-
Notifications
You must be signed in to change notification settings - Fork 4
/
VertexElementMap.h
120 lines (97 loc) · 2.42 KB
/
VertexElementMap.h
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
/**
* @file
* This file is part of PUML
*
* For conditions of distribution and use, please see the copyright
* notice in the file 'COPYING' at the root directory of this package
* and the copyright notice at https://github.com/TUM-I5/PUMGen
*
* @copyright 2017 Technische Universitaet Muenchen
* @author Sebastian Rettenberger <[email protected]>
*/
#ifndef PUML_VERTEXELEMENTMAP_H
#define PUML_VERTEXELEMENTMAP_H
#include <algorithm>
#include <cstring>
#include <unordered_map>
namespace PUML
{
namespace internal
{
/**
* Mapps from a list of local vertex ids to the local id of the element
*/
template<unsigned int N>
class VertexElementMap
{
private:
/**
* Description of a element by the local vertex ids
*/
struct Element
{
/** The vertices that define this element */
unsigned int vertices[N];
Element(const unsigned int vertices[N])
{
memcpy(this->vertices, vertices, N*sizeof(unsigned int));
std::sort(this->vertices, this->vertices+N);
}
bool operator==(const Element &other) const
{
return memcmp(vertices, other.vertices, N*sizeof(unsigned int)) == 0;
}
};
struct ElementHash
{
std::size_t operator()(const Element &element) const
{
std::size_t h = std::hash<unsigned int>{}(element.vertices[0]);
for (unsigned int i = 1; i < N; i++)
hash_combine(h, element.vertices[i]);
return h;
}
};
std::unordered_map<Element, unsigned int, ElementHash> m_elements;
public:
VertexElementMap()
{ }
unsigned int add(const unsigned int vertices[N])
{
const Element e(vertices);
typename std::unordered_map<Element, unsigned int, ElementHash>::const_iterator it = m_elements.find(e);
if (it == m_elements.end()) {
unsigned int id = m_elements.size();
it = m_elements.emplace(e, id).first;
}
return it->second;
}
size_t size() const
{
return m_elements.size();
}
int find(unsigned int vertices[N]) const
{
typename std::unordered_map<Element, unsigned int, ElementHash>::const_iterator it = m_elements.find(vertices);
if (it == m_elements.end())
return -1;
return it->second;
}
void clear()
{
m_elements.clear();
}
private:
/**
* Taken from: https://stackoverflow.com/questions/2590677/how-do-i-combine-hash-values-in-c0x
*/
template<typename T>
static void hash_combine(std::size_t& seed, const T& v)
{
std::hash<T> hasher;
seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
}
};
}
}
#endif // PUML_VERTEXELEMENTMAP_H