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// Copyright 2015 The Chromium Authors
// 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"
namespace blink {
RunSegmenter::RunSegmenter(base::span<const UChar> buffer,
FontOrientation run_orientation)
: buffer_size_(base::checked_cast<wtf_size_t>(buffer.size())),
script_run_iterator_(buffer),
symbols_iterator_(buffer),
at_end_(buffer.empty()) {
if (run_orientation == FontOrientation::kVerticalMixed) [[unlikely]] {
orientation_iterator_.emplace(buffer, run_orientation);
}
}
template <class Iterator, typename SegmentationCategory>
void RunSegmenter::ConsumeIteratorPastLastSplit(
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(symbols_iterator_, &symbols_iterator_position_,
&candidate_range_.font_fallback_priority);
if (orientation_iterator_) [[unlikely]] {
ConsumeIteratorPastLastSplit(*orientation_iterator_,
&orientation_iterator_position_,
&candidate_range_.render_orientation);
unsigned positions[] = {script_run_iterator_position_,
symbols_iterator_position_,
orientation_iterator_position_};
last_split_ = *std::ranges::min_element(positions);
} else {
last_split_ =
std::min(script_run_iterator_position_, symbols_iterator_position_);
}
candidate_range_.start = candidate_range_.end;
candidate_range_.end = last_split_;
*next_range = candidate_range_;
at_end_ = last_split_ == buffer_size_;
return true;
}
} // namespace blink
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