1 /*
2 * Copyright 2023 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 "ultrahdr/multipictureformat.h"
18
19 namespace ultrahdr {
calculateMpfSize()20 size_t calculateMpfSize() {
21 return sizeof(kMpfSig) + // Signature
22 kMpEndianSize + // Endianness
23 sizeof(uint32_t) + // Index IFD Offset
24 sizeof(uint16_t) + // Tag count
25 kTagSerializedCount * kTagSize + // 3 tags at 12 bytes each
26 sizeof(uint32_t) + // Attribute IFD offset
27 kNumPictures * kMPEntrySize; // MP Entries for each image
28 }
29
generateMpf(int primary_image_size,int primary_image_offset,int secondary_image_size,int secondary_image_offset)30 std::shared_ptr<DataStruct> generateMpf(int primary_image_size, int primary_image_offset,
31 int secondary_image_size, int secondary_image_offset) {
32 size_t mpf_size = calculateMpfSize();
33 std::shared_ptr<DataStruct> dataStruct = std::make_shared<DataStruct>(mpf_size);
34
35 dataStruct->write(static_cast<const void*>(kMpfSig), sizeof(kMpfSig));
36 #if USE_BIG_ENDIAN_IN_MPF
37 dataStruct->write(static_cast<const void*>(kMpBigEndian), kMpEndianSize);
38 #else
39 dataStruct->write(static_cast<const void*>(kMpLittleEndian), kMpEndianSize);
40 #endif
41
42 // Set the Index IFD offset be the position after the endianness value and this offset.
43 constexpr uint32_t indexIfdOffset = static_cast<uint16_t>(kMpEndianSize + sizeof(kMpfSig));
44 dataStruct->write32(Endian_SwapBE32(indexIfdOffset));
45
46 // We will write 3 tags (version, number of images, MP entries).
47 dataStruct->write16(Endian_SwapBE16(kTagSerializedCount));
48
49 // Write the version tag.
50 dataStruct->write16(Endian_SwapBE16(kVersionTag));
51 dataStruct->write16(Endian_SwapBE16(kVersionType));
52 dataStruct->write32(Endian_SwapBE32(kVersionCount));
53 dataStruct->write(kVersionExpected, kVersionSize);
54
55 // Write the number of images.
56 dataStruct->write16(Endian_SwapBE16(kNumberOfImagesTag));
57 dataStruct->write16(Endian_SwapBE16(kNumberOfImagesType));
58 dataStruct->write32(Endian_SwapBE32(kNumberOfImagesCount));
59 dataStruct->write32(Endian_SwapBE32(kNumPictures));
60
61 // Write the MP entries.
62 dataStruct->write16(Endian_SwapBE16(kMPEntryTag));
63 dataStruct->write16(Endian_SwapBE16(kMPEntryType));
64 dataStruct->write32(Endian_SwapBE32(kMPEntrySize * kNumPictures));
65 const uint32_t mpEntryOffset =
66 static_cast<uint32_t>(dataStruct->getBytesWritten() - // The bytes written so far
67 sizeof(kMpfSig) + // Excluding the MPF signature
68 sizeof(uint32_t) + // The 4 bytes for this offset
69 sizeof(uint32_t)); // The 4 bytes for the attribute IFD offset.
70 dataStruct->write32(Endian_SwapBE32(mpEntryOffset));
71
72 // Write the attribute IFD offset (zero because we don't write it).
73 dataStruct->write32(0);
74
75 // Write the MP entries for primary image
76 dataStruct->write32(Endian_SwapBE32(kMPEntryAttributeFormatJpeg | kMPEntryAttributeTypePrimary));
77 dataStruct->write32(Endian_SwapBE32(primary_image_size));
78 dataStruct->write32(Endian_SwapBE32(primary_image_offset));
79 dataStruct->write16(0);
80 dataStruct->write16(0);
81
82 // Write the MP entries for secondary image
83 dataStruct->write32(Endian_SwapBE32(kMPEntryAttributeFormatJpeg));
84 dataStruct->write32(Endian_SwapBE32(secondary_image_size));
85 dataStruct->write32(Endian_SwapBE32(secondary_image_offset));
86 dataStruct->write16(0);
87 dataStruct->write16(0);
88
89 return dataStruct;
90 }
91
92 } // namespace ultrahdr
93