# Exiv2::StringValueBase Class Reference

Abstract base class for a string based Value type. More...

`#include <value.hpp>`

Inheritance diagram for Exiv2::StringValueBase:

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Collaboration diagram for Exiv2::StringValueBase:

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List of all members.

## Public Types

typedef std::auto_ptr< StringValueBase > | AutoPtr
| Shortcut for a StringValueBase auto pointer.

## Public Member Functions

Creators
| StringValueBase (TypeId typeId)
| Constructor for subclasses.
| StringValueBase (TypeId typeId, const std::string &buf)
| Constructor for subclasses.
| StringValueBase (const StringValueBase &rhs)
| Copy constructor.
virtual | ~StringValueBase ()
| Virtual destructor.
Manipulators
StringValueBase & | operator= (const StringValueBase &rhs)
| Assignment operator.
virtual int | read (const std::string &buf)
| Read the value from buf. This default implementation uses buf as it is.
virtual int | read (const byte *buf, long len, ByteOrder byteOrder=invalidByteOrder)
| Read the value from a character buffer.
Accessors
AutoPtr | 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 long | copy (byte *buf, ByteOrder byteOrder=invalidByteOrder) const
| Write value to a character data buffer.
virtual long | count () const
| Return the number of components of the value.
virtual long | size () const
| Return the size of the value in bytes.
virtual long | toLong (long n=0) const
| Convert the n-th component of the value to a long. The behaviour of this method may be undefined if there is no n-th component.
virtual float | toFloat (long n=0) const
| 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 (long n=0) const
| 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 std::ostream & | write (std::ostream &os) const
| 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).

## Protected Member Functions

virtual StringValueBase * | clone_ () const =0
| Internal virtual copy constructor.

## Protected Attributes

std::string | value_
| Stores the string value.

## Detailed Description

Abstract base class for a string based Value type.

Uses a std::string to store the value and implements defaults for most operations.

## Member Function Documentation

long Exiv2::StringValueBase::copy | ( | byte * | buf,
|  | ByteOrder | byteOrder = `invalidByteOrder`
| ) | const`[virtual]`

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.

int Exiv2::StringValueBase::read | ( | const byte * | buf,
|  | long | len,
|  | ByteOrder | byteOrder = `invalidByteOrder`
| ) | `[virtual]`

Read the value from a character buffer.

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

Parameters:

  | buf | Pointer to the data buffer to read from
  | len | Number of bytes in the data buffer
  | byteOrder | Byte order. Not needed.

Returns:
  0 if successful.

Implements Exiv2::Value.

virtual float Exiv2::StringValueBase::toFloat | ( | long | n = `0` | ) | const`[inline, virtual]`

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.

Returns:
  The converted value.

Implements Exiv2::Value.

virtual long Exiv2::StringValueBase::toLong | ( | long | n = `0` | ) | const`[inline, virtual]`

Convert the n-th component of the value to a long. The behaviour of this method may be undefined if there is no n-th component.

Returns:
  The converted value.

Implements Exiv2::Value.

virtual Rational Exiv2::StringValueBase::toRational | ( | long | n = `0` | ) | const`[inline, virtual]`

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.

Returns:
  The converted value.

Implements Exiv2::Value.

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

- value.hpp
- value.cpp