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
|
# Audio Tools, a module and set of tools for manipulating audio data
# Copyright (C) 2007-2015 Brian Langenberger
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
from audiotools import MetaData
class ID3v1Comment(MetaData):
"""a complete ID3v1.1 tag"""
ID3v1_FIELDS = {"track_name": "__track_name__",
"artist_name": "__artist_name__",
"album_name": "__album_name__",
"year": "__year__",
"comment": "__comment__",
"track_number": "__track_number__"}
FIELD_LENGTHS = {"track_name": 30,
"artist_name": 30,
"album_name": 30,
"year": 4,
"comment": 28}
def __init__(self, track_name=u"",
artist_name=u"",
album_name=u"",
year=u"",
comment=u"",
track_number=0,
genre=0):
"""fields are as follows:
| field | length |
|--------------+--------|
| track_name | 30 |
| artist_name | 30 |
| album_name | 30 |
| year | 4 |
| comment | 28 |
| track_number | 1 |
| genre | 1 |
|--------------+--------|
track_name, artist_name, album_name, year and
comment are unicode strings
track_number and genre are integers
"""
if len(track_name) > 30:
raise ValueError("track_name cannot be longer than 30 characters")
if len(artist_name) > 30:
raise ValueError("artist_name cannot be longer than 30 characters")
if len(album_name) > 30:
raise ValueError("album_name cannot be longer than 30 characters")
if len(year) > 4:
raise ValueError("year cannot be longer than 4 characters")
if len(comment) > 28:
raise ValueError("comment cannot be longer than 28 characters")
MetaData.__setattr__(self, "__track_name__", track_name)
MetaData.__setattr__(self, "__artist_name__", artist_name)
MetaData.__setattr__(self, "__album_name__", album_name)
MetaData.__setattr__(self, "__year__", year)
MetaData.__setattr__(self, "__comment__", comment)
MetaData.__setattr__(self, "__track_number__", track_number)
MetaData.__setattr__(self, "__genre__", genre)
def __repr__(self):
return "ID3v1Comment(%s, %s, %s, %s, %s, %s, %s)" % \
(repr(self.__track_name__),
repr(self.__artist_name__),
repr(self.__album_name__),
repr(self.__year__),
repr(self.__comment__),
repr(self.__track_number__),
repr(self.__genre__))
def __getattr__(self, attr):
if attr == "track_number":
number = self.__track_number__
if number > 0:
return number
else:
return None
elif attr in self.ID3v1_FIELDS:
value = getattr(self, self.ID3v1_FIELDS[attr])
if len(value) > 0:
return value
else:
return None
elif attr in self.FIELDS:
return None
else:
return MetaData.__getattribute__(self, attr)
def __setattr__(self, attr, value):
if attr == "track_number":
MetaData.__setattr__(
self,
"__track_number__",
min(0 if (value is None) else int(value), 0xFF))
elif attr in self.FIELD_LENGTHS:
if value is None:
delattr(self, attr)
else:
# all are text fields
MetaData.__setattr__(
self,
self.ID3v1_FIELDS[attr],
value[0:self.FIELD_LENGTHS[attr]])
elif attr in self.FIELDS:
# field not supported by ID3v1Comment, so ignore it
pass
else:
MetaData.__setattr__(self, attr, value)
def __delattr__(self, attr):
if attr == "track_number":
MetaData.__setattr__(self, "__track_number__", 0)
elif attr in self.FIELD_LENGTHS:
MetaData.__setattr__(self,
self.ID3v1_FIELDS[attr],
u"")
elif attr in self.FIELDS:
# field not supported by ID3v1Comment, so ignore it
pass
else:
MetaData.__delattr__(self, attr)
def raw_info(self):
"""returns a human-readable version of this metadata
as a unicode string"""
from os import linesep
return linesep.join(
[u"ID3v1.1:"] +
[u"%s = %s" % (label, getattr(self, attr))
for (label, attr) in [(u" track name", "track_name"),
(u" artist name", "artist_name"),
(u" album name", "album_name"),
(u" year", "year"),
(u" comment", "comment"),
(u"track number", "track_number")]
if (getattr(self, attr) is not None)] +
[u" genre = %d" % (self.__genre__)])
@classmethod
def parse(cls, mp3_file):
"""given an MP3 file, returns an ID3v1Comment
raises ValueError if the comment is invalid"""
from audiotools.bitstream import parse
def decode_string(s):
return s.rstrip(b"\x00").decode("ascii", "replace")
mp3_file.seek(-128, 2)
(tag,
track_name,
artist_name,
album_name,
year,
comment,
track_number,
genre) = parse("3b 30b 30b 30b 4b 28b 8p 8u 8u",
False,
mp3_file.read(128))
if tag != b'TAG':
raise ValueError(u"invalid ID3v1 tag")
return ID3v1Comment(track_name=decode_string(track_name),
artist_name=decode_string(artist_name),
album_name=decode_string(album_name),
year=decode_string(year),
comment=decode_string(comment),
track_number=track_number,
genre=genre)
def build(self, mp3_file):
"""given an MP3 file positioned at the file's end, generate a tag"""
from audiotools.bitstream import build
def encode_string(u, max_chars):
s = u.encode("ascii", "replace")
if len(s) >= max_chars:
return s[0:max_chars]
else:
return s + b"\x00" * (max_chars - len(s))
mp3_file.write(
build("3b 30b 30b 30b 4b 28b 8p 8u 8u",
False,
(b"TAG",
encode_string(self.__track_name__, 30),
encode_string(self.__artist_name__, 30),
encode_string(self.__album_name__, 30),
encode_string(self.__year__, 4),
encode_string(self.__comment__, 28),
self.__track_number__,
self.__genre__)))
@classmethod
def supports_images(cls):
"""returns False"""
return False
@classmethod
def converted(cls, metadata):
"""converts a MetaData object to an ID3v1Comment object"""
if metadata is None:
return None
elif isinstance(metadata, ID3v1Comment):
# duplicate all fields as-is
return ID3v1Comment(track_name=metadata.__track_name__,
artist_name=metadata.__artist_name__,
album_name=metadata.__album_name__,
year=metadata.__year__,
comment=metadata.__comment__,
track_number=metadata.__track_number__,
genre=metadata.__genre__)
else:
# convert fields using setattr
id3v1 = ID3v1Comment()
for attr in ["track_name",
"artist_name",
"album_name",
"year",
"comment",
"track_number"]:
setattr(id3v1, attr, getattr(metadata, attr))
return id3v1
def images(self):
"""returns an empty list of Image objects"""
return []
def clean(self):
import sys
"""returns a new ID3v1Comment object that's been cleaned of problems"""
from audiotools.text import (CLEAN_REMOVE_TRAILING_WHITESPACE,
CLEAN_REMOVE_LEADING_WHITESPACE)
fixes_performed = []
fields = {}
for (attr,
name) in [("track_name", u"title"),
("artist_name", u"artist"),
("album_name", u"album"),
("year", u"year"),
("comment", u"comment")]:
# strip out trailing NULL bytes
initial_value = getattr(self, attr)
if initial_value is not None:
fix1 = initial_value.rstrip()
if fix1 != initial_value:
fixes_performed.append(CLEAN_REMOVE_TRAILING_WHITESPACE %
{"field": name})
fix2 = fix1.lstrip()
if fix2 != fix1:
fixes_performed.append(CLEAN_REMOVE_LEADING_WHITESPACE %
{"field": name})
# restore trailing NULL bytes
fields[attr] = fix2
# copy non-text fields as-is
return (ID3v1Comment(track_number=self.__track_number__,
genre=self.__genre__,
**fields), fixes_performed)
def intersection(self, metadata):
"""given a MetaData-compatible object,
returns a new MetaData object which contains
all the matching fields and images of this object and 'metadata'
"""
if type(metadata) is ID3v1Comment:
return ID3v1Comment(
genre=(self.__genre__ if
self.__genre__ == metadata.__genre__ else 0),
**{arg: getattr(self, field)
for arg, field in ID3v1Comment.ID3v1_FIELDS.items()
if getattr(self, field) == getattr(metadata, field)})
else:
return MetaData.intersection(self, metadata)
|