at.ac.fhstp.sonitalk.utils

Class DecoderUtils

java.lang.Object

at.ac.fhstp.sonitalk.utils.DecoderUtils

public final class DecoderUtils
extends java.lang.Object

Provides functions for removing filling characters and the crc-bits and for casting bytes back to utf-8 characters. Furthermore, methods like calculating the median and mean are included.

Method Summary

Modifier and Type	Method and Description
static byte[]	binaryToBytes(java.lang.String input) Takes a String containing a bit sequence and return the corresponding byte array
static java.lang.String	byteToUTF8(byte[] bytes)
static java.lang.String	decodeBitToText(java.lang.String bitOfText)
static float	freq2idx(int freq, int fs, int winlen) Get the index of a specific frequency depending on sample rate and window length
static double	getComplexAbsolute(double real, double imaginary) Calculates an absolute value of a complex number
static float	getRelativeIndexPosition(float value, float minValue, float maxValue)
static double	max(double[] values) Helper to get maximum value out of double array
static double	mean(double[] m) the array double[] m MUST BE SORTED
static double	median(double[] m) the array double[] m MUST BE SORTED
static int	nextPowerOfTwo(int n) Calculates power of two values
static java.lang.String	removeFillingCharsAndCRCChars(java.lang.String bitMessage, int generatorPolynomLength) Checks for filling characters and error correction bits and deletes them.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

decodeBitToText

public static java.lang.String decodeBitToText(java.lang.String bitOfText)

binaryToBytes

public static byte[] binaryToBytes(java.lang.String input)

Takes a String containing a bit sequence and return the corresponding byte array

Parameters:

input - A String containing bits

Returns:

A byte array corresponding to the input bit sequence

byteToUTF8

public static java.lang.String byteToUTF8(byte[] bytes)

removeFillingCharsAndCRCChars

public static java.lang.String removeFillingCharsAndCRCChars(java.lang.String bitMessage,
                                                             int generatorPolynomLength)

Checks for filling characters and error correction bits and deletes them.

Parameters:

bitMessage - message to check

generatorPolynomLength - length of crc generator polynom

Returns:

the clean message

max

public static double max(double[] values)

Helper to get maximum value out of double array

Parameters:

values - array to get the max of

Returns:

the highest value of the array passed

mean

public static double mean(double[] m)

the array double[] m MUST BE SORTED

Parameters:

m -

Returns:

the mean of the array passed

median

public static double median(double[] m)

the array double[] m MUST BE SORTED

Parameters:

m -

Returns:

the median of the array passed

getRelativeIndexPosition

public static float getRelativeIndexPosition(float value,
                                             float minValue,
                                             float maxValue)

freq2idx

public static float freq2idx(int freq,
                             int fs,
                             int winlen)

Get the index of a specific frequency depending on sample rate and window length

Parameters:

freq - frequency to get the index of

fs - sample rate

winlen - window length

Returns:

the index of the frequency passed

nextPowerOfTwo

public static int nextPowerOfTwo(int n)

Calculates power of two values

Parameters:

n - initial value

Returns:

the next power of two value of an integer passed

getComplexAbsolute

public static double getComplexAbsolute(double real,
                                        double imaginary)

Calculates an absolute value of a complex number

Parameters:

real -

imaginary -

Returns:

the absolute value of the real and imaginary parts passed