61 lines
2.2 KiB
C
61 lines
2.2 KiB
C
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#ifndef UTILS_H
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#define UTILS_H
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typedef __SIZE_TYPE__ size_t;
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template<class T, size_t N>constexpr size_t array_size (T (&) [N]) { return N; }
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template<class T, const int N> class TABLE {
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T data [N];
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public:
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/** @brief Konstruktor.
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* @param f Ukazatel na constexpr funkci, která pak vytvoří tabulku.
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* */
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template<typename F> explicit constexpr TABLE (F f) noexcept {
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for (int n=0; n<N; n++) data [n] = f (n);
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}
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/** operator[] vrátí konstantní odkaz na prvek pole, protože se předpokládá,
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* že instance této třídy bude jako taková též konstantní
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*/
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const T & operator[] (const int index) const {
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return data [index];
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}
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/** @class iterator
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* @brief range-based for () */
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class iterator {
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const T * ptr;
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public:
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iterator(const T * _ptr) : ptr (_ptr) {}
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iterator operator++ () { ++ptr; return * this; }
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bool operator!= (const iterator & other) const { return ptr != other.ptr; }
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const T & operator* () const { return * ptr; }
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};
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iterator begin () const { return iterator (data ); }
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iterator end () const { return iterator (data + N); }
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protected:
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};
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static constexpr double X_PI = 3.14159265358979323846;
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static constexpr double D_PI = 2.0 * X_PI;
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/* cmath nejde použít, tak si to mírně zjednodušíme, ale musí to fungovat */
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static constexpr double dabs (const double a) { return a < 0.0 ? -a : +a; }
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static constexpr int i_round (const double a) { return a < 0.0 ? int (a - 0.5) : int (a + 0.5); }
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/* tahle divná funkce počítá sinus, pokud even=true i kosinus, pokud even=false */
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static constexpr double sincos (const double x, const bool even) {
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double result (0.0), element(1.0), divider(0.0);
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if (even) { element *= x; divider += 1.0; }
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constexpr double eps = 1.0e-9; // maximální chyba výpočtu
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const double aa = - (x * x);
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for (;;) {
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result += element;
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if (dabs (element) < eps) break;
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divider += 1.0;
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double fact = divider;
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divider += 1.0;
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fact *= divider;
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element *= aa / fact;
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}
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return result;
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}
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#endif // UTILS_H
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