Mercurial > cpython-lru_cache-weakref
annotate Lib/chunk.py @ 80661:94de77bd0b4b 2.7
Issue #16194: document imp.load_dynamic problems
when read several extension modules from the same binary object file.
| author | Andrew Svetlov <andrew.svetlov@gmail.com> |
|---|---|
| date | Thu, 29 Nov 2012 19:51:28 +0200 |
| parents | 9d29daecb9fa |
| children | 0a389b47f129 |
| rev | line source |
|---|---|
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
1 """Simple class to read IFF chunks. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
2 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
3 An IFF chunk (used in formats such as AIFF, TIFF, RMFF (RealMedia File |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
4 Format)) has the following structure: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
5 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
6 +----------------+ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
7 | ID (4 bytes) | |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
8 +----------------+ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
9 | size (4 bytes) | |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
10 +----------------+ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
11 | data | |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
12 | ... | |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
13 +----------------+ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
14 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
15 The ID is a 4-byte string which identifies the type of chunk. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
16 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
17 The size field (a 32-bit value, encoded using big-endian byte order) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
18 gives the size of the whole chunk, including the 8-byte header. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
19 |
| 11050 | 20 Usually an IFF-type file consists of one or more chunks. The proposed |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
21 usage of the Chunk class defined here is to instantiate an instance at |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
22 the start of each chunk and read from the instance until it reaches |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
23 the end, after which a new instance can be instantiated. At the end |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
24 of the file, creating a new instance will fail with a EOFError |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
25 exception. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
26 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
27 Usage: |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
28 while True: |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
29 try: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
30 chunk = Chunk(file) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
31 except EOFError: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
32 break |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
33 chunktype = chunk.getname() |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
34 while True: |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
35 data = chunk.read(nbytes) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
36 if not data: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
37 pass |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
38 # do something with data |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
39 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
40 The interface is file-like. The implemented methods are: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
41 read, close, seek, tell, isatty. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
42 Extra methods are: skip() (called by close, skips to the end of the chunk), |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
43 getname() (returns the name (ID) of the chunk) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
44 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
45 The __init__ method has one required argument, a file-like object |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
46 (including a chunk instance), and one optional argument, a flag which |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
47 specifies whether or not chunks are aligned on 2-byte boundaries. The |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
48 default is 1, i.e. aligned. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
49 """ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
50 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
51 class Chunk: |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
52 def __init__(self, file, align=True, bigendian=True, inclheader=False): |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
53 import struct |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
54 self.closed = False |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
55 self.align = align # whether to align to word (2-byte) boundaries |
|
11227
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
56 if bigendian: |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
57 strflag = '>' |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
58 else: |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
59 strflag = '<' |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
60 self.file = file |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
61 self.chunkname = file.read(4) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
62 if len(self.chunkname) < 4: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
63 raise EOFError |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
64 try: |
|
36567
9d29daecb9fa
Patch #1373643: The chunk module can now read chunks larger than
Georg Brandl <georg@python.org>
parents:
22867
diff
changeset
|
65 self.chunksize = struct.unpack(strflag+'L', file.read(4))[0] |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
66 except struct.error: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
67 raise EOFError |
|
11227
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
68 if inclheader: |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
69 self.chunksize = self.chunksize - 8 # subtract header |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
70 self.size_read = 0 |
| 10993 | 71 try: |
| 72 self.offset = self.file.tell() | |
|
17797
a8fa9c0f1e0b
Clean up bare except: when determining whether a file is seekable.
Fred Drake <fdrake@acm.org>
parents:
17524
diff
changeset
|
73 except (AttributeError, IOError): |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
74 self.seekable = False |
| 10993 | 75 else: |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
76 self.seekable = True |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
77 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
78 def getname(self): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
79 """Return the name (ID) of the current chunk.""" |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
80 return self.chunkname |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
81 |
|
11227
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
82 def getsize(self): |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
83 """Return the size of the current chunk.""" |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
84 return self.chunksize |
|
e773d2f0741d
Sjoerd Mullender writes:
Guido van Rossum <guido@python.org>
parents:
11050
diff
changeset
|
85 |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
86 def close(self): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
87 if not self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
88 self.skip() |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
89 self.closed = True |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
90 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
91 def isatty(self): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
92 if self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
93 raise ValueError, "I/O operation on closed file" |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
94 return False |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
95 |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
96 def seek(self, pos, whence=0): |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
97 """Seek to specified position into the chunk. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
98 Default position is 0 (start of chunk). |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
99 If the file is not seekable, this will result in an error. |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
100 """ |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
101 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
102 if self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
103 raise ValueError, "I/O operation on closed file" |
| 10993 | 104 if not self.seekable: |
| 105 raise IOError, "cannot seek" | |
| 11050 | 106 if whence == 1: |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
107 pos = pos + self.size_read |
| 11050 | 108 elif whence == 2: |
|
17524
79efbc9a03de
Fix typo in attribute name (chunk_size should be chunksize) found by
Guido van Rossum <guido@python.org>
parents:
16657
diff
changeset
|
109 pos = pos + self.chunksize |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
110 if pos < 0 or pos > self.chunksize: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
111 raise RuntimeError |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
112 self.file.seek(self.offset + pos, 0) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
113 self.size_read = pos |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
114 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
115 def tell(self): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
116 if self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
117 raise ValueError, "I/O operation on closed file" |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
118 return self.size_read |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
119 |
|
22867
e2f2187c3d2c
Partial introduction of bools where appropriate.
Guido van Rossum <guido@python.org>
parents:
17797
diff
changeset
|
120 def read(self, size=-1): |
| 11050 | 121 """Read at most size bytes from the chunk. |
| 122 If size is omitted or negative, read until the end | |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
123 of the chunk. |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
124 """ |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
125 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
126 if self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
127 raise ValueError, "I/O operation on closed file" |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
128 if self.size_read >= self.chunksize: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
129 return '' |
| 11050 | 130 if size < 0: |
| 131 size = self.chunksize - self.size_read | |
| 132 if size > self.chunksize - self.size_read: | |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
133 size = self.chunksize - self.size_read |
| 11050 | 134 data = self.file.read(size) |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
135 self.size_read = self.size_read + len(data) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
136 if self.size_read == self.chunksize and \ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
137 self.align and \ |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
138 (self.chunksize & 1): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
139 dummy = self.file.read(1) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
140 self.size_read = self.size_read + len(dummy) |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
141 return data |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
142 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
143 def skip(self): |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
144 """Skip the rest of the chunk. |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
145 If you are not interested in the contents of the chunk, |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
146 this method should be called so that the file points to |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
147 the start of the next chunk. |
|
15867
f5a3d98a35bc
Whitespace normalization.
Tim Peters <tim.peters@gmail.com>
parents:
11227
diff
changeset
|
148 """ |
|
10937
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
149 |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
150 if self.closed: |
|
e8ff4b1298c2
Patch/new code by Sjoerd Mullender:
Guido van Rossum <guido@python.org>
parents:
diff
changeset
|
151 raise ValueError, "I/O operation on closed file" |
| 10993 | 152 if self.seekable: |
| 153 try: | |
| 154 n = self.chunksize - self.size_read | |
| 155 # maybe fix alignment | |
| 156 if self.align and (self.chunksize & 1): | |
| 157 n = n + 1 | |
| 158 self.file.seek(n, 1) | |
| 159 self.size_read = self.size_read + n | |
| 160 return | |
|
17797
a8fa9c0f1e0b
Clean up bare except: when determining whether a file is seekable.
Fred Drake <fdrake@acm.org>
parents:
17524
diff
changeset
|
161 except IOError: |
| 10993 | 162 pass |
| 163 while self.size_read < self.chunksize: | |
| 164 n = min(8192, self.chunksize - self.size_read) | |
| 165 dummy = self.read(n) | |
| 166 if not dummy: | |
| 167 raise EOFError |