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/*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* Copyright (C) 2020-2022 The DOSBox Staging Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef DOSBOX_MATH_UTILS_H
#define DOSBOX_MATH_UTILS_H
#include <algorithm>
#include <cmath>
#include "support.h"
// Clamp: given a value that can be compared with the given minimum and maximum
// values, this function will:
// * return the value if it's in-between or equal to either bounds, or
// * return either bound depending on which bound the value is beyond
template <class T> T clamp(const T& n, const T& lower, const T& upper) {
return std::max<T>(lower, std::min<T>(n, upper));
}
/*
Returns a number wrapped between the lower and upper bounds.
- wrap(-1, 0, 4); // Returns 4
- wrap(5, 0, 4); // Returns 0
All credit to Charles Bailey, https://stackoverflow.com/a/707426
*/
constexpr int wrap(int val, int const lower_bound, int const upper_bound)
{
const auto range_size = upper_bound - lower_bound + 1;
if (val < lower_bound)
val += range_size * ((lower_bound - val) / range_size + 1);
return lower_bound + (val - lower_bound) % range_size;
}
// Unsigned-only integer division with ceiling
template<typename T1, typename T2>
inline constexpr T1 ceil_udivide(const T1 x, const T2 y) noexcept {
static_assert(std::is_unsigned<T1>::value, "First parameter should be unsigned");
static_assert(std::is_unsigned<T2>::value, "Second parameter should be unsigned");
return (x != 0) ? 1 + ((x - 1) / y) : 0;
// https://stackoverflow.com/a/2745086
}
// Signed-only integer division with ceiling
template<typename T1, typename T2>
inline constexpr T1 ceil_sdivide(const T1 x, const T2 y) noexcept {
static_assert(std::is_signed<T1>::value, "First parameter should be signed");
static_assert(std::is_signed<T2>::value, "Second parameter should be signed.");
return x / y + (((x < 0) ^ (y > 0)) && (x % y));
// https://stackoverflow.com/a/33790603
}
template <typename T>
std::function<T()> CreateRandomizer(const T min_value, const T max_value);
inline int iround(double x)
{
assert(std::isfinite(x));
assert(x >= (std::numeric_limits<int>::min)());
assert(x <= (std::numeric_limits<int>::max)());
return static_cast<int>(round(x));
}
inline int iroundf(const float x)
{
assert(std::isfinite(x));
assert(x >= static_cast<float>((std::numeric_limits<int>::min)()));
assert(x <= static_cast<float>((std::numeric_limits<int>::max)()));
return static_cast<int>(roundf(x));
}
// Left-shifts a signed value by a given amount, with overflow detection
template <typename T1, typename T2>
constexpr T1 left_shift_signed(T1 value, T2 amount)
{
// Ensure we're using a signed type
static_assert(std::is_signed<T1>::value, "T1 must be signed");
// Ensure the two types are integers
static_assert(std::numeric_limits<T1>::is_integer, "T1 must be an integer type");
static_assert(std::numeric_limits<T2>::is_integer, "T2 must be an integer type");
// Ensure the amount we're shifting isn't negative
assert(amount >= 0);
// Ensure the amount we're shifting doesn't exceed the value's bit-size
assert(amount <= std::numeric_limits<T1>::digits);
#if defined(NDEBUG)
// For release builds, simply cast the value to the unsigned-equivalent
// to ensure performance isn't impacted. Debug and UBSAN builds catch issues.
typedef typename std::make_unsigned<T1>::type unsigned_T1;
const auto shifted = static_cast<unsigned_T1>(value) << amount;
#else
// Ensure we can accommodate the value being shifted
static_assert(sizeof(T1) <= sizeof(next_uint_t<T1>),
"T1 cannot be a larger than its next larger type");
// cast the value to the next larger unsigned-type before shifting
const auto shifted = static_cast<next_uint_t<T1>>(value) << amount;
// Ensure the value is in-bounds of its signed limits
assert(static_cast<next_int_t<T1>>(shifted) >= (std::numeric_limits<T1>::min)());
assert(static_cast<next_int_t<T1>>(shifted) <= (std::numeric_limits<T1>::max)());
#endif
// Cast it back to its original type
return static_cast<T1>(shifted);
}
template <typename T>
int8_t clamp_to_int8(const T val)
{
constexpr auto min_val = static_cast<T>(std::is_signed<T>{} ? INT8_MIN : 0);
constexpr auto max_val = static_cast<T>(INT8_MAX);
return static_cast<int8_t>(std::clamp(val, min_val, max_val));
}
template <typename T>
int16_t clamp_to_int16(const T val)
{
constexpr auto min_val = static_cast<T>(std::is_signed<T>{} ? INT16_MIN : 0);
constexpr auto max_val = static_cast<T>(INT16_MAX);
return static_cast<int16_t>(std::clamp(val, min_val, max_val));
}
template <typename T>
int32_t clamp_to_int32(const T val)
{
constexpr auto min_val = static_cast<T>(std::is_signed<T>{} ? INT32_MIN : 0);
constexpr auto max_val = static_cast<T>(INT32_MAX);
return static_cast<int32_t>(std::clamp(val, min_val, max_val));
}
inline float decibel_to_gain(const float decibel)
{
return powf(10.0f, decibel / 20.0f);
}
inline float gain_to_decibel(const float gain)
{
return 20.0f * logf(gain) / logf(10.0f);
}
// A wrapper to convert a scalar gain to a percentage.
// This avoids having a bunch of magic *100.0 throughout the code.
constexpr float gain_to_percentage(const float gain)
{
return gain * 100.0f;
}
// A wrapper to convert a percentage into a scalar gain.
// This avoids having a bunch of magic /100.0 throughout the code.
constexpr float percentage_to_gain(const float percentage)
{
return percentage / 100.0f;
}
template <typename T>
constexpr T lerp(const T a, const T b, const T t)
{
return a * (1 - t) + b * t;
}
template <typename T>
constexpr T invlerp(const T a, const T b, const T v)
{
return (v - a) / (b - a);
}
template <typename T>
constexpr T remap(const T in_min, const T in_max, const T out_min,
const T out_max, const T v)
{
const auto t = invlerp(in_min, in_max, v);
return lerp(out_min, out_max, t);
}
// Explicit instantiations for lerp, invlerp, and remap
template float lerp<float>(const float a, const float b, const float t);
template double lerp<double>(const double a, const double b, const double t);
template float invlerp<float>(const float a, const float b, const float v);
template double invlerp<double>(const double a, const double b, const double v);
template float remap<float>(const float in_min, const float in_max,
const float out_min, const float out_max, const float v);
template double remap<double>(const double in_min, const double in_max,
const double out_min, const double out_max,
const double v);
#endif
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