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/*
* Copyright 2023 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 "ultrahdr/multipictureformat.h"
namespace ultrahdr {
size_t calculateMpfSize() {
return sizeof(kMpfSig) + // Signature
kMpEndianSize + // Endianness
sizeof(uint32_t) + // Index IFD Offset
sizeof(uint16_t) + // Tag count
kTagSerializedCount * kTagSize + // 3 tags at 12 bytes each
sizeof(uint32_t) + // Attribute IFD offset
kNumPictures * kMPEntrySize; // MP Entries for each image
}
std::shared_ptr<DataStruct> generateMpf(int primary_image_size, int primary_image_offset,
int secondary_image_size, int secondary_image_offset) {
size_t mpf_size = calculateMpfSize();
std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(mpf_size);
dataStruct->write(static_cast<const void*>(kMpfSig), sizeof(kMpfSig));
#if USE_BIG_ENDIAN_IN_MPF
dataStruct->write(static_cast<const void*>(kMpBigEndian), kMpEndianSize);
#else
dataStruct->write(static_cast<const void*>(kMpLittleEndian), kMpEndianSize);
#endif
// Set the Index IFD offset be the position after the endianness value and this offset.
constexpr uint32_t indexIfdOffset = static_cast<uint16_t>(kMpEndianSize + sizeof(kMpfSig));
dataStruct->write32(Endian_SwapBE32(indexIfdOffset));
// We will write 3 tags (version, number of images, MP entries).
dataStruct->write16(Endian_SwapBE16(kTagSerializedCount));
// Write the version tag.
dataStruct->write16(Endian_SwapBE16(kVersionTag));
dataStruct->write16(Endian_SwapBE16(kVersionType));
dataStruct->write32(Endian_SwapBE32(kVersionCount));
dataStruct->write(kVersionExpected, kVersionSize);
// Write the number of images.
dataStruct->write16(Endian_SwapBE16(kNumberOfImagesTag));
dataStruct->write16(Endian_SwapBE16(kNumberOfImagesType));
dataStruct->write32(Endian_SwapBE32(kNumberOfImagesCount));
dataStruct->write32(Endian_SwapBE32(kNumPictures));
// Write the MP entries.
dataStruct->write16(Endian_SwapBE16(kMPEntryTag));
dataStruct->write16(Endian_SwapBE16(kMPEntryType));
dataStruct->write32(Endian_SwapBE32(kMPEntrySize * kNumPictures));
const uint32_t mpEntryOffset =
static_cast<uint32_t>(dataStruct->getBytesWritten() - // The bytes written so far
sizeof(kMpfSig) + // Excluding the MPF signature
sizeof(uint32_t) + // The 4 bytes for this offset
sizeof(uint32_t)); // The 4 bytes for the attribute IFD offset.
dataStruct->write32(Endian_SwapBE32(mpEntryOffset));
// Write the attribute IFD offset (zero because we don't write it).
dataStruct->write32(0);
// Write the MP entries for primary image
dataStruct->write32(Endian_SwapBE32(kMPEntryAttributeFormatJpeg | kMPEntryAttributeTypePrimary));
dataStruct->write32(Endian_SwapBE32(primary_image_size));
dataStruct->write32(Endian_SwapBE32(primary_image_offset));
dataStruct->write16(0);
dataStruct->write16(0);
// Write the MP entries for secondary image
dataStruct->write32(Endian_SwapBE32(kMPEntryAttributeFormatJpeg));
dataStruct->write32(Endian_SwapBE32(secondary_image_size));
dataStruct->write32(Endian_SwapBE32(secondary_image_offset));
dataStruct->write16(0);
dataStruct->write16(0);
return dataStruct;
}
} // namespace ultrahdr
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