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1# Copyright (C) 2001-2007 Python Software Foundation
2# Author: Anthony Baxter
3# Contact: email-sig@python.org
4
5"""Class representing audio/* type MIME documents."""
6
7__all__ = ['MIMEAudio']
8
9from email import encoders
10from email.mime.nonmultipart import MIMENonMultipart
11
12
13class MIMEAudio(MIMENonMultipart):
14    """Class for generating audio/* MIME documents."""
15
16    def __init__(self, _audiodata, _subtype=None,
17                 _encoder=encoders.encode_base64, *, policy=None, **_params):
18        """Create an audio/* type MIME document.
19
20        _audiodata contains the bytes for the raw audio data.  If this data
21        can be decoded as au, wav, aiff, or aifc, then the
22        subtype will be automatically included in the Content-Type header.
23        Otherwise, you can specify  the specific audio subtype via the
24        _subtype parameter.  If _subtype is not given, and no subtype can be
25        guessed, a TypeError is raised.
26
27        _encoder is a function which will perform the actual encoding for
28        transport of the image data.  It takes one argument, which is this
29        Image instance.  It should use get_payload() and set_payload() to
30        change the payload to the encoded form.  It should also add any
31        Content-Transfer-Encoding or other headers to the message as
32        necessary.  The default encoding is Base64.
33
34        Any additional keyword arguments are passed to the base class
35        constructor, which turns them into parameters on the Content-Type
36        header.
37        """
38        if _subtype is None:
39            _subtype = _what(_audiodata)
40        if _subtype is None:
41            raise TypeError('Could not find audio MIME subtype')
42        MIMENonMultipart.__init__(self, 'audio', _subtype, policy=policy,
43                                  **_params)
44        self.set_payload(_audiodata)
45        _encoder(self)
46
47
48_rules = []
49
50
51# Originally from the sndhdr module.
52#
53# There are others in sndhdr that don't have MIME types. :(
54# Additional ones to be added to sndhdr? midi, mp3, realaudio, wma??
55def _what(data):
56    # Try to identify a sound file type.
57    #
58    # sndhdr.what() had a pretty cruddy interface, unfortunately.  This is why
59    # we re-do it here.  It would be easier to reverse engineer the Unix 'file'
60    # command and use the standard 'magic' file, as shipped with a modern Unix.
61    for testfn in _rules:
62        if res := testfn(data):
63            return res
64    else:
65        return None
66
67
68def rule(rulefunc):
69    _rules.append(rulefunc)
70    return rulefunc
71
72
73@rule
74def _aiff(h):
75    if not h.startswith(b'FORM'):
76        return None
77    if h[8:12] in {b'AIFC', b'AIFF'}:
78        return 'x-aiff'
79    else:
80        return None
81
82
83@rule
84def _au(h):
85    if h.startswith(b'.snd'):
86        return 'basic'
87    else:
88        return None
89
90
91@rule
92def _wav(h):
93    # 'RIFF' <len> 'WAVE' 'fmt ' <len>
94    if not h.startswith(b'RIFF') or h[8:12] != b'WAVE' or h[12:16] != b'fmt ':
95        return None
96    else:
97        return "x-wav"
98