| // 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. |
| |
| #include "net/filter/gzip_header.h" |
| |
| #include <algorithm> |
| |
| #include "base/logging.h" |
| #include "third_party/zlib/zlib.h" |
| |
| namespace net { |
| |
| const uint8 GZipHeader::magic[] = { 0x1f, 0x8b }; |
| |
| GZipHeader::GZipHeader() { |
| Reset(); |
| } |
| |
| GZipHeader::~GZipHeader() { |
| } |
| |
| void GZipHeader::Reset() { |
| state_ = IN_HEADER_ID1; |
| flags_ = 0; |
| extra_length_ = 0; |
| } |
| |
| GZipHeader::Status GZipHeader::ReadMore(const char* inbuf, int inbuf_len, |
| const char** header_end) { |
| DCHECK_GE(inbuf_len, 0); |
| const uint8* pos = reinterpret_cast<const uint8*>(inbuf); |
| const uint8* const end = pos + inbuf_len; |
| |
| while ( pos < end ) { |
| switch ( state_ ) { |
| case IN_HEADER_ID1: |
| if ( *pos != magic[0] ) return INVALID_HEADER; |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_ID2: |
| if ( *pos != magic[1] ) return INVALID_HEADER; |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_CM: |
| if ( *pos != Z_DEFLATED ) return INVALID_HEADER; |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_FLG: |
| flags_ = (*pos) & (FLAG_FHCRC | FLAG_FEXTRA | |
| FLAG_FNAME | FLAG_FCOMMENT); |
| pos++; |
| state_++; |
| break; |
| |
| case IN_HEADER_MTIME_BYTE_0: |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_MTIME_BYTE_1: |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_MTIME_BYTE_2: |
| pos++; |
| state_++; |
| break; |
| case IN_HEADER_MTIME_BYTE_3: |
| pos++; |
| state_++; |
| break; |
| |
| case IN_HEADER_XFL: |
| pos++; |
| state_++; |
| break; |
| |
| case IN_HEADER_OS: |
| pos++; |
| state_++; |
| break; |
| |
| case IN_XLEN_BYTE_0: |
| if ( !(flags_ & FLAG_FEXTRA) ) { |
| state_ = IN_FNAME; |
| break; |
| } |
| // We have a two-byte little-endian length, followed by a |
| // field of that length. |
| extra_length_ = *pos; |
| pos++; |
| state_++; |
| break; |
| case IN_XLEN_BYTE_1: |
| extra_length_ += *pos << 8; |
| pos++; |
| state_++; |
| // We intentionally fall through, because if we have a |
| // zero-length FEXTRA, we want to check to notice that we're |
| // done reading the FEXTRA before we exit this loop... |
| |
| case IN_FEXTRA: { |
| // Grab the rest of the bytes in the extra field, or as many |
| // of them as are actually present so far. |
| const uint16 num_extra_bytes = static_cast<uint16>(std::min( |
| static_cast<ptrdiff_t>(extra_length_), |
| (end - pos))); |
| pos += num_extra_bytes; |
| extra_length_ -= num_extra_bytes; |
| if ( extra_length_ == 0 ) { |
| state_ = IN_FNAME; // advance when we've seen extra_length_ bytes |
| flags_ &= ~FLAG_FEXTRA; // we're done with the FEXTRA stuff |
| } |
| break; |
| } |
| |
| case IN_FNAME: |
| if ( !(flags_ & FLAG_FNAME) ) { |
| state_ = IN_FCOMMENT; |
| break; |
| } |
| // See if we can find the end of the \0-terminated FNAME field. |
| pos = reinterpret_cast<const uint8*>(memchr(pos, '\0', (end - pos))); |
| if ( pos != NULL ) { |
| pos++; // advance past the '\0' |
| flags_ &= ~FLAG_FNAME; // we're done with the FNAME stuff |
| state_ = IN_FCOMMENT; |
| } else { |
| pos = end; // everything we have so far is part of the FNAME |
| } |
| break; |
| |
| case IN_FCOMMENT: |
| if ( !(flags_ & FLAG_FCOMMENT) ) { |
| state_ = IN_FHCRC_BYTE_0; |
| break; |
| } |
| // See if we can find the end of the \0-terminated FCOMMENT field. |
| pos = reinterpret_cast<const uint8*>(memchr(pos, '\0', (end - pos))); |
| if ( pos != NULL ) { |
| pos++; // advance past the '\0' |
| flags_ &= ~FLAG_FCOMMENT; // we're done with the FCOMMENT stuff |
| state_ = IN_FHCRC_BYTE_0; |
| } else { |
| pos = end; // everything we have so far is part of the FNAME |
| } |
| break; |
| |
| case IN_FHCRC_BYTE_0: |
| if ( !(flags_ & FLAG_FHCRC) ) { |
| state_ = IN_DONE; |
| break; |
| } |
| pos++; |
| state_++; |
| break; |
| |
| case IN_FHCRC_BYTE_1: |
| pos++; |
| flags_ &= ~FLAG_FHCRC; // we're done with the FHCRC stuff |
| state_++; |
| break; |
| |
| case IN_DONE: |
| *header_end = reinterpret_cast<const char*>(pos); |
| return COMPLETE_HEADER; |
| } |
| } |
| |
| if ( (state_ > IN_HEADER_OS) && (flags_ == 0) ) { |
| *header_end = reinterpret_cast<const char*>(pos); |
| return COMPLETE_HEADER; |
| } else { |
| return INCOMPLETE_HEADER; |
| } |
| } |
| |
| } // namespace net |