| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // The GZipHeader class allows you to parse a gzip header, such as you |
| // might find at the beginning of a file compressed by gzip (ie, a .gz |
| // file), or at the beginning of an HTTP response that uses a gzip |
| // Content-Encoding. See RFC 1952 for the specification for the gzip |
| // header. |
| // |
| // The model is that you call ReadMore() for each chunk of bytes |
| // you've read from a file or socket. |
| // |
| |
| #ifndef NET_FILTER_GZIP_HEADER_H_ |
| #define NET_FILTER_GZIP_HEADER_H_ |
| |
| #include "base/macros.h" |
| #include "net/base/net_export.h" |
| #include "starboard/types.h" |
| |
| namespace net { |
| |
| class NET_EXPORT GZipHeader { |
| public: |
| enum Status { |
| INCOMPLETE_HEADER, // don't have all the bits yet... |
| COMPLETE_HEADER, // complete, valid header |
| INVALID_HEADER, // found something invalid in the header |
| }; |
| |
| GZipHeader(); |
| ~GZipHeader(); |
| |
| // Wipe the slate clean and start from scratch. |
| void Reset(); |
| |
| // Attempt to parse the given buffer as the next installment of |
| // bytes from a gzip header. If the bytes we've seen so far do not |
| // yet constitute a complete gzip header, return |
| // INCOMPLETE_HEADER. If these bytes do not constitute a *valid* |
| // gzip header, return INVALID_HEADER. When we've seen a complete |
| // gzip header, return COMPLETE_HEADER and set the pointer pointed |
| // to by header_end to the first byte beyond the gzip header. |
| Status ReadMore(const char* inbuf, |
| int inbuf_len, |
| const char** header_end); |
| private: |
| enum { // flags (see RFC) |
| FLAG_FTEXT = 0x01, // bit 0 set: file probably ascii text |
| FLAG_FHCRC = 0x02, // bit 1 set: header CRC present |
| FLAG_FEXTRA = 0x04, // bit 2 set: extra field present |
| FLAG_FNAME = 0x08, // bit 3 set: original file name present |
| FLAG_FCOMMENT = 0x10, // bit 4 set: file comment present |
| FLAG_RESERVED = 0xE0, // bits 5..7: reserved |
| }; |
| |
| enum State { |
| // The first 10 bytes are the fixed-size header: |
| IN_HEADER_ID1, |
| IN_HEADER_ID2, |
| IN_HEADER_CM, |
| IN_HEADER_FLG, |
| IN_HEADER_MTIME_BYTE_0, |
| IN_HEADER_MTIME_BYTE_1, |
| IN_HEADER_MTIME_BYTE_2, |
| IN_HEADER_MTIME_BYTE_3, |
| IN_HEADER_XFL, |
| IN_HEADER_OS, |
| |
| IN_XLEN_BYTE_0, |
| IN_XLEN_BYTE_1, |
| IN_FEXTRA, |
| |
| IN_FNAME, |
| |
| IN_FCOMMENT, |
| |
| IN_FHCRC_BYTE_0, |
| IN_FHCRC_BYTE_1, |
| |
| IN_DONE, |
| }; |
| |
| static const uint8_t magic[]; // gzip magic header |
| |
| int state_; // our current State in the parsing FSM: an int so we can ++ |
| uint8_t flags_; // the flags byte of the header ("FLG" in the RFC) |
| uint16_t extra_length_; // how much of the "extra field" we have yet to read |
| |
| DISALLOW_COPY_AND_ASSIGN(GZipHeader); |
| }; |
| |
| } // namespace net |
| |
| #endif // NET_FILTER_GZIP_HEADER_H_ |