Mercurial > hg > orthanc
annotate Core/Compression/GzipCompressor.cpp @ 3956:6e14f2da7c7e
integration transcoding->mainline
author | Sebastien Jodogne <s.jodogne@gmail.com> |
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date | Wed, 20 May 2020 16:42:44 +0200 |
parents | 94f4a18a79cc |
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rev | line source |
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1513 | 1 /** |
2 * Orthanc - A Lightweight, RESTful DICOM Store | |
1900 | 3 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics |
1513 | 4 * Department, University Hospital of Liege, Belgium |
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5 * Copyright (C) 2017-2020 Osimis S.A., Belgium |
1513 | 6 * |
7 * This program is free software: you can redistribute it and/or | |
8 * modify it under the terms of the GNU General Public License as | |
9 * published by the Free Software Foundation, either version 3 of the | |
10 * License, or (at your option) any later version. | |
11 * | |
12 * In addition, as a special exception, the copyright holders of this | |
13 * program give permission to link the code of its release with the | |
14 * OpenSSL project's "OpenSSL" library (or with modified versions of it | |
15 * that use the same license as the "OpenSSL" library), and distribute | |
16 * the linked executables. You must obey the GNU General Public License | |
17 * in all respects for all of the code used other than "OpenSSL". If you | |
18 * modify file(s) with this exception, you may extend this exception to | |
19 * your version of the file(s), but you are not obligated to do so. If | |
20 * you do not wish to do so, delete this exception statement from your | |
21 * version. If you delete this exception statement from all source files | |
22 * in the program, then also delete it here. | |
23 * | |
24 * This program is distributed in the hope that it will be useful, but | |
25 * WITHOUT ANY WARRANTY; without even the implied warranty of | |
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
27 * General Public License for more details. | |
28 * | |
29 * You should have received a copy of the GNU General Public License | |
30 * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
31 **/ | |
32 | |
33 | |
34 #include "../PrecompiledHeaders.h" | |
35 #include "GzipCompressor.h" | |
36 | |
37 #include <stdio.h> | |
38 #include <string.h> | |
39 #include <zlib.h> | |
40 | |
41 #include "../OrthancException.h" | |
42 #include "../Logging.h" | |
43 | |
44 namespace Orthanc | |
45 { | |
46 uint64_t GzipCompressor::GuessUncompressedSize(const void* compressed, | |
47 size_t compressedSize) | |
48 { | |
49 /** | |
50 * "Is there a way to find out the size of the original file which | |
51 * is inside a GZIP file? [...] There is no truly reliable way, | |
52 * other than gunzipping the stream. You do not need to save the | |
53 * result of the decompression, so you can determine the size by | |
54 * simply reading and decoding the entire file without taking up | |
55 * space with the decompressed result. | |
56 * | |
57 * There is an unreliable way to determine the uncompressed size, | |
58 * which is to look at the last four bytes of the gzip file, which | |
59 * is the uncompressed length of that entry modulo 232 in little | |
60 * endian order. | |
61 * | |
62 * It is unreliable because a) the uncompressed data may be longer | |
63 * than 2^32 bytes, and b) the gzip file may consist of multiple | |
64 * gzip streams, in which case you would find the length of only | |
65 * the last of those streams. | |
66 * | |
67 * If you are in control of the source of the gzip files, you know | |
68 * that they consist of single gzip streams, and you know that | |
69 * they are less than 2^32 bytes uncompressed, then and only then | |
70 * can you use those last four bytes with confidence." | |
71 * | |
72 * http://stackoverflow.com/a/9727599/881731 | |
73 **/ | |
74 | |
75 if (compressedSize < 4) | |
76 { | |
77 throw OrthancException(ErrorCode_BadFileFormat); | |
78 } | |
79 | |
80 const uint8_t* p = reinterpret_cast<const uint8_t*>(compressed) + compressedSize - 4; | |
81 | |
82 return ((static_cast<uint32_t>(p[0]) << 0) + | |
83 (static_cast<uint32_t>(p[1]) << 8) + | |
84 (static_cast<uint32_t>(p[2]) << 16) + | |
85 (static_cast<uint32_t>(p[3]) << 24)); | |
86 } | |
87 | |
88 | |
89 | |
90 void GzipCompressor::Compress(std::string& compressed, | |
91 const void* uncompressed, | |
92 size_t uncompressedSize) | |
93 { | |
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94 uLongf compressedSize = compressBound(static_cast<uLong>(uncompressedSize)) |
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95 + 1024 /* security margin */; |
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96 |
1513 | 97 if (compressedSize == 0) |
98 { | |
99 compressedSize = 1; | |
100 } | |
101 | |
102 uint8_t* target; | |
103 if (HasPrefixWithUncompressedSize()) | |
104 { | |
105 compressed.resize(compressedSize + sizeof(uint64_t)); | |
106 target = reinterpret_cast<uint8_t*>(&compressed[0]) + sizeof(uint64_t); | |
107 } | |
108 else | |
109 { | |
110 compressed.resize(compressedSize); | |
111 target = reinterpret_cast<uint8_t*>(&compressed[0]); | |
112 } | |
113 | |
114 z_stream stream; | |
115 memset(&stream, 0, sizeof(stream)); | |
116 | |
117 stream.next_in = const_cast<Bytef*>(reinterpret_cast<const Bytef*>(uncompressed)); | |
118 stream.next_out = reinterpret_cast<Bytef*>(target); | |
119 | |
120 stream.avail_in = static_cast<uInt>(uncompressedSize); | |
121 stream.avail_out = static_cast<uInt>(compressedSize); | |
122 | |
123 // Ensure no overflow (if the buffer is too large for the current archicture) | |
124 if (static_cast<size_t>(stream.avail_in) != uncompressedSize || | |
125 static_cast<size_t>(stream.avail_out) != compressedSize) | |
126 { | |
127 throw OrthancException(ErrorCode_NotEnoughMemory); | |
128 } | |
129 | |
130 // Initialize the compression engine | |
131 int error = deflateInit2(&stream, | |
132 GetCompressionLevel(), | |
133 Z_DEFLATED, | |
134 MAX_WBITS + 16, // ask for gzip output | |
135 8, // default memory level | |
136 Z_DEFAULT_STRATEGY); | |
137 | |
138 if (error != Z_OK) | |
139 { | |
140 // Cannot initialize zlib | |
141 compressed.clear(); | |
142 throw OrthancException(ErrorCode_InternalError); | |
143 } | |
144 | |
145 // Compress the input buffer | |
146 error = deflate(&stream, Z_FINISH); | |
147 | |
148 if (error != Z_STREAM_END) | |
149 { | |
150 deflateEnd(&stream); | |
151 compressed.clear(); | |
152 | |
153 switch (error) | |
154 { | |
155 case Z_MEM_ERROR: | |
156 throw OrthancException(ErrorCode_NotEnoughMemory); | |
157 | |
158 default: | |
159 throw OrthancException(ErrorCode_InternalError); | |
160 } | |
161 } | |
162 | |
163 size_t size = stream.total_out; | |
164 | |
165 if (deflateEnd(&stream) != Z_OK) | |
166 { | |
167 throw OrthancException(ErrorCode_InternalError); | |
168 } | |
169 | |
170 // The compression was successful | |
171 if (HasPrefixWithUncompressedSize()) | |
172 { | |
173 uint64_t s = static_cast<uint64_t>(uncompressedSize); | |
174 memcpy(&compressed[0], &s, sizeof(uint64_t)); | |
175 compressed.resize(size + sizeof(uint64_t)); | |
176 } | |
177 else | |
178 { | |
179 compressed.resize(size); | |
180 } | |
181 } | |
182 | |
183 | |
184 void GzipCompressor::Uncompress(std::string& uncompressed, | |
185 const void* compressed, | |
186 size_t compressedSize) | |
187 { | |
188 uint64_t uncompressedSize; | |
189 const uint8_t* source = reinterpret_cast<const uint8_t*>(compressed); | |
190 | |
191 if (HasPrefixWithUncompressedSize()) | |
192 { | |
193 uncompressedSize = ReadUncompressedSizePrefix(compressed, compressedSize); | |
194 source += sizeof(uint64_t); | |
195 compressedSize -= sizeof(uint64_t); | |
196 } | |
197 else | |
198 { | |
199 uncompressedSize = GuessUncompressedSize(compressed, compressedSize); | |
200 } | |
201 | |
202 try | |
203 { | |
1545 | 204 uncompressed.resize(static_cast<size_t>(uncompressedSize)); |
1513 | 205 } |
206 catch (...) | |
207 { | |
208 throw OrthancException(ErrorCode_NotEnoughMemory); | |
209 } | |
210 | |
211 z_stream stream; | |
212 memset(&stream, 0, sizeof(stream)); | |
213 | |
214 char dummy = '\0'; // zlib does not like NULL output buffers (even if the uncompressed data is empty) | |
215 stream.next_in = const_cast<Bytef*>(source); | |
216 stream.next_out = reinterpret_cast<Bytef*>(uncompressedSize == 0 ? &dummy : &uncompressed[0]); | |
217 | |
218 stream.avail_in = static_cast<uInt>(compressedSize); | |
219 stream.avail_out = static_cast<uInt>(uncompressedSize); | |
220 | |
221 // Ensure no overflow (if the buffer is too large for the current archicture) | |
222 if (static_cast<size_t>(stream.avail_in) != compressedSize || | |
223 static_cast<size_t>(stream.avail_out) != uncompressedSize) | |
224 { | |
225 throw OrthancException(ErrorCode_NotEnoughMemory); | |
226 } | |
227 | |
228 // Initialize the compression engine | |
229 int error = inflateInit2(&stream, | |
230 MAX_WBITS + 16); // this is a gzip input | |
231 | |
232 if (error != Z_OK) | |
233 { | |
234 // Cannot initialize zlib | |
235 uncompressed.clear(); | |
236 throw OrthancException(ErrorCode_InternalError); | |
237 } | |
238 | |
239 // Uncompress the input buffer | |
240 error = inflate(&stream, Z_FINISH); | |
241 | |
242 if (error != Z_STREAM_END) | |
243 { | |
244 inflateEnd(&stream); | |
245 uncompressed.clear(); | |
246 | |
247 switch (error) | |
248 { | |
249 case Z_MEM_ERROR: | |
250 throw OrthancException(ErrorCode_NotEnoughMemory); | |
251 | |
252 case Z_BUF_ERROR: | |
253 case Z_NEED_DICT: | |
254 throw OrthancException(ErrorCode_BadFileFormat); | |
255 | |
256 default: | |
257 throw OrthancException(ErrorCode_InternalError); | |
258 } | |
259 } | |
260 | |
261 size_t size = stream.total_out; | |
262 | |
263 if (inflateEnd(&stream) != Z_OK) | |
264 { | |
265 uncompressed.clear(); | |
266 throw OrthancException(ErrorCode_InternalError); | |
267 } | |
268 | |
269 if (size != uncompressedSize) | |
270 { | |
271 uncompressed.clear(); | |
272 | |
273 // The uncompressed size was not that properly guess, presumably | |
274 // because of a file size over 4GB. Should fallback to | |
275 // stream-based decompression. | |
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276 throw OrthancException(ErrorCode_NotImplemented, |
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277 "The uncompressed size of a gzip-encoded buffer was not properly guessed"); |
1513 | 278 } |
279 } | |
280 } |