1 // Protocol Buffers - Google's data interchange format
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30
31 // Author: brianolson@google.com (Brian Olson)
32 //
33 // This file contains the implementation of classes GzipInputStream and
34 // GzipOutputStream.
35
36 #include "config.h"
37
38 #if HAVE_ZLIB
39 #include <google/protobuf/io/gzip_stream.h>
40
41 #include <google/protobuf/stubs/common.h>
42
43 namespace google {
44 namespace protobuf {
45 namespace io {
46
47 static const int kDefaultBufferSize = 65536;
48
GzipInputStream(ZeroCopyInputStream * sub_stream,Format format,int buffer_size)49 GzipInputStream::GzipInputStream(
50 ZeroCopyInputStream* sub_stream, Format format, int buffer_size)
51 : format_(format), sub_stream_(sub_stream), zerror_(Z_OK) {
52 zcontext_.zalloc = Z_NULL;
53 zcontext_.zfree = Z_NULL;
54 zcontext_.opaque = Z_NULL;
55 zcontext_.total_out = 0;
56 zcontext_.next_in = NULL;
57 zcontext_.avail_in = 0;
58 zcontext_.total_in = 0;
59 zcontext_.msg = NULL;
60 if (buffer_size == -1) {
61 output_buffer_length_ = kDefaultBufferSize;
62 } else {
63 output_buffer_length_ = buffer_size;
64 }
65 output_buffer_ = operator new(output_buffer_length_);
66 GOOGLE_CHECK(output_buffer_ != NULL);
67 zcontext_.next_out = static_cast<Bytef*>(output_buffer_);
68 zcontext_.avail_out = output_buffer_length_;
69 output_position_ = output_buffer_;
70 }
~GzipInputStream()71 GzipInputStream::~GzipInputStream() {
72 operator delete(output_buffer_);
73 zerror_ = inflateEnd(&zcontext_);
74 }
75
internalInflateInit2(z_stream * zcontext,GzipInputStream::Format format)76 static inline int internalInflateInit2(
77 z_stream* zcontext, GzipInputStream::Format format) {
78 int windowBitsFormat = 0;
79 switch (format) {
80 case GzipInputStream::GZIP: windowBitsFormat = 16; break;
81 case GzipInputStream::AUTO: windowBitsFormat = 32; break;
82 case GzipInputStream::ZLIB: windowBitsFormat = 0; break;
83 }
84 return inflateInit2(zcontext, /* windowBits */15 | windowBitsFormat);
85 }
86
Inflate(int flush)87 int GzipInputStream::Inflate(int flush) {
88 if ((zerror_ == Z_OK) && (zcontext_.avail_out == 0)) {
89 // previous inflate filled output buffer. don't change input params yet.
90 } else if (zcontext_.avail_in == 0) {
91 const void* in;
92 int in_size;
93 bool first = zcontext_.next_in == NULL;
94 bool ok = sub_stream_->Next(&in, &in_size);
95 if (!ok) {
96 zcontext_.next_out = NULL;
97 zcontext_.avail_out = 0;
98 return Z_STREAM_END;
99 }
100 zcontext_.next_in = static_cast<Bytef*>(const_cast<void*>(in));
101 zcontext_.avail_in = in_size;
102 if (first) {
103 int error = internalInflateInit2(&zcontext_, format_);
104 if (error != Z_OK) {
105 return error;
106 }
107 }
108 }
109 zcontext_.next_out = static_cast<Bytef*>(output_buffer_);
110 zcontext_.avail_out = output_buffer_length_;
111 output_position_ = output_buffer_;
112 int error = inflate(&zcontext_, flush);
113 return error;
114 }
115
DoNextOutput(const void ** data,int * size)116 void GzipInputStream::DoNextOutput(const void** data, int* size) {
117 *data = output_position_;
118 *size = ((uintptr_t)zcontext_.next_out) - ((uintptr_t)output_position_);
119 output_position_ = zcontext_.next_out;
120 }
121
122 // implements ZeroCopyInputStream ----------------------------------
Next(const void ** data,int * size)123 bool GzipInputStream::Next(const void** data, int* size) {
124 bool ok = (zerror_ == Z_OK) || (zerror_ == Z_STREAM_END)
125 || (zerror_ == Z_BUF_ERROR);
126 if ((!ok) || (zcontext_.next_out == NULL)) {
127 return false;
128 }
129 if (zcontext_.next_out != output_position_) {
130 DoNextOutput(data, size);
131 return true;
132 }
133 if (zerror_ == Z_STREAM_END) {
134 if (zcontext_.next_out != NULL) {
135 // sub_stream_ may have concatenated streams to follow
136 zerror_ = inflateEnd(&zcontext_);
137 if (zerror_ != Z_OK) {
138 return false;
139 }
140 zerror_ = internalInflateInit2(&zcontext_, format_);
141 if (zerror_ != Z_OK) {
142 return false;
143 }
144 } else {
145 *data = NULL;
146 *size = 0;
147 return false;
148 }
149 }
150 zerror_ = Inflate(Z_NO_FLUSH);
151 if ((zerror_ == Z_STREAM_END) && (zcontext_.next_out == NULL)) {
152 // The underlying stream's Next returned false inside Inflate.
153 return false;
154 }
155 ok = (zerror_ == Z_OK) || (zerror_ == Z_STREAM_END)
156 || (zerror_ == Z_BUF_ERROR);
157 if (!ok) {
158 return false;
159 }
160 DoNextOutput(data, size);
161 return true;
162 }
BackUp(int count)163 void GzipInputStream::BackUp(int count) {
164 output_position_ = reinterpret_cast<void*>(
165 reinterpret_cast<uintptr_t>(output_position_) - count);
166 }
Skip(int count)167 bool GzipInputStream::Skip(int count) {
168 const void* data;
169 int size;
170 bool ok = Next(&data, &size);
171 while (ok && (size < count)) {
172 count -= size;
173 ok = Next(&data, &size);
174 }
175 if (size > count) {
176 BackUp(size - count);
177 }
178 return ok;
179 }
ByteCount() const180 int64 GzipInputStream::ByteCount() const {
181 return zcontext_.total_out +
182 (((uintptr_t)zcontext_.next_out) - ((uintptr_t)output_position_));
183 }
184
185 // =========================================================================
186
Options()187 GzipOutputStream::Options::Options()
188 : format(GZIP),
189 buffer_size(kDefaultBufferSize),
190 compression_level(Z_DEFAULT_COMPRESSION),
191 compression_strategy(Z_DEFAULT_STRATEGY) {}
192
GzipOutputStream(ZeroCopyOutputStream * sub_stream)193 GzipOutputStream::GzipOutputStream(ZeroCopyOutputStream* sub_stream) {
194 Init(sub_stream, Options());
195 }
196
GzipOutputStream(ZeroCopyOutputStream * sub_stream,const Options & options)197 GzipOutputStream::GzipOutputStream(ZeroCopyOutputStream* sub_stream,
198 const Options& options) {
199 Init(sub_stream, options);
200 }
201
Init(ZeroCopyOutputStream * sub_stream,const Options & options)202 void GzipOutputStream::Init(ZeroCopyOutputStream* sub_stream,
203 const Options& options) {
204 sub_stream_ = sub_stream;
205 sub_data_ = NULL;
206 sub_data_size_ = 0;
207
208 input_buffer_length_ = options.buffer_size;
209 input_buffer_ = operator new(input_buffer_length_);
210 GOOGLE_CHECK(input_buffer_ != NULL);
211
212 zcontext_.zalloc = Z_NULL;
213 zcontext_.zfree = Z_NULL;
214 zcontext_.opaque = Z_NULL;
215 zcontext_.next_out = NULL;
216 zcontext_.avail_out = 0;
217 zcontext_.total_out = 0;
218 zcontext_.next_in = NULL;
219 zcontext_.avail_in = 0;
220 zcontext_.total_in = 0;
221 zcontext_.msg = NULL;
222 // default to GZIP format
223 int windowBitsFormat = 16;
224 if (options.format == ZLIB) {
225 windowBitsFormat = 0;
226 }
227 zerror_ = deflateInit2(
228 &zcontext_,
229 options.compression_level,
230 Z_DEFLATED,
231 /* windowBits */15 | windowBitsFormat,
232 /* memLevel (default) */8,
233 options.compression_strategy);
234 }
235
~GzipOutputStream()236 GzipOutputStream::~GzipOutputStream() {
237 Close();
238 if (input_buffer_ != NULL) {
239 operator delete(input_buffer_);
240 }
241 }
242
243 // private
Deflate(int flush)244 int GzipOutputStream::Deflate(int flush) {
245 int error = Z_OK;
246 do {
247 if ((sub_data_ == NULL) || (zcontext_.avail_out == 0)) {
248 bool ok = sub_stream_->Next(&sub_data_, &sub_data_size_);
249 if (!ok) {
250 sub_data_ = NULL;
251 sub_data_size_ = 0;
252 return Z_BUF_ERROR;
253 }
254 GOOGLE_CHECK_GT(sub_data_size_, 0);
255 zcontext_.next_out = static_cast<Bytef*>(sub_data_);
256 zcontext_.avail_out = sub_data_size_;
257 }
258 error = deflate(&zcontext_, flush);
259 } while (error == Z_OK && zcontext_.avail_out == 0);
260 if ((flush == Z_FULL_FLUSH) || (flush == Z_FINISH)) {
261 // Notify lower layer of data.
262 sub_stream_->BackUp(zcontext_.avail_out);
263 // We don't own the buffer anymore.
264 sub_data_ = NULL;
265 sub_data_size_ = 0;
266 }
267 return error;
268 }
269
270 // implements ZeroCopyOutputStream ---------------------------------
Next(void ** data,int * size)271 bool GzipOutputStream::Next(void** data, int* size) {
272 if ((zerror_ != Z_OK) && (zerror_ != Z_BUF_ERROR)) {
273 return false;
274 }
275 if (zcontext_.avail_in != 0) {
276 zerror_ = Deflate(Z_NO_FLUSH);
277 if (zerror_ != Z_OK) {
278 return false;
279 }
280 }
281 if (zcontext_.avail_in == 0) {
282 // all input was consumed. reset the buffer.
283 zcontext_.next_in = static_cast<Bytef*>(input_buffer_);
284 zcontext_.avail_in = input_buffer_length_;
285 *data = input_buffer_;
286 *size = input_buffer_length_;
287 } else {
288 // The loop in Deflate should consume all avail_in
289 GOOGLE_LOG(DFATAL) << "Deflate left bytes unconsumed";
290 }
291 return true;
292 }
BackUp(int count)293 void GzipOutputStream::BackUp(int count) {
294 GOOGLE_CHECK_GE(zcontext_.avail_in, count);
295 zcontext_.avail_in -= count;
296 }
ByteCount() const297 int64 GzipOutputStream::ByteCount() const {
298 return zcontext_.total_in + zcontext_.avail_in;
299 }
300
Flush()301 bool GzipOutputStream::Flush() {
302 zerror_ = Deflate(Z_FULL_FLUSH);
303 // Return true if the flush succeeded or if it was a no-op.
304 return (zerror_ == Z_OK) ||
305 (zerror_ == Z_BUF_ERROR && zcontext_.avail_in == 0 &&
306 zcontext_.avail_out != 0);
307 }
308
Close()309 bool GzipOutputStream::Close() {
310 if ((zerror_ != Z_OK) && (zerror_ != Z_BUF_ERROR)) {
311 return false;
312 }
313 do {
314 zerror_ = Deflate(Z_FINISH);
315 } while (zerror_ == Z_OK);
316 zerror_ = deflateEnd(&zcontext_);
317 bool ok = zerror_ == Z_OK;
318 zerror_ = Z_STREAM_END;
319 return ok;
320 }
321
322 } // namespace io
323 } // namespace protobuf
324 } // namespace google
325
326 #endif // HAVE_ZLIB
327