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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/orientation_iterator.h"
#include <memory>
namespace blink {
OrientationIterator::OrientationIterator(base::span<const UChar> buffer,
FontOrientation run_orientation)
: utf16_iterator_(buffer), at_end_(buffer.empty()) {
// There's not much point in segmenting by IsUprightInMixedVertical if the
// text orientation is not "mixed".
DCHECK_EQ(run_orientation, FontOrientation::kVerticalMixed);
}
bool OrientationIterator::Consume(unsigned* orientation_limit,
RenderOrientation* render_orientation) {
if (at_end_)
return false;
RenderOrientation current_render_orientation = kOrientationInvalid;
UChar32 next_u_char32;
while (utf16_iterator_.Consume(next_u_char32)) {
if (current_render_orientation == kOrientationInvalid ||
!Character::IsGraphemeExtended(next_u_char32)) {
RenderOrientation previous_render_orientation =
current_render_orientation;
current_render_orientation =
Character::IsUprightInMixedVertical(next_u_char32)
? kOrientationKeep
: kOrientationRotateSideways;
if (previous_render_orientation != current_render_orientation &&
previous_render_orientation != kOrientationInvalid) {
*orientation_limit = utf16_iterator_.Offset();
*render_orientation = previous_render_orientation;
return true;
}
}
utf16_iterator_.Advance();
}
*orientation_limit = utf16_iterator_.Size();
*render_orientation = current_render_orientation;
at_end_ = true;
return true;
}
} // namespace blink
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