C # automatically change the name based on MP3 Information

Using system;
Using system. IO;
Using system. text;

Public partial class MP3: system. Web. UI. Page
{
Protected void page_load (Object sender, eventargs E)
{
//
}
Public struct mp3info
{
Public String identify; // tag, three bytes
Public String title; // song name, 30 bytes
Public String artist; // artist name, 30 bytes
Public String album; // The album name, 30 bytes.
Public String year; // year, 4 characters long
Public String comment; // comment, 28 bytes
Public char reserved1; // Reserved Bit, one byte
Public char reserved2; // Reserved Bit, one byte
Public char reserved3; // reserved byte
}

/// <Summary>
/// Obtain the last 128 bytes of the MP3 file
/// </Summary>
/// <Param name = "FILENAME"> file name </param>
/// <Returns> Returns a byte array </returns>
Private byte [] getlast128 (string filename)
{
Filestream FS = new filestream (filename, filemode. Open, fileaccess. Read );
Stream stream = FS;
Stream. Seek (-128, seekorigin. End );
Const int seekpos = 128;
Int RL = 0;
Byte [] info = new byte [seekpos];
RL = stream. Read (Info, 0, seekpos );
FS. Close ();
Stream. Close ();
Return Info;
}

/// <Summary>
/// Obtain information about mp3 songs, segment the byte array returned above, and save it to the mp3info structure.
/// </Summary>
/// <Param name = "info"> binary information captured from an MP3 file </param>
/// <Returns> Returns a mp3info structure </returns>
Private mp3info getmp3info (byte [] info)
{
Mp3info mp3info = new mp3info ();
String STR = NULL;
Int I;
Int position = 0; // The starting value of the loop
Int currentindex = 0; // The current index value of info
// Obtain the tag ID
For (I = currentindex; I <currentindex + 3; I ++)
{
STR = STR + (char) info [I];
Position ++;
}
Currentindex = position;
Mp3info. Identify = STR;

// Obtain the song name
STR = NULL;
Int J = 0;
Byte [] byttitle = new byte [30]; // read the song name to a separate array.
J = 0;
For (I = currentindex; I <currentindex + 30; I ++)
{
Byttitle [J] = info [I];
Position ++;
J ++;
}
Currentindex = position;
Mp3info. Title = This. bytetostring (byttitle );
// Obtain the artist name
STR = NULL;
J = 0;
Byte [] bytartist = new byte [30]; // read the singer's name in a separate array.
For (I = currentindex; I <currentindex + 30; I ++)
{
Bytartist [J] = info [I];
Position ++;
J ++;
}
Currentindex = position;
Mp3info. Artist = This. bytetostring (bytartist );
// Obtain the recording name
STR = NULL;
J = 0;
Byte [] bytalbum = new byte [30]; // read the recording name to a separate array.
For (I = currentindex; I <currentindex + 30; I ++)
{
Bytalbum [J] = info [I];
Position ++;
J ++;
}
Currentindex = position;
Mp3info. album = This. bytetostring (bytalbum );
// Obtain the year
STR = NULL;
J = 0;
Byte [] bytyear = new byte [4]; // read the year to a separate array.
For (I = currentindex; I <currentindex + 4; I ++)
{
Bytyear [J] = info [I];
Position ++;
J ++;
}
Currentindex = position;
Mp3info. Year = This. bytetostring (bytyear );
// Obtain comments
STR = NULL;
J = 0;
Byte [] bytcomment = new byte [28]; // read the comments to a separate array.
For (I = currentindex; I <currentindex + 25; I ++)
{
Bytcomment [J] = info [I];
Position ++;
J ++;
}
Currentindex = position;
Mp3info. Comment = This. bytetostring (bytcomment );
// Obtain the reserved bits
Mp3info. reserved1 = (char) info [++ position];
Mp3info. reserved2 = (char) info [++ position];
Mp3info. reserved3 = (char) info [++ position];
Return mp3info;
}

/// <Summary>
/// Convert the byte array into a string. the method used by the above program.
/// </Summary>
/// <Param name = "B"> byte array </param>
/// <Returns> returns the converted string </returns>
Private string bytetostring (byte [] B)
{
Encoding ENC = encoding. getencoding ("gb2312 ");
String STR = enc. getstring (B );
STR = Str. substring (0, str. indexof ('/0')> = 0? Str. indexof ('/0'): Str. Length); // Remove useless characters
Return STR;
}

/// <Summary>
/// Change the file name
/// </Summary>
/// <Param name = "filepath"> file name </param>
/// <Returns> </returns>
Private bool Rename (string filepath)
{
If (file. exists (filepath ))
{
Mp3info mp3info = new mp3info ();
Mp3info = This. getmp3info (this. getlast128 (filepath); // read the file information

If (mp3info. Artist. Trim (). Length = 0)
{
Mp3info. Artist = "not named ";
}
If (mp3info. Title. Trim (). Length = 0)
{
Mp3info. Title = "Unknown name song ";
}
Try
{
/// Rename
File. move (filepath, filepath. substring (0, filepath. tolower (). lastindexof ("//")). trim () + "//" + "(" + mp3info. artist. trim () + ")" + mp3info. title. trim () + ". MP3 ");
Response. Write ("<SCRIPT> alert ('mp3 renamed! '); </SCRIPT> ");
// String mp3infostr = "<Table border = '1' bordercolor = '#000000' cellpadding = '0' cellspacing = '0' style = 'border-collapse: collapse; '>"
// + "<Tr>"
// + "<TD> identify </TD> <TD> title </TD> <TD> artist </TD> <TD> album </TD> <TD> year </TD>"
// + "<TD> comment </TD> <TD> reserved1 </TD> <TD> reserved2 </TD> <TD> reserved3 </TD>"
// + "</Tr>"
// + "<Tr>"
// + "<TD>" + mp3info. Identify + "</TD>"
// + "<TD>" + mp3info. Title + "</TD>"
// + "<TD>" + mp3info. Artist + "</TD>"
// + "<TD>" + mp3info. album + "</TD>"
// + "<TD>" + mp3info. Year + "</TD>"
// + "<TD>" + mp3info. Comment + "</TD>"
// + "<TD>" + mp3info. reserved1 + "</TD>"
// + "<TD>" + mp3info. reserved2 + "</TD>"
// + "<TD>" + mp3info. reserved3 + "</TD>"
// + "</Tr>"
// + "</Table> ";
// Response. Write (mp3infostr );
Return true;
}
Catch (exception E)
{
Response. Write (E. tostring ());
Return false;
}
}
Else
{
Response. Write ("<SCRIPT> alert ('mp3 file does not exist! '); </SCRIPT> ");
Return false;
}
}
Protected void mp3rename_click (Object sender, eventargs E)
{
Rename (@ "D:/FFMPEG/df.mp3 ");
}
}