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Diffstat (limited to 'net/base/gzip_header.h')
| -rw-r--r-- | net/base/gzip_header.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/net/base/gzip_header.h b/net/base/gzip_header.h new file mode 100644 index 0000000..63ea5a9 --- /dev/null +++ b/net/base/gzip_header.h @@ -0,0 +1,120 @@ +// Copyright 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// 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_BASE_GZIPHEADER_H__ +#define NET_BASE_GZIPHEADER_H__ + +#include "base/basictypes.h" + +class GZipHeader { + public: + GZipHeader() { + Reset(); + } + ~GZipHeader() { + } + + // Wipe the slate clean and start from scratch. + void Reset() { + state_ = IN_HEADER_ID1; + flags_ = 0; + extra_length_ = 0; + } + + enum Status { + INCOMPLETE_HEADER, // don't have all the bits yet... + COMPLETE_HEADER, // complete, valid header + INVALID_HEADER, // found something invalid in the header + }; + + // 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: + + static const uint8 magic[]; // gzip magic header + + 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, + }; + + int state_; // our current State in the parsing FSM: an int so we can ++ + uint8 flags_; // the flags byte of the header ("FLG" in the RFC) + uint16 extra_length_; // how much of the "extra field" we have yet to read +}; + +#endif // NET_BASE_GZIPHEADER_H__ |