vector.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024, Paul Elder <paul.elder@ideasonboard.com>
 *
 * Vector and related operations
 */
#pragma once
 
#include <algorithm>
#include <array>
#include <cmath>
#include <functional>
#include <numeric>
#include <optional>
#include <ostream>
#include <type_traits>
 
#include <libcamera/base/log.h>
#include <libcamera/base/span.h>
 
#include "libcamera/internal/matrix.h"
#include "libcamera/internal/value_node.h"
 
namespace libcamera {
 
LOG_DECLARE_CATEGORY(Vector)
 
#ifndef __DOXYGEN__
template<typename T, unsigned int Rows,
     std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
#else
template<typename T, unsigned int Rows>
#endif /* __DOXYGEN__ */
class Vector
{
public:
    constexpr Vector() = default;
 
    constexpr explicit Vector(T scalar)
    {
        data_.fill(scalar);
    }
 
    constexpr Vector(const std::array<T, Rows> &data)
    {
        std::copy(data.begin(), data.end(), data_.begin());
    }
 
    constexpr Vector(const Span<const T, Rows> data)
    {
        std::copy(data.begin(), data.end(), data_.begin());
    }
 
    const T &operator[](size_t i) const
    {
        ASSERT(i < data_.size());
        return data_[i];
    }
 
    T &operator[](size_t i)
    {
        ASSERT(i < data_.size());
        return data_[i];
    }
 
    constexpr Vector<T, Rows> operator-() const
    {
        Vector<T, Rows> ret;
        for (unsigned int i = 0; i < Rows; i++)
            ret[i] = -data_[i];
        return ret;
    }
 
    constexpr Vector operator+(const Vector &other) const
    {
        return apply(*this, std::plus<>{}, other);
    }
 
    constexpr Vector operator+(T scalar) const
    {
        return apply(*this, std::plus<>{}, scalar);
    }
 
    constexpr Vector operator-(const Vector &other) const
    {
        return apply(*this, std::minus<>{}, other);
    }
 
    constexpr Vector operator-(T scalar) const
    {
        return apply(*this, std::minus<>{}, scalar);
    }
 
    constexpr Vector operator*(const Vector &other) const
    {
        return apply(*this, std::multiplies<>{}, other);
    }
 
    constexpr Vector operator*(T scalar) const
    {
        return apply(*this, std::multiplies<>{}, scalar);
    }
 
    constexpr Vector operator/(const Vector &other) const
    {
        return apply(*this, std::divides<>{}, other);
    }
 
    constexpr Vector operator/(T scalar) const
    {
        return apply(*this, std::divides<>{}, scalar);
    }
 
    constexpr Vector operator>>(unsigned int shift) const
    {
        static_assert(std::is_integral_v<T>,
                  "Vector::operator>> requires an integer element type");
        return apply(*this, [](T a, unsigned int b) { return a >> b; }, shift);
    }
 
    Vector &operator+=(const Vector &other)
    {
        return apply(std::plus<>{}, other);
    }
 
    Vector &operator+=(T scalar)
    {
        return apply(std::plus<>{}, scalar);
    }
 
    Vector &operator-=(const Vector &other)
    {
        return apply(std::minus<>{}, other);
    }
 
    Vector &operator-=(T scalar)
    {
        return apply(std::minus<>{}, scalar);
    }
 
    Vector &operator*=(const Vector &other)
    {
        return apply(std::multiplies<>{}, other);
    }
 
    Vector &operator*=(T scalar)
    {
        return apply(std::multiplies<>{}, scalar);
    }
 
    Vector &operator/=(const Vector &other)
    {
        return apply(std::divides<>{}, other);
    }
 
    Vector &operator/=(T scalar)
    {
        return apply(std::divides<>{}, scalar);
    }
 
    Vector &operator>>=(unsigned int shift)
    {
        static_assert(std::is_integral_v<T>,
                  "Vector::operator>>= requires an integer element type");
        return apply([](T a, unsigned int b) { return a >> b; }, shift);
    }
 
    constexpr Vector min(const Vector &other) const
    {
        return apply(*this, [](T a, T b) { return std::min(a, b); }, other);
    }
 
    constexpr Vector min(T scalar) const
    {
        return apply(*this, [](T a, T b) { return std::min(a, b); }, scalar);
    }
 
    constexpr Vector max(const Vector &other) const
    {
        return apply(*this, [](T a, T b) { return std::max(a, b); }, other);
    }
 
    constexpr Vector max(T scalar) const
    {
        return apply(*this, [](T a, T b) -> T { return std::max(a, b); }, scalar);
    }
 
    constexpr Vector clamp(T low, T high) const
    {
        return apply(*this,
                 [](T v, T lo, T hi) -> T { return std::clamp(v, lo, hi); },
                 low, high);
    }
 
    constexpr T dot(const Vector<T, Rows> &other) const
    {
        T ret = 0;
        for (unsigned int i = 0; i < Rows; i++)
            ret += data_[i] * other[i];
        return ret;
    }
 
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 1>>
#endif /* __DOXYGEN__ */
    constexpr const T &x() const { return data_[0]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 2>>
#endif /* __DOXYGEN__ */
    constexpr const T &y() const { return data_[1]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 3>>
#endif /* __DOXYGEN__ */
    constexpr const T &z() const { return data_[2]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 1>>
#endif /* __DOXYGEN__ */
    constexpr T &x() { return data_[0]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 2>>
#endif /* __DOXYGEN__ */
    constexpr T &y() { return data_[1]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 3>>
#endif /* __DOXYGEN__ */
    constexpr T &z() { return data_[2]; }
 
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 1>>
#endif /* __DOXYGEN__ */
    constexpr const T &r() const { return data_[0]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 2>>
#endif /* __DOXYGEN__ */
    constexpr const T &g() const { return data_[1]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 3>>
#endif /* __DOXYGEN__ */
    constexpr const T &b() const { return data_[2]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 1>>
#endif /* __DOXYGEN__ */
    constexpr T &r() { return data_[0]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 2>>
#endif /* __DOXYGEN__ */
    constexpr T &g() { return data_[1]; }
#ifndef __DOXYGEN__
    template<bool Dependent = false, typename = std::enable_if_t<Dependent || Rows >= 3>>
#endif /* __DOXYGEN__ */
    constexpr T &b() { return data_[2]; }
 
    constexpr double length2() const
    {
        double ret = 0;
        for (unsigned int i = 0; i < Rows; i++)
            ret += data_[i] * data_[i];
        return ret;
    }
 
    constexpr double length() const
    {
        return std::sqrt(length2());
    }
 
    template<typename R = T>
    constexpr R sum() const
    {
        return std::accumulate(data_.begin(), data_.end(), R{});
    }
 
private:
    template<typename BinaryOp>
    static constexpr Vector apply(const Vector &lhs, BinaryOp op, const Vector &rhs)
    {
        Vector result;
        std::transform(lhs.data_.begin(), lhs.data_.end(),
                   rhs.data_.begin(), result.data_.begin(),
                   op);
 
        return result;
    }
 
    template<typename Op, typename... U>
    static constexpr Vector apply(const Vector &vector, Op op, U... scalar)
    {
        Vector result;
        std::transform(vector.data_.begin(), vector.data_.end(),
                   result.data_.begin(),
                   [&op, scalar...](T v) { return op(v, scalar...); });
 
        return result;
    }
 
    template<typename BinaryOp>
    Vector &apply(BinaryOp op, const Vector &other)
    {
        auto itOther = other.data_.begin();
        std::for_each(data_.begin(), data_.end(),
                  [&op, &itOther](T &v) { v = op(v, *itOther++); });
 
        return *this;
    }
 
    template<typename Op, typename... U>
    Vector &apply(Op op, U... scalar)
    {
        std::for_each(data_.begin(), data_.end(),
                  [&op, scalar...](T &v) { v = op(v, scalar...); });
 
        return *this;
    }
 
    std::array<T, Rows> data_;
};
 
template<typename T>
using RGB = Vector<T, 3>;
 
template<typename T, typename U, unsigned int Rows, unsigned int Cols>
Vector<std::common_type_t<T, U>, Rows> operator*(const Matrix<T, Rows, Cols> &m, const Vector<U, Cols> &v)
{
    Vector<std::common_type_t<T, U>, Rows> result;
 
    for (unsigned int i = 0; i < Rows; i++) {
        std::common_type_t<T, U> sum = 0;
        for (unsigned int j = 0; j < Cols; j++)
            sum += m[i][j] * v[j];
        result[i] = sum;
    }
 
    return result;
}
 
template<typename T, unsigned int Rows>
bool operator==(const Vector<T, Rows> &lhs, const Vector<T, Rows> &rhs)
{
    for (unsigned int i = 0; i < Rows; i++) {
        if (lhs[i] != rhs[i])
            return false;
    }
 
    return true;
}
 
template<typename T, unsigned int Rows>
bool operator!=(const Vector<T, Rows> &lhs, const Vector<T, Rows> &rhs)
{
    return !(lhs == rhs);
}
 
#ifndef __DOXYGEN__
bool vectorValidateValueNode(const ValueNode &obj, unsigned int size);
 
template<typename T, unsigned int Rows>
std::ostream &operator<<(std::ostream &out, const Vector<T, Rows> &v)
{
    out << "Vector { ";
    for (unsigned int i = 0; i < Rows; i++) {
        out << v[i];
        out << ((i + 1 < Rows) ? ", " : " ");
    }
    out << " }";
 
    return out;
}
 
template<typename T, unsigned int Rows>
struct ValueNode::Accessor<Vector<T, Rows>> {
    std::optional<Vector<T, Rows>> get(const ValueNode &obj) const
    {
        if (!vectorValidateValueNode(obj, Rows))
            return std::nullopt;
 
        Vector<T, Rows> vector;
 
        unsigned int i = 0;
        for (const ValueNode &entry : obj.asList()) {
            const auto value = entry.get<T>();
            if (!value)
                return std::nullopt;
            vector[i++] = *value;
        }
 
        return vector;
    }
};
#endif /* __DOXYGEN__ */
 
} /* namespace libcamera */