
int currentPos = pos;
int character = dict[currentPos++];
while (CHARACTER_ARRAY_TERMINATOR != character) {
if (character < MINIMAL_ONE_BYTE_CHARACTER_VALUE) {
currentPos += MULTIPLE_BYTE_CHARACTER_ADDITIONAL_SIZE;
}
character = dict[currentPos++];
}
return currentPos;
}
static inline int attributeAddressSize(const uint8_t flags) {
static const int ATTRIBUTE_ADDRESS_SHIFT = 4;
return (flags & BinaryFormat::MASK_ATTRIBUTE_ADDRESS_TYPE) >> ATTRIBUTE_ADDRESS_SHIFT;
/* Note: this is a value-dependant optimization of what may probably be
more readably written this way:
switch (flags * BinaryFormat::MASK_ATTRIBUTE_ADDRESS_TYPE) {
case FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE: return 1;
case FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES: return 2;
case FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTE: return 3;
default: return 0;
}
*/
}
static AK_FORCE_INLINE int skipExistingBigrams(const uint8_t *const dict, const int pos) {
int currentPos = pos;
uint8_t flags = BinaryFormat::getFlagsAndForwardPointer(dict, &currentPos);
while (flags & BinaryFormat::FLAG_ATTRIBUTE_HAS_NEXT) {
currentPos += attributeAddressSize(flags);
flags = BinaryFormat::getFlagsAndForwardPointer(dict, &currentPos);
}
currentPos += attributeAddressSize(flags);
return currentPos;
}
static inline int childrenAddressSize(const uint8_t flags) {
static const int CHILDREN_ADDRESS_SHIFT = 6;
return (BinaryFormat::MASK_GROUP_ADDRESS_TYPE & flags) >> CHILDREN_ADDRESS_SHIFT;
/* See the note in attributeAddressSize. The same applies here */
}
static AK_FORCE_INLINE int shortcutByteSize(const uint8_t *const dict, const int pos) {
return (static_cast<int>(dict[pos] << 8)) + (dict[pos + 1]);
}
inline int BinaryFormat::skipChildrenPosition(const uint8_t flags, const int pos) {
return pos + childrenAddressSize(flags);
}
inline int BinaryFormat::skipProbability(const uint8_t flags, const int pos) {
return FLAG_IS_TERMINAL & flags ? pos + 1 : pos;
}
AK_FORCE_INLINE int BinaryFormat::skipShortcuts(const uint8_t *const dict, const uint8_t flags,
const int pos) {
if (FLAG_HAS_SHORTCUT_TARGETS & flags) {
return pos + shortcutByteSize(dict, pos);
} else {
return pos;
}
}
AK_FORCE_INLINE int BinaryFormat::skipBigrams(const uint8_t *const dict, const uint8_t flags,
const int pos) {
if (FLAG_HAS_BIGRAMS & flags) {
return skipExistingBigrams(dict, pos);
} else {
return pos;
}
}
AK_FORCE_INLINE int BinaryFormat::skipAllAttributes(const uint8_t *const dict, const uint8_t flags,
const int pos) {
// This function skips all attributes: shortcuts and bigrams.
int newPos = pos;
newPos = skipShortcuts(dict, flags, newPos);
newPos = skipBigrams(dict, flags, newPos);
return newPos;
}
AK_FORCE_INLINE int BinaryFormat::skipChildrenPosAndAttributes(const uint8_t *const dict,
const uint8_t flags, const int pos) {
int currentPos = pos;
currentPos = skipChildrenPosition(flags, currentPos);
currentPos = skipAllAttributes(dict, flags, currentPos);
return currentPos;
}
AK_FORCE_INLINE int BinaryFormat::readChildrenPosition(const uint8_t *const dict,
const uint8_t flags, const int pos) {
int offset = 0;
switch (MASK_GROUP_ADDRESS_TYPE & flags) {
case FLAG_GROUP_ADDRESS_TYPE_ONEBYTE:
offset = dict[pos];
break;
case FLAG_GROUP_ADDRESS_TYPE_TWOBYTES:
offset = dict[pos] << 8;
offset += dict[pos + 1];
break;
case FLAG_GROUP_ADDRESS_TYPE_THREEBYTES:
offset = dict[pos] << 16;
offset += dict[pos + 1] << 8;
offset += dict[pos + 2];
break;
default:
// If we come here, it means we asked for the children of a word with
// no children.
return -1;
}
return pos + offset;
}
inline bool BinaryFormat::hasChildrenInFlags(const uint8_t flags) {
return (FLAG_GROUP_ADDRESS_TYPE_NOADDRESS != (MASK_GROUP_ADDRESS_TYPE & flags));
}
// This function gets the byte position of the last chargroup of the exact matching word in the
// dictionary. If no match is found, it returns NOT_A_VALID_WORD_POS.
AK_FORCE_INLINE int BinaryFormat::getTerminalPosition(const uint8_t *const root,
const int *const inWord, const int length, const bool forceLowerCaseSearch) {
int pos = 0;
int wordPos = 0;
while (true) {
// If we already traversed the tree further than the word is long, there means
// there was no match (or we would have found it).
if (wordPos >= length) return NOT_A_VALID_WORD_POS;
int charGroupCount = BinaryFormat::getGroupCountAndForwardPointer(root, &pos);
const int wChar = forceLowerCaseSearch
? CharUtils::toLowerCase(inWord[wordPos]) : inWord[wordPos];
while (true) {
// If there are no more character groups in this node, it means we could not
// find a matching character for this depth, therefore there is no match.
if (0 >= charGroupCount) return NOT_A_VALID_WORD_POS;
const int charGroupPos = pos;
const uint8_t flags = BinaryFormat::getFlagsAndForwardPointer(root, &pos);
int character = BinaryFormat::getCodePointAndForwardPointer(root, &pos);
if (character == wChar) {
// This is the correct node. Only one character group may start with the same
// char within a node, so either we found our match in this node, or there is
// no match and we can return NOT_A_VALID_WORD_POS. So we will check all the
// characters in this character group indeed does match.
if (FLAG_HAS_MULTIPLE_CHARS & flags) {
character = BinaryFormat::getCodePointAndForwardPointer(root, &pos);
while (NOT_A_CODE_POINT != character) {
++wordPos;
// If we shoot the length of the word we search for, or if we find a single
// character that does not match, as explained above, it means the word is
// not in the dictionary (by virtue of this chargroup being the only one to
// match the word on the first character, but not matching the whole word).
if (wordPos >= length) return NOT_A_VALID_WORD_POS;
if (inWord[wordPos] != character) return NOT_A_VALID_WORD_POS;
character = BinaryFormat::getCodePointAndForwardPointer(root, &pos);
}
}
// If we come here we know that so far, we do match. Either we are on a terminal
// and we match the length, in which case we found it, or we traverse children.
// If we don't match the length AND don't have children, then a word in the
// dictionary fully matches a prefix of the searched word but not the full word.
++wordPos;
if (FLAG_IS_TERMINAL & flags) {
if (wordPos == length) {
return charGroupPos;
}
pos = BinaryFormat::skipProbability(FLAG_IS_TERMINAL, pos);
}
if (FLAG_GROUP_ADDRESS_TYPE_NOADDRESS == (MASK_GROUP_ADDRESS_TYPE & flags)) {
return NOT_A_VALID_WORD_POS;
}
// We have children and we are still shorter than the word we are searching for, so
// we need to traverse children. Put the pointer on the children position, and
// break
pos = BinaryFormat::readChildrenPosition(root, flags, pos);
break;
} else {
// This chargroup does not match, so skip the remaining part and go to the next.
if (FLAG_HAS_MULTIPLE_CHARS & flags) {
pos = BinaryFormat::skipOtherCharacters(root, pos);
}
pos = BinaryFormat::skipProbability(flags, pos);
pos = BinaryFormat::skipChildrenPosAndAttributes(root, flags, pos);
}
--charGroupCount;
}
}
}
// This function searches for a terminal in the dictionary by its address.
// Due to the fact that words are ordered in the dictionary in a strict breadth-first order,
// it is possible to check for this with advantageous complexity. For each node, we search
// for groups with children and compare the children address with the address we look for.
// When we shoot the address we look for, it means the word we look for is in the children
// of the previous group. The only tricky part is the fact that if we arrive at the end of a
// node with the last group's children address still less than what we are searching for, we
// must descend the last group's children (for example, if the word we are searching for starts
// with a z, it's the last group of the root node, so all children addresses will be smaller
// than the address we look for, and we have to descend the z node).
/* Parameters :
* root: the dictionary buffer
* address: the byte position of the last chargroup of the word we are searching for (this is
* what is stored as the "bigram address" in each bigram)
* outword: an array to write the found word, with MAX_WORD_LENGTH size.
* outUnigramProbability: a pointer to an int to write the probability into.
* Return value : the length of the word, of 0 if the word was not found.
*/
AK_FORCE_INLINE int BinaryFormat::getCodePointsAndProbabilityAndReturnCodePointCount(
const uint8_t *const root, const int nodePos, const int maxCodePointCount,
int *const outCodePoints, int *const outUnigramProbability) {
int pos = 0;
int wordPos = 0;
// One iteration of the outer loop iterates through nodes. As stated above, we will only
// traverse nodes that are actually a part of the terminal we are searching, so each time
// we enter this loop we are one depth level further than last time.
// The only reason we count nodes is because we want to reduce the probability of infinite
// looping in case there is a bug. Since we know there is an upper bound to the depth we are
// supposed to traverse, it does not hurt to count iterations.
for (int loopCount = maxCodePointCount; loopCount > 0; --loopCount) {
int lastCandidateGroupPos = 0;
// Let's loop through char groups in this node searching for either the terminal
// or one of its ascendants.
for (int charGroupCount = getGroupCountAndForwardPointer(root, &pos); charGroupCount > 0;
--charGroupCount) {
const int startPos = pos;
const uint8_t flags = getFlagsAndForwardPointer(root, &pos);
const int character = getCodePointAndForwardPointer(root, &pos);
if (nodePos == startPos) {
// We found the address. Copy the rest of the word in the buffer and return
// the length.
outCodePoints[wordPos] = character;
if (FLAG_HAS_MULTIPLE_CHARS & flags) {
int nextChar = getCodePointAndForwardPointer(root, &pos);
// We count chars in order to avoid infinite loops if the file is broken or
// if there is some other bug
int charCount = maxCodePointCount;
while (NOT_A_CODE_POINT != nextChar && --charCount > 0) {
outCodePoints[++wordPos] = nextChar;
nextChar = getCodePointAndForwardPointer(root, &pos);
}
}
*outUnigramProbability = readProbabilityWithoutMovingPointer(root, pos);
return ++wordPos;
}
// We need to skip past this char group, so skip any remaining chars after the
// first and possibly the probability.
if (FLAG_HAS_MULTIPLE_CHARS & flags) {
pos = skipOtherCharacters(root, pos);
}
pos = skipProbability(flags, pos);
// The fact that this group has children is very important. Since we already know
// that this group does not match, if it has no children we know it is irrelevant
// to what we are searching for.
const bool hasChildren = (FLAG_GROUP_ADDRESS_TYPE_NOADDRESS !=
(MASK_GROUP_ADDRESS_TYPE & flags));
// We will write in `found' whether we have passed the children address we are
// searching for. For example if we search for "beer", the children of b are less
// than the address we are searching for and the children of c are greater. When we
// come here for c, we realize this is too big, and that we should descend b.
bool found;
if (hasChildren) {
// Here comes the tricky part. First, read the children position.
const int childrenPos = readChildrenPosition(root, flags, pos);
if (childrenPos > nodePos) {
// If the children pos is greater than address, it means the previous chargroup,
// which address is stored in lastCandidateGroupPos, was the right one.
found = true;
} else if (1 >= charGroupCount) {
// However if we are on the LAST group of this node, and we have NOT shot the
// address we should descend THIS node. So we trick the lastCandidateGroupPos
// so that we will descend this node, not the previous one.
lastCandidateGroupPos = startPos;
found = true;
} else {
// Else, we should continue looking.
found = false;
}
} else {
// Even if we don't have children here, we could still be on the last group of this
// node. If this is the case, we should descend the last group that had children,
// and their address is already in lastCandidateGroup.
found = (1 >= charGroupCount);
}
if (found) {
// Okay, we found the group we should descend. Its address is in
// the lastCandidateGroupPos variable, so we just re-read it.
if (0 != lastCandidateGroupPos) {
const uint8_t lastFlags =
getFlagsAndForwardPointer(root, &lastCandidateGroupPos);
const int lastChar =
getCodePointAndForwardPointer(root, &lastCandidateGroupPos);
// We copy all the characters in this group to the buffer
outCodePoints[wordPos] = lastChar;
if (FLAG_HAS_MULTIPLE_CHARS & lastFlags) {
int nextChar = getCodePointAndForwardPointer(root, &lastCandidateGroupPos);
int charCount = maxCodePointCount;
while (-1 != nextChar && --charCount > 0) {
outCodePoints[++wordPos] = nextChar;
nextChar = getCodePointAndForwardPointer(root, &lastCandidateGroupPos);
}
}
++wordPos;
// Now we only need to branch to the children address. Skip the probability if
// it's there, read pos, and break to resume the search at pos.
lastCandidateGroupPos = skipProbability(lastFlags, lastCandidateGroupPos);
pos = readChildrenPosition(root, lastFlags, lastCandidateGroupPos);
break;
} else {
// Here is a little tricky part: we come here if we found out that all children
// addresses in this group are bigger than the address we are searching for.
// Should we conclude the word is not in the dictionary? No! It could still be
// one of the remaining chargroups in this node, so we have to keep looking in
// this node until we find it (or we realize it's not there either, in which
// case it's actually not in the dictionary). Pass the end of this group, ready
// to start the next one.
pos = skipChildrenPosAndAttributes(root, flags, pos);
}
} else {
// If we did not find it, we should record the last children address for the next
// iteration.
if (hasChildren) lastCandidateGroupPos = startPos;
// Now skip the end of this group (children pos and the attributes if any) so that
// our pos is after the end of this char group, at the start of the next one.
pos = skipChildrenPosAndAttributes(root, flags, pos);
}
}
}
// If we have looked through all the chargroups and found no match, the address is
// not the address of a terminal in this dictionary.
return 0;
}
} // namespace latinime
#endif // LATINIME_BINARY_FORMAT_H

265
native/jni/src/suggest/policyimpl/dictionary/patricia_trie_policy.cpp
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@ -20,7 +20,6 @@
#include "defines.h"
#include "suggest/core/dicnode/dic_node.h"
#include "suggest/core/dicnode/dic_node_vector.h"
#include "suggest/policyimpl/dictionary/binary_format.h"
#include "suggest/policyimpl/dictionary/patricia_trie_reading_utils.h"
namespace latinime {
@ -38,17 +37,273 @@ void PatriciaTriePolicy::createAndGetAllChildNodes(const DicNode *const dicNode,
}
}
// This retrieves code points and the probability of the word by its terminal position.
// Due to the fact that words are ordered in the dictionary in a strict breadth-first order,
// it is possible to check for this with advantageous complexity. For each node, we search
// for groups with children and compare the children position with the position we look for.
// When we shoot the position we look for, it means the word we look for is in the children
// of the previous group. The only tricky part is the fact that if we arrive at the end of a
// node with the last group's children position still less than what we are searching for, we
// must descend the last group's children (for example, if the word we are searching for starts
// with a z, it's the last group of the root node, so all children addresses will be smaller
// than the position we look for, and we have to descend the z node).
/* Parameters :
* nodePos: the byte position of the terminal chargroup of the word we are searching for (this is
* what is stored as the "bigram position" in each bigram)
* outCodePoints: an array to write the found word, with MAX_WORD_LENGTH size.
* outUnigramProbability: a pointer to an int to write the probability into.
* Return value : the code point count, of 0 if the word was not found.
*/
// TODO: Split this function to be more readable
int PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
const int nodePos, const int maxCodePointCount, int *const outCodePoints,
int *const outUnigramProbability) const {
return BinaryFormat::getCodePointsAndProbabilityAndReturnCodePointCount(mDictRoot, nodePos,
maxCodePointCount, outCodePoints, outUnigramProbability);
int pos = getRootPosition();
int wordPos = 0;
// One iteration of the outer loop iterates through nodes. As stated above, we will only
// traverse nodes that are actually a part of the terminal we are searching, so each time
// we enter this loop we are one depth level further than last time.
// The only reason we count nodes is because we want to reduce the probability of infinite
// looping in case there is a bug. Since we know there is an upper bound to the depth we are
// supposed to traverse, it does not hurt to count iterations.
for (int loopCount = maxCodePointCount; loopCount > 0; --loopCount) {
int lastCandidateGroupPos = 0;
// Let's loop through char groups in this node searching for either the terminal
// or one of its ascendants.
for (int charGroupCount = PatriciaTrieReadingUtils::getGroupCountAndAdvancePosition(
mDictRoot, &pos); charGroupCount > 0; --charGroupCount) {
const int startPos = pos;
const PatriciaTrieReadingUtils::NodeFlags flags =
PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(mDictRoot, &pos);
const int character = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &pos);
if (nodePos == startPos) {
// We found the position. Copy the rest of the code points in the buffer and return
// the length.
outCodePoints[wordPos] = character;
if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
int nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &pos);
// We count code points in order to avoid infinite loops if the file is broken
// or if there is some other bug
int charCount = maxCodePointCount;
while (NOT_A_CODE_POINT != nextChar && --charCount > 0) {
outCodePoints[++wordPos] = nextChar;
nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &pos);
}
}
*outUnigramProbability =
PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot,
&pos);
return ++wordPos;
}
// We need to skip past this char group, so skip any remaining code points after the
// first and possibly the probability.
if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
PatriciaTrieReadingUtils::skipCharacters(mDictRoot, flags, MAX_WORD_LENGTH, &pos);
}
if (PatriciaTrieReadingUtils::isTerminal(flags)) {
PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot, &pos);
}
// The fact that this group has children is very important. Since we already know
// that this group does not match, if it has no children we know it is irrelevant
// to what we are searching for.
const bool hasChildren = PatriciaTrieReadingUtils::hasChildrenInFlags(flags);
// We will write in `found' whether we have passed the children position we are
// searching for. For example if we search for "beer", the children of b are less
// than the address we are searching for and the children of c are greater. When we
// come here for c, we realize this is too big, and that we should descend b.
bool found;
if (hasChildren) {
int currentPos = pos;
// Here comes the tricky part. First, read the children position.
const int childrenPos = PatriciaTrieReadingUtils
::readChildrenPositionAndAdvancePosition(mDictRoot, flags, &currentPos);
if (childrenPos > nodePos) {
// If the children pos is greater than the position, it means the previous
// chargroup, which position is stored in lastCandidateGroupPos, was the right
// one.
found = true;
} else if (1 >= charGroupCount) {
// However if we are on the LAST group of this node, and we have NOT shot the
// position we should descend THIS node. So we trick the lastCandidateGroupPos
// so that we will descend this node, not the previous one.
lastCandidateGroupPos = startPos;
found = true;
} else {
// Else, we should continue looking.
found = false;
}
} else {
// Even if we don't have children here, we could still be on the last group of this
// node. If this is the case, we should descend the last group that had children,
// and their position is already in lastCandidateGroup.
found = (1 >= charGroupCount);
}
if (found) {
// Okay, we found the group we should descend. Its position is in
// the lastCandidateGroupPos variable, so we just re-read it.
if (0 != lastCandidateGroupPos) {
const PatriciaTrieReadingUtils::NodeFlags lastFlags =
PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(
mDictRoot, &lastCandidateGroupPos);
const int lastChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &lastCandidateGroupPos);
// We copy all the characters in this group to the buffer
outCodePoints[wordPos] = lastChar;
if (PatriciaTrieReadingUtils::hasMultipleChars(lastFlags)) {
int nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &lastCandidateGroupPos);
int charCount = maxCodePointCount;
while (-1 != nextChar && --charCount > 0) {
outCodePoints[++wordPos] = nextChar;
nextChar = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &lastCandidateGroupPos);
}
}
++wordPos;
// Now we only need to branch to the children address. Skip the probability if
// it's there, read pos, and break to resume the search at pos.
if (PatriciaTrieReadingUtils::isTerminal(lastFlags)) {
PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot,
&lastCandidateGroupPos);
}
pos = PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
mDictRoot, lastFlags, &lastCandidateGroupPos);
break;
} else {
// Here is a little tricky part: we come here if we found out that all children
// addresses in this group are bigger than the address we are searching for.
// Should we conclude the word is not in the dictionary? No! It could still be
// one of the remaining chargroups in this node, so we have to keep looking in
// this node until we find it (or we realize it's not there either, in which
// case it's actually not in the dictionary). Pass the end of this group, ready
// to start the next one.
if (PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
mDictRoot, flags, &pos);
}
if (PatriciaTrieReadingUtils::hasShortcutTargets(flags)) {
mShortcutListPolicy.skipAllShortcuts(&pos);
}
if (PatriciaTrieReadingUtils::hasBigrams(flags)) {
mBigramListPolicy.skipAllBigrams(&pos);
}
}
} else {
// If we did not find it, we should record the last children address for the next
// iteration.
if (hasChildren) lastCandidateGroupPos = startPos;
// Now skip the end of this group (children pos and the attributes if any) so that
// our pos is after the end of this char group, at the start of the next one.
if (PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(
mDictRoot, flags, &pos);
}
if (PatriciaTrieReadingUtils::hasShortcutTargets(flags)) {
mShortcutListPolicy.skipAllShortcuts(&pos);
}
if (PatriciaTrieReadingUtils::hasBigrams(flags)) {
mBigramListPolicy.skipAllBigrams(&pos);
}
}
}
}
// If we have looked through all the chargroups and found no match, the nodePos is
// not the position of a terminal in this dictionary.
return 0;
}
// This function gets the position of the terminal node of the exact matching word in the
// dictionary. If no match is found, it returns NOT_A_VALID_WORD_POS.
int PatriciaTriePolicy::getTerminalNodePositionOfWord(const int *const inWord,
const int length, const bool forceLowerCaseSearch) const {
return BinaryFormat::getTerminalPosition(mDictRoot, inWord,
length, forceLowerCaseSearch);
int pos = getRootPosition();
int wordPos = 0;
while (true) {
// If we already traversed the tree further than the word is long, there means
// there was no match (or we would have found it).
if (wordPos >= length) return NOT_A_VALID_WORD_POS;
int charGroupCount = PatriciaTrieReadingUtils::getGroupCountAndAdvancePosition(mDictRoot,
&pos);
const int wChar = forceLowerCaseSearch
? CharUtils::toLowerCase(inWord[wordPos]) : inWord[wordPos];
while (true) {
// If there are no more character groups in this node, it means we could not
// find a matching character for this depth, therefore there is no match.
if (0 >= charGroupCount) return NOT_A_VALID_WORD_POS;
const int charGroupPos = pos;
const PatriciaTrieReadingUtils::NodeFlags flags =
PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(mDictRoot, &pos);
int character = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(mDictRoot,
&pos);
if (character == wChar) {
// This is the correct node. Only one character group may start with the same
// char within a node, so either we found our match in this node, or there is
// no match and we can return NOT_A_VALID_WORD_POS. So we will check all the
// characters in this character group indeed does match.
if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
character = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(mDictRoot,
&pos);
while (NOT_A_CODE_POINT != character) {
++wordPos;
// If we shoot the length of the word we search for, or if we find a single
// character that does not match, as explained above, it means the word is
// not in the dictionary (by virtue of this chargroup being the only one to
// match the word on the first character, but not matching the whole word).
if (wordPos >= length) return NOT_A_VALID_WORD_POS;
if (inWord[wordPos] != character) return NOT_A_VALID_WORD_POS;
character = PatriciaTrieReadingUtils::getCodePointAndAdvancePosition(
mDictRoot, &pos);
}
}
// If we come here we know that so far, we do match. Either we are on a terminal
// and we match the length, in which case we found it, or we traverse children.
// If we don't match the length AND don't have children, then a word in the
// dictionary fully matches a prefix of the searched word but not the full word.
++wordPos;
if (PatriciaTrieReadingUtils::isTerminal(flags)) {
if (wordPos == length) {
return charGroupPos;
}
PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot, &pos);
}
if (!PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
return NOT_A_VALID_WORD_POS;
}
// We have children and we are still shorter than the word we are searching for, so
// we need to traverse children. Put the pointer on the children position, and
// break
pos = PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(mDictRoot,
flags, &pos);
break;
} else {
// This chargroup does not match, so skip the remaining part and go to the next.
if (PatriciaTrieReadingUtils::hasMultipleChars(flags)) {
PatriciaTrieReadingUtils::skipCharacters(mDictRoot, flags, MAX_WORD_LENGTH,
&pos);
}
if (PatriciaTrieReadingUtils::isTerminal(flags)) {
PatriciaTrieReadingUtils::readProbabilityAndAdvancePosition(mDictRoot, &pos);
}
if (PatriciaTrieReadingUtils::hasChildrenInFlags(flags)) {
PatriciaTrieReadingUtils::readChildrenPositionAndAdvancePosition(mDictRoot,
flags, &pos);
}
if (PatriciaTrieReadingUtils::hasShortcutTargets(flags)) {
mShortcutListPolicy.skipAllShortcuts(&pos);
}
if (PatriciaTrieReadingUtils::hasBigrams(flags)) {
mBigramListPolicy.skipAllBigrams(&pos);
}
}
--charGroupCount;
}
}
}
int PatriciaTriePolicy::getUnigramProbability(const int nodePos) const {