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AttachedPictureFrame.cs

//
// AttachedPictureFrame.cs:
//
// Author:
//   Brian Nickel (brian.nickel@gmail.com)
//
// Original Source:
//   attachedpictureframe.cpp from TagLib
//
// Copyright (C) 2005-2007 Brian Nickel
// Copyright (C) 2004 Scott Wheeler (Original Implementation)
// 
// 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307
// USA
//

using System.Collections;
using System;

using TagLib;

namespace TagLib.Id3v2 {
      /// <summary>
      ///    This class extends <see cref="Frame" />, implementing support for
      ///    ID3v2 Attached Picture (APIC) Frames.
      /// </summary>
      /// <remarks>
      ///    <para>A <see cref="AttachedPictureFrame" /> is used for storing
      ///    pictures that complement the media, including the album cover,
      ///    the physical medium, leaflets, file icons, etc. Other file and
      ///    object data can be encapulsated via <see
      ///    cref="GeneralEncapsulatedObjectFrame" />.</para>
      ///    <para>Additionally, <see cref="TagLib.Tag.Pictures" /> provides a
      ///    generic way or getting and setting pictures which is preferable
      ///    to format specific code.</para>
      /// </remarks>
00048       public class AttachedPictureFrame : Frame, IPicture
      {
            #region Private Properties
            
            /// <summary>
            ///    Contains the text encoding to use when rendering.
            /// </summary>
00055             private StringType text_encoding = Tag.DefaultEncoding;
            
            /// <summary>
            ///    Contains the mime type of <see cref="data" />.
            /// </summary>
00060             private string mime_type = null;
            
            /// <summary>
            ///    Contains the type of picture.
            /// </summary>
00065             private PictureType type = PictureType.Other;
            
            /// <summary>
            ///    Contains the description.
            /// </summary>
00070             private string description = null;
            
            /// <summary>
            ///    Contains the picture data.
            /// </summary>
00075             private ByteVector data = null;
            
            /// <summary>
            ///    Contains the raw field data of the current instance as
            ///    sent to <see cref="ParseFields" /> or <see
            ///    langword="null" /> if <see cref="ParseFields" /> has not
            ///    been called or <see cref="ParseRawData" /> has been
            ///    called.
            /// </summary>
            /// <remarks>
            ///    As this frame takes a while to parse and isn't read in
            ///    all cases, the raw data is stored here until it is
            ///    needed. This speeds up the file read time significantly.
            /// </remarks>
00089             private ByteVector raw_data = null;
            
            /// <summary>
            ///    Contains the ID3v2 version <see cref="raw_data" /> is
            ///    stored in.
            /// </summary>
00095             private byte raw_version = 0;
            
            #endregion
            
            
            
            #region Constructors
            /// <summary>
            ///    Constructs and initializes a new instance of <see
            ///    cref="AttachedPictureFrame" /> with no contents and the
            ///    default values.
            /// </summary>
            /// <remarks>
            ///    <para>When a frame is created, it is not automatically
            ///    added to the tag. Consider using <see
            ///    cref="Get(Tag,string,PictureType,bool)" /> for more
            ///    integrated frame creation.</para>
            ///    <para>Additionally, <see cref="TagLib.Tag.Pictures" />
            ///    provides a generic way or getting and setting
            ///    pictures which is preferable to format specific
            ///    code.</para>
            /// </remarks>
00117             public AttachedPictureFrame () : base (FrameType.APIC, 4)
            {
            }
            
            /// <summary>
            ///    Constructs and initializes a new instance of <see
            ///    cref="AttachedPictureFrame" /> by populating it with
            ///    the contents of another <see cref="IPicture" /> object.
            /// </summary>
            /// <param name="picture">
            ///    A <see cref="IPicture" /> object containing values to use
            ///    in the new instance.
            /// </param>
            /// <exception cref="ArgumentNullException">
            ///    <paramref name="picture" /> is <see langword="null" />.
            /// </exception>
            /// <remarks>
            ///    <para>When a frame is created, it is not automatically
            ///    added to the tag. Consider using <see
            ///    cref="Get(Tag,string,PictureType,bool)" /> for more
            ///    integrated frame creation.</para>
            ///    <para>Additionally, <see cref="TagLib.Tag.Pictures" />
            ///    provides a generic way or getting and setting
            ///    pictures which is preferable to format specific
            ///    code.</para>
            /// </remarks>
            /// <example>
            ///    <para>Add a picture to a file.</para>
            ///    <code lang="C#">
            /// using TagLib;
            /// using TagLib.Id3v2;
            ///
            /// public static class AddId3v2Picture
            /// {
            ///   public static void Main (string [] args)
            ///   {
            ///         if (args.Length != 2)
            ///               throw new ApplicationException (
            ///                     "USAGE: AddId3v2Picture.exe AUDIO_FILE PICTURE_FILE");
            ///
            ///         // Create the file. Can throw file to TagLib# exceptions.
            ///         File file = File.Create (args [0]);
            ///
            ///         // Get or create the ID3v2 tag.
            ///         TagLib.Id3v2.Tag tag = file.GetTag (TagTypes.Id3v2, true) as TagLib.Id3v2.Tag;
            ///         if (tag == null)
            ///               throw new ApplicationException ("File does not support ID3v2 tags.");
            ///
            ///         // Create a picture. Can throw file related exceptions.
            ///         TagLib.Picture picture = TagLib.Picture.CreateFromPath (path);
            ///
            ///         // Add a new picture frame to the tag.
            ///         tag.AddFrame (new AttachedPictureFrame (picture));
            ///
            ///         // Save the file.
            ///         file.Save ();
            ///   }
            /// }
            ///    </code>
            /// </example>
00177             public AttachedPictureFrame (IPicture picture)
                  : base(FrameType.APIC, 4)
            {
                  if (picture == null)
                        throw new ArgumentNullException ("picture");
                  
                  mime_type   = picture.MimeType;
                  type        = picture.Type;
                  description = picture.Description;
                  data        = picture.Data;
            }
            
            /// <summary>
            ///    Constructs and initializes a new instance of <see
            ///    cref="AttachedPictureFrame" /> by reading its raw data in
            ///    a specified ID3v2 version.
            /// </summary>
            /// <param name="data">
            ///    A <see cref="ByteVector" /> object starting with the raw
            ///    representation of the new frame.
            /// </param>
            /// <param name="version">
            ///    A <see cref="byte" /> indicating the ID3v2 version the
            ///    raw frame is encoded in.
            /// </param>
00202             public AttachedPictureFrame (ByteVector data, byte version)
                  : base (data, version)
            {
                  SetData (data, 0, version, true);
            }
            
            /// <summary>
            ///    Constructs and initializes a new instance of <see
            ///    cref="AttachedPictureFrame" /> by reading its raw data
            ///    in a specified ID3v2 version.
            /// </summary>
            /// <param name="data">
            ///    A <see cref="ByteVector" /> object containing the raw
            ///    representation of the new frame.
            /// </param>
            /// <param name="offset">
            ///    A <see cref="int" /> indicating at what offset in
            ///    <paramref name="data" /> the frame actually begins.
            /// </param>
            /// <param name="header">
            ///    A <see cref="FrameHeader" /> containing the header of the
            ///    frame found at <paramref name="offset" /> in the data.
            /// </param>
            /// <param name="version">
            ///    A <see cref="byte" /> indicating the ID3v2 version the
            ///    raw frame is encoded in.
            /// </param>
00229             protected internal AttachedPictureFrame (ByteVector data,
                                                     int offset,
                                                     FrameHeader header,
                                                     byte version)
                  : base(header)
            {
                  SetData (data, offset, version, false);
            }
            
            #endregion
            
            
            
            #region Public Properties
            
            /// <summary>
            ///    Gets and sets the text encoding to use when storing the
            ///    current instance.
            /// </summary>
            /// <value>
            ///    A <see cref="string" /> containing the text encoding to
            ///    use when storing the current instance.
            /// </value>
            /// <remarks>
            ///    This encoding is overridden when rendering if <see
            ///    cref="Tag.ForceDefaultEncoding" /> is <see
            ///    langword="true" /> or the render version does not support
            ///    it.
            /// </remarks>
00258             public StringType TextEncoding {
                  get {ParseRawData (); return text_encoding;}
                  set {text_encoding = value;}
            }
            
            /// <summary>
            ///    Gets and sets the mime-type of the picture stored in the
            ///    current instance.
            /// </summary>
            /// <value>
            ///    A <see cref="string" /> containing the mime-type of the
            ///    picture stored in the current instance.
            /// </value>
00271             public string MimeType {
                  get {
                        ParseRawData ();
                        if (mime_type != null)
                              return mime_type;
                        
                        return string.Empty;
                  }
                  set {mime_type = value;}
            }
            
            /// <summary>
            ///    Gets and sets the picture type stored in the current
            ///    instance.
            /// </summary>
            /// <value>
            ///    A <see cref="string" /> containing the picture type
            ///    stored in the current instance.
            /// </value>
            /// <remarks>
            ///    There should only be one frame with a matching
            ///    description and type per tag.
            /// </remarks>
00294             public PictureType Type {
                  get {ParseRawData (); return type;}
                  set {type = value;}
            }
            
            /// <summary>
            ///    Gets and sets the description stored in the current
            ///    instance.
            /// </summary>
            /// <value>
            ///    A <see cref="string" /> containing the description
            ///    stored in the current instance.
            /// </value>
            /// <remarks>
            ///    There should only be one frame with a matching
            ///    description and type per tag.
            /// </remarks>
00311             public string Description {
                  get {
                        ParseRawData ();
                        if (description != null)
                              return description;
                        
                        return string.Empty;
                  }
                  set {description = value;}
            }
            
            /// <summary>
            ///    Gets and sets the image data stored in the current
            ///    instance.
            /// </summary>
            /// <value>
            ///    A <see cref="ByteVector" /> containing the image data
            ///    stored in the current instance.
            /// </value>
00330             public ByteVector Data {
                  get {
                        ParseRawData ();
                        return data != null ? data : new ByteVector ();
                  }
                  set {data = value;}
            }
            
            #endregion
            
            
            
            #region Public Methods
            
            /// <summary>
            ///    Gets a string representation of the current instance.
            /// </summary>
            /// <returns>
            ///    A <see cref="string" /> representing the current
            ///    instance.
            /// </returns>
00351             public override string ToString ()
            {
                  System.Text.StringBuilder builder
                        = new System.Text.StringBuilder ();
                  
                  if (string.IsNullOrEmpty (Description)) {
                        builder.Append (Description);
                        builder.Append (" ");
                  }
                  
                  builder.AppendFormat (
                        System.Globalization.CultureInfo.InvariantCulture,
                        "[{0}] {1} bytes", MimeType, Data.Count);
                  
                  return builder.ToString ();
            }
            
            #endregion
            
            
            
            #region Public Static Methods
            
            /// <summary>
            ///    Gets a specified picture frame from the specified tag,
            ///    optionally creating it if it does not exist.
            /// </summary>
            /// <param name="tag">
            ///    A <see cref="Tag" /> object to search in.
            /// </param>
            /// <param name="description">
            ///    A <see cref="string" /> specifying the description to
            ///    match.
            /// </param>
            /// <param name="create">
            ///    A <see cref="bool" /> specifying whether or not to create
            ///    and add a new frame to the tag if a match is not found.
            /// </param>
            /// <returns>
            ///    A <see cref="AttachedPictureFrame" /> object containing
            ///    the matching frame, or <see langword="null" /> if a match
            ///    wasn't found and <paramref name="create" /> is <see
            ///    langword="false" />.
            /// </returns>
00395             public static AttachedPictureFrame Get (Tag tag,
                                                    string description,
                                                    bool create)
            {
                  return Get (tag, description, PictureType.Other, create);
            }
            
            /// <summary>
            ///    Gets a specified picture frame from the specified tag,
            ///    optionally creating it if it does not exist.
            /// </summary>
            /// <param name="tag">
            ///    A <see cref="Tag" /> object to search in.
            /// </param>
            /// <param name="type">
            ///    A <see cref="PictureType" /> specifying the picture type
            ///    to match.
            /// </param>
            /// <param name="create">
            ///    A <see cref="bool" /> specifying whether or not to create
            ///    and add a new frame to the tag if a match is not found.
            /// </param>
            /// <returns>
            ///    A <see cref="AttachedPictureFrame" /> object containing
            ///    the matching frame, or <see langword="null" /> if a match
            ///    wasn't found and <paramref name="create" /> is <see
            ///    langword="false" />.
            /// </returns>
00423             public static AttachedPictureFrame Get (Tag tag,
                                                    PictureType type,
                                                    bool create)
            {
                  return Get (tag, null, type, create);
            }
            
            /// <summary>
            ///    Gets a specified picture frame from the specified tag,
            ///    optionally creating it if it does not exist.
            /// </summary>
            /// <param name="tag">
            ///    A <see cref="Tag" /> object to search in.
            /// </param>
            /// <param name="description">
            ///    A <see cref="string" /> specifying the description to
            ///    match.
            /// </param>
            /// <param name="type">
            ///    A <see cref="PictureType" /> specifying the picture type
            ///    to match.
            /// </param>
            /// <param name="create">
            ///    A <see cref="bool" /> specifying whether or not to create
            ///    and add a new frame to the tag if a match is not found.
            /// </param>
            /// <returns>
            ///    A <see cref="AttachedPictureFrame" /> object containing
            ///    the matching frame, or <see langword="null" /> if a match
            ///    wasn't found and <paramref name="create" /> is <see
            ///    langword="false" />.
            /// </returns>
            /// <example>
            ///    <para>Sets a cover image with a description. Because <see
            ///    cref="Get(Tag,string,PictureType,bool)" /> is used, if
            ///    the program is called again with the same audio file and
            ///    desciption, the picture will be overwritten with the new
            ///    one.</para>
            ///    <code lang="C#">
            /// using TagLib;
            /// using TagLib.Id3v2;
            ///
            /// public static class SetId3v2Cover
            /// {
            ///   public static void Main (string [] args)
            ///   {
            ///         if (args.Length != 3)
            ///               throw new ApplicationException (
            ///                     "USAGE: SetId3v2Cover.exe AUDIO_FILE PICTURE_FILE DESCRIPTION");
            ///
            ///         // Create the file. Can throw file to TagLib# exceptions.
            ///         File file = File.Create (args [0]);
            ///
            ///         // Get or create the ID3v2 tag.
            ///         TagLib.Id3v2.Tag tag = file.GetTag (TagTypes.Id3v2, true) as TagLib.Id3v2.Tag;
            ///         if (tag == null)
            ///               throw new ApplicationException ("File does not support ID3v2 tags.");
            ///
            ///         // Create a picture. Can throw file related exceptions.
            ///         TagLib.Picture picture = TagLib.Picture.CreateFromPath (args [1]);
            ///
            ///         // Get or create the picture frame.
            ///         AttachedPictureFrame frame = AttachedPictureFrame.Get (
            ///               tag, args [2], PictureType.FrontCover, true);
            ///
            ///         // Set the data from the picture.
            ///         frame.MimeType = picture.MimeType;
            ///         frame.Data     = picture.data;
            ///         
            ///         // Save the file.
            ///         file.Save ();
            ///   }
            /// }
            ///    </code>
            /// </example>
00498             public static AttachedPictureFrame Get (Tag tag,
                                                    string description,
                                                    PictureType type,
                                                    bool create)
            {
                  AttachedPictureFrame apic;
                  foreach (Frame frame in tag.GetFrames (FrameType.APIC)) {
                        apic = frame as AttachedPictureFrame;
                        
                        if (apic == null)
                              continue;
                        
                        if (description != null && apic.Description != description)
                              continue;
                        
                        if (type != PictureType.Other && apic.Type != type)
                              continue;
                        
                        return apic;
                  }
                  
                  if (!create)
                        return null;
                  
                  apic = new AttachedPictureFrame ();
                  apic.Description = description;
                  apic.Type = type;
                  
                  tag.AddFrame (apic);
                  
                  return apic;
            }
            
            #endregion
            
            
            
            #region Protected Methods
            
            /// <summary>
            ///    Populates the values in the current instance by parsing
            ///    its field data in a specified version.
            /// </summary>
            /// <param name="data">
            ///    A <see cref="ByteVector" /> object containing the
            ///    extracted field data.
            /// </param>
            /// <param name="version">
            ///    A <see cref="byte" /> indicating the ID3v2 version the
            ///    field data is encoded in.
            /// </param>
            /// <exception cref="CorruptFileException">
            ///    <paramref name="data" /> contains less than 5 bytes.
            /// </exception>
00552             protected override void ParseFields (ByteVector data, byte version)
            {
                  if (data.Count < 5)
                        throw new CorruptFileException (
                              "A picture frame must contain at least 5 bytes.");
                  
                  raw_data = data;
                  raw_version = version;
            }
            
            /// <summary>
            ///    Performs the actual parsing of the raw data.
            /// </summary>
            /// <remarks>
            ///    Because of the high parsing cost and relatively low usage
            ///    of the class, <see cref="ParseFields" /> only stores the
            ///    field data so it can be parsed on demand. Whenever a
            ///    property or method is called which requires the data,
            ///    this method is called, and only on the first call does it
            ///    actually parse the data.
            /// </remarks>
00573             protected void ParseRawData ()
            {
                  if (raw_data == null)
                        return;
                  
                  int pos = 0;
                  int offset;
                  
                  text_encoding = (StringType) raw_data [pos++];
                  
                  if (raw_version > 2) {
                        offset = raw_data.Find (ByteVector.TextDelimiter (
                              StringType.Latin1), pos);
                        
                        if(offset < pos)
                              return;
                        
                        mime_type = raw_data.ToString (
                              StringType.Latin1, pos, offset - pos);
                        pos = offset + 1;
                  } else {
                        ByteVector ext = raw_data.Mid (pos, 3);
                        
                        if (ext == "JPG")
                              mime_type = "image/jpeg";
                        else if (ext == "PNG")
                              mime_type = "image/png";
                        else
                              mime_type = "image/unknown";
                        
                        pos += 3;
                  }
                  
                  ByteVector delim = ByteVector.TextDelimiter (
                        text_encoding);
                  
                  type = (PictureType) raw_data [pos++];
                  
                  offset = raw_data.Find (delim, pos, delim.Count);
                  
                  if(offset < pos)
                        return;
                  
                  description = raw_data.ToString (text_encoding, pos,
                        offset - pos);
                  pos = offset + delim.Count;
                  raw_data.RemoveRange (0, pos);
                  this.data = raw_data;
                  
                  this.raw_data = null;
            }
            
            /// <summary>
            ///    Renders the values in the current instance into field
            ///    data for a specified version.
            /// </summary>
            /// <param name="version">
            ///    A <see cref="byte" /> indicating the ID3v2 version the
            ///    field data is to be encoded in.
            /// </param>
            /// <returns>
            ///    A <see cref="ByteVector" /> object containing the
            ///    rendered field data.
            /// </returns>
00637             protected override ByteVector RenderFields (byte version)
            {
                  if (raw_data != null && raw_version == version)
                        return raw_data;
                  
                  StringType encoding = CorrectEncoding (TextEncoding,
                        version);
                  ByteVector data = new ByteVector ();
                  
                  data.Add ((byte) encoding);
                  
                  if (version == 2) {
                        switch (MimeType) {
                        case "image/png":
                              data.Add ("PNG");
                              break;
                        case "image/jpeg":
                              data.Add ("JPG");
                              break;
                        default:
                              data.Add ("XXX");
                              break;
                        }
                  } else {
                        data.Add (ByteVector.FromString (MimeType,
                              StringType.Latin1));
                        data.Add (ByteVector.TextDelimiter (
                              StringType.Latin1));
                  }
                  
                  data.Add ((byte) type);
                  data.Add (ByteVector.FromString (Description, encoding));
                  data.Add (ByteVector.TextDelimiter (encoding));
                  data.Add (this.data);
                  
                  return data;
            }
            
#endregion
            
            
            
#region ICloneable
            
            /// <summary>
            ///    Creates a deep copy of the current instance.
            /// </summary>
            /// <returns>
            ///    A new <see cref="Frame" /> object identical to the
            ///    current instance.
            /// </returns>
00688             public override Frame Clone ()
            {
                  AttachedPictureFrame frame = new AttachedPictureFrame ();
                  frame.text_encoding = text_encoding;
                  frame.mime_type = mime_type;
                  frame.type = type;
                  frame.description = description;
                  if (data != null)
                        frame.data = new ByteVector (data);
                  if (raw_data != null)
                        frame.data = new ByteVector (raw_data);
                  frame.raw_version = raw_version;
                  return frame;
            }
            
#endregion
      }
}

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