layers/evaluation_cache.h - TerrainGen coverage

layers/evaluation_cache.h

Line	Branch	Exec	Source
1			/// @file
2			/// @brief `EvaluationCache`, values one evaluation's batches of points share.
3			#pragma once
4
5			#include "terraingen/util/lru_cache.h"
6
7			#include <bit>
8			#include <cstddef>
9			#include <cstdint>
10			#include <functional>
11			#include <memory>
12
13			namespace terraingen {
14
15			/// Values that depend only on the terrain beneath a layer, such as crater datums, computed once
16			/// per evaluation of points and shared by its batches; thread-safe.
17			///
18			/// An evaluation makes one and drops it at its end, so a value never outlives the terrain it was
19			/// computed for. Keys name the layer that owns the value (`owner`), a feature ID and the sample
20			/// spacing.
21			class EvaluationCache {
22			public:
23			/// An empty cache holding at most `capacity` values.
24		75	explicit EvaluationCache(std::size_t capacity = 1 << 20)
25	1/1 ✓ Branch 3 taken 75 times.	16858	: values_(capacity, [](const Holder&) { return std::size_t{1}; }) {}
26
27			/// The value of `owner` for feature `id` at `spacing`, computed by `compute` when not held.
28			template <typename T>
29		132231	std::shared_ptr<const T> Get(const void* owner, std::uint64_t id, double spacing,
30			const std::function<T()>& compute) {
31		264462	const Key key{reinterpret_cast<std::uintptr_t>(owner), id,
32		132231	std::bit_cast<std::uint64_t>(spacing)};
33	2/2 std::shared_ptr<double const> terraingen::EvaluationCache::Get<double>(void const, unsigned long, double, std::function<double ()> const&): ✓ Branch 1 taken 5 times. std::shared_ptr<std::optional<terraingen::Plane> const> terraingen::EvaluationCache::Get<std::optional<terraingen::Plane> >(void const, unsigned long, double, std::function<std::optional<terraingen::Plane> ()> const&): ✓ Branch 1 taken 132226 times.	132231	const std::shared_ptr<const Holder> held =
34	4/4 terraingen::EvaluationCache::Get<double>(void const, unsigned long, double, std::function<double ()> const&)::{lambda()#1}::operator()() const: ✓ Branch 2 taken 4 times. ✓ Branch 5 taken 4 times. terraingen::EvaluationCache::Get<std::optional<terraingen::Plane> >(void const, unsigned long, double, std::function<std::optional<terraingen::Plane> ()> const&)::{lambda()#1}::operator()() const: ✓ Branch 2 taken 16779 times. ✓ Branch 5 taken 16779 times.	149014	values_.Get(key, [&] { return Holder{std::make_shared<const T>(compute())}; });
35		264462	return std::static_pointer_cast<const T>(held->value);
36		132231	}
37
38			private:
39			struct Key {
40		115720	std::uintptr_t owner = 0;
41		115720	std::uint64_t id = 0;
42		115720	std::uint64_t spacing = 0;
43
44	3/6 ✗ Branch 0 not taken. ✓ Branch 1 taken 115720 times. ✗ Branch 2 not taken. ✓ Branch 3 taken 115720 times. ✗ Branch 4 not taken. ✓ Branch 5 taken 115720 times.	115720	bool operator==(const Key&) const = default;
45			};
46			struct KeyHash {
47		297396	std::size_t operator()(const Key& key) const {
48		297396	return std::hash<std::uint64_t>{}(key.id * 0x9E3779B97F4A7C15ull ^ key.owner ^
49		297396	(key.spacing << 1));
50			}
51			};
52			struct Holder {
53			std::shared_ptr<const void> value;
54			};
55
56			LruCache<Key, Holder, KeyHash> values_;
57			};
58
59			} // namespace terraingen
60