Lots of random cleanups, mostly for native_theme_win.cc:
[chromium-blink-merge.git] / net / filter / gzip_header.h
blob986afc44a7bb75ad161122d680dc288d601cd145
1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 // The GZipHeader class allows you to parse a gzip header, such as you
6 // might find at the beginning of a file compressed by gzip (ie, a .gz
7 // file), or at the beginning of an HTTP response that uses a gzip
8 // Content-Encoding. See RFC 1952 for the specification for the gzip
9 // header.
11 // The model is that you call ReadMore() for each chunk of bytes
12 // you've read from a file or socket.
15 #ifndef NET_FILTER_GZIP_HEADER_H_
16 #define NET_FILTER_GZIP_HEADER_H_
18 #include "base/basictypes.h"
20 namespace net {
22 class GZipHeader {
23 public:
24 enum Status {
25 INCOMPLETE_HEADER, // don't have all the bits yet...
26 COMPLETE_HEADER, // complete, valid header
27 INVALID_HEADER, // found something invalid in the header
30 GZipHeader();
31 ~GZipHeader();
33 // Wipe the slate clean and start from scratch.
34 void Reset();
36 // Attempt to parse the given buffer as the next installment of
37 // bytes from a gzip header. If the bytes we've seen so far do not
38 // yet constitute a complete gzip header, return
39 // INCOMPLETE_HEADER. If these bytes do not constitute a *valid*
40 // gzip header, return INVALID_HEADER. When we've seen a complete
41 // gzip header, return COMPLETE_HEADER and set the pointer pointed
42 // to by header_end to the first byte beyond the gzip header.
43 Status ReadMore(const char* inbuf,
44 int inbuf_len,
45 const char** header_end);
46 private:
47 enum { // flags (see RFC)
48 FLAG_FTEXT = 0x01, // bit 0 set: file probably ascii text
49 FLAG_FHCRC = 0x02, // bit 1 set: header CRC present
50 FLAG_FEXTRA = 0x04, // bit 2 set: extra field present
51 FLAG_FNAME = 0x08, // bit 3 set: original file name present
52 FLAG_FCOMMENT = 0x10, // bit 4 set: file comment present
53 FLAG_RESERVED = 0xE0, // bits 5..7: reserved
56 enum State {
57 // The first 10 bytes are the fixed-size header:
58 IN_HEADER_ID1,
59 IN_HEADER_ID2,
60 IN_HEADER_CM,
61 IN_HEADER_FLG,
62 IN_HEADER_MTIME_BYTE_0,
63 IN_HEADER_MTIME_BYTE_1,
64 IN_HEADER_MTIME_BYTE_2,
65 IN_HEADER_MTIME_BYTE_3,
66 IN_HEADER_XFL,
67 IN_HEADER_OS,
69 IN_XLEN_BYTE_0,
70 IN_XLEN_BYTE_1,
71 IN_FEXTRA,
73 IN_FNAME,
75 IN_FCOMMENT,
77 IN_FHCRC_BYTE_0,
78 IN_FHCRC_BYTE_1,
80 IN_DONE,
83 static const uint8 magic[]; // gzip magic header
85 int state_; // our current State in the parsing FSM: an int so we can ++
86 uint8 flags_; // the flags byte of the header ("FLG" in the RFC)
87 uint16 extra_length_; // how much of the "extra field" we have yet to read
89 DISALLOW_COPY_AND_ASSIGN(GZipHeader);
92 } // namespace net
94 #endif // NET_FILTER_GZIP_HEADER_H_