1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
#ifndef LIFE_SRC_WORLD_H_
#define LIFE_SRC_WORLD_H_
#include <array>
#include <stack>
#include <tuple>
#include <cstdint>
#include "util/box_traverser.h"
namespace life {
template<
std::size_t WIDTH,
std::size_t HEIGHT
>
class World {
public:
static const std::size_t width = WIDTH;
static const std::size_t height = HEIGHT;
World():
area_(width, height) {
this->area_.for_each([&](std::size_t i, std::size_t j) {
this->matrix_[j][i] = false;
});
}
bool isLifeAt(std::ptrdiff_t x, std::ptrdiff_t y) const {
if ( this->area_(x, y) ) {
return this->matrix_[y][x];
} else {
return false; // end of world is dead
}
}
std::uint8_t lifeDensityAt(std::size_t x, std::size_t y) const {
std::uint8_t counter{};
counter += this->isLifeAt(x - 1, y);
counter += this->isLifeAt(x + 1, y);
counter += this->isLifeAt(x, y - 1);
counter += this->isLifeAt(x, y + 1);
counter += this->isLifeAt(x - 1, y + 1);
counter += this->isLifeAt(x - 1, y - 1);
counter += this->isLifeAt(x + 1, y + 1);
counter += this->isLifeAt(x + 1, y - 1);
return counter;
}
std::size_t getAge() const {
return this->age_;
}
void summonLifeAt(std::size_t x, std::size_t y) {
if ( this->area_(x, y) ) {
this->matrix_[y][x] = true;
}
}
void extinguishLifeAt(std::size_t x, std::size_t y) {
if ( this->area_(x, y) ) {
this->matrix_[y][x] = false;
}
}
void tick() {
this->age_++;
std::stack<std::tuple<std::size_t, std::size_t, bool>> updates;
this->area_.for_each([&](std::size_t i, std::size_t j) {
const std::uint8_t d{this->lifeDensityAt(i, j)};
if ( this->matrix_[j][i] ) {
if ( d < 2 ) {
updates.emplace(i, j, false);
} else if ( d == 2 || d == 3 ) {
updates.emplace(i, j, true);
} else if ( d > 3 ) {
updates.emplace(i, j, false);
}
} else {
if ( d == 3 ) {
updates.emplace(i, j, true);
}
}
});
while ( !updates.empty() ) {
const auto& update = updates.top();
if ( std::get<2>(update) ) {
this->summonLifeAt(
std::get<0>(update),
std::get<1>(update)
);
} else {
this->extinguishLifeAt(
std::get<0>(update),
std::get<1>(update)
);
}
updates.pop();
}
}
private:
const util::BoxTraverser area_;
std::size_t age_{};
std::array<std::array<bool, WIDTH>, HEIGHT> matrix_;
};
}
#endif // LIFE_SRC_WORLD_H_
|