nansi
/
src
/
ob
/
string.cc
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
121
122
123
124
125
126
127
128
129
130
131
132#include "ob/string.hh"
#include <cstddef>
#include <string>
#include <string_view>
#include <vector>
#include <limits>
#include <utility>
namespace OB::String
{
bool starts_with(std::string const& str, std::string const& val)
{
if (str.empty() || str.size() < val.size())
{
return false;
}
if (str.compare(0, val.size(), val) == 0)
{
return true;
}
return false;
}
std::size_t damerau_levenshtein(std::string const& lhs, std::string const& rhs,
std::size_t const weight_insert, std::size_t const weight_substitute,
std::size_t const weight_delete, std::size_t const weight_transpose)
{
if (lhs == rhs)
{
return 0;
}
std::string_view lhsv {lhs};
std::string_view rhsv {rhs};
bool swapped {false};
if (lhsv.size() > rhsv.size())
{
swapped = true;
std::swap(lhsv, rhsv);
}
for (std::size_t i = 0; i < lhsv.size(); ++i)
{
if (lhsv.at(i) != rhsv.at(i))
{
if (i)
{
lhsv.substr(i);
rhsv.substr(i);
}
break;
}
}
for (std::size_t i = 0; i < lhsv.size(); ++i)
{
if (lhsv.at(lhsv.size() - 1 - i) != rhsv.at(rhsv.size() - 1 - i))
{
if (i)
{
lhsv.substr(0, lhsv.size() - 1 - i);
rhsv.substr(0, rhsv.size() - 1 - i);
}
break;
}
}
if (swapped)
{
std::swap(lhsv, rhsv);
}
if (lhsv.empty())
{
return rhsv.size() * weight_insert;
}
if (rhsv.empty())
{
return lhsv.size() * weight_delete;
}
std::vector<std::size_t> v0 (rhsv.size() + 1, 0);
std::vector<std::size_t> v1 (rhsv.size() + 1, 0);
std::vector<std::size_t> v2 (rhsv.size() + 1, 0);
for (std::size_t i = 0; i <= rhsv.size(); ++i)
{
v1.at(i) = i * weight_insert;
}
for (std::size_t i = 0; i < lhsv.size(); ++i)
{
v2.at(0) = (i + 1) * weight_delete;
for (std::size_t j = 0; j < rhsv.size(); j++)
{
v2.at(j + 1) = std::min(
// deletion
v1.at(j + 1) + weight_delete,
std::min(
// insertion
v2.at(j) + weight_insert,
// substitution
v1.at(j) + (weight_substitute * (lhsv.at(i) != rhsv.at(j)))));
if (i > 0 && j > 0 &&
(lhsv.at(i - 1) == rhsv.at(j)) &&
(lhsv.at(i) == rhsv.at(j - 1)))
{
v2.at(j + 1) = std::min(
v0.at(j + 1),
// transposition
v0.at(j - 1) + weight_transpose);
}
}
std::swap(v0, v1);
std::swap(v1, v2);
}
return v1.at(rhsv.size());
}
} // namespace OB::String