1bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi/* 2bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * Copyright (C) 2017 The Android Open Source Project 3bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * 4bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * Licensed under the Apache License, Version 2.0 (the "License"); 5bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * you may not use this file except in compliance with the License. 6bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * You may obtain a copy of the License at 7bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * 8bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * http://www.apache.org/licenses/LICENSE-2.0 9bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * 10bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * Unless required by applicable law or agreed to in writing, software 11bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * distributed under the License is distributed on an "AS IS" BASIS, 12bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * See the License for the specific language governing permissions and 14bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi * limitations under the License. 15bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi */ 16bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 17bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi#include "smartselect/tokenizer.h" 18bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 19bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi#include "util/strings/utf8.h" 20bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi#include "util/utf8/unicodetext.h" 21bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 22bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifinamespace libtextclassifier { 23bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 24bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifivoid Tokenizer::PrepareTokenizationCodepointRanges( 2526e8c2edb55f8c4efc47bc586edd5f9506e281a7Lukas Zilka const std::vector<TokenizationCodepointRange>& codepoint_range_configs) { 26bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi codepoint_ranges_.clear(); 27bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi codepoint_ranges_.reserve(codepoint_range_configs.size()); 28bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi for (const TokenizationCodepointRange& range : codepoint_range_configs) { 29bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi codepoint_ranges_.push_back( 30bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi CodepointRange(range.start(), range.end(), range.role())); 31bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 32bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 33bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi std::sort(codepoint_ranges_.begin(), codepoint_ranges_.end(), 34bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi [](const CodepointRange& a, const CodepointRange& b) { 35bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi return a.start < b.start; 36bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi }); 37bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi} 38bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 39bda09f1da39ce38a5ece4757b82a64776e53214cMatt SharifiTokenizationCodepointRange::Role Tokenizer::FindTokenizationRole( 40bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi int codepoint) const { 41bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi auto it = std::lower_bound(codepoint_ranges_.begin(), codepoint_ranges_.end(), 42bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi codepoint, 43bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi [](const CodepointRange& range, int codepoint) { 44bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // This function compares range with the 45bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // codepoint for the purpose of finding the first 46bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // greater or equal range. Because of the use of 47bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // std::lower_bound it needs to return true when 48bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // range < codepoint; the first time it will 49bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // return false the lower bound is found and 50bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // returned. 51bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // 52bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi // It might seem weird that the condition is 5391f068673f5915dd4c12fac026e4a043e4a063a0Matt Sharifi // range.end <= codepoint here but when codepoint 5491f068673f5915dd4c12fac026e4a043e4a063a0Matt Sharifi // == range.end it means it's actually just 5591f068673f5915dd4c12fac026e4a043e4a063a0Matt Sharifi // outside of the range, thus the range is less 5691f068673f5915dd4c12fac026e4a043e4a063a0Matt Sharifi // than the codepoint. 57bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi return range.end <= codepoint; 58bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi }); 59bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (it != codepoint_ranges_.end() && it->start <= codepoint && 60bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi it->end > codepoint) { 61bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi return it->role; 62bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } else { 63bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi return TokenizationCodepointRange::DEFAULT_ROLE; 64bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 65bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi} 66bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 67bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifistd::vector<Token> Tokenizer::Tokenize(const std::string& utf8_text) const { 68bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi UnicodeText context_unicode = UTF8ToUnicodeText(utf8_text, /*do_copy=*/false); 69bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 70bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi std::vector<Token> result; 71bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi Token new_token("", 0, 0); 72bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi int codepoint_index = 0; 73bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi for (auto it = context_unicode.begin(); it != context_unicode.end(); 74bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi ++it, ++codepoint_index) { 75bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi TokenizationCodepointRange::Role role = FindTokenizationRole(*it); 76bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (role & TokenizationCodepointRange::SPLIT_BEFORE) { 77bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (!new_token.value.empty()) { 78bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi result.push_back(new_token); 79bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 80bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi new_token = Token("", codepoint_index, codepoint_index); 81bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 82bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (!(role & TokenizationCodepointRange::DISCARD_CODEPOINT)) { 83bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi new_token.value += std::string( 84bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi it.utf8_data(), 85bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi it.utf8_data() + GetNumBytesForNonZeroUTF8Char(it.utf8_data())); 86bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi ++new_token.end; 87bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 88bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (role & TokenizationCodepointRange::SPLIT_AFTER) { 89bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (!new_token.value.empty()) { 90bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi result.push_back(new_token); 91bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 92bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi new_token = Token("", codepoint_index + 1, codepoint_index + 1); 93bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 94bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 95bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi if (!new_token.value.empty()) { 96bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi result.push_back(new_token); 97bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi } 98bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 99bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi return result; 100bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi} 101bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi 102bda09f1da39ce38a5ece4757b82a64776e53214cMatt Sharifi} // namespace libtextclassifier 103