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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.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_RUN_SEGMENTER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_RUN_SEGMENTER_H_
#include <unicode/uscript.h>
#include <memory>
#include <optional>
#include "base/containers/span.h"
#include "third_party/blink/renderer/platform/fonts/font_orientation.h"
#include "third_party/blink/renderer/platform/fonts/orientation_iterator.h"
#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/wtf/allocator/allocator.h"
namespace blink {
// A tool for segmenting runs prior to shaping, combining ScriptIterator,
// OrientationIterator and SmallCapsIterator, depending on orientaton and
// font-variant of the text run.
class PLATFORM_EXPORT RunSegmenter {
STACK_ALLOCATED();
public:
// Indices into the UTF-16 buffer that is passed in
struct PLATFORM_EXPORT RunSegmenterRange {
unsigned start = 0;
unsigned end = 0;
UScriptCode script = USCRIPT_INVALID_CODE;
OrientationIterator::RenderOrientation render_orientation =
OrientationIterator::kOrientationKeep;
FontFallbackPriority font_fallback_priority = FontFallbackPriority::kText;
};
// Initialize a RunSegmenter.
RunSegmenter(base::span<const UChar> buffer, FontOrientation);
RunSegmenter(const RunSegmenter&) = delete;
RunSegmenter& operator=(const RunSegmenter&) = delete;
bool Consume(RunSegmenterRange*);
private:
template <class Iterator, typename SegmentationCategory>
void ConsumeIteratorPastLastSplit(
Iterator& iterator,
unsigned* iterator_position,
SegmentationCategory* segmentation_category);
unsigned buffer_size_;
RunSegmenterRange candidate_range_;
ScriptRunIterator script_run_iterator_;
std::optional<OrientationIterator> orientation_iterator_;
SymbolsIterator symbols_iterator_;
unsigned last_split_ = 0;
unsigned script_run_iterator_position_ = 0;
unsigned orientation_iterator_position_ = 0;
unsigned symbols_iterator_position_ = 0;
bool at_end_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_RUN_SEGMENTER_H_
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