/***************************************************************************
copyright : (C) 2002 - 2008 by Scott Wheeler
email : wheeler@kde.org
***************************************************************************/
/***************************************************************************
* This library is free software; you can redistribute it and/or modify *
* it under the terms of the GNU Lesser General Public License version *
* 2.1 as published by the Free Software Foundation. *
* *
* This library is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this library; if not, write to the Free Software *
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA *
* 02110-1301 USA *
* *
* Alternatively, this file is available under the Mozilla Public *
* License Version 1.1. You may obtain a copy of the License at *
* http://www.mozilla.org/MPL/ *
***************************************************************************/
#ifndef TAGLIB_ID3V2FRAME_H
#define TAGLIB_ID3V2FRAME_H
#include "tstring.h"
#include "tbytevector.h"
#include "taglib_export.h"
namespace TagLib {
class StringList;
class PropertyMap;
namespace ID3v2 {
class Tag;
class FrameFactory;
//! ID3v2 frame 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.
*/
class TAGLIB_EXPORT Frame
{
friend class Tag;
friend class FrameFactory;
public:
/*!
* 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.
*/
static Frame *createTextualFrame(const String &key, const StringList &values);
/*!
* Destroys this Frame instance.
*/
virtual ~Frame();
/*!
* Returns the Frame ID (Structure, 4)
* (Frames, 4)
*/
ByteVector frameID() const;
/*!
* Returns the size of the frame.
*/
unsigned int size() const;
/*!
* Returns the size of the frame header
*
* \deprecated This is only accurate for ID3v2.3 or ID3v2.4. Please use
* the call below which accepts an ID3v2 version number. In the next
* non-binary compatible release this will be made into a non-static
* member that checks the internal ID3v2 version.
*/
static unsigned int headerSize(); // BIC: remove and make non-static
/*!
* Returns the size of the frame header for the given ID3v2 version.
*
* \deprecated Please see the explanation above.
*/
static unsigned int headerSize(unsigned int version); // BIC: remove and make non-static
/*!
* 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().
*/
void setData(const ByteVector &data);
/*!
* 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.
*/
virtual void setText(const String &text);
/*!
* This returns the textual representation of the data in the frame.
* Subclasses must reimplement this method to provide a string
* representation of the frame's data.
*/
virtual String toString() const = 0;
/*!
* Render the frame back to its binary format in a ByteVector.
*/
ByteVector render() const;
/*!
* Returns the text delimiter that is used between fields for the string
* type \a t.
*/
static ByteVector textDelimiter(String::Type t);
/*!
* 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:".
*/
static const String instrumentPrefix;
/*!
* 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:".
*/
static const String commentPrefix;
/*!
* 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:".
*/
static const String lyricsPrefix;
/*!
* 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:".
*/
static const String urlPrefix;
protected:
class Header;
/*!
* Constructs an ID3v2 frame using \a data to read the header information.
* All other processing of \a data should be handled in a subclass.
*
* \note This need not contain anything more than a frame ID, but
* \e must contain at least that.
*/
explicit Frame(const ByteVector &data);
/*!
* This creates an Frame using the header \a h.
*
* The ownership of this header will be assigned to the frame and the
* header will be deleted when the frame is destroyed.
*/
Frame(Header *h);
/*!
* Returns a pointer to the frame header.
*/
Header *header() const;
/*!
* Sets the header to \a h. If \a 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 setHeader(Header *h, bool deleteCurrent = true);
/*!
* Called by setData() to parse the frame data. It makes this information
* available through the public API.
*/
void parse(const ByteVector &data);
/*!
* Called by parse() to parse the field data. It makes this information
* available through the public API. This must be overridden by the
* subclasses.
*/
virtual void parseFields(const ByteVector &data) = 0;
/*!
* Render the field data back to a binary format in a ByteVector. This
* must be overridden by subclasses.
*/
virtual ByteVector renderFields() const = 0;
/*!
* 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.
*/
ByteVector fieldData(const ByteVector &frameData) const;
/*!
* Reads a String of type \a encoding from the ByteVector \a data. If \a
* 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.
*/
String readStringField(const ByteVector &data, String::Type encoding,
int *positon = 0);
/*!
* Checks a the list of string values to see if they can be used with the
* specified encoding and returns the recommended encoding.
*/
// BIC: remove and make non-static
static String::Type checkEncoding(const StringList &fields,
String::Type encoding);
/*!
* 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.
*/
// BIC: remove and make non-static
static String::Type checkEncoding(const StringList &fields,
String::Type encoding, unsigned int version);
/*!
* 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.
*/
String::Type checkTextEncoding(const StringList &fields,
String::Type encoding) const;
/*!
* 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.
*/
PropertyMap asProperties() const;
/*!
* 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 ByteVector keyToFrameID(const String &);
/*!
* 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 frameIDToKey(const ByteVector &);
/*!
* Returns an appropriate TXXX frame description for the given free-form tag key.
*/
static String keyToTXXX(const String &);
/*!
* Returns a free-form tag name for the given ID3 frame description.
*/
static String txxxToKey(const String &);
/*!
* This helper function splits the PropertyMap \a original into three ProperytMaps
* \a singleFrameProperties, \a tiplProperties, and \a tmclProperties, such that:
* - \a 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.
* - \a tiplProperties will consist of those keys that are present in
* TextIdentificationFrame::involvedPeopleMap()
* - \a tmclProperties contains the "musician credits" keys which should be mapped
* to a TMCL frame
*/
static void splitProperties(const PropertyMap &original, PropertyMap &singleFrameProperties,
PropertyMap &tiplProperties, PropertyMap &tmclProperties);
private:
Frame(const Frame &);
Frame &operator=(const Frame &);
class FramePrivate;
friend class FramePrivate;
FramePrivate *d;
};
//! ID3v2 frame header implementation
/*!
* 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.
*/
class TAGLIB_EXPORT Frame::Header
{
public:
/*!
* Construct a Frame Header based on \a data. \a 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.
*
* \deprecated Please use the constructor below that accepts a version
* number.
*/
Header(const ByteVector &data, bool synchSafeInts);
/*!
* Construct a Frame Header based on \a data. \a 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.
*
* \a version should be the ID3v2 version of the tag.
*/
explicit Header(const ByteVector &data, unsigned int version = 4);
/*!
* Destroys this Header instance.
*/
virtual ~Header();
/*!
* Sets the data for the Header.
*
* \deprecated Please use the version below that accepts an ID3v2 version
* number.
*/
void setData(const ByteVector &data, bool synchSafeInts);
/*!
* Sets the data for the Header. \a version should indicate the ID3v2
* version number of the tag that this frame is contained in.
*/
void setData(const ByteVector &data, unsigned int version = 4);
/*!
* Returns the Frame ID (Structure, 4)
* (Frames, 4)
*/
ByteVector frameID() const;
/*!
* Sets the frame's ID to \a id. Only the first four bytes of \a 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.
*/
void setFrameID(const ByteVector &id);
/*!
* Returns the size of the frame data portion, as set when setData() was
* called or set explicitly via setFrameSize().
*/
unsigned int frameSize() const;
/*!
* Sets the size of the frame data portion.
*/
void setFrameSize(unsigned int size);
/*!
* Returns the ID3v2 version of the header, as passed in from the
* construction of the header or set via setVersion().
*/
unsigned int version() const;
/*!
* Sets the ID3v2 version of the header, changing has impact on the
* correct parsing/rendering of frame data.
*/
void setVersion(unsigned int version);
/*!
* Returns the size of the frame header in bytes.
*
* \deprecated Please use the version of this method that accepts a
* version. This is only accurate for ID3v2.3 and ID3v2.4. This will be
* removed in the next binary incompatible release (2.0) and will be
* replaced with a non-static method that checks the frame version.
*/
static unsigned int size();
/*!
* Returns the size of the frame header in bytes for the ID3v2 version
* that's given.
*
* \deprecated Please see the explanation in the version above.
*/
static unsigned int size(unsigned int version);
/*!
* 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 setTagAlterPreservation()
*/
bool tagAlterPreservation() const;
/*!
* 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 tagAlterPreservation()
*/
void setTagAlterPreservation(bool discard);
/*!
* Returns true if the flag for file alter preservation is set.
*
* \note This flag is currently ignored internally in TagLib.
*/
bool fileAlterPreservation() const;
/*!
* Returns true if the frame is meant to be read only.
*
* \note This flag is currently ignored internally in TagLib.
*/
bool readOnly() const;
/*!
* Returns true if the flag for the grouping identity is set.
*
* \note This flag is currently ignored internally in TagLib.
*/
bool groupingIdentity() const;
/*!
* Returns true if compression is enabled for this frame.
*
* \note This flag is currently ignored internally in TagLib.
*/
bool compression() const;
/*!
* Returns true if encryption is enabled for this frame.
*
* \note This flag is currently ignored internally in TagLib.
*/
bool encryption() const;
#ifndef DO_NOT_DOCUMENT
bool unsycronisation() const;
#endif
/*!
* Returns true if unsynchronisation is enabled for this frame.
*/
bool unsynchronisation() const;
/*!
* Returns true if the flag for a data length indicator is set.
*/
bool dataLengthIndicator() const;
/*!
* Render the Header back to binary format in a ByteVector.
*/
ByteVector render() const;
/*!
* \deprecated
*/
bool frameAlterPreservation() const;
private:
Header(const Header &);
Header &operator=(const Header &);
class HeaderPrivate;
HeaderPrivate *d;
};
}
}
#endif