Base class for all Exiv2 values used to store XMP property values. More...

#include <value.hpp>

Inheritance diagram for Exiv2::XmpValue:

[legend]

Public Types
enum	XmpArrayType { xaNone , xaAlt , xaBag , xaSeq }
	XMP array types.

enum	XmpStruct { xsNone , xsStruct }
	XMP structure indicator.

using	UniquePtr = std::unique_ptr< XmpValue >
	Shortcut for a XmpValue auto pointer.

Public Types inherited from Exiv2::Value
using	UniquePtr = std::unique_ptr< Value >
	Shortcut for a Value auto pointer.

Public Member Functions
Accessors
XmpArrayType	xmpArrayType () const
	Return XMP array type, indicates if an XMP value is an array.

XmpStruct	xmpStruct () const
	Return XMP struct, indicates if an XMP value is a structure.

size_t	size () const override
	Return the size of the value in bytes.

size_t	copy (byte *buf, ByteOrder byteOrder=invalidByteOrder) const override
	Write value to a character data buffer.

Public Member Functions inherited from Exiv2::Value
	Value (TypeId typeId)
	Constructor, taking a type id to initialize the base class with.

virtual	~Value ()=default
	Virtual destructor.

virtual int	setDataArea (const byte *buf, size_t len)
	Set the data area, if the value has one by copying (cloning) the buffer pointed to by buf.

TypeId	typeId () const
	Return the type identifier (Exif data format type).

UniquePtr	clone () const
	Return an auto-pointer to a copy of itself (deep copy). The caller owns this copy and the auto-pointer ensures that it will be deleted.

virtual size_t	count () const =0
	Return the number of components of the value.

virtual std::ostream &	write (std::ostream &os) const =0
	Write the value to an output stream. You do not usually have to use this function; it is used for the implementation of the output operator for Value, operator<<(std::ostream &os, const Value &value).

std::string	toString () const
	Return the value as a string. Implemented in terms of write(std::ostream& os) const of the concrete class.

virtual std::string	toString (size_t n) const
	Return the n-th component of the value as a string. The default implementation returns toString(). The behaviour of this method may be undefined if there is no n-th component.

virtual int64_t	toInt64 (size_t n=0) const =0
	Convert the n-th component of the value to an int64_t. The behaviour of this method may be undefined if there is no n-th component.

virtual uint32_t	toUint32 (size_t n=0) const =0
	Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

virtual float	toFloat (size_t n=0) const =0
	Convert the n-th component of the value to a float. The behaviour of this method may be undefined if there is no n-th component.

virtual Rational	toRational (size_t n=0) const =0
	Convert the n-th component of the value to a Rational. The behaviour of this method may be undefined if there is no n-th component.

virtual size_t	sizeDataArea () const
	Return the size of the data area, 0 if there is none.

virtual DataBuf	dataArea () const
	Return a copy of the data area if the value has one. The caller owns this copy and DataBuf ensures that it will be deleted.

bool	ok () const
	Check the ok status indicator. After a to<Type> conversion, this indicator shows whether the conversion was successful.

Manipulators
void	setXmpArrayType (XmpArrayType xmpArrayType)
	Set the XMP array type to indicate that an XMP value is an array.

void	setXmpStruct (XmpStruct xmpStruct=xsStruct)
	Set the XMP struct type to indicate that an XMP value is a structure.

int	read (const byte *buf, size_t len, ByteOrder byteOrder=invalidByteOrder) override

int	read (const std::string &buf) override=0
	Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

static XmpArrayType	xmpArrayType (TypeId typeId)
	Return XMP array type for an array Value TypeId, xaNone if typeId is not an XMP array value type.

Additional Inherited Members
Static Public Member Functions inherited from Exiv2::Value
static UniquePtr	create (TypeId typeId)
	A (simple) factory to create a Value type.

Protected Member Functions inherited from Exiv2::Value
	Value (const Value &)=default

Value &	operator= (const Value &)=default
	Assignment operator. Protected so that it can only be used by subclasses but not directly.

Protected Attributes inherited from Exiv2::Value
bool	ok_ {true}
	Indicates the status of the previous to<Type> conversion.

Detailed Description

Base class for all Exiv2 values used to store XMP property values.

Member Function Documentation

◆ copy()

size_t Exiv2::XmpValue::copy	(	byte *	buf,
		ByteOrder	byteOrder = `invalidByteOrder`
	)		const

overridevirtual

Write value to a character data buffer.

The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour.

Note: The byte order is required by the interface but not used by this method, so just use the default.

Parameters

buf	Data buffer to write to.
byteOrder	Byte order. Not used.

Returns: Number of characters written.

Implements Exiv2::Value.

References Exiv2::Value::write().

◆ read() [1/2]

int Exiv2::XmpValue::read	(	const byte *	buf,
		size_t	len,
		ByteOrder	byteOrder = `invalidByteOrder`
	)

overridevirtual

Note: Uses read(const std::string& buf)

Implements Exiv2::Value.

References read().

Referenced by read().

◆ read() [2/2]

int Exiv2::XmpValue::read ( const std::string & buf )

overridepure virtual

Set the value from a string buffer. The format of the string corresponds to that of the write() method, i.e., a string obtained through the write() method can be read by this function.

Parameters