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
|
"""
This module implements the algorithm for converting between a "user name" -
something that a user can choose arbitrarily inside a font editor - and a file
name suitable for use in a wide range of operating systems and filesystems.
The `UFO 3 specification <http://unifiedfontobject.org/versions/ufo3/conventions/>`_
provides an example of an algorithm for such conversion, which avoids illegal
characters, reserved file names, ambiguity between upper- and lower-case
characters, and clashes with existing files.
This code was originally copied from
`ufoLib <https://github.com/unified-font-object/ufoLib/blob/8747da7/Lib/ufoLib/filenames.py>`_
by Tal Leming and is copyright (c) 2005-2016, The RoboFab Developers:
- Erik van Blokland
- Tal Leming
- Just van Rossum
"""
illegalCharacters = r"\" * + / : < > ? [ \ ] | \0".split(" ")
illegalCharacters += [chr(i) for i in range(1, 32)]
illegalCharacters += [chr(0x7F)]
reservedFileNames = "CON PRN AUX CLOCK$ NUL A:-Z: COM1".lower().split(" ")
reservedFileNames += "LPT1 LPT2 LPT3 COM2 COM3 COM4".lower().split(" ")
maxFileNameLength = 255
class NameTranslationError(Exception):
pass
def userNameToFileName(userName, existing=[], prefix="", suffix=""):
"""Converts from a user name to a file name.
Takes care to avoid illegal characters, reserved file names, ambiguity between
upper- and lower-case characters, and clashes with existing files.
Args:
userName (str): The input file name.
existing: A case-insensitive list of all existing file names.
prefix: Prefix to be prepended to the file name.
suffix: Suffix to be appended to the file name.
Returns:
A suitable filename.
Raises:
NameTranslationError: If no suitable name could be generated.
Examples::
>>> 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 str
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
import sys
sys.exit(doctest.testmod().failed)
|
