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/*
* Copyright (C) 2015 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 <vector>
#include <memory>
#include <algorithm>
#include <string>
#include <unicode/uchar.h>
// HACK: for reading pattern file
#include <fcntl.h>
#define LOG_TAG "Minikin"
#include "utils/Log.h"
#include "minikin/Hyphenator.h"
using std::vector;
namespace android {
static const uint16_t CHAR_SOFT_HYPHEN = 0x00AD;
void Hyphenator::addPattern(const uint16_t* pattern, size_t size) {
vector<uint16_t> word;
vector<uint8_t> result;
// start by parsing the Liang-format pattern into a word and a result vector, the
// vector right-aligned but without leading zeros. Examples:
// a1bc2d -> abcd [1, 0, 2, 0]
// abc1 -> abc [1]
// 1a2b3c4d5 -> abcd [1, 2, 3, 4, 5]
bool lastWasLetter = false;
bool haveSeenNumber = false;
for (size_t i = 0; i < size; i++) {
uint16_t c = pattern[i];
if (isdigit(c)) {
result.push_back(c - '0');
lastWasLetter = false;
haveSeenNumber = true;
} else {
word.push_back(c);
if (lastWasLetter && haveSeenNumber) {
result.push_back(0);
}
lastWasLetter = true;
}
}
if (lastWasLetter) {
result.push_back(0);
}
Trie* t = &root;
for (size_t i = 0; i < word.size(); i++) {
t = &t->succ[word[i]];
}
t->result = result;
}
// If any soft hyphen is present in the word, use soft hyphens to decide hyphenation,
// as recommended in UAX #14 (Use of Soft Hyphen)
void Hyphenator::hyphenateSoft(vector<uint8_t>* result, const uint16_t* word, size_t len) {
(*result)[0] = 0;
for (size_t i = 1; i < len; i++) {
(*result)[i] = word[i - 1] == CHAR_SOFT_HYPHEN;
}
}
void Hyphenator::hyphenate(vector<uint8_t>* result, const uint16_t* word, size_t len) {
result->clear();
result->resize(len);
if (len < MIN_PREFIX + MIN_SUFFIX) return;
size_t maxOffset = len - MIN_SUFFIX + 1;
for (size_t i = 0; i < len + 1; i++) {
const Trie* node = &root;
for (size_t j = i; j < len + 2; j++) {
uint16_t c;
if (j == 0 || j == len + 1) {
c = '.'; // word boundary character in pattern data files
} else {
c = word[j - 1];
if (c == CHAR_SOFT_HYPHEN) {
hyphenateSoft(result, word, len);
return;
}
// TODO: This uses ICU's simple character to character lowercasing, which ignores
// the locale, and ignores cases when lowercasing a character results in more than
// one character. It should be fixed to consider the locale (in order for it to work
// correctly for Turkish and Azerbaijani), as well as support one-to-many, and
// many-to-many case conversions (including non-BMP cases).
if (c < 0x00C0) { // U+00C0 is the lowest uppercase non-ASCII character
// Convert uppercase ASCII to lowercase ASCII, but keep other characters as-is
if (0x0041 <= c && c <= 0x005A) {
c += 0x0020;
}
} else {
c = u_tolower(c);
}
}
auto search = node->succ.find(c);
if (search != node->succ.end()) {
node = &search->second;
} else {
break;
}
if (!node->result.empty()) {
int resultLen = node->result.size();
int offset = j + 1 - resultLen;
int start = std::max(MIN_PREFIX - offset, 0);
int end = std::min(resultLen, (int)maxOffset - offset);
// TODO performance: this inner loop can profitably be optimized
for (int k = start; k < end; k++) {
(*result)[offset + k] = std::max((*result)[offset + k], node->result[k]);
}
#if 0
// debug printing of matched patterns
std::string dbg;
for (size_t k = i; k <= j + 1; k++) {
int off = k - j - 2 + resultLen;
if (off >= 0 && node->result[off] != 0) {
dbg.push_back((char)('0' + node->result[off]));
}
if (k < j + 1) {
uint16_t c = (k == 0 || k == len + 1) ? '.' : word[k - 1];
dbg.push_back((char)c);
}
}
ALOGD("%d:%d %s", i, j, dbg.c_str());
#endif
}
}
}
// Since the above calculation does not modify values outside
// [MIN_PREFIX, len - MIN_SUFFIX], they are left as 0.
for (size_t i = MIN_PREFIX; i < maxOffset; i++) {
(*result)[i] &= 1;
}
}
Hyphenator* Hyphenator::load(const uint16_t *patternData, size_t size) {
Hyphenator* result = new Hyphenator;
for (size_t i = 0; i < size; i++) {
size_t end = i;
while (patternData[end] != '\n') end++;
result->addPattern(patternData + i, end - i);
i = end;
}
return result;
}
} // namespace android
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