Simple Audio Out Oscilloscope and Spectrum Analyzer

#ifndef _SAMPLEITER
#define _SAMPLEITER

#include <stdlib.h>

enum WorkChannel  {WRKCHANNEL_LEFT = 0, WRKCHANNEL_RIGHT = 1, WRKCHANNEL_MONO = 2, WRKCHANNEL_STEREO = 3};
class SampleIter
{
protected:
    WorkChannel c_curChannel;
    char*       c_pSamples;
    int         c_sampleLen;
    int         c_byteWidth;
    bool        c_stereoSamples;
    int         c_interRWIdx;

public:
    SampleIter ()
    { 
        c_curChannel    = WRKCHANNEL_STEREO;
        c_pSamples      = NULL;
        c_sampleLen     = 0;
        c_byteWidth     = 0;
        c_interRWIdx    = 0;
        c_stereoSamples = false;
    };
	
	void SetWorkChannel (WorkChannel workChhannel)
    {
        c_curChannel = workChhannel;
    }

    bool SetSampleWorkSet (char* pSamples, int sampleLen, int byteWidth, bool stereo)
    {
        if (pSamples == NULL)
            return false;

        c_pSamples = pSamples;

        if (byteWidth <= 0)
            return false;

        c_sampleLen = sampleLen;
        c_byteWidth = byteWidth;

        if ((c_stereoSamples = stereo) == false)
            c_curChannel = WRKCHANNEL_MONO;
        else
            c_curChannel = WRKCHANNEL_STEREO;        

        
        SetPos (0);
        return true;
    }

    int Count ()
    {
        if (c_pSamples == NULL)
            return 0;
        
        if (c_sampleLen <= 0)
            return 0;

        int c = c_sampleLen / c_byteWidth;

        if (c_stereoSamples != false)
            c /= 2;

        return c;
    }

    void SetPos (int idx)
    {
        c_interRWIdx = (idx * c_byteWidth);

        if (c_stereoSamples != false)
            c_interRWIdx *= 2;
    }

    int GetPos ()
    {
        int pos = c_interRWIdx / c_byteWidth;

        if (c_stereoSamples != false)
            pos /= 2;

        return pos;
    }

    void Advance ()
    {   
        c_interRWIdx += c_byteWidth;

        if (c_stereoSamples != false)
            c_interRWIdx += c_byteWidth;        
    }

    void BartlettWindow (void)
    {
        int fullRange = Count();
        short* pData  = (short*) c_pSamples;
        
        int    idx;
        float  pwr  = (float)(1.0 / (float)(fullRange / 2));

        switch (c_curChannel)
        {
            case WRKCHANNEL_LEFT:
                idx = 0;
                break;

            case WRKCHANNEL_RIGHT:
                idx = 2;
                break;
        }

        for (int c = 0; c < fullRange; c++)
        {
            if (c < (fullRange/2))
            {
                pData[idx] = (int)((float)pData[idx] * (pwr * (float)idx));
            }
            else
            {
                pData[idx] = (int)((float)pData[idx] * (1.0 - (pwr * (float)((fullRange / 2) - idx))));
            }
            if (c_stereoSamples != false)
                idx += 4;
            else
                idx+= 2;
        }
    }

    short GetSample ()
    {
        if (c_pSamples == NULL)
            return -1;

        switch (c_byteWidth)
        {
            case 0:
                return -1;

            case 1:
                if (c_curChannel != WRKCHANNEL_RIGHT) // left channel
                {
                    return c_pSamples[c_interRWIdx];
                }

                return c_pSamples[c_interRWIdx+1];

            case 2:
                if (c_curChannel != WRKCHANNEL_RIGHT) // left channel
                {
                    return *((short*)(c_pSamples+c_interRWIdx)); 
                } 
                
                return *((short*)(c_pSamples+c_interRWIdx+2));                
        }
        return -1;
    }
};

#endif