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| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 // The GZipHeader class allows you to parse a gzip header, such as you | 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 | 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 | 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 | 8 // Content-Encoding. See RFC 1952 for the specification for the gzip |
| 9 // header. | 9 // header. |
| 10 // | 10 // |
| 11 // The model is that you call ReadMore() for each chunk of bytes | 11 // The model is that you call ReadMore() for each chunk of bytes |
| 12 // you've read from a file or socket. | 12 // you've read from a file or socket. |
| 13 // | 13 // |
| 14 | 14 |
| 15 #ifndef NET_FILTER_GZIP_HEADER_H_ | 15 #ifndef NET_FILTER_GZIP_HEADER_H_ |
| 16 #define NET_FILTER_GZIP_HEADER_H_ | 16 #define NET_FILTER_GZIP_HEADER_H_ |
| 17 | 17 |
| 18 #include "base/basictypes.h" | 18 #include "base/basictypes.h" |
| 19 | 19 |
| 20 namespace net { | 20 namespace net { |
| 21 | 21 |
| 22 class GZipHeader { | 22 class GZipHeader { |
| 23 public: | 23 public: |
| 24 enum Status { | 24 enum Status { |
| 25 INCOMPLETE_HEADER, // don't have all the bits yet... | 25 INCOMPLETE_HEADER, // don't have all the bits yet... |
| 26 COMPLETE_HEADER, // complete, valid header | 26 COMPLETE_HEADER, // complete, valid header |
| 27 INVALID_HEADER, // found something invalid in the header | 27 INVALID_HEADER, // found something invalid in the header |
| 28 }; | 28 }; |
| 29 | 29 |
| 30 GZipHeader(); | 30 GZipHeader(); |
| 31 ~GZipHeader(); | 31 ~GZipHeader(); |
| 32 | 32 |
| 33 // Wipe the slate clean and start from scratch. | 33 // Wipe the slate clean and start from scratch. |
| 34 void Reset(); | 34 void Reset(); |
| 35 | 35 |
| 36 // Attempt to parse the given buffer as the next installment of | 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 | 37 // bytes from a gzip header. If the bytes we've seen so far do not |
| 38 // yet constitute a complete gzip header, return | 38 // yet constitute a complete gzip header, return |
| 39 // INCOMPLETE_HEADER. If these bytes do not constitute a *valid* | 39 // INCOMPLETE_HEADER. If these bytes do not constitute a *valid* |
| 40 // gzip header, return INVALID_HEADER. When we've seen a complete | 40 // gzip header, return INVALID_HEADER. When we've seen a complete |
| 41 // gzip header, return COMPLETE_HEADER and set the pointer pointed | 41 // gzip header, return COMPLETE_HEADER and set the pointer pointed |
| 42 // to by header_end to the first byte beyond the gzip header. | 42 // to by header_end to the first byte beyond the gzip header. |
| 43 Status ReadMore(const char* inbuf, | 43 Status ReadMore(const char* inbuf, int inbuf_len, const char** header_end); |
| 44 int inbuf_len, | 44 |
| 45 const char** header_end); | |
| 46 private: | 45 private: |
| 47 enum { // flags (see RFC) | 46 enum { // flags (see RFC) |
| 48 FLAG_FTEXT = 0x01, // bit 0 set: file probably ascii text | 47 FLAG_FTEXT = 0x01, // bit 0 set: file probably ascii text |
| 49 FLAG_FHCRC = 0x02, // bit 1 set: header CRC present | 48 FLAG_FHCRC = 0x02, // bit 1 set: header CRC present |
| 50 FLAG_FEXTRA = 0x04, // bit 2 set: extra field present | 49 FLAG_FEXTRA = 0x04, // bit 2 set: extra field present |
| 51 FLAG_FNAME = 0x08, // bit 3 set: original file name present | 50 FLAG_FNAME = 0x08, // bit 3 set: original file name present |
| 52 FLAG_FCOMMENT = 0x10, // bit 4 set: file comment present | 51 FLAG_FCOMMENT = 0x10, // bit 4 set: file comment present |
| 53 FLAG_RESERVED = 0xE0, // bits 5..7: reserved | 52 FLAG_RESERVED = 0xE0, // bits 5..7: reserved |
| 54 }; | 53 }; |
| 55 | 54 |
| 56 enum State { | 55 enum State { |
| 57 // The first 10 bytes are the fixed-size header: | 56 // The first 10 bytes are the fixed-size header: |
| 58 IN_HEADER_ID1, | 57 IN_HEADER_ID1, |
| 59 IN_HEADER_ID2, | 58 IN_HEADER_ID2, |
| 60 IN_HEADER_CM, | 59 IN_HEADER_CM, |
| 61 IN_HEADER_FLG, | 60 IN_HEADER_FLG, |
| 62 IN_HEADER_MTIME_BYTE_0, | 61 IN_HEADER_MTIME_BYTE_0, |
| 63 IN_HEADER_MTIME_BYTE_1, | 62 IN_HEADER_MTIME_BYTE_1, |
| 64 IN_HEADER_MTIME_BYTE_2, | 63 IN_HEADER_MTIME_BYTE_2, |
| 65 IN_HEADER_MTIME_BYTE_3, | 64 IN_HEADER_MTIME_BYTE_3, |
| 66 IN_HEADER_XFL, | 65 IN_HEADER_XFL, |
| 67 IN_HEADER_OS, | 66 IN_HEADER_OS, |
| 68 | |
| 69 IN_XLEN_BYTE_0, | 67 IN_XLEN_BYTE_0, |
| 70 IN_XLEN_BYTE_1, | 68 IN_XLEN_BYTE_1, |
| 71 IN_FEXTRA, | 69 IN_FEXTRA, |
| 72 | |
| 73 IN_FNAME, | 70 IN_FNAME, |
| 74 | |
| 75 IN_FCOMMENT, | 71 IN_FCOMMENT, |
| 76 | |
| 77 IN_FHCRC_BYTE_0, | 72 IN_FHCRC_BYTE_0, |
| 78 IN_FHCRC_BYTE_1, | 73 IN_FHCRC_BYTE_1, |
| 79 | |
| 80 IN_DONE, | 74 IN_DONE, |
| 81 }; | 75 }; |
| 82 | 76 |
| 83 static const uint8 magic[]; // gzip magic header | 77 static const uint8 magic[]; // gzip magic header |
| 84 | 78 |
| 85 int state_; // our current State in the parsing FSM: an int so we can ++ | 79 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) | 80 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 | 81 uint16 extra_length_; // how much of the "extra field" we have yet to read |
| 88 | 82 |
| 89 DISALLOW_COPY_AND_ASSIGN(GZipHeader); | 83 DISALLOW_COPY_AND_ASSIGN(GZipHeader); |
| 90 }; | 84 }; |
| 91 | 85 |
| 92 } // namespace net | 86 } // namespace net |
| 93 | 87 |
| 94 #endif // NET_FILTER_GZIP_HEADER_H_ | 88 #endif // NET_FILTER_GZIP_HEADER_H_ |
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