TagLib 1.11 (TagLib: TagLib::ID3v2::Frame Class Reference)

TagLib::ID3v2::Frame Class Reference

ID3v2 frame implementation. More...

#include <id3v2frame.h>

Inheritance diagram for TagLib::ID3v2::Frame:
Collaboration diagram for TagLib::ID3v2::Frame:

List of all members.

Public Member Functions

virtual ~Frame ()
ByteVector frameID () const
unsigned int size () const
void setData (const ByteVector &data)
virtual void setText (const String &text)
virtual String toString () const =0
ByteVector render () const
 Header (const ByteVector &data, bool synchSafeInts)
 Header (const ByteVector &data, unsigned int version=4)
virtual ~Header ()
void setData (const ByteVector &data, bool synchSafeInts)
void setData (const ByteVector &data, unsigned int version=4)
ByteVector frameID () const
void setFrameID (const ByteVector &id)
unsigned int frameSize () const
void setFrameSize (unsigned int size)
unsigned int version () const
void setVersion (unsigned int version)
bool tagAlterPreservation () const
void setTagAlterPreservation (bool discard)
bool fileAlterPreservation () const
bool readOnly () const
bool groupingIdentity () const
bool compression () const
bool encryption () const
bool unsynchronisation () const
bool dataLengthIndicator () const
ByteVector render () const
bool frameAlterPreservation () const

Static Public Member Functions

static FramecreateTextualFrame (const String &key, const StringList &values)
static unsigned int headerSize ()
static unsigned int headerSize (unsigned int version)
static ByteVector textDelimiter (String::Type t)
static unsigned int size ()
static unsigned int size (unsigned int version)

Static Public Attributes

static const String instrumentPrefix
static const String commentPrefix
static const String lyricsPrefix
static const String urlPrefix

Protected Member Functions

 Frame (const ByteVector &data)
 Frame (Header *h)
Headerheader () const
void setHeader (Header *h, bool deleteCurrent=true)
void parse (const ByteVector &data)
virtual void parseFields (const ByteVector &data)=0
virtual ByteVector renderFields () const =0
ByteVector fieldData (const ByteVector &frameData) const
String readStringField (const ByteVector &data, String::Type encoding, int *positon=0)
String::Type checkTextEncoding (const StringList &fields, String::Type encoding) const
PropertyMap asProperties () const

Static Protected Member Functions

static String::Type checkEncoding (const StringList &fields, String::Type encoding)
static String::Type checkEncoding (const StringList &fields, String::Type encoding, unsigned int version)
static ByteVector keyToFrameID (const String &)
static String frameIDToKey (const ByteVector &)
static String keyToTXXX (const String &)
static String txxxToKey (const String &)
static void splitProperties (const PropertyMap &original, PropertyMap &singleFrameProperties, PropertyMap &tiplProperties, PropertyMap &tmclProperties)

Friends

class Tag
class FrameFactory
class FramePrivate


Detailed Description

ID3v2 frame implementation.

ID3v2 frame header implementation.

This class is the main ID3v2 frame implementation. In ID3v2, a tag is split between a collection of frames (which are in turn split into fields (Structure, 4) (Frames). This class provides an API for gathering information about and modifying ID3v2 frames. Funtionallity specific to a given frame type is handed in one of the many subclasses.

The ID3v2 Frame Header (Structure, 4)

Every ID3v2::Frame has an associated header that gives some general properties of the frame and also makes it possible to identify the frame type.

As such when reading an ID3v2 tag ID3v2::FrameFactory first creates the frame headers and then creates the appropriate Frame subclass based on the type and attaches the header.


Constructor & Destructor Documentation

virtual TagLib::ID3v2::Frame::~Frame (  )  [virtual]

Destroys this Frame instance.

TagLib::ID3v2::Frame::Frame ( const ByteVector data  )  [explicit, protected]

Constructs an ID3v2 frame using data to read the header information. All other processing of data should be handled in a subclass.

Note:
This need not contain anything more than a frame ID, but must contain at least that.

TagLib::ID3v2::Frame::Frame ( Header h  )  [protected]

This creates an Frame using the header h.

The ownership of this header will be assigned to the frame and the header will be deleted when the frame is destroyed.

virtual TagLib::ID3v2::Frame::~Header (  )  [virtual]

Destroys this Header instance.

Reimplemented from TagLib::ID3v2::Header.


Member Function Documentation

static Frame* TagLib::ID3v2::Frame::createTextualFrame ( const String key,
const StringList values 
) [static]

Creates a textual frame which corresponds to a single key in the PropertyMap interface. These are all (User)TextIdentificationFrames except TIPL and TMCL, all (User)URLLinkFrames, CommentsFrames, and UnsynchronizedLyricsFrame.

ByteVector TagLib::ID3v2::Frame::frameID (  )  const

Returns the Frame ID (Structure, 4) (Frames, 4)

unsigned int TagLib::ID3v2::Frame::size (  )  const

Returns the size of the frame.

static unsigned int TagLib::ID3v2::Frame::headerSize (  )  [static]

Returns the size of the frame header

static unsigned int TagLib::ID3v2::Frame::headerSize ( unsigned int  version  )  [static]

Returns the size of the frame header for the given ID3v2 version.

void TagLib::ID3v2::Frame::setData ( const ByteVector data  ) 

Sets the data that will be used as the frame. Since the length is not known before the frame has been parsed, this should just be a pointer to the first byte of the frame. It will determine the length internally and make that available through size().

Reimplemented from TagLib::ID3v2::Header.

Reimplemented in TagLib::ID3v2::PrivateFrame.

virtual void TagLib::ID3v2::Frame::setText ( const String text  )  [virtual]

Set the text of frame in the sanest way possible. This should only be reimplemented in frames where there is some logical mapping to text.

Note:
If the frame type supports multiple text encodings, this will not change the text encoding of the frame; the string will be converted to that frame's encoding. Please use the specific APIs of the frame types to set the encoding if that is desired.

Reimplemented in TagLib::ID3v2::CommentsFrame, TagLib::ID3v2::TextIdentificationFrame, TagLib::ID3v2::UserTextIdentificationFrame, TagLib::ID3v2::UnsynchronizedLyricsFrame, and TagLib::ID3v2::UrlLinkFrame.

ByteVector TagLib::ID3v2::Frame::render (  )  const

Render the frame back to its binary format in a ByteVector.

Reimplemented from TagLib::ID3v2::Header.

static ByteVector TagLib::ID3v2::Frame::textDelimiter ( String::Type  t  )  [static]

Returns the text delimiter that is used between fields for the string type t.

Header* TagLib::ID3v2::Frame::header (  )  const [protected]

Returns a pointer to the frame header.

void TagLib::ID3v2::Frame::setHeader ( Header h,
bool  deleteCurrent = true 
) [protected]

Sets the header to h. If deleteCurrent is true, this will free the memory of the current header.

The ownership of this header will be assigned to the frame and the header will be deleted when the frame is destroyed.

void TagLib::ID3v2::Frame::parse ( const ByteVector data  )  [protected]

Called by setData() to parse the frame data. It makes this information available through the public API.

Reimplemented from TagLib::ID3v2::Header.

ByteVector TagLib::ID3v2::Frame::fieldData ( const ByteVector frameData  )  const [protected]

Returns a ByteVector containing the field data given the frame data. This correctly adjusts for the header size plus any additional frame data that's specified in the frame header flags.

String TagLib::ID3v2::Frame::readStringField ( const ByteVector data,
String::Type  encoding,
int *  positon = 0 
) [protected]

Reads a String of type encoding from the ByteVector data. If position is passed in it is used both as the starting point and is updated to return the position just after the string that has been read. This is useful for reading strings sequentially.

static String::Type TagLib::ID3v2::Frame::checkEncoding ( const StringList fields,
String::Type  encoding 
) [static, protected]

Checks a the list of string values to see if they can be used with the specified encoding and returns the recommended encoding.

static String::Type TagLib::ID3v2::Frame::checkEncoding ( const StringList fields,
String::Type  encoding,
unsigned int  version 
) [static, protected]

Checks a the list of string values to see if they can be used with the specified encoding and returns the recommended encoding. This method also checks the ID3v2 version and makes sure the encoding can be used in the specified version.

String::Type TagLib::ID3v2::Frame::checkTextEncoding ( const StringList fields,
String::Type  encoding 
) const [protected]

Checks a the list of string values to see if they can be used with the specified encoding and returns the recommended encoding. This method also checks the ID3v2 version and makes sure the encoding can be used in the version specified by the frame's header.

PropertyMap TagLib::ID3v2::Frame::asProperties (  )  const [protected]

Parses the contents of this frame as PropertyMap. If that fails, the returend PropertyMap will be empty, and its unsupportedData() will contain this frame's ID. BIC: Will be a virtual function in future releases.

Reimplemented in TagLib::ID3v2::ChapterFrame, TagLib::ID3v2::CommentsFrame, TagLib::ID3v2::TableOfContentsFrame, TagLib::ID3v2::TextIdentificationFrame, TagLib::ID3v2::UserTextIdentificationFrame, TagLib::ID3v2::UniqueFileIdentifierFrame, TagLib::ID3v2::UnsynchronizedLyricsFrame, TagLib::ID3v2::UrlLinkFrame, and TagLib::ID3v2::UserUrlLinkFrame.

static ByteVector TagLib::ID3v2::Frame::keyToFrameID ( const String  )  [static, protected]

Returns an appropriate ID3 frame ID for the given free-form tag key. This method will return an empty ByteVector if no specialized translation is found.

static String TagLib::ID3v2::Frame::frameIDToKey ( const ByteVector  )  [static, protected]

Returns a free-form tag name for the given ID3 frame ID. Note that this does not work for general frame IDs such as TXXX or WXXX; in such a case an empty string is returned.

static String TagLib::ID3v2::Frame::keyToTXXX ( const String  )  [static, protected]

Returns an appropriate TXXX frame description for the given free-form tag key.

static String TagLib::ID3v2::Frame::txxxToKey ( const String  )  [static, protected]

Returns a free-form tag name for the given ID3 frame description.

static void TagLib::ID3v2::Frame::splitProperties ( const PropertyMap original,
PropertyMap singleFrameProperties,
PropertyMap tiplProperties,
PropertyMap tmclProperties 
) [static, protected]

This helper function splits the PropertyMap original into three ProperytMaps singleFrameProperties, tiplProperties, and tmclProperties, such that:

  • singleFrameProperties contains only of keys which can be represented with exactly one ID3 frame per key. In the current implementation this is everything except for the fixed "involved people" keys and keys of the form "TextIdentificationFrame::instrumentPrefix" + "instrument", which are mapped to a TMCL frame.
  • tiplProperties will consist of those keys that are present in TextIdentificationFrame::involvedPeopleMap()
  • tmclProperties contains the "musician credits" keys which should be mapped to a TMCL frame

TagLib::ID3v2::Frame::Header ( const ByteVector data,
bool  synchSafeInts 
)

Construct a Frame Header based on data. data must at least contain a 4 byte frame ID, and optionally can contain flag data and the frame size. i.e. Just the frame id -- "TALB" -- is a valid value.

TagLib::ID3v2::Frame::Header ( const ByteVector data,
unsigned int  version = 4 
) [explicit]

Construct a Frame Header based on data. data must at least contain a 4 byte frame ID, and optionally can contain flag data and the frame size. i.e. Just the frame id -- "TALB" -- is a valid value.

version should be the ID3v2 version of the tag.

void TagLib::ID3v2::Frame::setData ( const ByteVector data,
bool  synchSafeInts 
)

Sets the data for the Header.

void TagLib::ID3v2::Frame::setData ( const ByteVector data,
unsigned int  version = 4 
)

Sets the data for the Header. version should indicate the ID3v2 version number of the tag that this frame is contained in.

ByteVector TagLib::ID3v2::Frame::frameID (  )  const

Returns the Frame ID (Structure, 4) (Frames, 4)

void TagLib::ID3v2::Frame::setFrameID ( const ByteVector id  ) 

Sets the frame's ID to id. Only the first four bytes of id will be used.

Warning:
This method should in general be avoided. It exists simply to provide a mechanism for transforming frames from a deprecated frame type to a newer one -- i.e. TYER to TDRC from ID3v2.3 to ID3v2.4.

unsigned int TagLib::ID3v2::Frame::frameSize (  )  const

Returns the size of the frame data portion, as set when setData() was called or set explicitly via setFrameSize().

void TagLib::ID3v2::Frame::setFrameSize ( unsigned int  size  ) 

Sets the size of the frame data portion.

unsigned int TagLib::ID3v2::Frame::version (  )  const

Returns the ID3v2 version of the header, as passed in from the construction of the header or set via setVersion().

void TagLib::ID3v2::Frame::setVersion ( unsigned int  version  ) 

Sets the ID3v2 version of the header, changing has impact on the correct parsing/rendering of frame data.

static unsigned int TagLib::ID3v2::Frame::size (  )  [static]

Returns the size of the frame header in bytes.

Reimplemented from TagLib::ID3v2::Header.

static unsigned int TagLib::ID3v2::Frame::size ( unsigned int  version  )  [static]

Returns the size of the frame header in bytes for the ID3v2 version that's given.

bool TagLib::ID3v2::Frame::tagAlterPreservation (  )  const

Returns true if the flag for tag alter preservation is set.

The semantics are a little backwards from what would seem natural (setting the preservation flag to throw away the frame), but this follows the ID3v2 standard.

See also:
setTagAlterPreservation()

void TagLib::ID3v2::Frame::setTagAlterPreservation ( bool  discard  ) 

Sets the flag for preservation of this frame if the tag is set. If this is set to true the frame will not be written when the tag is saved.

The semantics are a little backwards from what would seem natural (setting the preservation flag to throw away the frame), but this follows the ID3v2 standard.

See also:
tagAlterPreservation()

bool TagLib::ID3v2::Frame::fileAlterPreservation (  )  const

Returns true if the flag for file alter preservation is set.

Note:
This flag is currently ignored internally in TagLib.

bool TagLib::ID3v2::Frame::readOnly (  )  const

Returns true if the frame is meant to be read only.

Note:
This flag is currently ignored internally in TagLib.

bool TagLib::ID3v2::Frame::groupingIdentity (  )  const

Returns true if the flag for the grouping identity is set.

Note:
This flag is currently ignored internally in TagLib.

bool TagLib::ID3v2::Frame::compression (  )  const

Returns true if compression is enabled for this frame.

Note:
This flag is currently ignored internally in TagLib.

bool TagLib::ID3v2::Frame::encryption (  )  const

Returns true if encryption is enabled for this frame.

Note:
This flag is currently ignored internally in TagLib.

bool TagLib::ID3v2::Frame::unsynchronisation (  )  const

Returns true if unsynchronisation is enabled for this frame.

Reimplemented from TagLib::ID3v2::Header.

bool TagLib::ID3v2::Frame::dataLengthIndicator (  )  const

Returns true if the flag for a data length indicator is set.

ByteVector TagLib::ID3v2::Frame::render (  )  const

Render the Header back to binary format in a ByteVector.

Reimplemented from TagLib::ID3v2::Header.

bool TagLib::ID3v2::Frame::frameAlterPreservation (  )  const


Friends And Related Function Documentation

friend class Tag [friend]

friend class FramePrivate [friend]


Member Data Documentation

The string with which an instrument name is prefixed to build a key in a PropertyMap; used to translate PropertyMaps to TMCL frames. In the current implementation, this is "PERFORMER:".

The PropertyMap key prefix which triggers the use of a COMM frame instead of a TXXX frame for a non-standard key. In the current implementation, this is "COMMENT:".

The PropertyMap key prefix which triggers the use of a USLT frame instead of a TXXX frame for a non-standard key. In the current implementation, this is "LYRICS:".

The PropertyMap key prefix which triggers the use of a WXXX frame instead of a TXX frame for a non-standard key. In the current implementation, this is "URL:".


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