CMp3Tags - id3v1.1 Tag Reader/Writer

if ( strTmp == "TAG" )
{
    //If we get here, then it's a ID3v1.0/1 Tag.
    //Read the next 30 bytes, which is the TrackName.
    ...
}
else
{
    // MP3 file does not have a ID3v1.0/1 Tag: we write it!
    // This new chunk is 128 byte long, at the end of the
    // file, starting with 'TAG':
    BYTE buff [128];
    memset (buff, 0, 128);
    memcpy(buff, "TAG", 3);
    m_fHandle.SeekToEnd();
    m_fHandle.Write(buff, 128);
    m_fHandle.Flush();
    m_iFileBytes += 128;
}

#if !defined(AFX_MP3TAGS__INCLUDED_)<br />
#define AFX_MP3TAGS__INCLUDED_<br />
<br />
#if _MSC_VER > 1000<br />
#pragma once<br />
#endif // _MSC_VER > 1000<br />
<br />
<br />
#define MP3_BUFFER_SIZE	30<br />
<br />
<br />
class CMp3Tags<br />
{<br />
public:<br />
	CMp3Tags(void);<br />
	~CMp3Tags(void);<br />
	<br />
	int OpenFile(LPCTSTR lpFileName);<br />
<br />
	void CloseFile() { m_fHandle.Close(); }<br />
	CString ReadString (int nBytes);<br />
<br />
	CString GetSongTitle() { return m_strSongTitle; }<br />
	CString GetArtist()	   { return m_strArtist; }<br />
	CString GetAlbum()	   { return m_strAlbum; }<br />
	CString GetYear()	   { return m_strYear; }<br />
	CString GetComment()   { return m_strComment; }<br />
<br />
private:<br />
	CFile m_fHandle;<br />
	int m_iFileBytes;<br />
<br />
	CString m_strSongTitle;<br />
	CString m_strArtist;<br />
	CString m_strAlbum;<br />
	CString m_strYear;<br />
	CString m_strComment;<br />
};<br />
<br />
#endif // !defined(AFX_MP3TAGS__INCLUDED_<br />

#include "stdafx.h"<br />
#include "Mp3Tags.h"<br />
<br />
#ifdef _DEBUG<br />
#undef THIS_FILE<br />
static char THIS_FILE[]=__FILE__;<br />
#define new DEBUG_NEW<br />
#endif<br />
<br />
CMp3Tags::CMp3Tags()<br />
{<br />
	m_iFileBytes = 0;<br />
}<br />
<br />
CMp3Tags::~CMp3Tags()<br />
{<br />
}<br />
<br />
int CMp3Tags::OpenFile(LPCTSTR lpFileName)<br />
{<br />
	if ( !m_fHandle.Open(lpFileName, CFile::modeRead | CFile::typeBinary ) )<br />
		return -1;<br />
<br />
	// If we get here, the file's opened. So, we need to parse the data!<br />
<br />
	// We want to set the 'cursor' at 128 bytes before the end of the file. <br />
	m_iFileBytes = m_fHandle.GetLength();<br />
<br />
	int nTagStart = m_fHandle.GetLength() - 128;<br />
	m_fHandle.Seek(nTagStart, 0);<br />
<br />
	// See if this contains "TAG"<br />
	CString strRead = ReadString(3);<br />
	if (strRead.Compare(_T("TAG")) == 0)<br />
	{<br />
		// Yes! Read the data<br />
		m_strSongTitle = ReadString(30);<br />
		m_strArtist = ReadString(30);<br />
		m_strAlbum = ReadString(30);<br />
		m_strYear = ReadString(4);<br />
		m_strComment = ReadString(28);<br />
<br />
		return 0;<br />
	}<br />
<br />
	return -1;<br />
}<br />
<br />
// Read a specified number of bytes from the current file pointer<br />
CString CMp3Tags::ReadString(int nBytes)<br />
{<br />
	CString cResultString;<br />
<br />
	char buf[MP3_BUFFER_SIZE];			// Declare the ASCII buffer<br />
	::ZeroMemory(buf,MP3_BUFFER_SIZE);<br />
<br />
	m_fHandle.Read(buf, nBytes);<br />
<br />
#ifdef _UNICODE<br />
	TCHAR tBuf[MP3_BUFFER_SIZE];		// Declare the Unicode buffer <br />
	MultiByteToWideChar(CP_ACP, 0, buf, -1, tBuf, MP3_BUFFER_SIZE);<br />
	cResultString = tBuf;<br />
#else<br />
	cResultString = buf;<br />
#endif<br />
<br />
	return cResultString;<br />
}

<br />
//The next 30 are the Album Name.<br />
iBytesRead = m_fHandle.Read(pBuf, 30);<br />
m_strAlbum.Format("%s", pBuf);<br />
m_strArtist.Insert(iBytesRead, '\0'); // <--- BUG HERE<br />

<br />
//The next 30 are the Album Name.<br />
iBytesRead = m_fHandle.Read(pBuf, 30);<br />
m_strAlbum.Format("%s", pBuf);<br />
m_strAlbum.Insert(iBytesRead, '\0');<br />

class CMp3Tags
{
public:
	// Public parts as before
private:
	// Enumerate the items and use them as indexes to a offset array in SetText.
	enum ItemType { Title, Artist, Album, Year, Comment };
	
	// All public Set...() functions calls this worker function.
	int SetText(const char* text, ItemType type);
	
	// File instance and member strings as before.
};

int CMp3Tags::SetSongTitle(const char* title)
{
	return SetText(title, Title);
}

int CMp3Tags::SetArtist(const char* artist)
{
	return SetText(artist, Artist);
}

int CMp3Tags::SetAlbum(const char* album)
{
	return SetText(album, Album);
}

int CMp3Tags::SetYear(const char* year)
{
	return SetText(year, Year);
}

int CMp3Tags::SetComment(const char* comment)
{
	return SetText(comment, Comment);
}

int CMp3Tags::SetText(const char* text, ItemType type)
{
	static const size_t relative_offsets[] = { 3, 33, 63, 93, 97 };
	static const size_t max_lengths[] = { 30, 30, 30, 5, 28 };
	
	const byte* data = static_cast<const byte*>(text);
	const size_t bytesize = min(max_lengths[type], strlen(text));
	const std::vector<byte> safedata(data, data + bytesize);

	TRY
	{
		m_fHandle.SeekToBegin();
		m_fHandle.Seek(relative_offsets[type], 0);
		m_fHandle.Write(&safedata.front(), safedata.size());
	}
	CATCH( CFileException, e )
	{
		LPSTR lpError = "";
		e->GetErrorMessage(lpError, 255);
		OutputDebugString(lpError);
		e->Delete();
		return -1;
	}
	END_CATCH

	return 0;
}