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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/intl/Bidi.h"
#include "mozilla/Casting.h"
#include "mozilla/intl/ICU4CGlue.h"
#include "unicode/ubidi.h"
namespace mozilla::intl {
Bidi::Bidi() { mBidi = ubidi_open(); }
Bidi::~Bidi() { ubidi_close(mBidi.GetMut()); }
ICUResult Bidi::SetParagraph(Span<const char16_t> aParagraph,
BidiEmbeddingLevel aLevel) {
// Do not allow any reordering of the runs, as this can change the
// performance characteristics of working with runs. In the default mode,
// the levels can be iterated over directly, rather than relying on computing
// logical runs on the fly. This can have negative performance characteristics
// compared to iterating over the levels.
//
// In the UBIDI_REORDER_RUNS_ONLY the levels are encoded with additional
// information which can be safely ignored in this Bidi implementation.
// Note that this check is here since setting the mode must be done before
// calls to setting the paragraph.
MOZ_ASSERT(ubidi_getReorderingMode(mBidi.GetMut()) == UBIDI_REORDER_DEFAULT);
UErrorCode status = U_ZERO_ERROR;
ubidi_setPara(mBidi.GetMut(), aParagraph.Elements(),
AssertedCast<int32_t>(aParagraph.Length()), aLevel, nullptr,
&status);
mLevels = nullptr;
return ToICUResult(status);
}
Bidi::ParagraphDirection Bidi::GetParagraphDirection() const {
switch (ubidi_getDirection(mBidi.GetConst())) {
case UBIDI_LTR:
return Bidi::ParagraphDirection::LTR;
case UBIDI_RTL:
return Bidi::ParagraphDirection::RTL;
case UBIDI_MIXED:
return Bidi::ParagraphDirection::Mixed;
case UBIDI_NEUTRAL:
// This is only used in `ubidi_getBaseDirection` which is unused in this
// API.
MOZ_ASSERT_UNREACHABLE("Unexpected UBiDiDirection value.");
};
return Bidi::ParagraphDirection::Mixed;
}
/* static */
void Bidi::ReorderVisual(const BidiEmbeddingLevel* aLevels, int32_t aLength,
int32_t* aIndexMap) {
ubidi_reorderVisual(reinterpret_cast<const uint8_t*>(aLevels), aLength,
aIndexMap);
}
/* static */
Bidi::BaseDirection Bidi::GetBaseDirection(Span<const char16_t> aParagraph) {
UBiDiDirection direction = ubidi_getBaseDirection(
aParagraph.Elements(), AssertedCast<int32_t>(aParagraph.Length()));
switch (direction) {
case UBIDI_LTR:
return Bidi::BaseDirection::LTR;
case UBIDI_RTL:
return Bidi::BaseDirection::RTL;
case UBIDI_NEUTRAL:
return Bidi::BaseDirection::Neutral;
case UBIDI_MIXED:
MOZ_ASSERT_UNREACHABLE("Unexpected UBiDiDirection value.");
}
return Bidi::BaseDirection::Neutral;
}
static BidiDirection ToBidiDirection(UBiDiDirection aDirection) {
switch (aDirection) {
case UBIDI_LTR:
return BidiDirection::LTR;
case UBIDI_RTL:
return BidiDirection::RTL;
case UBIDI_MIXED:
case UBIDI_NEUTRAL:
MOZ_ASSERT_UNREACHABLE("Unexpected UBiDiDirection value.");
}
return BidiDirection::LTR;
}
Result<int32_t, ICUError> Bidi::CountRuns() {
UErrorCode status = U_ZERO_ERROR;
int32_t runCount = ubidi_countRuns(mBidi.GetMut(), &status);
if (U_FAILURE(status)) {
return Err(ToICUError(status));
}
mLength = ubidi_getProcessedLength(mBidi.GetConst());
mLevels = mLength > 0 ? reinterpret_cast<const BidiEmbeddingLevel*>(
ubidi_getLevels(mBidi.GetMut(), &status))
: nullptr;
if (U_FAILURE(status)) {
return Err(ToICUError(status));
}
return runCount;
}
void Bidi::GetLogicalRun(int32_t aLogicalStart, int32_t* aLogicalLimitOut,
BidiEmbeddingLevel* aLevelOut) {
MOZ_ASSERT(mLevels, "CountRuns hasn't been run?");
MOZ_RELEASE_ASSERT(aLogicalStart < mLength, "Out of bound");
BidiEmbeddingLevel level = mLevels[aLogicalStart];
int32_t limit;
for (limit = aLogicalStart + 1; limit < mLength; limit++) {
if (mLevels[limit] != level) {
break;
}
}
*aLogicalLimitOut = limit;
*aLevelOut = level;
}
BidiEmbeddingLevel Bidi::GetParagraphEmbeddingLevel() const {
return BidiEmbeddingLevel(ubidi_getParaLevel(mBidi.GetConst()));
}
BidiDirection Bidi::GetVisualRun(int32_t aRunIndex, int32_t* aLogicalStart,
int32_t* aLength) {
return ToBidiDirection(
ubidi_getVisualRun(mBidi.GetMut(), aRunIndex, aLogicalStart, aLength));
}
} // namespace mozilla::intl
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