math.h File

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

Included Headers

#include <array> #include "inlines/math-inlines.h"

Namespaces Index

namespace	micro_os_plus
	The primary namespace for the µOS++ framework. More...
namespace	micro_test_plus
	Primary namespace for the µTest++ testing framework. More...
namespace	math
	Mathematical utilities for the µTest++ testing framework. More...

Functions Index

template <class T>
constexpr T	abs (const T t) noexcept
	Computes the absolute value of a given comparable value. More...
template <class T, char... Cs>
T	den (void)
	Computes the decimal part of a number represented as an array of characters. More...
template <class T, class Value_T>
constexpr T	den_size (Value_T value)
	Computes the number of decimal places of a value, up to 7 digits. More...
template <class T, char... Cs>
T	den_size (void)
	Computes the number of decimal places in a number represented as an array of characters. More...
template <class T>
constexpr const T &	min_value (const T &lhs, const T &rhs) noexcept
	Computes the minimum of two comparable values. More...
template <class T, char... Cs>
T	num (void)
	Computes the integral value of a number represented as an array of characters. More...
template <class T, class Exp_T>
constexpr T	pow (const T base, const Exp_T exp) noexcept
	Generic exponentiation function to compute the power of a base raised to an exponent. More...

Description

C++ header file with declarations for the µTest++ mathematical utilities.

This header provides the declarations for the mathematical utility templates used within the µTest++ framework. It defines interfaces for a suite of constexpr mathematical functions, 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 across a wide range of platforms.

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)

nodiscard constexpr noexcept

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 97 of file math-inlines.h.

97 abs (const T t) noexcept -> T

98 {

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

100 }

Referenced by micro_os_plus::micro_test_plus::detail::eq_< Lhs_T, Rhs_T >::eq_ and micro_os_plus::micro_test_plus::detail::ne_< Lhs_T, Rhs_T >::ne_.

den()

template <class T, char... Cs>

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

nodiscard

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 203 of file math-inlines.h.

203 den (void) -> T

204 {

205 static_assert ((... || (Cs == '.')),

206 "den(): no decimal point in literal");

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

208 T result{};

209 auto i = 0u;

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

211 {

212 }

213

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

215 {

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

217 }

218 return result;

219 }

Reference micro_os_plus::micro_test_plus::math::pow.

Referenced by micro_os_plus::micro_test_plus::literals::operator""_d, micro_os_plus::micro_test_plus::literals::operator""_f and micro_os_plus::micro_test_plus::literals::operator""_ld.

den_size()

template <class T, class Value_T>

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

nodiscard constexpr

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 276 of file math-inlines.h.

276 den_size (Value_T value) -> T

277 {

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

279 T result{};

280 Value_T tmp{};

281 do

282 {

283 value *= 10;

284#if defined(__GNUC__)

285#pragma GCC diagnostic push

286#if defined(__clang__)

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

288#else // GCC only

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

290#endif

291#endif

292 tmp = value - T (value);

293#if defined(__GNUC__)

294#pragma GCC diagnostic pop

295#endif

296 ++result;

297 }

298 while (tmp > precision);

299

300 return result;

301 }

den_size()

template <class T, char... Cs>

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

nodiscard

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 238 of file math-inlines.h.

238 den_size (void) -> T

239 {

240 static_assert ((... || (Cs == '.')),

241 "den_size(): no decimal point in literal");

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

243 T i{};

244#if defined(__GNUC__)

245#pragma GCC diagnostic push

246#pragma GCC diagnostic ignored "-Wconversion"

247#endif

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

249#if defined(__GNUC__)

250#pragma GCC diagnostic pop

251#endif

252 {

253 }

254

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

256 }

Referenced by micro_os_plus::micro_test_plus::literals::operator""_d, micro_os_plus::micro_test_plus::literals::operator""_f and micro_os_plus::micro_test_plus::literals::operator""_ld.

min_value()

template <class T>

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

nodiscard constexpr noexcept

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 118 of file math-inlines.h.

118 min_value (const T& lhs, const T& rhs) noexcept -> const T&

119 {

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

121 }

Referenced by micro_os_plus::micro_test_plus::detail::eq_< Lhs_T, Rhs_T >::eq_ and micro_os_plus::micro_test_plus::detail::ne_< Lhs_T, Rhs_T >::ne_.

num()

template <class T, char... Cs>

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

nodiscard

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 163 of file math-inlines.h.

163 num (void) -> T

164 {

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

166 static_assert (

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

168 T result{};

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

170 {

171 if (c == '.')

172 {

173 break;

174 }

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

176 {

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

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

179 }

180 }

181 return result;

182 }

Referenced by micro_os_plus::micro_test_plus::literals::operator""_c, micro_os_plus::micro_test_plus::literals::operator""_d, micro_os_plus::micro_test_plus::literals::operator""_f, micro_os_plus::micro_test_plus::literals::operator""_i, micro_os_plus::micro_test_plus::literals::operator""_i16, micro_os_plus::micro_test_plus::literals::operator""_i32, micro_os_plus::micro_test_plus::literals::operator""_i64, micro_os_plus::micro_test_plus::literals::operator""_i8, micro_os_plus::micro_test_plus::literals::operator""_l, micro_os_plus::micro_test_plus::literals::operator""_ld, micro_os_plus::micro_test_plus::literals::operator""_ll, micro_os_plus::micro_test_plus::literals::operator""_s, micro_os_plus::micro_test_plus::literals::operator""_sc, micro_os_plus::micro_test_plus::literals::operator""_u, micro_os_plus::micro_test_plus::literals::operator""_u16, micro_os_plus::micro_test_plus::literals::operator""_u32, micro_os_plus::micro_test_plus::literals::operator""_u64, micro_os_plus::micro_test_plus::literals::operator""_u8, micro_os_plus::micro_test_plus::literals::operator""_uc, micro_os_plus::micro_test_plus::literals::operator""_ul, micro_os_plus::micro_test_plus::literals::operator""_ull and micro_os_plus::micro_test_plus::literals::operator""_us.

pow()

template <class T, class Exp_T>

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

nodiscard constexpr noexcept

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.

The function iteratively 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 139 of file math-inlines.h.

139 pow (const T base, const Exp_T exp) noexcept -> T

140 {

141 T result{ 1 };

142 for (Exp_T i{}; i < exp; ++i)

143 result *= base;

144 return result;

145 }

Referenced by micro_os_plus::micro_test_plus::math::den.

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/).

3 * Copyright (c) 2021-2026 Liviu Ionescu. All rights reserved.

4 *

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

6 * 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 be

9 * 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 */

15

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

17

48

49#ifndef MICRO_TEST_PLUS_MATH_H_

50#define MICRO_TEST_PLUS_MATH_H_

51

52// ----------------------------------------------------------------------------

53

54#ifdef __cplusplus

55

56// ----------------------------------------------------------------------------

57

58#include <array>

59

60// ----------------------------------------------------------------------------

61

62#if defined(__GNUC__)

63#pragma GCC diagnostic push

64#pragma GCC diagnostic ignored "-Wconversion"

65#if defined(__clang__)

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

67#pragma clang diagnostic ignored "-Wc++20-compat"

68#endif

69#endif

70

71// ============================================================================

72

73namespace micro_os_plus::micro_test_plus

74{

75 // --------------------------------------------------------------------------

76

96 namespace math

97 {

107 template <class T>

108 [[nodiscard]] constexpr auto

109 abs (const T t) noexcept -> T;

110

121 template <class T>

122 [[nodiscard]] constexpr auto

123 min_value (const T& lhs, const T& rhs) noexcept -> const T&;

124

138 template <class T, class Exp_T>

139 [[nodiscard]] constexpr auto

140 pow (const T base, const Exp_T exp) noexcept -> T;

141

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

154 [[nodiscard]] consteval auto

155 num (void) -> T;

156

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

169 [[nodiscard]] consteval auto

170 den (void) -> T;

171

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

184 [[nodiscard]] consteval auto

185 den_size (void) -> T;

186

198 template <class T, class Value_T>

199 [[nodiscard]] constexpr auto

200 den_size (Value_T value) -> T;

201

202 // ------------------------------------------------------------------------

203 } // namespace math

204

205 // --------------------------------------------------------------------------

206} // namespace micro_os_plus::micro_test_plus

207

208#if defined(__GNUC__)

209#pragma GCC diagnostic pop

210#endif

211

212// ----------------------------------------------------------------------------

213

214#endif // __cplusplus

215

216// ============================================================================

217// Templates & constexpr implementations.

218

219#include "inlines/math-inlines.h"

220

221// ----------------------------------------------------------------------------

222

223#endif // MICRO_TEST_PLUS_MATH_H_

224

225// ----------------------------------------------------------------------------

---

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