The `math-inlines.h` File Reference

C++ header file with inline implementations for the µTest++ mathematical utilities. More...

Included Headers

#include <cstdint>

Namespaces Index

namespace	micro_os_plus
	The primary namespace for the µOS++ framework. More...

namespace	micro_os_plus::micro_test_plus
	Primary namespace for the µTest++ testing framework. More...

namespace	micro_os_plus::micro_test_plus::math
	Mathematical utilities for the µTest++ testing framework. More...

Functions Index

constexpr T	abs (const T t)
	Computes the absolute value of a given comparable value. More...

constexpr T	den (void)
	Computes the decimal part of a number represented as an array of characters. More...

constexpr T	den_size (Value_T value)
	Computes the number of decimal places of a value, up to 7 digits. More...

constexpr T	den_size (void)
	Computes the number of decimal places in a number represented as an array of characters. More...

constexpr const T &	min_value (const T &lhs, const T &rhs)
	Computes the minimum of two comparable values. More...

constexpr T	num (void)
	Computes the integral value of a number represented as an array of characters. More...

constexpr T	pow (const T base, const Exp_T exp)
	Generic exponentiation function to compute the power of a base raised to an exponent. More...

Description

C++ header file with inline implementations for the µTest++ mathematical utilities.

This header provides the inline implementations for the mathematical utility templates used within the µTest++ framework. It defines constexpr logic for common mathematical operations, including absolute value, minimum value selection, exponentiation, and compile-time parsing of numeric values from character sequences.

These utilities are designed to be lightweight and suitable for embedded environments, supporting both integral and floating-point types, and enabling expressive, type-safe, and efficient compile-time computations. Special attention is given to constexpr compatibility and minimal reliance on the standard library, ensuring portability and performance.

All definitions reside within the micro_os_plus::micro_test_plus::math namespace, ensuring clear separation from user code and minimising the risk of naming conflicts.

The header files are organised within the include/micro-os-plus/micro-test-plus folder to maintain a structured and modular codebase.

This file is intended solely for internal use within the framework and should not be included directly by user code.

Functions

abs()

template <class T>

T micro_os_plus::micro_test_plus::math::abs (const T t)

nodiscardconstexpr

Computes the absolute value of a given comparable value.

This function template provides a generic, constexpr implementation for obtaining the absolute value of any type that supports comparison and unary negation.

The function returns the non-negative value of the input. If the input is less than the default-constructed value of its type (typically zero), the negated value is returned; otherwise, the original value is returned.

This utility is designed to be lightweight and suitable for embedded environments, where standard library alternatives may be unavailable, less efficient, or not constexpr.

Template Parameters

T	The type of the input value. Must support comparison and unary negation.

Parameters

t	The value for which the absolute value is to be computed.

Returns: The absolute value of the input.

Definition at line 96 of file math-inlines.h.

den()

template <class T, char... Cs>

T micro_os_plus::micro_test_plus::math::den (void)

nodiscardconstexpr

Computes the decimal part of a number represented as an array of characters.

This function template performs compile-time extraction of the decimal (fractional) part from a sequence of characters, typically provided as a template parameter pack.

The function expects the character sequence to represent a numeric value, where all characters are either digits, a dot (.), or an apostrophe (‘``). Parsing begins after the first dot, accumulating the decimal digits as an integer value, each weighted by its decimal position.

This utility is particularly useful for user-defined literals and other compile-time constant expressions, enabling efficient and type-safe conversion from character sequences to the decimal part of numeric values.

Template Parameters

T	The target integral type for the result.
Cs	The character pack representing the numeric value.

Parameters: None.

Returns: The parsed decimal part as an integral value of type T.

Definition at line 200 of file math-inlines.h.

den_size()

template <class T, class Value_T>

T micro_os_plus::micro_test_plus::math::den_size (Value_T value)

nodiscardconstexpr

Computes the number of decimal places of a value, up to 7 digits.

This function template determines, at compile time, the number of decimal (fractional) digits present in a floating-point value, up to a maximum of seven digits of precision.

The function repeatedly multiplies the input value by ten, incrementing a counter until the fractional part is less than a defined precision threshold (1e-7). This approach provides a robust means of estimating decimal precision for values where exact representation is not possible due to floating-point limitations.

This utility is particularly useful for user-defined literals and compile-time constant expressions, enabling efficient and type-safe determination of decimal precision from floating-point values.

Template Parameters

T	The integral type for the result.
Value_T	The type of the input value, typically a floating-point type.

Parameters

value

The value whose decimal precision is to be determined.

Returns: The number of decimal places, as a value of type T, up to a maximum of seven.

Definition at line 269 of file math-inlines.h.

den_size()

template <class T, char... Cs>

T micro_os_plus::micro_test_plus::math::den_size (void)

nodiscardconstexpr

Computes the number of decimal places in a number represented as an array of characters.

This function template determines, at compile time, the number of decimal (fractional) digits present in a numeric value represented by a character sequence, typically provided as a template parameter pack.

The function expects the character sequence to represent a numeric value, where all characters are either digits, a dot (.), or an apostrophe (‘``). It locates the first dot and counts the number of digits that follow, returning the count as the number of decimal places.

This utility is particularly useful for user-defined literals and other compile-time constant expressions, enabling efficient and type-safe determination of decimal precision from character sequences.

Template Parameters

T	The integral type for the result.
Cs	The character pack representing the numeric value.

Parameters: None.

Returns: The number of decimal places as a value of type T.

Definition at line 233 of file math-inlines.h.

min_value()

template <class T>

const T & micro_os_plus::micro_test_plus::math::min_value (const T & lhs, const T & rhs)

nodiscardconstexpr

Computes the minimum of two comparable values.

This function template provides a generic, constexpr implementation for determining the minimum of two values of any type that supports comparison.

The function returns a reference to the lesser of the two input values, as determined by the < operator. If the second argument is less than the first, it is returned; otherwise, the first argument is returned.

This utility is designed to be lightweight and suitable for embedded environments, where standard library alternatives may be unavailable, less efficient, or not constexpr.

Template Parameters

T	The type of the input values. Must support comparison via the `<` operator.

Parameters

lhs	The first value to compare.
rhs	The second value to compare.

Returns: A reference to the minimum of the two input values.

Definition at line 117 of file math-inlines.h.

num()

template <class T, char... Cs>

T micro_os_plus::micro_test_plus::math::num (void)

nodiscardconstexpr

Computes the integral value of a number represented as an array of characters.

This function template performs compile-time parsing of a numeric value from a sequence of characters, typically provided as a template parameter pack.

The function assumes that all characters are either digits, a dot (.), or an apostrophe (‘``). Parsing stops at the first dot, allowing the function to extract only the integral part of the number.

This utility is particularly useful for user-defined literals and other compile-time constant expressions, enabling efficient and type-safe conversion from character sequences to integral values.

Template Parameters

T	The target integral type for the result.
Cs	The character pack representing the numeric value.

Parameters: None.

Returns: The parsed integral value of type T.

Definition at line 160 of file math-inlines.h.

pow()

template <class T, class Exp_T>

T micro_os_plus::micro_test_plus::math::pow (const T base, const Exp_T exp)

nodiscardconstexpr

Generic exponentiation function to compute the power of a base raised to an exponent.

This function template provides a constexpr implementation for raising a base value to a given exponent, supporting any types that allow multiplication and subtraction.

The function recursively multiplies the base by itself exponent times. If the exponent is zero, the function returns one (the multiplicative identity for the type).

This utility is designed to be lightweight and suitable for embedded environments, where standard library alternatives may be unavailable, less efficient, or not constexpr.

Template Parameters

T	The type of the base value. Must support multiplication and construction from an integer.
Exp_T	The type of the exponent. Must support subtraction and comparison to zero.

Parameters

base	The base value to be raised to the power of `exp`.
exp	The exponent value.

Returns: The result of raising base to the power of exp.

Definition at line 138 of file math-inlines.h.

File Listing

The file content with the documentation metadata removed is:

1/*

2 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).

4 *

5 * Permission to use, copy, modify, and/or distribute this software

6 * for any purpose is hereby granted, under the terms of the MIT license.

7 *

8 * If a copy of the license was not distributed with this file, it can

9 * be obtained from https://opensource.org/licenses/mit.

10 *

11 * Major parts of the code are inspired from v1.1.8 of the Boost UT project,

12 * released under the terms of the Boost Version 1 Software License,

13 * which can be obtained from https://www.boost.org/LICENSE_1_0.txt.

14 */

16// ----------------------------------------------------------------------------

48#ifndef MICRO_TEST_PLUS_MATH_INLINES_H_

49#define MICRO_TEST_PLUS_MATH_INLINES_H_

51// ----------------------------------------------------------------------------

53#ifdef __cplusplus

55// ----------------------------------------------------------------------------

57#include <cstdint>

59// #include "type-traits.h"

61// ----------------------------------------------------------------------------

63#if defined(__GNUC__)

64#pragma GCC diagnostic push

65#pragma GCC diagnostic ignored "-Waggregate-return"

66#if defined(__clang__)

67#pragma clang diagnostic ignored "-Wc++98-compat"

68#pragma clang diagnostic ignored "-Wc++98-compat-pedantic"

69#endif

70#endif

72namespace micro_os_plus::micro_test_plus

73{

74 // --------------------------------------------------------------------------

76 namespace math

77 {

94 template <class T>

95 [[nodiscard]] constexpr auto

96 abs (const T t) -> T

97 {

98 return t < T{} ? -t : t;

99 }

100

115 template <class T>

116 [[nodiscard]] constexpr auto

117 min_value (const T& lhs, const T& rhs) -> const T&

118 {

119 return (rhs < lhs) ? rhs : lhs;

120 }

121

136 template <class T, class Exp_T>

137 [[nodiscard]] constexpr auto

138 pow (const T base, const Exp_T exp) -> T

139 {

140 // If the exponent is 0, return 1, otherwise recurse.

141 return exp ? T (base * pow (base, exp - Exp_T (1))) : T (1);

142 }

143

158 template <class T, char... Cs>

159 [[nodiscard]] constexpr auto

160 num (void) -> T

161 {

162 // Assume all are digits or dot or apostrophe.

163 static_assert (

164 ((Cs == '.' or Cs == '\'' or (Cs >= '0' and Cs <= '9')) and ...));

165 T result{};

166 for (const char c : { Cs... })

167 {

168 if (c == '.')

169 {

170 break;

171 }

172 if (c >= '0' and c <= '9')

173 {

174 result = static_cast<T> (result * static_cast<T> (10)

175 + static_cast<T> (c - '0'));

176 }

177 }

178 return result;

179 }

180

198 template <class T, char... Cs>

199 [[nodiscard]] constexpr auto

200 den (void) -> T

201 {

202 constexpr const std::array cs{ Cs... };

203 T result{};

204 auto i = 0u;

205 while (cs[i++] != '.')

206 {

207 }

208

209 for (auto j = i; j < sizeof...(Cs); ++j)

210 {

211 result += pow (T (10), sizeof...(Cs) - j) * T (cs[j] - '0');

212 }

213 return result;

214 }

215

231 template <class T, char... Cs>

232 [[nodiscard]] constexpr auto

233 den_size (void) -> T

234 {

235 constexpr const std::array cs{ Cs... };

236 T i{};

237#if defined(__GNUC__)

238#pragma GCC diagnostic push

239#pragma GCC diagnostic ignored "-Wconversion"

240#endif

241 while (cs[i++] != '.')

242#if defined(__GNUC__)

243#pragma GCC diagnostic pop

244#endif

245 {

246 }

247

248 return T (sizeof...(Cs)) - i + T (1);

249 }

250

267 template <class T, class Value_T>

268 [[nodiscard]] constexpr auto

269 den_size (Value_T value) -> T

270 {

271 constexpr auto precision = Value_T (1e-7);

272 T result{};

273 Value_T tmp{};

274 do

275 {

276 value *= 10;

277#if defined(__GNUC__)

278#pragma GCC diagnostic push

279#if !defined(__clang__) // GCC only

280#pragma GCC diagnostic ignored "-Warith-conversion"

281#endif

282#if defined(__clang__)

283#pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"

284#endif

285#endif

286 tmp = value - T (value);

287#if defined(__GNUC__)

288#pragma GCC diagnostic pop

289#endif

290 ++result;

291 }

292 while (tmp > precision);

293

294 return result;

295 }

296

297 // ------------------------------------------------------------------------

298 } // namespace math

299

300 // --------------------------------------------------------------------------

301} // namespace micro_os_plus::micro_test_plus

302

303#if defined(__GNUC__)

304#pragma GCC diagnostic pop

305#endif

306

307// ----------------------------------------------------------------------------

308

309#endif // __cplusplus

310

311// ----------------------------------------------------------------------------

312

313#endif // MICRO_TEST_PLUS_MATH_INLINES_H_

314

315// ----------------------------------------------------------------------------

Generated via docusaurus-plugin-doxygen by Doxygen 1.14.0.

Included Headers​

Namespaces Index​

Functions Index​

Description​

Functions​

abs()​

den()​

den_size()​

den_size()​

min_value()​

num()​

pow()​

File Listing​

Included Headers

Namespaces Index

Functions Index

Description

Functions

abs()

den()

den_size()

den_size()

min_value()

num()

pow()

File Listing