omni::util Namespace Reference

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Detailed Description

Auxiliary constants and functions.

This namespace contains some useful constants and auxiliary functions.

Constants

• const double SQRT2

  Square root of 2.
  

• const double SQRT3

  Square root of 3.
  

• const double LG2

  Decimal logarithm of 2.
  

• const double LN2

  Natural logarithm of 2.
  

• const double PI

  The Pi value.
  

Conversions

• double deg2rad (double deg)

  Convert degrees to the radians.
  

• double rad2deg (double rad)

  Convert radians to the degrees.
  

• double dB2line (double dB)

  Convert dB to the value in linear scale.
  

• double line2dB (double L)

  Convert value in linear scale to the dB.
  

• double dBm2watt (double dBm)

  Convert dBm to the watts.
  

• double watt2dBm (double W)

  Convert watts to the dBm.
  

• double kph2mps (double kph)

  Convert kph to the mps.
  

• double mps2kph (double mps)

  Convert mps to the kph.
  

Power of two and parity

• template<typename T> bool is_ipow2 (T x)

  Is integer power of two?
  

• template<typename T> T log2 (T x)

  Binary integer logarithm.
  

• template<typename T> T flp2 (T x)

  Nearest (floor) integer power of two.
  

• template<typename T> T clp2 (T x)

  Nearest (ceil) integer power of two.
  

• template<typename T> T parity (T x)

  Parity bit.
  

Bits packing/unpacking and flip

• template<typename T, typename In> T bi2de_msb (In first, size_t Nbits, T x=T())

  Binary to decimal (MSB first).
  

• template<typename T, typename Out> Out de2bi_msb (T x, size_t Nbits, Out first)

  Decimal to binary (MSB first).
  

• template<typename T, typename In> T bi2de_lsb (In first, size_t Nbits, T x=T())

  Binary to decimal (LSB first).
  

• template<typename T, typename Out> Out de2bi_lsb (T x, size_t Nbits, Out first)

  Decimal to binary (LSB first).
  

• template<typename T> T bits_flip (T x, size_t Nbits)

  Reverse the bit order.
  

Polynomials

• template<typename TY, typename TX, typename Bi> TY poly (const TX &x, Bi first, Bi last, const TY &)

  Calculate the polynomial's function.
  

• template<typename T, typename Bi> T poly (const T &x, Bi first, Bi last)

  Calculate the polynomial's function.
  

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Function Documentation

double deg2rad

(

double

deg

)

Convert degrees to the radians.

This function converts the deg value in degrees to the corresponding value in radians.

  double rad = deg * 3.14/180;

Parameters:

[in]

deg

The value in degrees.

Returns:

The value in radians.

See also:

rad2deg()

double rad2deg

(

double

rad

)

Convert radians to the degrees.

This function converts the rad value in radians to the corresponding value in degrees.

  double deg = rad * 180/3.14;

Parameters:

[in]

rad

The value in radians.

Returns:

The value in degrees.

See also:

deg2rad()

double dB2line

(

double

dB

)

Convert dB to the value in linear scale.

This function converts the dB value in logarithmic (dB) scale to the corresponding value in linear scale.

  double L = pow(10, dB/10);

Parameters:

[in]

dB

The value in logarithmic scale.

Returns:

The value in linear scale.

See also:

line2dB()

double line2dB

(

double

L

)

Convert value in linear scale to the dB.

This function converts the L value in linear scale to the corresponding value in logarithmic (dB) scale.

  double dB = 10*log10(L);

Parameters:

[in]

L

The value in linear scale. Should be positive nonzero value!

Returns:

The value in logarithmic scale.

See also:

dB2line()

double dBm2watt

(

double

dBm

)

Convert dBm to the watts.

This function converts the dBm value in logarithmic (dBm) scale to the value in watts.

  double W = pow(10, dBm/10) / 1000;

Parameters:

[in]

dBm

The value in dBm.

Returns:

The value in watts.

See also:

watt2dBm()

double watt2dBm

(

double

W

)

Convert watts to the dBm.

This function converts the W value in watts to the value in logarithmic (dBm) scale.

  double dBm = 10*log10(W*1000);

Parameters:

[in]

W

The value in watts. Should be positive nonzero value!

Returns:

The value in dBm.

See also:

dBm2watt()

double kph2mps

(

double

kph

)

Convert kph to the mps.

This function converts the value in kilometers per hour (kph) to the value in meters per second (mps).

  double mps = kph / 3.6;

Parameters:

[in]

kph

The value in kph.

Returns:

The value in mps.

See also:

mps2kph()

double mps2kph

(

double

mps

)

Convert mps to the kph.

This function converts the value in meters per second (mps) to the value in kilometers per hour (kph).

  double kph = mps * 3.6;

Parameters:

[in]

mps

The value in mps.

Returns:

The value in kph.

See also:

kph2mps()

bool omni::util::is_ipow2

(

T

x

)

[inline]

Is integer power of two?

This functions checks the x arguments - is it integer power of two?

The valid integer powers of two: 0, 1, 2, 4, 8, 16, 32, 64, 128, etc...

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]

x

The unsigned integer.

Returns:

true if argument is integer power of two, otherwise false.

See also:

log2()

flp2()

clp2()

T omni::util::log2

(

T

x

)

[inline]

Binary integer logarithm.

This function calculates a binary integer logarithm of the x argument. The input argument should be integer power of two and can't be zero.

  log2(1) == 0;
  log2(2) == 1;
  log2(4) == 2;
  log2(8) == 3;

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]

x

The unsigned integer.

Returns:

The binary logarithm.

See also:

is_ipow2()

flp2()

clp2()

T omni::util::flp2

(

T

x

)

[inline]

Nearest (floor) integer power of two.

This function calculates an integer value representing the largest integer power of two that is less than or equal to x argument.

  flp2(4) == 4;
  flp2(5) == 4;
  flp2(7) == 4;
  flp2(9) == 8;

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]

x

The unsigned integer.

Returns:

The nearest (floor) integer power of two.

See also:

is_ipow2()

log2()

clp2()

T omni::util::clp2

(

T

x

)

[inline]

Nearest (ceil) integer power of two.

This function calculates an integer value representing the smallest integer power of two that is greater than or equal to x argument.

  clp2(4) == 4;
  clp2(5) == 8;
  clp2(7) == 8;
  clp2(9) == 16;

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]

x

The unsigned integer.

Returns:

The nearest (ceil) integer power of two.

See also:

is_ipow2()

log2()

flp2()

T omni::util::parity

(

T

x

)

[inline]

Parity bit.

This function calculates a parity bit of the input argument x.

The parity bit is equal to:

• 1, if x has even number of nonzero bits,
• 0, if x has odd number of nonzero bits.

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]

x

The unsigned integer.

Returns:

The parity bit.

T omni::util::bi2de_msb	(	In	first,
		size_t	Nbits,
		T	x = T()
	)			[inline]

Binary to decimal (MSB first).

This function converts input binary sequence [first, first + Nbits) to the one "decimal" value. First element of the input bit sequence is correspond to the most significant bit of the returned "decimal" value.

The number of bits Nbits should be less than or equal to the size of returned "decimal" value (i.e. 8*sizeof(T)).

For example, the following code will print "13" (1101b):

  const int bits[] = { 1, 1, 0, 1 };
  std::cout << bi2de_msb<unsigned>(bits, 4) << "\n";

The last argument x is used for result type deduction. The following two lines are equivalent:

  bi2de_msb<unsigned>(bits, 4);
  bi2de_msb(bits, 4, unsigned(0));

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]	first	Begin of the input bit sequence.
[in]	Nbits	Number of bits to converting.
[in]	x	Initial value, by default is zero.

Returns:

The "decimal" value.

Out omni::util::de2bi_msb	(	T	x,
		size_t	Nbits,
		Out	first
	)			[inline]

Decimal to binary (MSB first).

This function convert "decimal" value x to the output bit sequence [first, first + Nbits). First element of the output bit sequence is correspond to the most significant bit of the input "decimal" value.

The number of bits Nbits should be less than or equal to the size of input "decimal" value (i.e. 8*sizeof(T)).

For example, the following code will print "1101b" (13):

  std::vector<int> bits(4);
  de2bi_msb(13, bits.size(), bits.begin());
  std::copy(bits.begin(), bits.end(),
    std::ostream_iterator<int>(std::cout, ""));
  std::cout << "b\n";

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]	x	Input "decimal" value.
[in]	Nbits	Number of bits to converting.
[in]	first	Begin of the output bit sequence.

Returns:

End of the output bit sequence.

T omni::util::bi2de_lsb	(	In	first,
		size_t	Nbits,
		T	x = T()
	)			[inline]

Binary to decimal (LSB first).

This function converts input binary sequence [first, first + Nbits) to the one "decimal" value. First element of the input bit sequence is correspond to the least significant bit of the returned "decimal" value.

The number of bits Nbits should be less than or equal to the size of returned "decimal" value (i.e. 8*sizeof(T)).

For example, the following code will print "13" (1101b):

  const int bits[] = { 1, 0, 1, 1 };
  std::cout << bi2de_lsb<unsigned>(bits, 4) << "\n";

The last argument x is used for result type deduction. The following two lines are equivalent:

  bi2de_lsb<unsigned>(bits, 4);
  bi2de_lsb(bits, 4, unsigned(0));

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]	first	Begin of the input bit sequence.
[in]	Nbits	Number of bits to converting.
[in]	x	Initial value, by default is zero.

Returns:

The "decimal" value.

Out omni::util::de2bi_lsb	(	T	x,
		size_t	Nbits,
		Out	first
	)			[inline]

Decimal to binary (LSB first).

This function convert "decimal" value x to the output bit sequence [first, first + Nbits). First element of the output bit sequence is correspond to the least significant bit of the input "decimal" value.

The number of bits Nbits should be less than or equal to the size of input "decimal" value (i.e. 8*sizeof(T)).

For example, the following code will print "1011b" (13):

  std::vector<int> bits(4);
  de2bi_lsb(13, bits.size(), bits.begin());
  std::copy(bits.begin(), bits.end(),
    std::ostream_iterator<int>(std::cout, ""));
  std::cout << "b\n";

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]	x	Input "decimal" value.
[in]	Nbits	Number of bits to converting.
[in]	first	Begin of the output bit sequence.

Returns:

End of the output bit sequence.

T omni::util::bits_flip	(	T	x,
		size_t	Nbits
	)			[inline]

Reverse the bit order.

This function returns the flipped Nbits least significant bits of the argument x.

To flip all bits, you can use the following code:

  bits_flip(x, sizeof(x)*8);

Note:

The template argument T should be unsigned integer type.

Parameters:

[in]	x	The input integer value.
[in]	Nbits	Number of least significant bits.

Returns:

The flipped value.

TY omni::util::poly	(	const TX &	x,
		Bi	first,
		Bi	last,
		const TY &
	)			[inline]

Calculate the polynomial's function.

This function calculates the value of polynomial's function:

  A[0]*pow(x,N-1) + A[1]*pow(x,N-2)... + A[N-2]*x + A[N-1]

where

• A is a polynomial's coefficients defined by sequence [first, last),
• N is polynomial's order.

The last argument is used for result type deduction.

Parameters:

[in]	x	The polynomial's argument.
[in]	first	Begin of polynomial's coefficients.
[in]	last	End of polynomial's coefficients.

Returns:

The value of polynomial's function.

T omni::util::poly	(	const T &	x,
		Bi	first,
		Bi	last
	)			[inline]

Calculate the polynomial's function.

This function calculates the value of polynomial's function:

  A[0]*pow(x,N-1) + A[1]*pow(x,N-2)... + A[N-2]*x + A[N-1]

where

• A is a polynomial's coefficients defined by sequence [first, last),
• N is polynomial's order.

Note:

The result's type is equal to the x argument's type.

Parameters:

[in]	x	The polynomial's argument.
[in]	first	Begin of polynomial's coefficients.
[in]	last	End of polynomial's coefficients.

Returns:

The value of polynomial's function.

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Variable Documentation

const double SQRT2

Square root of 2.

const double SQRT3

Square root of 3.

const double LG2

Decimal logarithm of 2.

const double LN2

Natural logarithm of 2.

const double PI

The Pi value.

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