/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "Minikin"
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#include "BidiUtils.h"
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#include <algorithm>
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#include <unicode/ubidi.h>
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#include <unicode/utf16.h>
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#include "minikin/Emoji.h"
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#include "MinikinInternal.h"
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namespace minikin {
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static inline UBiDiLevel bidiToUBidiLevel(Bidi bidi) {
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switch (bidi) {
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case Bidi::LTR:
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return 0x00;
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case Bidi::RTL:
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return 0x01;
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case Bidi::DEFAULT_LTR:
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return UBIDI_DEFAULT_LTR;
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case Bidi::DEFAULT_RTL:
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return UBIDI_DEFAULT_RTL;
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case Bidi::FORCE_LTR:
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case Bidi::FORCE_RTL:
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MINIKIN_NOT_REACHED("FORCE_LTR/FORCE_RTL can not be converted to UBiDiLevel.");
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return 0x00;
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default:
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MINIKIN_NOT_REACHED("Unknown Bidi value.");
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return 0x00;
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}
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}
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BidiText::RunInfo BidiText::getRunInfoAt(uint32_t runOffset) const {
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MINIKIN_ASSERT(runOffset < mRunCount, "Out of range access. %d/%d", runOffset, mRunCount);
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if (mRunCount == 1) {
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// Single run. No need to iteract with UBiDi.
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return {mRange, mIsRtl};
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}
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int32_t startRun = -1;
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int32_t lengthRun = -1;
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const UBiDiDirection runDir = ubidi_getVisualRun(mBidi.get(), runOffset, &startRun, &lengthRun);
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if (startRun == -1 || lengthRun == -1) {
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ALOGE("invalid visual run");
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return {Range::invalidRange(), false};
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}
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const uint32_t runStart = std::max(static_cast<uint32_t>(startRun), mRange.getStart());
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const uint32_t runEnd = std::min(static_cast<uint32_t>(startRun + lengthRun), mRange.getEnd());
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if (runEnd <= runStart) {
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// skip the empty run.
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return {Range::invalidRange(), false};
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}
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return {Range(runStart, runEnd), (runDir == UBIDI_RTL)};
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}
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BidiText::BidiText(const U16StringPiece& textBuf, const Range& range, Bidi bidiFlags)
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: mRange(range), mIsRtl(isRtl(bidiFlags)), mRunCount(1 /* by default, single run */) {
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if (isOverride(bidiFlags)) {
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// force single run.
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return;
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}
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mBidi.reset(ubidi_open());
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if (!mBidi) {
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ALOGE("error creating bidi object");
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return;
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}
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UErrorCode status = U_ZERO_ERROR;
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// Set callbacks to override bidi classes of new emoji
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ubidi_setClassCallback(mBidi.get(), emojiBidiOverride, nullptr, nullptr, nullptr, &status);
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if (!U_SUCCESS(status)) {
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ALOGE("error setting bidi callback function, status = %d", status);
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return;
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}
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const UBiDiLevel bidiReq = bidiToUBidiLevel(bidiFlags);
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ubidi_setPara(mBidi.get(), reinterpret_cast<const UChar*>(textBuf.data()), textBuf.size(),
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bidiReq, nullptr, &status);
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if (!U_SUCCESS(status)) {
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ALOGE("error calling ubidi_setPara, status = %d", status);
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return;
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}
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// RTL paragraphs get an odd level, while LTR paragraphs get an even level,
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const bool paraIsRTL = ubidi_getParaLevel(mBidi.get()) & 0x01;
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const ssize_t rc = ubidi_countRuns(mBidi.get(), &status);
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if (!U_SUCCESS(status) || rc < 0) {
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ALOGW("error counting bidi runs, status = %d", status);
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return;
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}
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if (rc == 0) {
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mIsRtl = paraIsRTL;
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return;
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}
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if (rc == 1) {
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// If the paragraph is a single run, override the paragraph dirction with the run
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// (actually the whole text) direction.
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const UBiDiDirection runDir = ubidi_getVisualRun(mBidi.get(), 0, nullptr, nullptr);
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mIsRtl = (runDir == UBIDI_RTL);
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return;
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}
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mRunCount = rc;
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}
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} // namespace minikin
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