A simple C# Wave editor, part 1: Background and analysis

// CEditWaveFile.h: interface for the CEditWaveFile class.
//
//
// Created for editing a wav file
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_CEDITWAVEFILE_H__4D07CE61_46F7_11D3_9A58_0080C605ADA4__INCLUDED_)
#define AFX_CEDITWAVEFILE_H__4D07CE61_46F7_11D3_9A58_0080C605ADA4__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
//############################################################################
// Wav file structures
typedef DWORD FOURCC;	// a four character code 

typedef struct CHUNKHDR {
  FOURCC ckid;		// chunk ID 
  DWORD dwSize; 	// chunk size 
} CHUNKHDR;

#if	0
/* general waveform format structure (information common to all formats) */
typedef struct waveformat_tag {
  WORD wFormatTag;	/* format type */
  WORD nChannels;	/* number of channels (i.e. mono, stereo, etc.) */
  DWORD nSamplesPerSec; /* sample rate */
  DWORD nAvgBytesPerSec;/* for buffer size estimation */
  WORD nBlockAlign;	/* block size of data */
} WAVEFORMAT;
typedef WAVEFORMAT	 *PWAVEFORMAT;
#endif

/* flags for 'wFormatTag' field of WAVEFORMAT */
#define WAVE_FORMAT_PCM 1

/* specific waveform format structure for PCM data */
typedef struct pcmwaveformat_tag {
  WORD wFormatTag;	/* format type */
  WORD nChannels;	/* number of channels (i.e. mono, stereo, etc.) */
  DWORD nSamplesPerSec; /* sample rate */
  DWORD nAvgBytesPerSec;/* for buffer size estimation */
  WORD nBlockAlign;	/* block size of data */
  WORD wBitsPerSample;
} PCMWAVEFORMAT;
typedef PCMWAVEFORMAT *PPCMWAVEFORMAT;


/* MMIO macros */
#define mmioFOURCC(ch0, ch1, ch2, ch3) \
  ((DWORD)(BYTE)(ch0) | ((DWORD)(BYTE)(ch1) << 8) | \
  ((DWORD)(BYTE)(ch2) << 16) | ((DWORD)(BYTE)(ch3) << 24))

#define FOURCC_RIFF	mmioFOURCC ('R', 'I', 'F', 'F')
#define FOURCC_SFPK	mmioFOURCC ('S', 'F', 'P', 'K')
#define FOURCC_LIST	mmioFOURCC ('L', 'I', 'S', 'T')
#define FOURCC_WAVE	mmioFOURCC ('W', 'A', 'V', 'E')
#define FOURCC_FMT	mmioFOURCC ('f', 'm', 't', ' ')
#define FOURCC_DATA	mmioFOURCC ('d', 'a', 't', 'a')


/* simplified header for standard WAV files */
typedef struct WAVEHDR {
  CHUNKHDR chkRiff; // 8 bytes
  FOURCC fccWave; // 4 bytes
  CHUNKHDR chkFmt;//8 bytes
  WORD wFormatTag;	/* format type  2 bytes*/
  WORD nChannels;	/* 2 bytes number of channels (i.e. mono, stereo, etc.) */
  DWORD nSamplesPerSec; /* 4 bytes sample rate */
  DWORD nAvgBytesPerSec;/* 4 bytes for buffer size estimation */
  WORD nBlockAlign;	/* 2 bytes block size of data */
  WORD wBitsPerSample;//4 bytes
  CHUNKHDR chkData;//8 bytes
} WAVEHDR;/*
 * ---------------------------------------------------------------------
 *  definitions for RIFF output (from Windows MMSYSTEM)
 * ---------------------------------------------------------------------
 */

typedef DWORD FOURCC;	/* a four character code */



/* general waveform format structure (information common to all formats) */
typedef struct waveformat_tag {
  WORD wFormatTag;	/* format type */
  WORD nChannels;	/* number of channels (i.e. mono, stereo, etc.) */
  DWORD nSamplesPerSec; /* sample rate */
  DWORD nAvgBytesPerSec;/* for buffer size estimation */
  WORD nBlockAlign;	/* block size of data */
} WAVEFORMAT;
typedef WAVEFORMAT	 *PWAVEFORMAT;

#include "CPeak.h"
#include <deque>
using namespace std;
//#include "MMWaveEditXCtl.h"
class CMMWaveEditXCtrl;
class CEditWaveFile  
{
	public:
		CEditWaveFile();
		virtual ~CEditWaveFile();

		// Variables
		CString				m_sWaveFileName;

		long				m_lMaxZoom;
		long				m_lTotalFileLength;
		long				m_lCurrentZoomFactor;
		long				m_lLastZoomFactorUsed;
		WAVEHDR				m_WaveHeader;
		BOOL				m_bPeakFileBeingUsed;
		BOOL				m_bInitialized;
		long				m_lCurFilePosition;
		deque<CPoint>		m_lPoints;
		deque<CPoint>		m_rPoints;
		long				m_lTotalLPoints;
		long				m_lCursorPosition;
		long				m_lStartOfSelection;
		CRect				m_rcLastSelectRect;
		BOOL				m_bDraggingCursorInSel;

		//Temp
		CMMWaveEditXCtrl*	m_lpOwnerCtrl;
		// Fucntions

	public:

		long				GetSamplesPerSecond				();
		long				GetNumberOfChannels				();
		long				GetTotalFileLength				();
		void				GetScrollRanges					(long& lLow,long&lHigh,CRect& rcBounds);

		BOOL				InitializeFile					(CString sFilename);
		void				BuildPeakFile16BS				();
		void				BuildPeakFile16B				();
		void				BuildPeakFile8BS				();
		void				BuildPeakFile8B					();
		// Manipulations
		void				ZoomInToNextLevel				();
		void				ZoomOutToNextLevel				();
		// Bitmap Creation
		void				Draw							(CDC* lpDC,CRect rcBounds);
		float				GetFileLengthInSeconds			();

		void				SetCursorPosition				(long lPosition);
		void				SetSelectionPosition			(long lPosition);
		void				GetSelectionRanges				(long& lLow,long& lHigh);	

		CRect				SizingSelection					(long lPosition,CRect rcBounds);
		void				BeginingDragOfSelection			(long lPosition,CRect rcBounds,BOOL bLeft);


		void				SetCursorAsStartSelec			();
		BOOL				IsCursorVisible					(CRect& rcBounds);

		CRect				GetSelectionRect				(CRect& rcBounds);
		// Playing curosr
		BOOL				IsPointVisible					(CRect& rcBounds,long lFilePosition);

	private:
		BOOL				IsThereACurrentPeakFile			();
		long				GetMaxZoomFactor16BS			(CFile* lpFile);
		long				GetMaxZoomFactor16B				(CFile* lpFile);
		long				GetMaxZoomFactor8BS				(CFile* lpFile);
		long				GetMaxZoomFactor8B				(CFile* lpFile);

		// Bitmap
		void				Create16BSWaveFormBmp			(CDC* lpDC,CRect rcBounds);
		void				Create16BWaveFormBmp			(CDC* lpDC,CRect rcBounds);
		void				Create8BSWaveFormBmp			(CDC* lpDC,CRect rcBounds);
		void				Create8BWaveFormBmp				(CDC* lpDC,CRect rcBounds);

		void				Draw16BSdbLine					(CDC* lpDC,CRect rcBounds,float& scale);
		void				Draw16BScale					(CDC* lpDC,CRect rcBounds,float& scale);
		void				Draw16BSWaveformDirectlyFromFile(CDC* lpDC,CRect rcBounds);
		void				DrawUnInitialized				(CDC* lpDC,CRect rcBounds);

};

#endif // !defined(AFX_CEDITWAVEFILE_H__4D07CE61_46F7_11D3_9A58_0080C605ADA4__INCLUDED_)