blob: f9eb3b9c4fbe8b715c409a542e410ee83b2207c4 (
plain) (
blame)
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
|
#include <Common/likePatternToRegexp.h>
#include <Common/Exception.h>
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_PARSE_ESCAPE_SEQUENCE;
}
String likePatternToRegexp(std::string_view pattern)
{
String res;
res.reserve(pattern.size() * 2);
const char * pos = pattern.data();
const char * const end = pattern.begin() + pattern.size();
if (pos < end && *pos == '%')
/// Eat leading %
while (++pos < end)
{
if (*pos != '%')
break;
}
else
res = "^";
while (pos < end)
{
switch (*pos)
{
/// Quote characters which have a special meaning in re2
case '^':
case '$':
case '.':
case '[':
case '|':
case '(':
case ')':
case '?':
case '*':
case '+':
case '{':
res += '\\';
res += *pos;
break;
case '%':
if (pos + 1 != end)
res += ".*";
else
return res;
break;
case '_':
res += ".";
break;
case '\\':
if (pos + 1 == end)
throw Exception(ErrorCodes::CANNOT_PARSE_ESCAPE_SEQUENCE, "Invalid escape sequence at the end of LIKE pattern '{}'", pattern);
switch (pos[1])
{
/// Interpret quoted LIKE metacharacters %, _ and \ as literals:
case '%':
case '_':
res += pos[1];
++pos;
break;
case '\\':
res += "\\\\"; /// backslash has a special meaning in re2 --> quote it
++pos;
break;
/// Unknown escape sequence treated literally: as backslash (which must be quoted in re2) + the following character
default:
res += "\\\\";
break;
}
break;
default:
res += *pos;
break;
}
++pos;
}
res += '$';
return res;
}
}
|
