blob: 560b30988ab40af4bebccc463944cb4759241a6c [file] [log] [blame]
/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "FontUtils.h"
#include <cstdint>
#include <log/log.h>
namespace minikin {
static uint16_t readU16(const uint8_t* data, size_t offset) {
return data[offset] << 8 | data[offset + 1];
}
static uint32_t readU32(const uint8_t* data, size_t offset) {
return ((uint32_t)data[offset]) << 24 | ((uint32_t)data[offset + 1]) << 16 |
((uint32_t)data[offset + 2]) << 8 | ((uint32_t)data[offset + 3]);
}
bool analyzeStyle(const uint8_t* os2_data, size_t os2_size, int* weight, bool* italic) {
const size_t kUsWeightClassOffset = 4;
const size_t kFsSelectionOffset = 62;
const uint16_t kItalicFlag = (1 << 0);
if (os2_size < kFsSelectionOffset + 2) {
return false;
}
uint16_t weightClass = readU16(os2_data, kUsWeightClassOffset);
*weight = weightClass;
uint16_t fsSelection = readU16(os2_data, kFsSelectionOffset);
*italic = (fsSelection & kItalicFlag) != 0;
return true;
}
bool analyzeAxes(const uint8_t* fvar_data, size_t fvar_size, std::unordered_set<uint32_t>* axes) {
const size_t kMajorVersionOffset = 0;
const size_t kMinorVersionOffset = 2;
const size_t kOffsetToAxesArrayOffset = 4;
const size_t kAxisCountOffset = 8;
const size_t kAxisSizeOffset = 10;
axes->clear();
if (fvar_size < kAxisSizeOffset + 2) {
return false;
}
const uint16_t majorVersion = readU16(fvar_data, kMajorVersionOffset);
const uint16_t minorVersion = readU16(fvar_data, kMinorVersionOffset);
const uint32_t axisOffset = readU16(fvar_data, kOffsetToAxesArrayOffset);
const uint32_t axisCount = readU16(fvar_data, kAxisCountOffset);
const uint32_t axisSize = readU16(fvar_data, kAxisSizeOffset);
if (majorVersion != 1 || minorVersion != 0 || axisOffset != 0x10 || axisSize != 0x14) {
return false; // Unsupported version.
}
if (fvar_size < axisOffset + axisSize * axisCount) {
if (axisOffset > axisSize) {
android_errorWriteLog(0x534e4554, "77822336");
}
return false; // Invalid table size.
}
for (uint32_t i = 0; i < axisCount; ++i) {
size_t axisRecordOffset = axisOffset + i * axisSize;
uint32_t tag = readU32(fvar_data, axisRecordOffset);
axes->insert(tag);
}
return true;
}
} // namespace minikin