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 #include <ultrahdr/multipictureformat.h>
17 #include <ultrahdr/jpegrutils.h>
18
19 namespace android::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 sp<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 sp<DataStruct> dataStruct = sp<DataStruct>::make(mpf_size);
34
35 dataStruct->write(static_cast<const void*>(kMpfSig), sizeof(kMpfSig));
36 #if USE_BIG_ENDIAN
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 =
44 static_cast<uint16_t>(kMpEndianSize + sizeof(kMpfSig));
45 dataStruct->write32(Endian_SwapBE32(indexIfdOffset));
46
47 // We will write 3 tags (version, number of images, MP entries).
48 dataStruct->write16(Endian_SwapBE16(kTagSerializedCount));
49
50 // Write the version tag.
51 dataStruct->write16(Endian_SwapBE16(kVersionTag));
52 dataStruct->write16(Endian_SwapBE16(kVersionType));
53 dataStruct->write32(Endian_SwapBE32(kVersionCount));
54 dataStruct->write(kVersionExpected, kVersionSize);
55
56 // Write the number of images.
57 dataStruct->write16(Endian_SwapBE16(kNumberOfImagesTag));
58 dataStruct->write16(Endian_SwapBE16(kNumberOfImagesType));
59 dataStruct->write32(Endian_SwapBE32(kNumberOfImagesCount));
60 dataStruct->write32(Endian_SwapBE32(kNumPictures));
61
62 // Write the MP entries.
63 dataStruct->write16(Endian_SwapBE16(kMPEntryTag));
64 dataStruct->write16(Endian_SwapBE16(kMPEntryType));
65 dataStruct->write32(Endian_SwapBE32(kMPEntrySize * kNumPictures));
66 const uint32_t mpEntryOffset =
67 static_cast<uint32_t>(dataStruct->getBytesWritten() - // The bytes written so far
68 sizeof(kMpfSig) + // Excluding the MPF signature
69 sizeof(uint32_t) + // The 4 bytes for this offset
70 sizeof(uint32_t)); // The 4 bytes for the attribute IFD offset.
71 dataStruct->write32(Endian_SwapBE32(mpEntryOffset));
72
73 // Write the attribute IFD offset (zero because we don't write it).
74 dataStruct->write32(0);
75
76 // Write the MP entries for primary image
77 dataStruct->write32(
78 Endian_SwapBE32(kMPEntryAttributeFormatJpeg | kMPEntryAttributeTypePrimary));
79 dataStruct->write32(Endian_SwapBE32(primary_image_size));
80 dataStruct->write32(Endian_SwapBE32(primary_image_offset));
81 dataStruct->write16(0);
82 dataStruct->write16(0);
83
84 // Write the MP entries for secondary image
85 dataStruct->write32(Endian_SwapBE32(kMPEntryAttributeFormatJpeg));
86 dataStruct->write32(Endian_SwapBE32(secondary_image_size));
87 dataStruct->write32(Endian_SwapBE32(secondary_image_offset));
88 dataStruct->write16(0);
89 dataStruct->write16(0);
90
91 return dataStruct;
92 }
93
94 } // namespace android::ultrahdr
95