Exiv2::Exifdatum Class Reference

Information related to one Exif tag. More...

#include <exif.hpp>

Inheritance diagram for Exiv2::Exifdatum:

[legend]Collaboration diagram for Exiv2::Exifdatum:

[legend]List of all members.

Public Member Functions
Creators
	Exifdatum (const ExifKey &key, const Value *pValue=0)
	Constructor for new tags created by an application. The Exifdatum is created from a key / value pair. Exifdatum copies (clones) the key and value if one is provided. Alternatively, a program can create an 'empty' Exifdatum with only a key and set the value using setValue().
	Exifdatum (const Entry &e, ByteOrder byteOrder)
	Constructor to build a Exifdatum from an IFD entry.
	Exifdatum (const Exifdatum &rhs)
	Copy constructor.
virtual	~Exifdatum ()
	Destructor.
Manipulators
Exifdatum &	operator= (const Exifdatum &rhs)
	Assignment operator.
void	setValue (const Value *pValue)
	Set the value. This method copies (clones) the value pointed to by pValue.
void	setValue (const Entry &e, ByteOrder byteOrder)
	Set the value from an IFD entry.
void	setValue (const std::string &buf)
	Set the value to the string buf. Uses Value::read(const std::string& buf). If the Exifdatum does not have a value yet, then an AsciiValue is created.
Accessors
std::string	key () const
	Return the key of the Exifdatum.
std::string	groupName () const
	Return the name of the group (the second part of the key).
std::string	tagName () const
	Return the name of the tag (which is also the third part of the key).
uint16	tag () const
	Return the tag.
IfdId	ifdId () const
	Return the IFD id.
const char *	ifdName () const
	Return the name of the IFD.
const char *	ifdItem () const
	Return the related image item (deprecated).
int	idx () const
	Return the index (unique id of this key within the original IFD).
long	copy (byte *buf, ByteOrder byteOrder) const
	Write value to a data buffer and return the number of bytes written.
TypeId	typeId () const
	Return the type id of the value.
const char *	typeName () const
	Return the name of the type.
long	typeSize () const
	Return the size in bytes of one component of this type.
long	count () const
	Return the number of components in the value.
long	size () const
	Return the size of the value in bytes.
std::string	toString () const
	Return the value as a string.
long	toLong (long n=0) const
	Return the n-th component of the value converted to long. The return value is -1 if the value of the Exifdatum is not set and the behaviour of the method is undefined if there is no n-th component.
float	toFloat (long n=0) const
	Return the n-th component of the value converted to float. The return value is -1 if the value of the Exifdatum is not set and the behaviour of the method is undefined if there is no n-th component.
Rational	toRational (long n=0) const
	Return the n-th component of the value converted to Rational. The return value is -1/1 if the value of the Exifdatum is not set and the behaviour of the method is undefined if there is no n-th component.
Value *	getValue () const
	Return a pointer to a copy (clone) of the value. The caller is responsible to delete this copy when it's no longer needed.
const Value &	value () const
	Return a constant reference to the value.
Friends
std::ostream &	operator<< (std::ostream &, const Exifdatum &)
	Output operator for Exifdatum types, prints the interpreted tag value.

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Detailed Description

Information related to one Exif tag.

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Constructor & Destructor Documentation

Exiv2::Exifdatum::Exifdatum (  const ExifKey &  key, const Value *  pValue = 0 )  [explicit]

Constructor for new tags created by an application. The Exifdatum is created from a key / value pair. Exifdatum copies (clones) the key and value if one is provided. Alternatively, a program can create an 'empty' Exifdatum with only a key and set the value using setValue(). Parameters: key  ExifKey. pValue  Pointer to a Exifdatum value. Exceptions: Error  ("Invalid key") if the key cannot be parsed and converted.

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Member Function Documentation

long Exiv2::Exifdatum::copy (  byte *  buf, ByteOrder  byteOrder )  const [inline, virtual]

Write value to a data buffer and return the number of bytes written. The user must ensure that the buffer has enough memory. Otherwise the call results in undefined behaviour. Parameters: buf  Data buffer to write to. byteOrder  Applicable byte order (little or big endian). Returns: Number of characters written. Implements Exiv2::Metadatum.

Value* Exiv2::Exifdatum::getValue (   )  const [inline, virtual]

Return a pointer to a copy (clone) of the value. The caller is responsible to delete this copy when it's no longer needed. This method is provided for users who need full control over the value. A caller may, e.g., downcast the pointer to the appropriate subclass of Value to make use of the interface of the subclass to set or modify its contents. Returns: A pointer to a copy (clone) of the value, 0 if the value is not set. Implements Exiv2::Metadatum.

const Value& Exiv2::Exifdatum::value (   )  const [inline, virtual]

Return a constant reference to the value. This method is provided mostly for convenient and versatile output of the value which can (to some extent) be formatted through standard stream manipulators. Do not attempt to write to the value through this reference. Example: ExifData::const_iterator i = exifData.findKey(key); if (i != exifData.end()) { std::cout << i->key() << " " << std::hex << i->value() << "\n"; } Returns: A constant reference to the value. Exceptions: Error  ("Value not set") if the value is not set. Implements Exiv2::Metadatum.

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

• exif.hpp
• exif.cpp

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