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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
|
#
# Secret Labs' Regular Expression Engine
#
# convert template to internal format
#
# Copyright (c) 1997-2000 by Secret Labs AB. All rights reserved.
#
# See the sre.py file for information on usage and redistribution.
#
import _sre
from sre_constants import *
MAXCODE = 65535
def _charset(charset, fixup=None):
# internal: optimize character set
if not fixup:
fixup = lambda x: x
out = []
charmap = [0]*256
try:
for op, av in charset:
if op is NEGATE:
out.append((op, av))
elif op is LITERAL:
charmap[fixup(av)] = 1
elif op is RANGE:
for i in range(fixup(av[0]), fixup(av[1])+1):
charmap[i] = 1
elif op is CATEGORY:
# FIXME: could append to charmap tail
return charset # cannot compress
except IndexError:
# unicode
return charset
# compress character map
i = p = n = 0
runs = []
for c in charmap:
if c:
if n == 0:
p = i
n = n + 1
elif n:
runs.append((p, n))
n = 0
i = i + 1
if n:
runs.append((p, n))
if len(runs) <= 2:
# use literal/range
for p, n in runs:
if n == 1:
out.append((LITERAL, p))
else:
out.append((RANGE, (p, p+n-1)))
if len(out) < len(charset):
return out
else:
# use bitmap
data = []
m = 1; v = 0
for c in charmap:
if c:
v = v + m
m = m << 1
if m > MAXCODE:
data.append(v)
m = 1; v = 0
out.append((CHARSET, data))
return out
return charset
def _simple(av):
# check if av is a "simple" operator
lo, hi = av[2].getwidth()
if lo == 0:
raise error, "nothing to repeat"
return lo == hi == 1 and av[2][0][0] != SUBPATTERN
def _compile(code, pattern, flags):
# internal: compile a (sub)pattern
emit = code.append
for op, av in pattern:
if op in (LITERAL, NOT_LITERAL):
if flags & SRE_FLAG_IGNORECASE:
emit(OPCODES[OP_IGNORE[op]])
else:
emit(OPCODES[op])
emit(av)
elif op is IN:
if flags & SRE_FLAG_IGNORECASE:
emit(OPCODES[OP_IGNORE[op]])
def fixup(literal, flags=flags):
return _sre.getlower(literal, flags)
else:
emit(OPCODES[op])
fixup = lambda x: x
skip = len(code); emit(0)
for op, av in _charset(av, fixup):
emit(OPCODES[op])
if op is NEGATE:
pass
elif op is LITERAL:
emit(fixup(av))
elif op is RANGE:
emit(fixup(av[0]))
emit(fixup(av[1]))
elif op is CHARSET:
code.extend(av)
elif op is CATEGORY:
if flags & SRE_FLAG_LOCALE:
emit(CHCODES[CH_LOCALE[av]])
elif flags & SRE_FLAG_UNICODE:
emit(CHCODES[CH_UNICODE[av]])
else:
emit(CHCODES[av])
else:
raise error, "internal: unsupported set operator"
emit(OPCODES[FAILURE])
code[skip] = len(code) - skip
elif op is ANY:
if flags & SRE_FLAG_DOTALL:
emit(OPCODES[ANY_ALL])
else:
emit(OPCODES[ANY])
elif op in (REPEAT, MIN_REPEAT, MAX_REPEAT):
if flags & SRE_FLAG_TEMPLATE:
raise error, "internal: unsupported template operator"
emit(OPCODES[REPEAT])
skip = len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
emit(OPCODES[SUCCESS])
code[skip] = len(code) - skip
elif _simple(av) and op == MAX_REPEAT:
emit(OPCODES[REPEAT_ONE])
skip = len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
emit(OPCODES[SUCCESS])
code[skip] = len(code) - skip
else:
emit(OPCODES[REPEAT])
skip = len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
code[skip] = len(code) - skip
if op == MAX_REPEAT:
emit(OPCODES[MAX_UNTIL])
else:
emit(OPCODES[MIN_UNTIL])
elif op is SUBPATTERN:
if av[0]:
emit(OPCODES[MARK])
emit((av[0]-1)*2)
_compile(code, av[1], flags)
if av[0]:
emit(OPCODES[MARK])
emit((av[0]-1)*2+1)
elif op in (SUCCESS, FAILURE):
emit(OPCODES[op])
elif op in (ASSERT, ASSERT_NOT):
emit(OPCODES[op])
skip = len(code); emit(0)
if av[0] >= 0:
emit(0) # look ahead
else:
lo, hi = av[1].getwidth()
if lo != hi:
raise error, "look-behind requires fixed-width pattern"
emit(lo) # look behind
_compile(code, av[1], flags)
emit(OPCODES[SUCCESS])
code[skip] = len(code) - skip
elif op is CALL:
emit(OPCODES[op])
skip = len(code); emit(0)
_compile(code, av, flags)
emit(OPCODES[SUCCESS])
code[skip] = len(code) - skip
elif op is AT:
emit(OPCODES[op])
if flags & SRE_FLAG_MULTILINE:
emit(ATCODES[AT_MULTILINE.get(av, av)])
else:
emit(ATCODES[av])
elif op is BRANCH:
emit(OPCODES[op])
tail = []
for av in av[1]:
skip = len(code); emit(0)
_compile(code, av, flags)
emit(OPCODES[JUMP])
tail.append(len(code)); emit(0)
code[skip] = len(code) - skip
emit(0) # end of branch
for tail in tail:
code[tail] = len(code) - tail
elif op is CATEGORY:
emit(OPCODES[op])
if flags & SRE_FLAG_LOCALE:
emit(CHCODES[CH_LOCALE[av]])
elif flags & SRE_FLAG_UNICODE:
emit(CHCODES[CH_UNICODE[av]])
else:
emit(CHCODES[av])
elif op is GROUPREF:
if flags & SRE_FLAG_IGNORECASE:
emit(OPCODES[OP_IGNORE[op]])
else:
emit(OPCODES[op])
emit(av-1)
else:
raise ValueError, ("unsupported operand type", op)
def _compile_info(code, pattern, flags):
# internal: compile an info block. in the current version,
# this contains min/max pattern width, and an optional literal
# prefix or a character map
lo, hi = pattern.getwidth()
if lo == 0:
return # not worth it
# look for a literal prefix
prefix = []
charset = [] # not used
if not (flags & SRE_FLAG_IGNORECASE):
for op, av in pattern.data:
if op is LITERAL:
prefix.append(av)
else:
break
# add an info block
emit = code.append
emit(OPCODES[INFO])
skip = len(code); emit(0)
# literal flag
mask = 0
if prefix:
mask = SRE_INFO_PREFIX
if len(prefix) == len(pattern.data):
mask = mask + SRE_INFO_LITERAL
elif charset:
mask = mask + SRE_INFO_CHARSET
emit(mask)
# pattern length
if lo < MAXCODE:
emit(lo)
else:
emit(MAXCODE)
prefix = prefix[:MAXCODE]
if hi < MAXCODE:
emit(hi)
else:
emit(0)
# add literal prefix
if prefix:
emit(len(prefix))
if prefix:
code.extend(prefix)
# generate overlap table
table = [-1] + ([0]*len(prefix))
for i in range(len(prefix)):
table[i+1] = table[i]+1
while table[i+1] > 0 and prefix[i] != prefix[table[i+1]-1]:
table[i+1] = table[table[i+1]-1]+1
code.extend(table[1:]) # don't store first entry
elif charset:
# FIXME: use charset optimizer!
for char in charset:
emit(OPCODES[LITERAL])
emit(char)
emit(OPCODES[FAILURE])
code[skip] = len(code) - skip
STRING_TYPES = [type("")]
try:
STRING_TYPES.append(type(unicode("")))
except NameError:
pass
def _code(p, flags):
flags = p.pattern.flags | flags
code = []
# compile info block
_compile_info(code, p, flags)
# compile the pattern
_compile(code, p.data, flags)
code.append(OPCODES[SUCCESS])
return code
def compile(p, flags=0):
# internal: convert pattern list to internal format
if type(p) in STRING_TYPES:
import sre_parse
pattern = p
p = sre_parse.parse(p, flags)
else:
pattern = None
code = _code(p, flags)
# print code
# FIXME: <fl> get rid of this limitation!
assert p.pattern.groups <= 100,\
"sorry, but this version only supports 100 named groups"
# map in either direction
groupindex = p.pattern.groupdict
indexgroup = [None] * p.pattern.groups
for k, i in groupindex.items():
indexgroup[i] = k
return _sre.compile(
pattern, flags, code,
p.pattern.groups-1,
groupindex, indexgroup
)
|
