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* Copyright 2023 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkJpegMultiPicture_codec_DEFINED
#define SkJpegMultiPicture_codec_DEFINED
#include "include/core/SkRefCnt.h"
#include "include/core/SkStream.h"
#include <cstdint>
#include <memory>
#include <vector>
class SkData;
class SkJpegSeekableScan;
* Parsed Jpeg Multi-Picture Format structure as specified in CIPA DC-x007-2009. An introduction to
* the format can be found in Figure 1 (Basic MP File format data structure) and Figure 6 (Internal
* Structure of the MP Index IFD) in that document. This parsing will extract only the size and
* offset parameters from the images in the Index Image File Directory.
struct SkJpegMultiPictureParameters {
// An individual image.
struct Image {
// The size of the image in bytes.
uint32_t size;
// The offset of the image in bytes. This offset is specified relative to the address of
// the MP Endian field in the MP Header, unless the image is a First Individual Image, in
// which case the value of the offest [sic] shall be NULL (from section
uint32_t dataOffset;
// The images listed in the Index Image File Directory.
std::vector<Image> images;
* Parse Jpeg Multi-Picture Format parameters. The specified data should start with the MP Header.
* Returns nullptr on error.
std::unique_ptr<SkJpegMultiPictureParameters> SkJpegParseMultiPicture(
const sk_sp<const SkData>& data);
* Create SkStreams for all MultiPicture images, given a SkJpegSeekableScan of the image. This will
* return nullptr if there is not MultiPicture segment, or if the MultiPicture parameters fail to
* parse.
struct SkJpegMultiPictureStreams {
// An individual image.
struct Image {
// An SkStream from which the image's data may be read. This is nullptr for the First
// Individual Image and for any images which encounter errors (e.g, they are outside of
// the range of the stream).
std::unique_ptr<SkStream> stream;
// The images as listed in the Index Image File Directory.
std::vector<Image> images;
std::unique_ptr<SkJpegMultiPictureStreams> SkJpegExtractMultiPictureStreams(
SkJpegSeekableScan* scan);