1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "FontUtils.h" 18 19 #include <cstdint> 20 21 #include <log/log.h> 22 23 namespace minikin { 24 25 static uint16_t readU16(const uint8_t* data, size_t offset) { 26 return data[offset] << 8 | data[offset + 1]; 27 } 28 29 static uint32_t readU32(const uint8_t* data, size_t offset) { 30 return ((uint32_t)data[offset]) << 24 | ((uint32_t)data[offset + 1]) << 16 | 31 ((uint32_t)data[offset + 2]) << 8 | ((uint32_t)data[offset + 3]); 32 } 33 34 bool analyzeStyle(const uint8_t* os2_data, size_t os2_size, int* weight, bool* italic) { 35 const size_t kUsWeightClassOffset = 4; 36 const size_t kFsSelectionOffset = 62; 37 const uint16_t kItalicFlag = (1 << 0); 38 if (os2_size < kFsSelectionOffset + 2) { 39 return false; 40 } 41 uint16_t weightClass = readU16(os2_data, kUsWeightClassOffset); 42 *weight = weightClass; 43 uint16_t fsSelection = readU16(os2_data, kFsSelectionOffset); 44 *italic = (fsSelection & kItalicFlag) != 0; 45 return true; 46 } 47 48 bool analyzeAxes(const uint8_t* fvar_data, size_t fvar_size, std::unordered_set<uint32_t>* axes) { 49 const size_t kMajorVersionOffset = 0; 50 const size_t kMinorVersionOffset = 2; 51 const size_t kOffsetToAxesArrayOffset = 4; 52 const size_t kAxisCountOffset = 8; 53 const size_t kAxisSizeOffset = 10; 54 55 axes->clear(); 56 57 if (fvar_size < kAxisSizeOffset + 2) { 58 return false; 59 } 60 const uint16_t majorVersion = readU16(fvar_data, kMajorVersionOffset); 61 const uint16_t minorVersion = readU16(fvar_data, kMinorVersionOffset); 62 const uint32_t axisOffset = readU16(fvar_data, kOffsetToAxesArrayOffset); 63 const uint32_t axisCount = readU16(fvar_data, kAxisCountOffset); 64 const uint32_t axisSize = readU16(fvar_data, kAxisSizeOffset); 65 66 if (majorVersion != 1 || minorVersion != 0 || axisOffset != 0x10 || axisSize != 0x14) { 67 return false; // Unsupported version. 68 } 69 if (fvar_size < axisOffset + axisSize * axisCount) { 70 if (axisOffset > axisSize) { 71 android_errorWriteLog(0x534e4554, "77822336"); 72 } 73 return false; // Invalid table size. 74 } 75 for (uint32_t i = 0; i < axisCount; ++i) { 76 size_t axisRecordOffset = axisOffset + i * axisSize; 77 uint32_t tag = readU32(fvar_data, axisRecordOffset); 78 axes->insert(tag); 79 } 80 return true; 81 } 82 } // namespace minikin 83
