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/***************************************************************************
copyright : (C) 2005 by Brian Nickel
email : brian.nickel@gmail.com
based on : flacfile.cpp from TagLib
***************************************************************************/
/***************************************************************************
* 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;
namespace TagLib.Flac
{
[SupportedMimeType("taglib/flac", "flac")]
[SupportedMimeType("audio/x-flac")]
[SupportedMimeType("application/x-flac")]
[SupportedMimeType("audio/flac")]
public class File : TagLib.File
{
//////////////////////////////////////////////////////////////////////////
// private properties
//////////////////////////////////////////////////////////////////////////
private Id3v2.Tag id3v2_tag;
private Id3v1.Tag id3v1_tag;
private Ogg.XiphComment comment;
private CombinedTag tag;
private Properties properties;
private ByteVector stream_info_data;
private ByteVector xiph_comment_data;
private long flac_start;
private long stream_start;
private long stream_length;
private bool scanned;
//////////////////////////////////////////////////////////////////////////
// public methods
//////////////////////////////////////////////////////////////////////////
public File (string file, Properties.ReadStyle properties_style) : base (file)
{
id3v2_tag = null;
id3v1_tag = null;
comment = null;
properties = null;
flac_start = 0;
stream_start = 0;
stream_length = 0;
scanned = false;
tag = new CombinedTag ();
try {Mode = AccessMode.Read;}
catch {return;}
Read (properties_style);
Mode = AccessMode.Closed;
}
public File (string file) : this (file, Properties.ReadStyle.Average)
{
}
public override void Save ()
{
if(IsReadOnly) {
throw new ReadOnlyException();
}
Mode = AccessMode.Write;
long flac_data_begin;
long flac_data_end;
// Update ID3 tags
if(id3v2_tag != null)
{
ByteVector id3v2_tag_data = id3v2_tag.Render ();
long id3v2_location = FindId3v2 ();
if (id3v2_location >= 0)
{
int id3v2_size = 0;
Seek (id3v2_location);
Id3v2.Header header = new Id3v2.Header (ReadBlock ((int) Id3v2.Header.Size));
if (header.TagSize == 0)
Debugger.Debug ("Flac.File.Save() -- Id3v2 header is broken. Ignoring.");
else
id3v2_size = (int) header.CompleteTagSize;
Insert (id3v2_tag_data, id3v2_location, id3v2_size);
System.Console.WriteLine ("ID3v2: " + id3v2_size + " " + id3v2_tag_data.Count);
flac_data_begin = id3v2_location + id3v2_tag_data.Count;
}
else
{
Insert (id3v2_tag_data, 0, 0);
flac_data_begin = id3v2_tag_data.Count;
}
}
else
flac_data_begin = 0;
if(id3v1_tag != null)
{
long id3v1_location = FindId3v1 ();
if (id3v1_location >= 0)
Seek (id3v1_location);
else
Seek (0, System.IO.SeekOrigin.End);
flac_data_end = Tell;
WriteBlock (id3v1_tag.Render ());
}
else
flac_data_end = Length;
// Create new vorbis comments is they don't exist.
GetTag (TagTypes.Xiph, true);
xiph_comment_data = comment.Render (false);
ByteVector v = ByteVector.FromUInt((uint) xiph_comment_data.Count);
// Set the type of the comment to be a Xiph / Vorbis comment
// (See scan() for comments on header-format)
v [0] = 4;
v.Add (xiph_comment_data);
// If file already have comment => find and update it
// if not => insert one
scanned = false;
if (Scan (flac_data_begin, flac_data_end) != null)
{
long next_page_offset = flac_start;
Seek (next_page_offset);
ByteVector header = ReadBlock (4);
uint length = header.Mid(1, 3).ToUInt ();
next_page_offset += length + 4;
// Search through the remaining metadata
byte block_type = (byte) (header[0] & 0x7f);
bool last_block = (header[0] & 0x80) != 0;
while (!last_block)
{
Seek (next_page_offset);
header = ReadBlock (4);
block_type = (byte) (header[0] & 0x7f);
last_block = (header[0] & 0x80) != 0;
length = header.Mid(1, 3).ToUInt ();
// Type is vorbiscomment
if(block_type == 4)
{
long next_keep = (last_block ? 0 : FindPaddingBreak (next_page_offset + length + 4,
next_page_offset + XiphCommentData.Count + 8,
ref last_block));
uint padding_length;
if(next_keep != 0)
{
// There is space for comment and padding blocks without rewriting the whole file.
// Note this can not overflow.
padding_length = (uint) (next_keep - (next_page_offset + XiphCommentData.Count + 8));
}
else
{
// Not enough space, so we will have to rewrite the whole file following this block
padding_length = (uint) XiphCommentData.Count;
if (padding_length < 4096)
padding_length = 4096;
next_keep = next_page_offset + length + 4;
}
ByteVector padding = ByteVector.FromUInt (padding_length);
padding [0] = 1;
if (last_block)
padding [0] = (byte) (padding [0] | 0x80);
padding.Resize ((int)(padding_length + 4));
Insert (v + padding, next_page_offset, next_keep - next_page_offset);
//System.Console.WriteLine ("OGG: " + (next_keep - next_page_offset) + " " + (v.Count + padding.Count));
break;
}
next_page_offset += length + 4;
}
}
else
{
long next_page_offset = flac_start;
Seek (next_page_offset);
ByteVector header = ReadBlock (4);
bool last_block = (header[0] & 0x80) != 0;
uint length = header.Mid(1, 3).ToUInt ();
// If last block was last, make this one last
if(last_block)
{
// Copy the bottom seven bits into the new value
ByteVector h = (byte)(header[0] & 0x7F);
Insert (h, next_page_offset, 1);
// Set the last bit
v [0] = (byte) (v [0] | 0x80);
}
Insert (v, next_page_offset + length + 4, 0);
}
Mode = AccessMode.Closed;
}
public override TagLib.Tag GetTag (TagTypes type, bool create)
{
switch (type)
{
case TagTypes.Id3v1:
{
if (create && id3v1_tag == null)
{
id3v1_tag = new Id3v1.Tag ();
if (tag != null)
TagLib.Tag.Duplicate (tag, id3v1_tag, true);
tag.SetTags (comment, id3v2_tag, id3v1_tag);
}
return id3v1_tag;
}
case TagTypes.Id3v2:
{
if (create && id3v2_tag == null)
{
id3v2_tag = new Id3v2.Tag ();
if (tag != null)
TagLib.Tag.Duplicate (tag, id3v2_tag, true);
tag.SetTags (comment, id3v2_tag, id3v1_tag);
}
return id3v2_tag;
}
case TagTypes.Xiph:
{
if (create && comment == null)
{
comment = new Ogg.XiphComment ();
if (tag != null)
TagLib.Tag.Duplicate (tag, comment, true);
tag.SetTags (comment, id3v2_tag, id3v1_tag);
}
return comment;
}
default:
return null;
}
}
//////////////////////////////////////////////////////////////////////////
// public properties
//////////////////////////////////////////////////////////////////////////
public override TagLib.Tag Tag {get {return tag;}}
public override AudioProperties AudioProperties {get {return properties;}}
//////////////////////////////////////////////////////////////////////////
// private methods
//////////////////////////////////////////////////////////////////////////
private void Read (Properties.ReadStyle properties_style)
{
long flac_data_begin;
long flac_data_end;
// Look for an ID3v2 tag
long id3v2_location = FindId3v2 ();
if(id3v2_location >= 0)
{
id3v2_tag = new Id3v2.Tag (this, id3v2_location);
flac_data_begin = id3v2_location + id3v2_tag.Header.CompleteTagSize;
}
else
flac_data_begin = 0;
// Look for an ID3v1 tag
long id3v1_location = FindId3v1 ();
if(id3v1_location >= 0)
{
id3v1_tag = new Id3v1.Tag (this, id3v1_location);
flac_data_end = id3v1_location;
}
else
flac_data_end = Length;
// Look for FLAC metadata, including vorbis comments
xiph_comment_data = Scan (flac_data_begin, flac_data_end);
if (!IsValid) return;
if (XiphCommentData.Count > 0)
comment = new Ogg.XiphComment (XiphCommentData);
tag.SetTags (comment, id3v2_tag, id3v1_tag);
GetTag (TagTypes.Xiph, true);
if(properties_style != Properties.ReadStyle.None)
properties = new Properties (stream_info_data, stream_length, properties_style);
}
private ByteVector Scan (long begin, long end)
{
ByteVector xiph_comment_data = null;
// Scan the metadata pages
if(scanned || !IsValid)
return null;
long next_page_offset;
long file_size = Length;
next_page_offset = Find ("fLaC", begin);
if (next_page_offset < 0)
{
Debugger.Debug ("Flac.File.Scan () -- FLAC stream not found");
SetValid (false);
return null;
}
next_page_offset += 4;
flac_start = next_page_offset;
Seek (next_page_offset);
ByteVector header = ReadBlock (4);
// Header format (from spec):
// <1> Last-metadata-block flag
// <7> BLOCK_TYPE
// 0 : STREAMINFO
// 1 : PADDING
// ..
// 4 : VORBIS_COMMENT
// ..
// <24> Length of metadata to follow
byte block_type = (byte) (header [0] & 0x7f);
bool last_block = (header [0] & 0x80) != 0;
uint length = header.Mid (1, 3).ToUInt ();
// First block should be the stream_info metadata
if (block_type != 0)
{
Debugger.Debug ("Flac.File.Scan() -- invalid FLAC stream");
SetValid (false);
return null;
}
stream_info_data = ReadBlock ((int) length);
next_page_offset += length + 4;
// Search through the remaining metadata
while (!last_block)
{
header = ReadBlock (4);
block_type = (byte) (header [0] & 0x7f);
last_block = (header [0] & 0x80) != 0;
length = header.Mid (1, 3).ToUInt ();
// Found the vorbis-comment
if(block_type == 4)
xiph_comment_data = ReadBlock ((int) length);
next_page_offset += length + 4;
if (next_page_offset >= file_size)
{
Debugger.Debug ("Flac.File.Scan() -- FLAC stream corrupted");
SetValid (false);
return null;
}
Seek (next_page_offset);
}
// End of metadata, now comes the datastream
stream_start = next_page_offset;
stream_length = end - stream_start;
scanned = true;
return xiph_comment_data;
}
private long FindId3v1 ()
{
if (IsValid)
{
Seek (-128, System.IO.SeekOrigin.End);
long p = Tell;
if (ReadBlock (3) == Id3v1.Tag.FileIdentifier)
return p;
}
return -1;
}
private long FindId3v2 ()
{
if (IsValid)
{
Seek (0);
if (ReadBlock (3) == Id3v2.Header.FileIdentifier)
return 0;
}
return -1;
}
private long FindPaddingBreak (long next_page_offset, long target_offset, ref bool last)
{
// Starting from nextPageOffset, step over padding blocks to find the
// address of a block which is after targetOffset. Return zero if
// a non-padding block occurs before that point
while (true)
{
Seek (next_page_offset);
ByteVector header = ReadBlock (4);
byte block_type = (byte) (header[0] & 0x7f);
bool last_block = (header[0] & 0x80) != 0;
uint length = header.Mid(1, 3).ToUInt ();
if (block_type != 1)
break;
next_page_offset += 4 + length;
if(next_page_offset >= target_offset)
{
last = last_block;
return next_page_offset;
}
if (last_block)
break;
}
return 0;
}
private ByteVector XiphCommentData
{
get
{
return (IsValid && xiph_comment_data != null) ? xiph_comment_data : new ByteVector ();
}
}
}
}
|
