/*
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* Copyright (C) 2017 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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#include "FontUtils.h"
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#include <cstdint>
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#include <log/log.h>
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namespace minikin {
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static uint16_t readU16(const uint8_t* data, size_t offset) {
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return data[offset] << 8 | data[offset + 1];
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}
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static uint32_t readU32(const uint8_t* data, size_t offset) {
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return ((uint32_t)data[offset]) << 24 | ((uint32_t)data[offset + 1]) << 16 |
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((uint32_t)data[offset + 2]) << 8 | ((uint32_t)data[offset + 3]);
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}
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bool analyzeStyle(const uint8_t* os2_data, size_t os2_size, int* weight, bool* italic) {
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const size_t kUsWeightClassOffset = 4;
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const size_t kFsSelectionOffset = 62;
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const uint16_t kItalicFlag = (1 << 0);
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if (os2_size < kFsSelectionOffset + 2) {
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return false;
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}
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uint16_t weightClass = readU16(os2_data, kUsWeightClassOffset);
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*weight = weightClass;
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uint16_t fsSelection = readU16(os2_data, kFsSelectionOffset);
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*italic = (fsSelection & kItalicFlag) != 0;
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return true;
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}
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bool analyzeAxes(const uint8_t* fvar_data, size_t fvar_size, std::unordered_set<uint32_t>* axes) {
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const size_t kMajorVersionOffset = 0;
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const size_t kMinorVersionOffset = 2;
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const size_t kOffsetToAxesArrayOffset = 4;
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const size_t kAxisCountOffset = 8;
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const size_t kAxisSizeOffset = 10;
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axes->clear();
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if (fvar_size < kAxisSizeOffset + 2) {
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return false;
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}
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const uint16_t majorVersion = readU16(fvar_data, kMajorVersionOffset);
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const uint16_t minorVersion = readU16(fvar_data, kMinorVersionOffset);
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const uint32_t axisOffset = readU16(fvar_data, kOffsetToAxesArrayOffset);
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const uint32_t axisCount = readU16(fvar_data, kAxisCountOffset);
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const uint32_t axisSize = readU16(fvar_data, kAxisSizeOffset);
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if (majorVersion != 1 || minorVersion != 0 || axisOffset != 0x10 || axisSize != 0x14) {
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return false; // Unsupported version.
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}
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if (fvar_size < axisOffset + axisSize * axisCount) {
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if (axisOffset > axisSize) {
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android_errorWriteLog(0x534e4554, "77822336");
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}
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return false; // Invalid table size.
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}
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for (uint32_t i = 0; i < axisCount; ++i) {
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size_t axisRecordOffset = axisOffset + i * axisSize;
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uint32_t tag = readU32(fvar_data, axisRecordOffset);
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axes->insert(tag);
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}
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return true;
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}
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} // namespace minikin
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