| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "third_party/blink/renderer/platform/fonts/shaping/run_segmenter.h" |
| |
| #include <algorithm> |
| #include <memory> |
| |
| #include "third_party/blink/renderer/platform/fonts/script_run_iterator.h" |
| #include "third_party/blink/renderer/platform/fonts/small_caps_iterator.h" |
| #include "third_party/blink/renderer/platform/fonts/symbols_iterator.h" |
| #include "third_party/blink/renderer/platform/fonts/utf16_text_iterator.h" |
| #include "third_party/blink/renderer/platform/text/character.h" |
| #include "third_party/blink/renderer/platform/wtf/assertions.h" |
| |
| namespace blink { |
| |
| RunSegmenter::RunSegmenter(const UChar* buffer, |
| unsigned buffer_size, |
| FontOrientation run_orientation, |
| unsigned start_offset) |
| : buffer_size_(buffer_size), |
| start_offset_(start_offset), |
| candidate_range_(NullRange(start_offset)), |
| script_run_iterator_( |
| std::make_unique<ScriptRunIterator>(buffer + start_offset, |
| buffer_size)), |
| orientation_iterator_( |
| run_orientation == FontOrientation::kVerticalMixed |
| ? std::make_unique<OrientationIterator>(buffer + start_offset, |
| buffer_size, |
| run_orientation) |
| : nullptr), |
| symbols_iterator_(std::make_unique<SymbolsIterator>(buffer + start_offset, |
| buffer_size)), |
| last_split_(0), |
| script_run_iterator_position_(0), |
| orientation_iterator_position_( |
| run_orientation == FontOrientation::kVerticalMixed ? 0 |
| : buffer_size_), |
| symbols_iterator_position_(0), |
| at_end_(!buffer_size_) {} |
| |
| template <class Iterator, typename SegmentationCategory> |
| void RunSegmenter::ConsumeIteratorPastLastSplit( |
| std::unique_ptr<Iterator>& iterator, |
| unsigned* iterator_position, |
| SegmentationCategory* segmentation_category) { |
| if (*iterator_position <= last_split_ && *iterator_position < buffer_size_) { |
| while (iterator->Consume(iterator_position, segmentation_category)) { |
| if (*iterator_position > last_split_) |
| return; |
| } |
| } |
| } |
| |
| // Consume the input until the next range. Returns false if no more ranges are |
| // available. |
| bool RunSegmenter::Consume(RunSegmenterRange* next_range) { |
| if (at_end_) |
| return false; |
| |
| ConsumeIteratorPastLastSplit(script_run_iterator_, |
| &script_run_iterator_position_, |
| &candidate_range_.script); |
| ConsumeIteratorPastLastSplit(orientation_iterator_, |
| &orientation_iterator_position_, |
| &candidate_range_.render_orientation); |
| ConsumeIteratorPastLastSplit(symbols_iterator_, &symbols_iterator_position_, |
| &candidate_range_.font_fallback_priority); |
| |
| unsigned positions[] = {script_run_iterator_position_, |
| orientation_iterator_position_, |
| symbols_iterator_position_}; |
| |
| last_split_ = *std::min_element(std::begin(positions), std::end(positions)); |
| |
| candidate_range_.start = candidate_range_.end; |
| candidate_range_.end = last_split_ + start_offset_; |
| *next_range = candidate_range_; |
| |
| at_end_ = (last_split_ == buffer_size_); |
| return true; |
| } |
| |
| } // namespace blink |
