Exiv2::CommentValue Class Reference
Value for an Exif comment. More...
#include <value.hpp>
Inheritance diagram for Exiv2::CommentValue:
Classes | |
| class | CharsetInfo |
| Charset information lookup functions. Implemented as a static class. More... | |
| struct | CharsetTable |
| Information pertaining to the defined character sets. More... | |
Public Types | |
| enum | CharsetId { ascii, jis, unicode, undefined, invalidCharsetId, lastCharsetId } |
| Character set identifiers for the character sets defined by Exif. | |
| typedef std::auto_ptr< CommentValue > | AutoPtr |
| Shortcut for a CommentValue auto pointer. | |
 Public Types inherited from Exiv2::StringValueBase | |
| typedef std::auto_ptr< StringValueBase > | AutoPtr |
| Shortcut for a StringValueBase auto pointer. | |
| Public Types inherited from Exiv2::Value | |
| typedef std::auto_ptr< Value > | AutoPtr |
| Shortcut for a Value auto pointer. | |
Public Member Functions | |
Creators | |
| CommentValue () | |
| Default constructor. | |
| CommentValue (const std::string &comment) | |
| Constructor, uses read(const std::string& comment) | |
| virtual | ~CommentValue () |
| Virtual destructor. | |
Manipulators | |
| int | read (const std::string &comment) |
| Read the value from a comment. More... | |
| int | read (const byte *buf, long len, ByteOrder byteOrder) |
| Read the comment from a byte buffer. | |
| Public Member Functions inherited from Exiv2::StringValueBase | |
| 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. | |
| AutoPtr | clone () const |
| 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. More... | |
| 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. More... | |
| 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. More... | |
| Public Member Functions inherited from Exiv2::Value | |
| Value (TypeId typeId) | |
| Constructor, taking a type id to initialize the base class with. | |
| virtual | ~Value () |
| Virtual destructor. | |
| virtual int | setDataArea (const byte *buf, long len) |
| Set the data area, if the value has one by copying (cloning) the buffer pointed to by buf. More... | |
| TypeId | typeId () const |
| Return the type identifier (Exif data format type). | |
| 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. | |
| 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 (long 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 long | 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. More... | |
| bool | ok () const |
| Check the ok status indicator. After a to<Type> conversion, this indicator shows whether the conversion was successful. | |
Accessors | |
| ByteOrder | byteOrder_ |
| Byte order of the comment string that was read. | |
| AutoPtr | clone () const |
| long | copy (byte *buf, ByteOrder byteOrder) const |
| Write value to a character data buffer. More... | |
| std::ostream & | write (std::ostream &os) const |
| Write the comment in a format which can be read by read(const std::string& comment). | |
| std::string | comment (const char *encoding=0) const |
| Return the comment (without a charset="..." prefix) More... | |
| const char * | detectCharset (std::string &c) const |
| Determine the character encoding that was used to encode the UNICODE comment value as an iconv(3) name. More... | |
| CharsetId | charsetId () const |
| Return the Exif charset id of the comment. | |
Additional Inherited Members | |
| Static Public Member Functions inherited from Exiv2::Value | |
| static AutoPtr | create (TypeId typeId) |
| A (simple) factory to create a Value type. More... | |
| Public Attributes inherited from Exiv2::StringValueBase | |
| std::string | value_ |
| Stores the string value. | |
| Protected Member Functions inherited from Exiv2::StringValueBase | |
| StringValueBase & | operator= (const StringValueBase &rhs) |
| Assignment operator. | |
| Protected Member Functions inherited from Exiv2::Value | |
| Value & | operator= (const Value &rhs) |
| Assignment operator. Protected so that it can only be used by subclasses but not directly. | |
| Protected Attributes inherited from Exiv2::Value | |
| bool | ok_ |
| Indicates the status of the previous to<Type> conversion. | |
Detailed Description
Value for an Exif comment.
This can be a plain Ascii string or a multipe byte encoded string. The comment is expected to be encoded in the character set indicated (default undefined), but this is not checked. It is left to caller to decode and encode the string to and from readable text if that is required.
Member Function Documentation
◆ comment()
| std::string Exiv2::CommentValue::comment | ( | const char * | encoding = 0 | ) | const |
Return the comment (without a charset="..." prefix)
The comment is decoded to UTF-8. For Exif UNICODE comments, the function makes an attempt to correctly determine the character encoding of the value. Alternatively, the optional encoding parameter can be used to specify it.
- Parameters
-
encoding Optional argument to specify the character encoding that the comment is encoded in, as an iconv(3) name. Only used for Exif UNICODE comments.
- Returns
- A string containing the comment converted to UTF-8.
◆ copy()
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.
Reimplemented from Exiv2::StringValueBase.
◆ detectCharset()
| const char* Exiv2::CommentValue::detectCharset | ( | std::string & | c | ) | const |
Determine the character encoding that was used to encode the UNICODE comment value as an iconv(3) name.
If the comment c starts with a BOM, the BOM is interpreted and removed from the string.
Todo: Implement rules to guess if the comment is UTF-8 encoded.
◆ read()
|
virtual |
Read the value from a comment.
The format of comment is:
[charset=["]Ascii|Jis|Unicode|Undefined["] ]comment
The default charset is Undefined.
- Returns
- 0 if successful
1 if an invalid character set is encountered
Reimplemented from Exiv2::StringValueBase.
The documentation for this class was generated from the following file:
- value.hpp