fftlib.c

Fast Fourier Transform algorithm for labview, C++

/*============================================================================  
    A static library to make using FFT.DLL easier than putting  
    the FFT code into your own app.  
    Why is it so freaky?  Because I wrote it in five minutes, of  
    course.  What do you care?  You don't need to look at it.  
    Just compile it. =D  
      
    Murphy McCauley 08/01/99  
============================================================================*/   
   
#include <WINDOWS.H>    
#include "FFTLib.h"    
   
typedef void (WINAPI *FFTDOUBLE)(unsigned, int, double *, double *, double *, double *);   
typedef void (WINAPI *FFTFLOAT)(unsigned, int, float *, float *, float *, float *);   
typedef ULONG (WINAPI *INDEXTOFREQ)(unsigned, unsigned);   
   
HANDLE      hFFTDLL;   
FFTDOUBLE   fpFftDouble;   
FFTFLOAT    fpFftFloat;   
INDEXTOFREQ fpIndexToFreq;   
   
   
// The other three prototypes are in FFTLib.h (where they belong).    
BOOL LoadFFTDLL ();   
void UnloadFFTDLL ();   
   
   
BOOL LoadFFTDLL (void) {   
    // Returns True if the library is loaded, False otherwise.    
    BOOL    AllIsWell = TRUE;   
   
    if (hFFTDLL) {   
        return TRUE;   
    }   
   
    if ((hFFTDLL = LoadLibrary("FFT.DLL")) < (HANDLE)32) {   
        hFFTDLL = 0;   
        return FALSE; // Get outta here if we can't load DLL.    
    }   
   
    if ((fpFftDouble = (FFTDOUBLE)GetProcAddress(hFFTDLL, "fft_double")) == NULL) {   
        AllIsWell = FALSE;   
    } else {   
        if ((fpFftFloat = (FFTFLOAT)GetProcAddress(hFFTDLL, "fft_float")) == NULL) {   
            AllIsWell = FALSE;   
        } else {   
            if ((fpIndexToFreq = (INDEXTOFREQ)GetProcAddress(hFFTDLL, "Index_to_frequency")) == NULL) {   
                AllIsWell = FALSE;   
            }   
        }   
    }   
   
    if (AllIsWell == FALSE) {   
        // Ack!  Bad news.  Unload the DLL.    
        UnloadFFTDLL();   
        return FALSE;   
    }   
   
    return TRUE;   
   
}   
   
void UnloadFFTDLL () {   
    if (hFFTDLL) {   
        FreeLibrary(hFFTDLL);   
        hFFTDLL = 0;   
    }   
}   
   
BOOL fftDouble (   
    unsigned  NumSamples,   
    int       InverseTransform,   
    double   *RealIn,   
    double   *ImagIn,   
    double   *RealOut,   
    double   *ImagOut ) {   
       
    BOOL Success;   
    if (LoadFFTDLL()) {   
        Success = TRUE;   
        fpFftDouble(NumSamples, InverseTransform, RealIn, ImagIn, RealOut, ImagOut);   
    } else {   
        Success = FALSE;   
    }   
   
    return Success;   
}   
   
BOOL fftFloat (   
    unsigned  NumSamples,   
    int       InverseTransform,   
    float   *RealIn,   
    float   *ImagIn,   
    float   *RealOut,   
    float   *ImagOut ) {   
       
    BOOL Success;   
    if (LoadFFTDLL()) {   
        Success = TRUE;   
        fpFftFloat(NumSamples, InverseTransform, RealIn, ImagIn, RealOut, ImagOut);   
    } else {   
        Success = FALSE;   
    }   
   
    return Success;   
}   
   
double indexToFrequency ( unsigned NumSamples, unsigned Index ) {   
    double ReturnVal = -1; // returns -1 if it fails.  Stupid, but easy.    
   
    if (LoadFFTDLL()) {   
        ReturnVal = fpIndexToFreq(NumSamples, Index);          
    }   
   
    return ReturnVal;   
}   

/*============================================================================ 
	A static library to make using FFT.DLL easier than putting 
	the FFT code into your own app. 
	Why is it so freaky?  Because I wrote it in five minutes, of 
	course.  What do you care?  You don't need to look at it. 
	Just compile it. =D 
	 
	Murphy McCauley 08/01/99 
============================================================================*/ 
 
#include  
#include "FFTLib.h" 
 
typedef void (WINAPI *FFTDOUBLE)(unsigned, int, double *, double *, double *, double *); 
typedef void (WINAPI *FFTFLOAT)(unsigned, int, float *, float *, float *, float *); 
typedef ULONG (WINAPI *INDEXTOFREQ)(unsigned, unsigned); 
 
HANDLE		hFFTDLL; 
FFTDOUBLE	fpFftDouble; 
FFTFLOAT	fpFftFloat; 
INDEXTOFREQ	fpIndexToFreq; 
 
 
// The other three prototypes are in FFTLib.h (where they belong). 
BOOL LoadFFTDLL (); 
void UnloadFFTDLL (); 
 
 
BOOL LoadFFTDLL (void) { 
	// Returns True if the library is loaded, False otherwise. 
	BOOL	AllIsWell = TRUE; 
 
	if (hFFTDLL) { 
		return TRUE; 
	} 
 
	if ((hFFTDLL = LoadLibrary("FFT.DLL")) < (HANDLE)32) { 
		hFFTDLL = 0; 
    	return FALSE; // Get outta here if we can't load DLL. 
	} 
 
	if ((fpFftDouble = (FFTDOUBLE)GetProcAddress(hFFTDLL, "fft_double")) == NULL) { 
    	AllIsWell = FALSE; 
	} else { 
		if ((fpFftFloat = (FFTFLOAT)GetProcAddress(hFFTDLL, "fft_float")) == NULL) { 
			AllIsWell = FALSE; 
		} else { 
			if ((fpIndexToFreq = (INDEXTOFREQ)GetProcAddress(hFFTDLL, "Index_to_frequency")) == NULL) { 
				AllIsWell = FALSE; 
			} 
		} 
	} 
 
	if (AllIsWell == FALSE) { 
		// Ack!  Bad news.  Unload the DLL. 
		UnloadFFTDLL(); 
		return FALSE; 
	} 
 
	return TRUE; 
 
} 
 
void UnloadFFTDLL () { 
	if (hFFTDLL) { 
		FreeLibrary(hFFTDLL); 
		hFFTDLL = 0; 
	} 
} 
 
BOOL fftDouble ( 
    unsigned  NumSamples, 
    int       InverseTransform, 
    double   *RealIn, 
    double   *ImagIn, 
    double   *RealOut, 
    double   *ImagOut ) { 
	 
	BOOL Success; 
	if (LoadFFTDLL()) { 
		Success = TRUE; 
 		fpFftDouble(NumSamples, InverseTransform, RealIn, ImagIn, RealOut, ImagOut); 
	} else { 
		Success = FALSE; 
	} 
 
	return Success; 
} 
 
BOOL fftFloat ( 
    unsigned  NumSamples, 
    int       InverseTransform, 
    float   *RealIn, 
    float   *ImagIn, 
    float   *RealOut, 
    float   *ImagOut ) { 
	 
	BOOL Success; 
	if (LoadFFTDLL()) { 
		Success = TRUE; 
 		fpFftFloat(NumSamples, InverseTransform, RealIn, ImagIn, RealOut, ImagOut); 
	} else { 
		Success = FALSE; 
	} 
 
	return Success; 
} 
 
double indexToFrequency ( unsigned NumSamples, unsigned Index ) { 
	double ReturnVal = -1; // returns -1 if it fails.  Stupid, but easy. 
 
	if (LoadFFTDLL()) { 
		ReturnVal = fpIndexToFreq(NumSamples, Index);		 
	} 
 
	return ReturnVal; 
}