1 // Copyright (c) 2011 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 #include "net/base/gzip_header.h"
9 #include "base/logging.h"
10 #include "third_party/zlib/zlib.h"
14 const uint8 GZipHeader::magic[] = { 0x1f, 0x8b };
16 GZipHeader::GZipHeader() {
20 GZipHeader::~GZipHeader() {
23 void GZipHeader::Reset() {
24 state_ = IN_HEADER_ID1;
29 GZipHeader::Status GZipHeader::ReadMore(const char* inbuf, int inbuf_len,
30 const char** header_end) {
31 DCHECK_GE(inbuf_len, 0);
32 const uint8* pos = reinterpret_cast<const uint8*>(inbuf);
33 const uint8* const end = pos + inbuf_len;
38 if ( *pos != magic[0] ) return INVALID_HEADER;
43 if ( *pos != magic[1] ) return INVALID_HEADER;
48 if ( *pos != Z_DEFLATED ) return INVALID_HEADER;
53 flags_ = (*pos) & (FLAG_FHCRC | FLAG_FEXTRA |
54 FLAG_FNAME | FLAG_FCOMMENT);
59 case IN_HEADER_MTIME_BYTE_0:
63 case IN_HEADER_MTIME_BYTE_1:
67 case IN_HEADER_MTIME_BYTE_2:
71 case IN_HEADER_MTIME_BYTE_3:
87 if ( !(flags_ & FLAG_FEXTRA) ) {
91 // We have a two-byte little-endian length, followed by a
92 // field of that length.
98 extra_length_ += *pos << 8;
101 // We intentionally fall through, because if we have a
102 // zero-length FEXTRA, we want to check to notice that we're
103 // done reading the FEXTRA before we exit this loop...
106 // Grab the rest of the bytes in the extra field, or as many
107 // of them as are actually present so far.
108 const int num_extra_bytes = static_cast<const int>(std::min(
109 static_cast<ptrdiff_t>(extra_length_),
111 pos += num_extra_bytes;
112 extra_length_ -= num_extra_bytes;
113 if ( extra_length_ == 0 ) {
114 state_ = IN_FNAME; // advance when we've seen extra_length_ bytes
115 flags_ &= ~FLAG_FEXTRA; // we're done with the FEXTRA stuff
121 if ( !(flags_ & FLAG_FNAME) ) {
122 state_ = IN_FCOMMENT;
125 // See if we can find the end of the \0-terminated FNAME field.
126 pos = reinterpret_cast<const uint8*>(memchr(pos, '\0', (end - pos)));
128 pos++; // advance past the '\0'
129 flags_ &= ~FLAG_FNAME; // we're done with the FNAME stuff
130 state_ = IN_FCOMMENT;
132 pos = end; // everything we have so far is part of the FNAME
137 if ( !(flags_ & FLAG_FCOMMENT) ) {
138 state_ = IN_FHCRC_BYTE_0;
141 // See if we can find the end of the \0-terminated FCOMMENT field.
142 pos = reinterpret_cast<const uint8*>(memchr(pos, '\0', (end - pos)));
144 pos++; // advance past the '\0'
145 flags_ &= ~FLAG_FCOMMENT; // we're done with the FCOMMENT stuff
146 state_ = IN_FHCRC_BYTE_0;
148 pos = end; // everything we have so far is part of the FNAME
152 case IN_FHCRC_BYTE_0:
153 if ( !(flags_ & FLAG_FHCRC) ) {
161 case IN_FHCRC_BYTE_1:
163 flags_ &= ~FLAG_FHCRC; // we're done with the FHCRC stuff
168 *header_end = reinterpret_cast<const char*>(pos);
169 return COMPLETE_HEADER;
173 if ( (state_ > IN_HEADER_OS) && (flags_ == 0) ) {
174 *header_end = reinterpret_cast<const char*>(pos);
175 return COMPLETE_HEADER;
177 return INCOMPLETE_HEADER;