| /* |
| * Copyright (C) 2018 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 "annotator/strip-unpaired-brackets.h" |
| |
| #include <iterator> |
| |
| #include "utils/base/logging.h" |
| #include "utils/utf8/unicodetext.h" |
| |
| namespace libtextclassifier3 { |
| namespace { |
| |
| // Returns true if given codepoint is contained in the given span in context. |
| bool IsCodepointInSpan(const char32 codepoint, |
| const UnicodeText& context_unicode, |
| const CodepointSpan span) { |
| auto begin_it = context_unicode.begin(); |
| std::advance(begin_it, span.first); |
| auto end_it = context_unicode.begin(); |
| std::advance(end_it, span.second); |
| |
| return std::find(begin_it, end_it, codepoint) != end_it; |
| } |
| |
| // Returns the first codepoint of the span. |
| char32 FirstSpanCodepoint(const UnicodeText& context_unicode, |
| const CodepointSpan span) { |
| auto it = context_unicode.begin(); |
| std::advance(it, span.first); |
| return *it; |
| } |
| |
| // Returns the last codepoint of the span. |
| char32 LastSpanCodepoint(const UnicodeText& context_unicode, |
| const CodepointSpan span) { |
| auto it = context_unicode.begin(); |
| std::advance(it, span.second - 1); |
| return *it; |
| } |
| |
| } // namespace |
| |
| CodepointSpan StripUnpairedBrackets(const std::string& context, |
| CodepointSpan span, const UniLib& unilib) { |
| const UnicodeText context_unicode = |
| UTF8ToUnicodeText(context, /*do_copy=*/false); |
| return StripUnpairedBrackets(context_unicode, span, unilib); |
| } |
| |
| // If the first or the last codepoint of the given span is a bracket, the |
| // bracket is stripped if the span does not contain its corresponding paired |
| // version. |
| CodepointSpan StripUnpairedBrackets(const UnicodeText& context_unicode, |
| CodepointSpan span, const UniLib& unilib) { |
| if (context_unicode.empty() || !ValidNonEmptySpan(span)) { |
| return span; |
| } |
| |
| const char32 begin_char = FirstSpanCodepoint(context_unicode, span); |
| const char32 paired_begin_char = unilib.GetPairedBracket(begin_char); |
| if (paired_begin_char != begin_char) { |
| if (!unilib.IsOpeningBracket(begin_char) || |
| !IsCodepointInSpan(paired_begin_char, context_unicode, span)) { |
| ++span.first; |
| } |
| } |
| |
| if (span.first == span.second) { |
| return span; |
| } |
| |
| const char32 end_char = LastSpanCodepoint(context_unicode, span); |
| const char32 paired_end_char = unilib.GetPairedBracket(end_char); |
| if (paired_end_char != end_char) { |
| if (!unilib.IsClosingBracket(end_char) || |
| !IsCodepointInSpan(paired_end_char, context_unicode, span)) { |
| --span.second; |
| } |
| } |
| |
| // Should not happen, but let's make sure. |
| if (span.first > span.second) { |
| TC3_LOG(WARNING) << "Inverse indices result: " << span.first << ", " |
| << span.second; |
| span.second = span.first; |
| } |
| |
| return span; |
| } |
| |
| } // namespace libtextclassifier3 |