mirror of https://github.com/PrimeDecomp/prime.git
102 lines
2.1 KiB
C++
102 lines
2.1 KiB
C++
#ifndef _RSTL_ALGORITHM
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#define _RSTL_ALGORITHM
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#include "rstl/pointer_iterator.hpp"
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namespace rstl {
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template < class It, class T >
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inline It find(It first, It last, const T& val) {
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while (first != last && !(*first == val))
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++first;
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return first;
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}
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template < typename T >
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inline void swap(T& a, T& b) {
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T tmp(a);
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a = b;
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b = tmp;
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}
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template < typename I1, typename I2 >
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inline void iter_swap(I1 a, I2 b) {
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swap(*a, *b);
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}
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template < typename It, class Cmp >
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void __insertion_sort(It first, It last, Cmp cmp);
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template < class T, class Cmp >
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void __sort3(T& a, T& b, T& c, Cmp comp); // TODO
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template < typename It, class Cmp >
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void sort(It first, It last, Cmp cmp); // TODO
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// Implementations
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template < typename It, class Cmp >
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void __insertion_sort(It first, It last, Cmp cmp) {
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for (It next = first + 1; next < last; ++next) {
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typename iterator_traits< It >::value_type value = *next;
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It t1 = next;
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for (It t2 = next - 1; first < t1 && cmp(value, *t2); --t2) {
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*t1 = *t2;
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--t1;
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}
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*t1 = value;
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}
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}
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template < typename T, class Cmp >
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void __sort3(T& a, T& b, T& c, Cmp comp) {
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if (comp(b, a)) {
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swap(a, b);
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}
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if (comp(c, b)) {
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T tmp(c);
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c = b;
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if (comp(tmp, a)) {
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b = a;
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a = tmp;
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} else {
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b = tmp;
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}
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}
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}
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template < typename It, class Cmp >
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void sort(It first, It last, Cmp cmp) {
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int count = last - first;
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if (count > 1) {
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if (count <= 20) {
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__insertion_sort(first, last, cmp);
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} else {
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It beforeLast = last - 1;
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It middle = first + count / 2;
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__sort3(*first, *middle, *(last - 1), cmp);
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typename iterator_traits< It >::value_type value = *middle;
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It it = first + 1;
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while (true) {
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for (; cmp(*it, value); ++it)
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;
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for (; cmp(value, *beforeLast); --beforeLast)
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;
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if (it > beforeLast)
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break;
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rstl::swap(*it, *beforeLast);
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++it;
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--beforeLast;
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}
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sort(first, it, cmp);
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sort(it, last, cmp);
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}
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}
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}
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} // namespace rstl
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#endif // _RSTL_ALGORITHM
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