id3lib
3.8.3
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The representative class of an id3 tag. More...
#include <id3/tag.h>
Classes | |
class | ConstIterator |
class | Iterator |
Public Member Functions | |||
ID3_Tag (const char *name=NULL) | |||
Default constructor; it can accept an optional filename as a parameter. More... | |||
ID3_Tag (const ID3_Tag &tag) | |||
Standard copy constructor. More... | |||
virtual | ~ID3_Tag () | ||
void | Clear () | ||
Clears the object and disassociates it from any files. More... | |||
bool | HasChanged () const | ||
Indicates whether the tag has been altered since the last parse, render, or update. More... | |||
size_t | Size () const | ||
Returns an over estimate of the number of bytes required to store a binary version of a tag. More... | |||
bool | SetUnsync (bool) | ||
Turns unsynchronization on or off, dependant on the value of the boolean parameter. More... | |||
bool | SetExtendedHeader (bool) | ||
Turns extended header rendering on or off, dependant on the value of the boolean parameter. More... | |||
bool | SetExperimental (bool) | ||
bool | GetUnsync () const | ||
bool | GetExtendedHeader () const | ||
bool | GetExperimental () const | ||
bool | SetPadding (bool) | ||
Turns padding on or off, dependant on the value of the boolean parameter. More... | |||
void | AddFrame (const ID3_Frame &) | ||
void | AddFrame (const ID3_Frame *) | ||
Attaches a frame to the tag; the tag doesn't take responsibility for releasing the frame's memory when tag goes out of scope. More... | |||
bool | AttachFrame (ID3_Frame *) | ||
Attaches a frame to the tag; the tag takes responsibility for releasing the frame's memory when tag goes out of scope. More... | |||
ID3_Frame * | RemoveFrame (const ID3_Frame *) | ||
Removes a frame from the tag. More... | |||
size_t | Parse (const uchar *, size_t) | ||
bool | Parse (ID3_Reader &reader) | ||
size_t | Render (uchar *, ID3_TagType=ID3TT_ID3V2) const | ||
Renders the tag and writes it to the attached file; the type of tag rendered can be specified as a parameter. More... | |||
size_t | Render (ID3_Writer &, ID3_TagType=ID3TT_ID3V2) const | ||
size_t | Link (const char *fileInfo, flags_t=(flags_t) ID3TT_ALL) | ||
Attaches a file to the tag, parses the file, and adds any tag information found in the file to the tag. More... | |||
size_t | Link (ID3_Reader &reader, flags_t=(flags_t) ID3TT_ALL) | ||
Same as above, but takes a ID3_Reader as argument. More... | |||
flags_t | Update (flags_t=(flags_t) ID3TT_ALL) | ||
flags_t | Strip (flags_t=(flags_t) ID3TT_ALL) | ||
Strips the tag(s) from the attached file. More... | |||
size_t | GetPrependedBytes () const | ||
size_t | GetAppendedBytes () const | ||
size_t | GetFileSize () const | ||
const char * | GetFileName () const | ||
const Mp3_Headerinfo * | GetMp3HeaderInfo () const | ||
Get's the mp3 Info like bitrate, mpeg version, etc. More... | |||
size_t | Parse (const uchar header[ID3_TAGHEADERSIZE], const uchar *buffer) | ||
Turns a binary tag into a series of ID3_Frame objects attached to the tag. More... | |||
Find | |||
Finds frame with given frame id Returns a pointer to the next ID3_Frame with the given ID3_FrameID; returns NULL if no such frame found. If there are multiple frames in the tag with the same ID (which, for some frames, is allowed), then subsequent calls to Find() will return subsequent frame pointers, wrapping if necessary. ID3_Frame *myFrame;
if (myFrame = myTag.Find(ID3FID_TITLE))
{
// do something with the frame, like copy
// the contents into a buffer, display the
// contents in a window, etc.
// ...
}
The representative class of an id3v2 frame. You may optionally supply to more parameters ot this method, being an ID3_FieldID and a value of some sort. Depending on the field name/ID you supply, you may supply an integer, a char* or a unicode_t* as the third parameter. If you supply an ID3_FrameID, you must also supply a data value to compare against. This method will then return the first frame that has a matching frame ID, and which has a field with the same name as that which you supplied in the second parameter, whose calue matches that which you supplied as the third parameter. For example: This example will return the first TITLE frame and whose TEXT field is 'Nirvana'. Currently there is no provision for things like 'contains', 'greater than', or 'less than'. If there happens to be more than one of these frames, subsequent calls to the Find() method will return subsequent frames and will wrap around to the beginning. Another example... This returns the first COMMENT frame that uses Unicode as its text encdoing.
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ID3_Frame * | Find (ID3_FrameID) const | ||
Finds frame with given frame id, fld id, and integer data. More... | |||
ID3_Frame * | Find (ID3_FrameID, ID3_FieldID, uint32) const | ||
Finds frame with given frame id, fld id, and integer data. More... | |||
ID3_Frame * | Find (ID3_FrameID, ID3_FieldID, const char *) const | ||
Finds frame with given frame id, fld id, and ascii data. More... | |||
ID3_Frame * | Find (ID3_FrameID, ID3_FieldID, const unicode_t *) const | ||
Finds frame with given frame id, fld id, and unicode data. More... | |||
size_t | NumFrames () const | ||
Returns the number of frames present in the tag object. More... | |||
operator<< | |||
Copies a frame to the tag. The frame parameter can thus safely be deleted or allowed to go out of scope. Operator<< supports the addition of a pointer to a frame object, or the frame object itself. Both these methods copy the given frame to the tag—the tag creates its own copy of the frame.
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Iterator * | CreateIterator () | ||
ConstIterator * | CreateIterator () const | ||
ID3_Tag & | operator<< (const ID3_Frame &) | ||
ID3_Tag & | operator<< (const ID3_Frame *) | ||
operator[] | |||||
Returns a pointer to the frame with the given index; returns NULL if there is no such frame at that index. Optionally, operator[](size_t) can be used as an alternative to this method. Indexing is 0-based (that is, the first frame is number 0, and the last frame in a tag that holds n frames is n-1). If you wish to have a more comlex searching facility, then at least for now you will have to devise it yourself and implement it useing these methods.
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ID3_Tag & | operator= (const ID3_Tag &) | ||||
Deprecated. More... | |||||
bool | HasTagType (ID3_TagType tt) const | ||||
Deprecated. More... | |||||
ID3_V2Spec | GetSpec () const | ||||
Deprecated. More... | |||||
bool | SetSpec (ID3_V2Spec) | ||||
Deprecated. More... | |||||
void | AddNewFrame (ID3_Frame *f) | ||||
Deprecated. More... | |||||
size_t | Link (const char *fileInfo, bool parseID3v1, bool parseLyrics3) | ||||
Deprecated. More... | |||||
void | SetCompression (bool) | ||||
Deprecated. More... | |||||
void | AddFrames (const ID3_Frame *, size_t) | ||||
Copies an array of frames to the tag. More... | |||||
bool | HasLyrics () const | ||||
Deprecated. More... | |||||
bool | HasV2Tag () const | ||||
Deprecated. More... | |||||
bool | HasV1Tag () const | ||||
Deprecated. More... | |||||
static size_t | IsV2Tag (const uchar *) | ||||
Analyses a buffer to determine if we have a valid ID3v2 tag header. More... | |||||
static size_t | IsV2Tag (ID3_Reader &) | ||||
Deprecated. More... | |||||
The representative class of an id3 tag.
The ID3_Tag is, at its simplest, a container for ID3v2 frames. At its most complicated, it's a kitchen-sink, monolithic "catch-all" class for handling almost every task associated with creating, parsing, rendering, and manipulating digital audio data using id3lib.
This simple #include
does it all. In order to read an existing tag, do the following:
That is all there is to it. Now all you have to do is use the Find() method to locate the frames you are interested in is the following:
This code snippet locates the ID3FID_TITLE frame and displays the text field.
When using the ID3_Tag::Link() method, you automatically gain access to any ID3v1/1.1, ID3v2, Lyrics3 v2.0, and MusicMatch tags present in the file. The class will automaticaly parse and convert any of these foreign tag formats into ID3v2 tags. Also, id3lib will correctly parse any correctly formatted 'CDM' frames from the unreleased ID3v2 2.01 draft specification.
ID3_Tag::ID3_Tag | ( | const char * | name = NULL | ) |
Default constructor; it can accept an optional filename as a parameter.
If this file exists, it will be opened and all id3lib-supported tags will be parsed and converted to ID3v2 if necessary. After the conversion, the file will remain unchanged, and will continue to do so until you use the Update() method on the tag (if you choose to Update() at all).
name | The filename of the mp3 file to link to |
ID3_Tag::ID3_Tag | ( | const ID3_Tag & | tag | ) |
void ID3_Tag::AddFrame | ( | const ID3_Frame * | frame | ) |
Attaches a frame to the tag; the tag doesn't take responsibility for releasing the frame's memory when tag goes out of scope.
Optionally, operator<< can also be used to attach a frame to a tag. To use, simply supply its parameter a pointer to the ID3_Frame object you wish to attach.
As stated, this method attaches the frames to the tag—the tag does not create its own copy of the frame. Frames created by an application must exist until the frame is removed or the tag is finished with it.
pFrame | A pointer to the frame that is being added to the tag. |
void ID3_Tag::AddFrames | ( | const ID3_Frame * | frames, |
size_t | numFrames | ||
) |
Copies an array of frames to the tag.
This method copies each frame in an array to the tag. As in AddFrame, the tag adds a copy of the frame, and it assumes responsiblity for freeing the frames' memory when the tag goes out of scope.
pNewFrames | A pointer to an array of frames to be added to the tag. |
nFrames | The number of frames in the array pNewFrames. |
bool ID3_Tag::AttachFrame | ( | ID3_Frame * | frame | ) |
Attaches a frame to the tag; the tag takes responsibility for releasing the frame's memory when tag goes out of scope.
This method accepts responsibility for the attached frame's memory, and will delete the frame and its contents when the tag goes out of scope or is deleted. Therefore, be sure the frame isn't "Attached" to other tags.
frame | A pointer to the frame that is being added to the tag. |
void ID3_Tag::Clear | ( | ) |
ID3_Tag::Iterator * ID3_Tag::CreateIterator | ( | ) |
ID3_Tag::ConstIterator * ID3_Tag::CreateIterator | ( | ) | const |
ID3_Frame * ID3_Tag::Find | ( | ID3_FrameID | id | ) | const |
ID3_Frame * ID3_Tag::Find | ( | ID3_FrameID | id, |
ID3_FieldID | fld, | ||
const char * | data | ||
) | const |
ID3_Frame * ID3_Tag::Find | ( | ID3_FrameID | id, |
ID3_FieldID | fld, | ||
const unicode_t * | data | ||
) | const |
ID3_Frame * ID3_Tag::Find | ( | ID3_FrameID | id, |
ID3_FieldID | fld, | ||
uint32 | data | ||
) | const |
const Mp3_Headerinfo * ID3_Tag::GetMp3HeaderInfo | ( | ) | const |
ID3_V2Spec ID3_Tag::GetSpec | ( | ) | const |
bool ID3_Tag::HasChanged | ( | ) | const |
Indicates whether the tag has been altered since the last parse, render, or update.
If you have a tag linked to a file, you do not need this method since the Update() method will check for changes before writing the tag.
This method is primarily intended as a status indicator for applications and for applications that use the Parse() and Render() methods.
Setting a field, changed the ID of an attached frame, setting or grouping or encryption IDs, and clearing a frame or field all constitute a change to the tag, as do calls to the SetUnsync(), SetExtendedHeader(), and SetPadding() methods.
bool ID3_Tag::HasTagType | ( | ID3_TagType | tt | ) | const |
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static |
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static |
size_t ID3_Tag::Link | ( | const char * | fileInfo, |
bool | parseID3v1, | ||
bool | parseLyrics3 | ||
) |
Attaches a file to the tag, parses the file, and adds any tag information found in the file to the tag.
Use this method if you created your ID3_Tag object without supplying a parameter to the constructor (maybe you created an array of ID3_Tag pointers). This is the preferred method of interacting with files, since id3lib can automatically do things like parse foreign tag formats and handle padding when linked to a file. When a tag is linked to a file, you do not need to use the Size(), Render(const uchar*, size_t), or Parse(ID3_Reader&) methods or the IsV2Tag(ID3_Reader&) static function– id3lib will take care of those details for you. The single parameter is a pointer to a file name.
Link returns the size of the the ID3v2 tag (if any) that begins the file.
fileInfo | The filename of the file to link to. |
size_t ID3_Tag::Link | ( | ID3_Reader & | reader, |
flags_t | flags = (flags_t) ID3TT_ALL |
||
) |
Same as above, but takes a ID3_Reader as argument.
size_t ID3_Tag::NumFrames | ( | ) | const |
size_t ID3_Tag::Parse | ( | const uchar * | buffer, |
size_t | bytes | ||
) |
Turns a binary tag into a series of ID3_Frame objects attached to the tag.
header | The byte header read in from the data source. |
buffer | The remainder of the tag (not including the data source) read in from the data source. |
bool ID3_Tag::Parse | ( | ID3_Reader & | reader | ) |
Removes a frame from the tag.
If you already own the frame object in question, then you should already have a pointer to the frame you want to delete. If not, or if you wish to delete a pre-existing frame (from a tag you have parsed, for example), the use one of the Find methods to obtain a frame pointer to pass to this method.
pOldFrame | A pointer to the frame that is to be removed from the tag |
size_t ID3_Tag::Render | ( | ID3_Writer & | writer, |
ID3_TagType | tt = ID3TT_ID3V2 |
||
) | const |
size_t ID3_Tag::Render | ( | uchar * | buffer, |
ID3_TagType | tt = ID3TT_ID3V2 |
||
) | const |
Renders the tag and writes it to the attached file; the type of tag rendered can be specified as a parameter.
The default is to update only the ID3v2 tag. See the ID3_TagType enumeration for the constants that can be used.
Make sure the rendering parameters are set before calling the method. See the Link documentation for an example of this method in use.
tt | The type of tag to update. Renders a binary image of the tag into the supplied buffer. |
See Size() for an example. This method returns the actual number of the bytes of the buffer used to store the tag. This will be no more than the size of the buffer itself, because Size() over estimates the required buffer size when padding is enabled.
Before calling this method, it is advisable to call HasChanged() first as this will let you know whether you should bother rendering the tag.
buffer | The buffer that will contain the rendered tag. |
bool ID3_Tag::SetExtendedHeader | ( | bool | ext | ) |
Turns extended header rendering on or off, dependant on the value of the boolean parameter.
This option is currently ignored as id3lib doesn't yet create extended headers. This option only applies when rendering tags for ID3v2 versions that support extended headers.
bExt | Whether to render an extended header |
bool ID3_Tag::SetPadding | ( | bool | pad | ) |
Turns padding on or off, dependant on the value of the boolean parameter.
When using ID3v2 tags in association with files, id3lib can optionally add padding to the tags to ensure minmal file write times when updating the tag in the future.
When the padding option is switched on, id3lib automatically creates padding according to the 'ID3v2 Programming Guidelines'. Specifically, enough padding will be added to round out the entire file (song plus tag) to an even multiple of 2K. Padding will only be created when the tag is attached to a file and that file is not empty (aside from a pre-existing tag).
id3lib's addition to the guidelines for padding, is that if frames are removed from a pre-existing tag (or the tag simply shrinks because of other reasons), the new tag will continue to stay the same size as the old tag (with padding making the difference of course) until such time as the padding is greater than 4K. When this happens, the padding will be reduced and the new tag will be smaller than the old.
By default, padding is switched on.
bPad | Whether or not render the tag with padding. |
bool ID3_Tag::SetSpec | ( | ID3_V2Spec | spec | ) |
bool ID3_Tag::SetUnsync | ( | bool | b | ) |
Turns unsynchronization on or off, dependant on the value of the boolean parameter.
If you call this method with 'false' as the parameter, the binary tag will not be unsync'ed, regardless of whether the tag should be. This option is useful when the file is only going to be used by ID3v2-compliant software. See the ID3v2 standard document for futher details on unsync.
Be default, tags are created without unsync.
bSync | Whether the tag should be unsynchronized |
size_t ID3_Tag::Size | ( | ) | const |
Returns an over estimate of the number of bytes required to store a binary version of a tag.
When using Render() to render a binary tag to a memory buffer, first use the result of this call to allocate a buffer of unsigned chars.
Strips the tag(s) from the attached file.
The type of tag stripped can be specified as a parameter. The default is to strip all tag types.
tt | The type of tag to strip |