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
|
"""
User name to file name conversion.
This was taken from the UFO 3 spec.
"""
# Restrictions are taken mostly from
# https://docs.microsoft.com/en-gb/windows/win32/fileio/naming-a-file#naming-conventions.
#
# 1. Integer value zero, sometimes referred to as the ASCII NUL character.
# 2. Characters whose integer representations are in the range 1 to 31,
# inclusive.
# 3. Various characters that (mostly) Windows and POSIX-y filesystems don't
# allow, plus "(" and ")", as per the specification.
illegalCharacters = {
"\x00",
"\x01",
"\x02",
"\x03",
"\x04",
"\x05",
"\x06",
"\x07",
"\x08",
"\t",
"\n",
"\x0b",
"\x0c",
"\r",
"\x0e",
"\x0f",
"\x10",
"\x11",
"\x12",
"\x13",
"\x14",
"\x15",
"\x16",
"\x17",
"\x18",
"\x19",
"\x1a",
"\x1b",
"\x1c",
"\x1d",
"\x1e",
"\x1f",
'"',
"*",
"+",
"/",
":",
"<",
">",
"?",
"[",
"\\",
"]",
"(",
")",
"|",
"\x7f",
}
reservedFileNames = {
"aux",
"clock$",
"com1",
"com2",
"com3",
"com4",
"com5",
"com6",
"com7",
"com8",
"com9",
"con",
"lpt1",
"lpt2",
"lpt3",
"lpt4",
"lpt5",
"lpt6",
"lpt7",
"lpt8",
"lpt9",
"nul",
"prn",
}
maxFileNameLength = 255
class NameTranslationError(Exception):
pass
def userNameToFileName(userName: str, existing=(), prefix="", suffix=""):
"""
`existing` should be a set-like object.
>>> userNameToFileName("a") == "a"
True
>>> userNameToFileName("A") == "A_"
True
>>> userNameToFileName("AE") == "A_E_"
True
>>> userNameToFileName("Ae") == "A_e"
True
>>> userNameToFileName("ae") == "ae"
True
>>> userNameToFileName("aE") == "aE_"
True
>>> userNameToFileName("a.alt") == "a.alt"
True
>>> userNameToFileName("A.alt") == "A_.alt"
True
>>> userNameToFileName("A.Alt") == "A_.A_lt"
True
>>> userNameToFileName("A.aLt") == "A_.aL_t"
True
>>> userNameToFileName(u"A.alT") == "A_.alT_"
True
>>> userNameToFileName("T_H") == "T__H_"
True
>>> userNameToFileName("T_h") == "T__h"
True
>>> userNameToFileName("t_h") == "t_h"
True
>>> userNameToFileName("F_F_I") == "F__F__I_"
True
>>> userNameToFileName("f_f_i") == "f_f_i"
True
>>> userNameToFileName("Aacute_V.swash") == "A_acute_V_.swash"
True
>>> userNameToFileName(".notdef") == "_notdef"
True
>>> userNameToFileName("con") == "_con"
True
>>> userNameToFileName("CON") == "C_O_N_"
True
>>> userNameToFileName("con.alt") == "_con.alt"
True
>>> userNameToFileName("alt.con") == "alt._con"
True
"""
# the incoming name must be a string
if not isinstance(userName, str):
raise ValueError("The value for userName must be a string.")
# establish the prefix and suffix lengths
prefixLength = len(prefix)
suffixLength = len(suffix)
# replace an initial period with an _
# if no prefix is to be added
if not prefix and userName[0] == ".":
userName = "_" + userName[1:]
# filter the user name
filteredUserName = []
for character in userName:
# replace illegal characters with _
if character in illegalCharacters:
character = "_"
# add _ to all non-lower characters
elif character != character.lower():
character += "_"
filteredUserName.append(character)
userName = "".join(filteredUserName)
# clip to 255
sliceLength = maxFileNameLength - prefixLength - suffixLength
userName = userName[:sliceLength]
# test for illegal files names
parts = []
for part in userName.split("."):
if part.lower() in reservedFileNames:
part = "_" + part
parts.append(part)
userName = ".".join(parts)
# test for clash
fullName = prefix + userName + suffix
if fullName.lower() in existing:
fullName = handleClash1(userName, existing, prefix, suffix)
# finished
return fullName
def handleClash1(userName, existing=[], prefix="", suffix=""):
"""
existing should be a case-insensitive list
of all existing file names.
>>> prefix = ("0" * 5) + "."
>>> suffix = "." + ("0" * 10)
>>> existing = ["a" * 5]
>>> e = list(existing)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000001.0000000000')
True
>>> e = list(existing)
>>> e.append(prefix + "aaaaa" + "1".zfill(15) + suffix)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000002.0000000000')
True
>>> e = list(existing)
>>> e.append(prefix + "AAAAA" + "2".zfill(15) + suffix)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000001.0000000000')
True
"""
# if the prefix length + user name length + suffix length + 15 is at
# or past the maximum length, silce 15 characters off of the user name
prefixLength = len(prefix)
suffixLength = len(suffix)
if prefixLength + len(userName) + suffixLength + 15 > maxFileNameLength:
l = (prefixLength + len(userName) + suffixLength + 15)
sliceLength = maxFileNameLength - l
userName = userName[:sliceLength]
finalName = None
# try to add numbers to create a unique name
counter = 1
while finalName is None:
name = userName + str(counter).zfill(15)
fullName = prefix + name + suffix
if fullName.lower() not in existing:
finalName = fullName
break
else:
counter += 1
if counter >= 999999999999999:
break
# if there is a clash, go to the next fallback
if finalName is None:
finalName = handleClash2(existing, prefix, suffix)
# finished
return finalName
def handleClash2(existing=[], prefix="", suffix=""):
"""
existing should be a case-insensitive list
of all existing file names.
>>> prefix = ("0" * 5) + "."
>>> suffix = "." + ("0" * 10)
>>> existing = [prefix + str(i) + suffix for i in range(100)]
>>> e = list(existing)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.100.0000000000')
True
>>> e = list(existing)
>>> e.remove(prefix + "1" + suffix)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.1.0000000000')
True
>>> e = list(existing)
>>> e.remove(prefix + "2" + suffix)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.2.0000000000')
True
"""
# calculate the longest possible string
maxLength = maxFileNameLength - len(prefix) - len(suffix)
maxValue = int("9" * maxLength)
# try to find a number
finalName = None
counter = 1
while finalName is None:
fullName = prefix + str(counter) + suffix
if fullName.lower() not in existing:
finalName = fullName
break
else:
counter += 1
if counter >= maxValue:
break
# raise an error if nothing has been found
if finalName is None:
raise NameTranslationError("No unique name could be found.")
# finished
return finalName
if __name__ == "__main__":
import doctest
doctest.testmod()
|
