/* FFT function:

 * Real[] is the real part of complex input/output data;

 * Imag[] is the imaginary part of complex input/output data;

 * FFTSize is the data length equal to 2^M;

 * Sign represents the FFT() function: 1  -> FFT

 *                                     -1 -> IFFT;

 * Results are stored back in Real[] and Imag[];

 */

void FFT(long int Real[], long int Imag[], WordType sign);



/* CONVBASE Converts the number base of the input data (DataIn):

 *   ConvBase(DType DataIn[], DType DataOut[], DType DataLen, DType sign)

 * From the current base (CurrBase) to the new base required (NewBase);

 * If the new base is less than the old base, e.g

 * NewBase = 2 and CurrBase = 8, the DataOut will have more

 * data words. For the above example DataOut will be 4 times

 * longer than DataIn;

 * The actual base used = 2^NewBase, thus NewBase = 8, is base 256;

 * E.g. DataIn = [ 2 64 20 ] with CurrBase = 8, NewBase = 2

 * DataOut = [2 0 0 0, 0 0 0 1, 0 1 1 0]

 * Note : Both the input and output data is in a serial format;

 * DataLen is the length of DataIn[];

 * Sign represents the ConvBase() function: 1 -> NewBase < CurrBase

 *                                          0 -> NewBase > CurrBase;

 *                                          Other -> No change;

 */

void ConvBase(DType DataIn[], DType DataOut[], WordType DataLen, WordType Sign);



/* Convert 2-bit binary code to Gray code */

void Gray2(DType DataIn[], WordType Length);



/* Change the source data format to fit the channel encoder */

void SrcToChan(int SrcData[], DType ReqData[], WordType SymbolMark[], WordType BitMark[]);



/* Change the data format to fit the source decoder */

void ChanToSrc(DType ChannelData[], short SrcData[], WordType PosMark[]);



/* Round the data to nearest integer */

WordType Round(float RealData);



/* Generates a pseudorandom number:

 * *Seed is the seed of this function;

 * RandMax is the maximum number of pseudorandom;

 */

unsigned short Random(unsigned long int *Seed, unsigned short RandMax);


long int arctan2(long int y, long int x);