1 // Written by James Turner
3 // Copyright (C) 2013 James Turner <zakalawe@mac.com>
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Library General Public
7 // License as published by the Free Software Foundation; either
8 // version 2 of the License, or (at your option) any later version.
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Library General Public License for more details.
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 #include "HTTPContentDecode.hxx"
23 #include <cstdlib> // rand()
26 #include <simgear/debug/logstream.hxx>
27 #include <simgear/structure/exception.hxx>
28 #include <simgear/io/lowlevel.hxx> // for sgEndian stuff
36 const int ZLIB_DECOMPRESS_BUFFER_SIZE = 32 * 1024;
37 const int ZLIB_INFLATE_WINDOW_BITS = -MAX_WBITS;
39 // see http://www.ietf.org/rfc/rfc1952.txt for these values and
40 // detailed description of the logic
41 const int GZIP_HEADER_ID1 = 31;
42 const int GZIP_HEADER_ID2 = 139;
43 const int GZIP_HEADER_METHOD_DEFLATE = 8;
44 const unsigned int GZIP_HEADER_SIZE = 10;
45 const int GZIP_HEADER_FEXTRA = 1 << 2;
46 const int GZIP_HEADER_FNAME = 1 << 3;
47 const int GZIP_HEADER_COMMENT = 1 << 4;
48 const int GZIP_HEADER_CRC = 1 << 1;
50 ContentDecoder::ContentDecoder() :
59 ContentDecoder::~ContentDecoder()
66 void ContentDecoder::setEncoding(const std::string& encoding)
68 std::cout << "setEncoding:" << encoding << std::endl;
69 if (encoding == "gzip") {
70 _contentDeflate = true;
71 _needGZipHeader = true;
72 } else if (encoding == "deflate") {
73 _contentDeflate = true;
74 _needGZipHeader = false;
75 } else if (encoding != "identity") {
76 SG_LOG(SG_IO, SG_WARN, "unsupported content encoding:" << encoding);
80 void ContentDecoder::reset()
83 _contentDeflate = false;
84 _needGZipHeader = false;
88 void ContentDecoder::initWithRequest(Request_ptr req)
91 if (!_contentDeflate) {
96 _zlib = (z_stream*) malloc(sizeof(z_stream));
99 memset(_zlib, 0, sizeof(z_stream));
101 _output = (unsigned char*) malloc(ZLIB_DECOMPRESS_BUFFER_SIZE);
105 // NULLs means we'll get default alloc+free methods
106 // which is absolutely fine
107 _zlib->avail_out = ZLIB_DECOMPRESS_BUFFER_SIZE;
108 _zlib->next_out = _output;
109 if (inflateInit2(_zlib, ZLIB_INFLATE_WINDOW_BITS) != Z_OK) {
110 SG_LOG(SG_IO, SG_WARN, "inflateInit2 failed");
114 void ContentDecoder::finish()
116 if (_contentDeflate) {
122 void ContentDecoder::receivedBytes(const char* n, size_t s)
124 if (!_contentDeflate) {
125 _request->processBodyBytes(n, s);
129 // allocate more space if needed (this will only happen rarely once the
130 // buffer has hit something proportionate to the server's compression
132 size_t requiredSize = _inputSize + s;
133 if (requiredSize > _inputAllocated) {
134 reallocateInputBuffer(requiredSize);
137 // copy newly recieved bytes into the buffer
138 memcpy(_input + _inputSize, n, s);
141 if (_needGZipHeader && !consumeGZipHeader()) {
142 std::cout << "waiting on GZIP header" << std::endl;
143 // still waiting on the full GZIP header, so done
150 void ContentDecoder::consumeBytes(size_t consumed)
152 assert(_inputSize >= consumed);
153 // move existing (consumed) bytes down
155 size_t newSize = _inputSize - consumed;
156 memmove(_input, _input + consumed, newSize);
157 _inputSize = newSize;
161 void ContentDecoder::reallocateInputBuffer(size_t newSize)
163 std::cout << "reallocate:" << newSize << std::endl;
166 _input = (unsigned char*) realloc(_input, newSize);
167 _inputAllocated = newSize;
170 void ContentDecoder::runDecoder()
172 _zlib->next_in = (unsigned char*) _input;
173 _zlib->avail_in = _inputSize;
176 // loop, running zlib() inflate and sending output bytes to
177 // our request body handler. Keep calling inflate until no bytes are
178 // written, and ZLIB has consumed all available input
180 _zlib->next_out = _output;
181 _zlib->avail_out = ZLIB_DECOMPRESS_BUFFER_SIZE;
182 int result = inflate(_zlib, Z_NO_FLUSH);
183 if (result == Z_OK || result == Z_STREAM_END) {
185 } else if (result == Z_BUF_ERROR) {
186 // transient error, fall through
192 writtenSize = ZLIB_DECOMPRESS_BUFFER_SIZE - _zlib->avail_out;
193 if (writtenSize > 0) {
194 _request->processBodyBytes((char*) _output, writtenSize);
197 if (result == Z_STREAM_END) {
200 } while ((_zlib->avail_in > 0) || (writtenSize > 0));
202 // update input buffers based on what we consumed
203 consumeBytes(_inputSize - _zlib->avail_in);
206 bool ContentDecoder::consumeGZipHeader()
208 size_t avail = _inputSize;
209 if (avail < GZIP_HEADER_SIZE) {
210 return false; // need more header bytes
213 if ((_input[0] != GZIP_HEADER_ID1) ||
214 (_input[1] != GZIP_HEADER_ID2) ||
215 (_input[2] != GZIP_HEADER_METHOD_DEFLATE))
217 return false; // invalid GZip header
220 char flags = _input[3];
221 unsigned int gzipHeaderSize = GZIP_HEADER_SIZE;
222 if (flags & GZIP_HEADER_FEXTRA) {
224 if (avail < gzipHeaderSize) {
225 return false; // need more header bytes
228 unsigned short extraHeaderBytes = *(reinterpret_cast<unsigned short*>(_input + GZIP_HEADER_FEXTRA));
229 if ( sgIsBigEndian() ) {
230 sgEndianSwap( &extraHeaderBytes );
233 gzipHeaderSize += extraHeaderBytes;
234 if (avail < gzipHeaderSize) {
235 return false; // need more header bytes
240 if (flags & GZIP_HEADER_FNAME) {
242 while (gzipHeaderSize <= avail) {
243 if (_input[gzipHeaderSize-1] == 0) {
244 break; // found terminating NULL character
249 if (flags & GZIP_HEADER_COMMENT) {
251 while (gzipHeaderSize <= avail) {
252 if (_input[gzipHeaderSize-1] == 0) {
253 break; // found terminating NULL character
259 if (flags & GZIP_HEADER_CRC) {
263 if (avail < gzipHeaderSize) {
264 return false; // need more header bytes
267 consumeBytes(gzipHeaderSize);
268 _needGZipHeader = false;
272 } // of namespace HTTP
274 } // of namespace simgear