FazBrowse GitHub Viewer
|
Trending
|
URL:
|
Home
Tools:
[Download Repo ZIP]
[View Raw Code]
[Original HTTPS Page]
cpython/Objects/stringlib/fastsearch.h at 2.7 · python-emscripten/cpython · GitHub
python-emscripten
cpython
Repository navigation
Code
Pull requests
Actions
Projects
Security and quality
Insights
Expand file tree
Breadcrumbs
cpython
/
Objects
/
stringlib
/
fastsearch.h
Copy path
More file actions
More file actions
Latest commit
History
History
History
160 lines (140 loc) · 4.85 KB
Breadcrumbs
cpython
/
Objects
/
stringlib
/
fastsearch.h
Copy path
File metadata and controls
160 lines (140 loc) · 4.85 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/* stringlib: fastsearch implementation */
#ifndef
STRINGLIB_FASTSEARCH_H
#define
STRINGLIB_FASTSEARCH_H
/* fast search/count implementation, based on a mix between boyer-
moore and horspool, with a few more bells and whistles on the top.
for some more background, see: http://effbot.org/zone/stringlib.htm */
/* note: fastsearch may access s[n], which isn't a problem when using
Python's ordinary string types, but may cause problems if you're
using this code in other contexts. also, the count mode returns -1
if there cannot possible be a match in the target string, and 0 if
it has actually checked for matches, but didn't find any. callers
beware! */
#define
FAST_COUNT
0
#define
FAST_SEARCH
1
#define
FAST_RSEARCH
2
#if
LONG_BIT
>=
128
#define
STRINGLIB_BLOOM_WIDTH
128
#elif
LONG_BIT
>=
64
#define
STRINGLIB_BLOOM_WIDTH
64
#elif
LONG_BIT
>=
32
#define
STRINGLIB_BLOOM_WIDTH
32
#else
#error
"LONG_BIT is smaller than 32"
#endif
#define
STRINGLIB_BLOOM_ADD
(
mask
,
ch
) \
((mask |= (1UL << ((ch) & (STRINGLIB_BLOOM_WIDTH -1)))))
#define
STRINGLIB_BLOOM
(
mask
,
ch
) \
((mask & (1UL << ((ch) & (STRINGLIB_BLOOM_WIDTH -1)))))
Py_LOCAL_INLINE
(
Py_ssize_t
)
fastsearch
(
const
STRINGLIB_CHAR
*
s
,
Py_ssize_t
n
,
const
STRINGLIB_CHAR
*
p
,
Py_ssize_t
m
,
Py_ssize_t
maxcount
,
int
mode
)
{
unsigned long
mask
;
Py_ssize_t
skip
,
count
=
0
;
Py_ssize_t
i
,
j
,
mlast
,
w
;
w
=
n
-
m
;
if
(
w
<
0
||
(
mode
==
FAST_COUNT
&&
maxcount
==
0
))
return
-1
;
/* look for special cases */
if
(
m
<=
1
) {
if
(
m
<=
0
)
return
-1
;
/* use special case for 1-character strings */
if
(
mode
==
FAST_COUNT
) {
for
(
i
=
0
;
i
<
n
;
i
++
)
if
(
s
[
i
]
==
p
[
0
]) {
count
++
;
if
(
count
==
maxcount
)
return
maxcount
;
}
return
count
;
}
else
if
(
mode
==
FAST_SEARCH
) {
for
(
i
=
0
;
i
<
n
;
i
++
)
if
(
s
[
i
]
==
p
[
0
])
return
i
;
}
else
{
/* FAST_RSEARCH */
for
(
i
=
n
-
1
;
i
>
-1
;
i
--
)
if
(
s
[
i
]
==
p
[
0
])
return
i
;
}
return
-1
;
}
mlast
=
m
-
1
;
skip
=
mlast
-
1
;
mask
=
0
;
if
(
mode
!=
FAST_RSEARCH
) {
/* create compressed boyer-moore delta 1 table */
/* process pattern[:-1] */
for
(
i
=
0
;
i
<
mlast
;
i
++
) {
STRINGLIB_BLOOM_ADD
(
mask
,
p
[
i
]);
if
(
p
[
i
]
==
p
[
mlast
])
skip
=
mlast
-
i
-
1
;
}
/* process pattern[-1] outside the loop */
STRINGLIB_BLOOM_ADD
(
mask
,
p
[
mlast
]);
for
(
i
=
0
;
i
<=
w
;
i
++
) {
/* note: using mlast in the skip path slows things down on x86 */
if
(
s
[
i
+
m
-
1
]
==
p
[
m
-
1
]) {
/* candidate match */
for
(
j
=
0
;
j
<
mlast
;
j
++
)
if
(
s
[
i
+
j
]
!=
p
[
j
])
break
;
if
(
j
==
mlast
) {
/* got a match! */
if
(
mode
!=
FAST_COUNT
)
return
i
;
count
++
;
if
(
count
==
maxcount
)
return
maxcount
;
i
=
i
+
mlast
;
continue
;
}
/* miss: check if next character is part of pattern */
if
(!
STRINGLIB_BLOOM
(
mask
,
s
[
i
+
m
]))
i
=
i
+
m
;
else
i
=
i
+
skip
;
}
else
{
/* skip: check if next character is part of pattern */
if
(!
STRINGLIB_BLOOM
(
mask
,
s
[
i
+
m
]))
i
=
i
+
m
;
}
}
}
else
{
/* FAST_RSEARCH */
/* create compressed boyer-moore delta 1 table */
/* process pattern[0] outside the loop */
STRINGLIB_BLOOM_ADD
(
mask
,
p
[
0
]);
/* process pattern[:0:-1] */
for
(
i
=
mlast
;
i
>
0
;
i
--
) {
STRINGLIB_BLOOM_ADD
(
mask
,
p
[
i
]);
if
(
p
[
i
]
==
p
[
0
])
skip
=
i
-
1
;
}
for
(
i
=
w
;
i
>=
0
;
i
--
) {
if
(
s
[
i
]
==
p
[
0
]) {
/* candidate match */
for
(
j
=
mlast
;
j
>
0
;
j
--
)
if
(
s
[
i
+
j
]
!=
p
[
j
])
break
;
if
(
j
==
0
)
/* got a match! */
return
i
;
/* miss: check if previous character is part of pattern */
if
(
i
>
0
&&
!
STRINGLIB_BLOOM
(
mask
,
s
[
i
-
1
]))
i
=
i
-
m
;
else
i
=
i
-
skip
;
}
else
{
/* skip: check if previous character is part of pattern */
if
(
i
>
0
&&
!
STRINGLIB_BLOOM
(
mask
,
s
[
i
-
1
]))
i
=
i
-
m
;
}
}
}
if
(
mode
!=
FAST_COUNT
)
return
-1
;
return
count
;
}
#endif
Back
|
FazBrowse Home
|
New Git URL