Reader class for reading a manifest. More...

#include <c2pa.hpp>

Public Member Functions
	Reader (IContextProvider &context, const std::string &format, std::istream &stream)
	Create a Reader from a context and stream.

	Reader (IContextProvider &context, const std::filesystem::path &source_path)
	Create a Reader from a context and file path.

	Reader (std::shared_ptr< IContextProvider > context, const std::string &format, std::istream &stream)
	Create a Reader from a shared context and stream.

	Reader (std::shared_ptr< IContextProvider > context, std::istream &stream)
	Create a Reader from a shared context and stream, guessing the format from content.

	Reader (std::shared_ptr< IContextProvider > context, const std::filesystem::path &source_path)
	Create a Reader from a shared context and file path.

	Reader (std::shared_ptr< IContextProvider > context, const std::string &format, std::istream &image_stream, const std::vector< uint8_t > &manifest_jumbf)
	Create a Reader from a shared context, image stream, and external JUMBF manifest.

	Reader (const std::string &format, std::istream &stream)
	Create a Reader from a stream (will use global settings if any loaded).

	Reader (const std::filesystem::path &source_path)
	Create a Reader from a file path (will use global settings if any loaded).

	Reader (const Reader &)=delete

Reader &	operator= (const Reader &)=delete

	Reader (Reader &&other) noexcept

Reader &	operator= (Reader &&other) noexcept

	~Reader ()

bool	is_embedded () const
	Check if the reader was created from an embedded manifest.

std::optional< std::string >	remote_url () const
	Returns the remote url of the manifest if this `Reader` obtained the manifest remotely.

Reader &	with_fragment (const std::string &format, std::istream &stream, std::istream &fragment)
	Process a BMFF fragment stream with this Reader instance.

std::string	json () const
	Get the manifest as a JSON string.

std::string	detailed_json () const
	Get the manifest as a detailed JSON string.

std::string	crjson () const
	Get the manifest store as a pretty-printed crJSON string.

int64_t	get_resource (const std::string &uri, const std::filesystem::path &path)
	Get a resource from the reader and write it to a file.

int64_t	get_resource (const std::string &uri, std::ostream &stream)
	Get a resource from the reader and write it to an output stream.

C2paReader *	get_api_internal_raw_reader () const
	Get the raw C2paReader pointer.

Static Public Member Functions
static std::optional< Reader >	from_asset (IContextProvider &context, const std::filesystem::path &source_path)
	Try to open a Reader from a context and file path when the asset may lack C2PA data.

static std::optional< Reader >	from_asset (IContextProvider &context, const std::string &format, std::istream &stream)
	Try to create a Reader from a context and stream when the asset may lack C2PA data.

static std::optional< Reader >	from_asset (std::shared_ptr< IContextProvider > context, const std::filesystem::path &source_path)
	Try to open a Reader from a shared context and file path when the asset may lack C2PA data.

static std::optional< Reader >	from_asset (std::shared_ptr< IContextProvider > context, const std::string &format, std::istream &stream)
	Try to create a Reader from a shared context and stream when the asset may lack C2PA data.

static std::optional< Reader >	from_asset (std::shared_ptr< IContextProvider > context, std::istream &stream)
	Try to create a Reader from a shared context and stream, guessing the format from content.

static std::vector< std::string >	supported_mime_types ()
	Get a list of mime types that the SDK can read manifests from.

Detailed Description

Reader class for reading a manifest.

This class is used to read and validate a manifest from a stream or file. Resources are managed using RAII; member order ensures cpp_stream (which holds a C stream pointing at the ifstream) is destroyed before owned_stream.

Constructor & Destructor Documentation

◆ Reader() [1/10]

c2pa::Reader::Reader	(	IContextProvider &	context,
		const std::string &	format,
		std::istream &	stream
	)

Create a Reader from a context and stream.

Parameters

context	Context provider; used at construction to configure settings.
format	The mime format of the stream.
stream	The input stream to read from.

Exceptions

C2paException if context.is_valid() returns false, or for other errors encountered by the C2PA library.

Deprecated:: Use Reader(std::shared_ptr<IContextProvider>, format, stream) instead. The reference overload does not extend the lifetime of the context, which can be problematic when progress callbacks fire after the context is destroyed.

◆ Reader() [2/10]

c2pa::Reader::Reader	(	IContextProvider &	context,
		const std::filesystem::path &	source_path
	)

Create a Reader from a context and file path.

Parameters

context	Context provider; used at construction only to configure settings.
source_path	The path to the file to read.

Exceptions

C2paException if context.is_valid() returns false, or for other errors encountered by the C2PA library.

Note: Prefer using the streaming APIs if possible.

Deprecated:: Use Reader(std::shared_ptr<IContextProvider>, source_path) instead. The reference overload does not extend the lifetime of the context, which can be problematic when progress callbacks fire after the context is destroyed.

◆ Reader() [3/10]

c2pa::Reader::Reader	(	std::shared_ptr< IContextProvider >	context,
		const std::string &	format,
		std::istream &	stream
	)

Create a Reader from a shared context and stream.

The Reader retains a shared reference to the context, keeping it alive for the lifetime of the Reader.

Parameters

context	Shared context provider.
format	The mime type or file extension of the stream. Treated as a hint and reconciled against the container detected in the leading bytes: the same container keeps `format` (so "dng" is not widened to "image/tiff"), a different one wins over `format`, and if nothing is detected `format` is used as given. Pass an empty string to rely on detection alone. A format absent from supported_mime_types() is not rejected here.
stream	The input stream to read from. Must support seeking; it is rewound before inspection.

Exceptions

C2paException if context is null or context->is_valid() returns false, or if no container is detected and format does not name a supported one.

◆ Reader() [4/10]

c2pa::Reader::Reader	(	std::shared_ptr< IContextProvider >	context,
		std::istream &	stream
	)

Create a Reader from a shared context and stream, guessing the format from content.

Equivalent to passing an empty format. Detection is best effort; prefer the overload taking a format when the format is known. The stream is rewound before inspection, so it must support seeking.

Parameters

context	Shared context provider.
stream	The input stream to read from. Must support seeking.

Exceptions

C2paException if context is null, context->is_valid() returns false, or the container type cannot be determined from the bytes.

◆ Reader() [5/10]

c2pa::Reader::Reader	(	std::shared_ptr< IContextProvider >	context,
		const std::filesystem::path &	source_path
	)

Create a Reader from a shared context and file path.

The Reader retains a shared reference to the context, keeping it alive for the lifetime of the Reader.

Parameters

context	Shared context provider.
source_path	The path to the file to read.

Exceptions

C2paException if context is null or context->is_valid() returns false.

Note: The extension is used as a hint only. With no extension, the container is guessed from the leading bytes (best-effort). A wrong or unrecognized extension is accepted, since a detected container overrides it.

◆ Reader() [6/10]

c2pa::Reader::Reader	(	std::shared_ptr< IContextProvider >	context,
		const std::string &	format,
		std::istream &	image_stream,
		const std::vector< uint8_t > &	manifest_jumbf
	)

Create a Reader from a shared context, image stream, and external JUMBF manifest.

Performs full C2PA binding verification between image_stream and the provided JUMBF manifest bytes without requiring the manifest to be embedded in the asset. Typical use: sidecar .c2pa files, database-stored manifests, in-memory pipelines. The Reader retains a shared reference to the context for its lifetime.

Parameters

context	Shared context provider (trust anchors, verification policy).
format	MIME type of the image stream (e.g., "image/jpeg").
image_stream	Asset data. Must support seeking (used for exclusion-range hashing).
manifest_jumbf	Raw JUMBF manifest bytes (e.g., contents of a .c2pa sidecar file).

Note: image_stream, manifest_jumbf, and format need only remain valid for the duration of the construction call. The Reader does not retain their references.

Exceptions

C2paException if context is null, context->is_valid() is false, manifest_jumbf is empty, or the C2PA library reports an error.

◆ Reader() [7/10]

c2pa::Reader::Reader	(	const std::string &	format,
		std::istream &	stream
	)

Create a Reader from a stream (will use global settings if any loaded).

The validation_status field in the JSON contains validation results.

Parameters

format	The mime format of the stream.
stream	The input stream to read from.

Exceptions

C2paException for errors encountered by the C2PA library.

Deprecated:: Use Reader(IContextProvider& context, format, stream) instead.

◆ Reader() [8/10]

c2pa::Reader::Reader ( const std::filesystem::path & source_path )

Create a Reader from a file path (will use global settings if any loaded).

Parameters

source_path The path to the file to read.

Exceptions

C2paException for errors encountered by the C2PA library.

Deprecated:: Use Reader(IContextProvider& context, source_path) instead.

Note: Prefer using the streaming APIs if possible.

◆ Reader() [9/10]

c2pa::Reader::Reader ( const Reader & )

delete

◆ Reader() [10/10]

c2pa::Reader::Reader ( Reader && other )

inlinenoexcept

            : c2pa_reader(std::exchange(other.c2pa_reader, nullptr)),
              owned_stream(std::move(other.owned_stream)),
              cpp_stream(std::move(other.cpp_stream)),
              context_ref(std::move(other.context_ref)) {
        }

◆ ~Reader()

c2pa::Reader::~Reader ( )

Member Function Documentation

◆ crjson()

std::string c2pa::Reader::crjson ( ) const

Get the manifest store as a pretty-printed crJSON string.

crJSON is a standardized JSON format for C2PA manifest data. This call is infallible at yields valid empty JSON ("{}") if there are no Content Credentials.

Returns: The manifest store as a crJSON string.

Exceptions

C2paException if the underlying C call returns null.

◆ detailed_json()

std::string c2pa::Reader::detailed_json ( ) const

Get the manifest as a detailed JSON string.

The detailed view more closely resembles the underlying JUMBF manifest store. Unlike json(), it exposes the full assertion_store map for each manifest, including assertions that the regular view filters out (such as c2pa.thumbnail.*, c2pa.actions.*, and c2pa.hash.*). Use this when building redaction URIs or otherwise needing the canonical assertion labels embedded in the manifest.

Returns: The detailed manifest as a JSON string.

Exceptions

C2paException for errors encountered by the C2PA library.

◆ from_asset() [1/5]

static std::optional< Reader > c2pa::Reader::from_asset	(	IContextProvider &	context,
		const std::filesystem::path &	source_path
	)

static

Try to open a Reader from a context and file path when the asset may lack C2PA data.

Returns: A Reader if JUMBF (c2pa/manifest) data is present; std::nullopt if none.

Exceptions

C2paException	for errors other than a missing manifest (e.g. invalid asset).
std::system_error	if the file cannot be opened.

Deprecated:: Use from_asset(std::shared_ptr<IContextProvider>, source_path) instead. The reference overload does not extend the lifetime of the context, which can cause a use-after-free crash when progress callbacks fire after the context is destroyed.

◆ from_asset() [2/5]

static std::optional< Reader > c2pa::Reader::from_asset	(	IContextProvider &	context,
		const std::string &	format,
		std::istream &	stream
	)

static

Try to create a Reader from a context and stream when the asset may lack C2PA data.

Returns: A Reader if JUMBF (c2pa/manifest) data is present; std::nullopt if none.

Exceptions

C2paException for errors other than a missing manifest.

Deprecated:: Use from_asset(std::shared_ptr<IContextProvider>, format, stream) instead. The reference overload does not extend the lifetime of the context, which can cause a use-after-free crash when progress callbacks fire after the context is destroyed.

◆ from_asset() [3/5]

static std::optional< Reader > c2pa::Reader::from_asset	(	std::shared_ptr< IContextProvider >	context,
		const std::filesystem::path &	source_path
	)

static

Try to open a Reader from a shared context and file path when the asset may lack C2PA data.

The Reader retains a shared reference to the context if C2PA data is found.

Returns: A Reader if JUMBF (c2pa/manifest) data is present; std::nullopt if none.

Exceptions

C2paException for errors other than a missing manifest.

◆ from_asset() [4/5]

static std::optional< Reader > c2pa::Reader::from_asset	(	std::shared_ptr< IContextProvider >	context,
		const std::string &	format,
		std::istream &	stream
	)

static

Try to create a Reader from a shared context and stream when the asset may lack C2PA data.

The Reader retains a shared reference to the context if C2PA data is found.

Parameters

context	Shared context provider.
format	The mime type or file extension of the stream, used as a hint and reconciled against the detected container. See the corresponding constructor.
stream	The input stream to read from. Must support seeking.

Returns: A Reader if JUMBF (c2pa/manifest) data is present; std::nullopt if none.

Exceptions

C2paException for errors other than a missing manifest.

◆ from_asset() [5/5]

static std::optional< Reader > c2pa::Reader::from_asset	(	std::shared_ptr< IContextProvider >	context,
		std::istream &	stream
	)

static

Try to create a Reader from a shared context and stream, guessing the format from content.

The Reader retains a shared reference to the context if C2PA data is found. Detection is best effort; prefer the overload taking a format when it is known.

Parameters

context	Shared context provider.
stream	The input stream to read from. Must support seeking.

Returns: A Reader if JUMBF (c2pa/manifest) data is present; std::nullopt if none.

Exceptions

C2paException for errors other than a missing manifest. Content whose container cannot be identified raises an error rather than returning nullopt.

◆ get_api_internal_raw_reader()

C2paReader * c2pa::Reader::get_api_internal_raw_reader ( ) const

inline

Get the raw C2paReader pointer.

Returns: The raw C2paReader pointer.

Note: This is intended for internal API use and compatibility with C APIs.

1022{ return c2pa_reader; }

◆ get_resource() [1/2]

int64_t c2pa::Reader::get_resource	(	const std::string &	uri,
		const std::filesystem::path &	path
	)

Get a resource from the reader and write it to a file.

Parameters

uri	The URI of the resource.
path	The file path to write the resource to.

Returns: The number of bytes written.

Exceptions

C2paException for errors encountered by the C2PA library.

Note: Prefer using the streaming APIs if possible.

◆ get_resource() [2/2]

int64_t c2pa::Reader::get_resource	(	const std::string &	uri,
		std::ostream &	stream
	)

Get a resource from the reader and write it to an output stream.

Parameters

uri	The URI of the resource.
stream	The output stream to write the resource to.

Returns: The number of bytes written.

Exceptions

C2paException for errors encountered by the C2PA library.

◆ is_embedded()

bool c2pa::Reader::is_embedded ( ) const

inline

Check if the reader was created from an embedded manifest.

Returns: true if the manifest was embedded in the asset, false if external.

Exceptions

C2paException if the Reader holds no valid handle (e.g. it was moved from, or a prior with_fragment() failed and consumed it), or for other errors encountered by the C2PA library.

                                                      {
            ensure_initialized();
            return c2pa_reader_is_embedded(c2pa_reader);
        }

◆ json()

std::string c2pa::Reader::json ( ) const

Get the manifest as a JSON string.

Returns: The manifest as a JSON string.

Exceptions

C2paException for errors encountered by the C2PA library.

◆ operator=() [1/2]

Reader & c2pa::Reader::operator= ( const Reader & )

delete

◆ operator=() [2/2]

Reader & c2pa::Reader::operator= ( Reader && other )

inlinenoexcept

                                                   {
            if (this != &other) {
                c2pa_free(c2pa_reader);
                c2pa_reader = std::exchange(other.c2pa_reader, nullptr);
                owned_stream = std::move(other.owned_stream);
                cpp_stream = std::move(other.cpp_stream);
                context_ref = std::move(other.context_ref);
            }
            return *this;
        }

◆ remote_url()

std::optional< std::string > c2pa::Reader::remote_url ( ) const

Returns the remote url of the manifest if this Reader obtained the manifest remotely.

Returns: Optional string containing the remote URL, or std::nullopt if manifest was embedded.

Exceptions

C2paException for errors encountered by the C2PA library.

◆ supported_mime_types()

static std::vector< std::string > c2pa::Reader::supported_mime_types ( )

static

Get a list of mime types that the SDK can read manifests from.

Returns: Vector of supported MIME type strings.

◆ with_fragment()

Reader & c2pa::Reader::with_fragment	(	const std::string &	format,
		std::istream &	stream,
		std::istream &	fragment
	)

Process a BMFF fragment stream with this Reader instance.

Used for fragmented BMFF media (DASH/HLS streaming) where content is split into an init/main segment and separate fragment files. The Reader is created from the init segment (e.g. Reader(context, "video/mp4", init)), then goes through one fragment at a time via this method. The underlying native SDK consumes the current reader and returns a new one configured with the fragment. This method swaps the handle in place and returns *this for chaining across fragments as the reading steps go through fragments.

Parameters

format	MIME type of the media (e.g., "video/mp4").
stream	The main/init segment.
fragment	The current fragment to process.

Returns: *this, for chaining across multiple fragments.

Note: stream and fragment need only remain valid for the duration of this call. The Reader does not retain a reference to either after returning.

Exceptions

C2paException if the C2PA library reports an error. On failure the underlying reader handle is consumed and this Reader must not be used further.

The documentation for this class was generated from the following file:

c2pa.hpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Reader() [1/10]

◆ Reader() [2/10]

◆ Reader() [3/10]

◆ Reader() [4/10]

◆ Reader() [5/10]

◆ Reader() [6/10]

◆ Reader() [7/10]

◆ Reader() [8/10]

◆ Reader() [9/10]

◆ Reader() [10/10]

◆ ~Reader()

Member Function Documentation

◆ crjson()

◆ detailed_json()

◆ from_asset() [1/5]

◆ from_asset() [2/5]

◆ from_asset() [3/5]

◆ from_asset() [4/5]

◆ from_asset() [5/5]

◆ get_api_internal_raw_reader()

◆ get_resource() [1/2]

◆ get_resource() [2/2]

◆ is_embedded()

◆ json()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ remote_url()

◆ supported_mime_types()

◆ with_fragment()