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Commit | Line | Data |
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7c673cae FG |
1 | /* |
2 | * A C++ I/O streams interface to the zlib gz* functions | |
3 | * | |
4 | * by Ludwig Schwardt <schwardt@sun.ac.za> | |
5 | * original version by Kevin Ruland <kevin@rodin.wustl.edu> | |
6 | * | |
7 | * This version is standard-compliant and compatible with gcc 3.x. | |
8 | */ | |
9 | ||
10 | #include "zfstream.h" | |
11 | #include <cstring> // for strcpy, strcat, strlen (mode strings) | |
12 | #include <cstdio> // for BUFSIZ | |
13 | ||
14 | // Internal buffer sizes (default and "unbuffered" versions) | |
15 | #define BIGBUFSIZE BUFSIZ | |
16 | #define SMALLBUFSIZE 1 | |
17 | ||
18 | /*****************************************************************************/ | |
19 | ||
20 | // Default constructor | |
21 | gzfilebuf::gzfilebuf() | |
22 | : file(NULL), io_mode(std::ios_base::openmode(0)), own_fd(false), | |
23 | buffer(NULL), buffer_size(BIGBUFSIZE), own_buffer(true) | |
24 | { | |
25 | // No buffers to start with | |
26 | this->disable_buffer(); | |
27 | } | |
28 | ||
29 | // Destructor | |
30 | gzfilebuf::~gzfilebuf() | |
31 | { | |
32 | // Sync output buffer and close only if responsible for file | |
33 | // (i.e. attached streams should be left open at this stage) | |
34 | this->sync(); | |
35 | if (own_fd) | |
36 | this->close(); | |
37 | // Make sure internal buffer is deallocated | |
38 | this->disable_buffer(); | |
39 | } | |
40 | ||
41 | // Set compression level and strategy | |
42 | int | |
43 | gzfilebuf::setcompression(int comp_level, | |
44 | int comp_strategy) | |
45 | { | |
46 | return gzsetparams(file, comp_level, comp_strategy); | |
47 | } | |
48 | ||
49 | // Open gzipped file | |
50 | gzfilebuf* | |
51 | gzfilebuf::open(const char *name, | |
52 | std::ios_base::openmode mode) | |
53 | { | |
54 | // Fail if file already open | |
55 | if (this->is_open()) | |
56 | return NULL; | |
57 | // Don't support simultaneous read/write access (yet) | |
58 | if ((mode & std::ios_base::in) && (mode & std::ios_base::out)) | |
59 | return NULL; | |
60 | ||
61 | // Build mode string for gzopen and check it [27.8.1.3.2] | |
62 | char char_mode[6] = "\0\0\0\0\0"; | |
63 | if (!this->open_mode(mode, char_mode)) | |
64 | return NULL; | |
65 | ||
66 | // Attempt to open file | |
67 | if ((file = gzopen(name, char_mode)) == NULL) | |
68 | return NULL; | |
69 | ||
70 | // On success, allocate internal buffer and set flags | |
71 | this->enable_buffer(); | |
72 | io_mode = mode; | |
73 | own_fd = true; | |
74 | return this; | |
75 | } | |
76 | ||
77 | // Attach to gzipped file | |
78 | gzfilebuf* | |
79 | gzfilebuf::attach(int fd, | |
80 | std::ios_base::openmode mode) | |
81 | { | |
82 | // Fail if file already open | |
83 | if (this->is_open()) | |
84 | return NULL; | |
85 | // Don't support simultaneous read/write access (yet) | |
86 | if ((mode & std::ios_base::in) && (mode & std::ios_base::out)) | |
87 | return NULL; | |
88 | ||
89 | // Build mode string for gzdopen and check it [27.8.1.3.2] | |
90 | char char_mode[6] = "\0\0\0\0\0"; | |
91 | if (!this->open_mode(mode, char_mode)) | |
92 | return NULL; | |
93 | ||
94 | // Attempt to attach to file | |
95 | if ((file = gzdopen(fd, char_mode)) == NULL) | |
96 | return NULL; | |
97 | ||
98 | // On success, allocate internal buffer and set flags | |
99 | this->enable_buffer(); | |
100 | io_mode = mode; | |
101 | own_fd = false; | |
102 | return this; | |
103 | } | |
104 | ||
105 | // Close gzipped file | |
106 | gzfilebuf* | |
107 | gzfilebuf::close() | |
108 | { | |
109 | // Fail immediately if no file is open | |
110 | if (!this->is_open()) | |
111 | return NULL; | |
112 | // Assume success | |
113 | gzfilebuf* retval = this; | |
114 | // Attempt to sync and close gzipped file | |
115 | if (this->sync() == -1) | |
116 | retval = NULL; | |
117 | if (gzclose(file) < 0) | |
118 | retval = NULL; | |
119 | // File is now gone anyway (postcondition [27.8.1.3.8]) | |
120 | file = NULL; | |
121 | own_fd = false; | |
122 | // Destroy internal buffer if it exists | |
123 | this->disable_buffer(); | |
124 | return retval; | |
125 | } | |
126 | ||
127 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ | |
128 | ||
129 | // Convert int open mode to mode string | |
130 | bool | |
131 | gzfilebuf::open_mode(std::ios_base::openmode mode, | |
132 | char* c_mode) const | |
133 | { | |
134 | bool testb = mode & std::ios_base::binary; | |
135 | bool testi = mode & std::ios_base::in; | |
136 | bool testo = mode & std::ios_base::out; | |
137 | bool testt = mode & std::ios_base::trunc; | |
138 | bool testa = mode & std::ios_base::app; | |
139 | ||
140 | // Check for valid flag combinations - see [27.8.1.3.2] (Table 92) | |
141 | // Original zfstream hardcoded the compression level to maximum here... | |
142 | // Double the time for less than 1% size improvement seems | |
143 | // excessive though - keeping it at the default level | |
144 | // To change back, just append "9" to the next three mode strings | |
145 | if (!testi && testo && !testt && !testa) | |
146 | strcpy(c_mode, "w"); | |
147 | if (!testi && testo && !testt && testa) | |
148 | strcpy(c_mode, "a"); | |
149 | if (!testi && testo && testt && !testa) | |
150 | strcpy(c_mode, "w"); | |
151 | if (testi && !testo && !testt && !testa) | |
152 | strcpy(c_mode, "r"); | |
153 | // No read/write mode yet | |
154 | // if (testi && testo && !testt && !testa) | |
155 | // strcpy(c_mode, "r+"); | |
156 | // if (testi && testo && testt && !testa) | |
157 | // strcpy(c_mode, "w+"); | |
158 | ||
159 | // Mode string should be empty for invalid combination of flags | |
160 | if (strlen(c_mode) == 0) | |
161 | return false; | |
162 | if (testb) | |
163 | strcat(c_mode, "b"); | |
164 | return true; | |
165 | } | |
166 | ||
167 | // Determine number of characters in internal get buffer | |
168 | std::streamsize | |
169 | gzfilebuf::showmanyc() | |
170 | { | |
171 | // Calls to underflow will fail if file not opened for reading | |
172 | if (!this->is_open() || !(io_mode & std::ios_base::in)) | |
173 | return -1; | |
174 | // Make sure get area is in use | |
175 | if (this->gptr() && (this->gptr() < this->egptr())) | |
176 | return std::streamsize(this->egptr() - this->gptr()); | |
177 | else | |
178 | return 0; | |
179 | } | |
180 | ||
181 | // Fill get area from gzipped file | |
182 | gzfilebuf::int_type | |
183 | gzfilebuf::underflow() | |
184 | { | |
185 | // If something is left in the get area by chance, return it | |
186 | // (this shouldn't normally happen, as underflow is only supposed | |
187 | // to be called when gptr >= egptr, but it serves as error check) | |
188 | if (this->gptr() && (this->gptr() < this->egptr())) | |
189 | return traits_type::to_int_type(*(this->gptr())); | |
190 | ||
191 | // If the file hasn't been opened for reading, produce error | |
192 | if (!this->is_open() || !(io_mode & std::ios_base::in)) | |
193 | return traits_type::eof(); | |
194 | ||
195 | // Attempt to fill internal buffer from gzipped file | |
196 | // (buffer must be guaranteed to exist...) | |
197 | int bytes_read = gzread(file, buffer, buffer_size); | |
198 | // Indicates error or EOF | |
199 | if (bytes_read <= 0) | |
200 | { | |
201 | // Reset get area | |
202 | this->setg(buffer, buffer, buffer); | |
203 | return traits_type::eof(); | |
204 | } | |
205 | // Make all bytes read from file available as get area | |
206 | this->setg(buffer, buffer, buffer + bytes_read); | |
207 | ||
208 | // Return next character in get area | |
209 | return traits_type::to_int_type(*(this->gptr())); | |
210 | } | |
211 | ||
212 | // Write put area to gzipped file | |
213 | gzfilebuf::int_type | |
214 | gzfilebuf::overflow(int_type c) | |
215 | { | |
216 | // Determine whether put area is in use | |
217 | if (this->pbase()) | |
218 | { | |
219 | // Double-check pointer range | |
220 | if (this->pptr() > this->epptr() || this->pptr() < this->pbase()) | |
221 | return traits_type::eof(); | |
222 | // Add extra character to buffer if not EOF | |
223 | if (!traits_type::eq_int_type(c, traits_type::eof())) | |
224 | { | |
225 | *(this->pptr()) = traits_type::to_char_type(c); | |
226 | this->pbump(1); | |
227 | } | |
228 | // Number of characters to write to file | |
229 | int bytes_to_write = this->pptr() - this->pbase(); | |
230 | // Overflow doesn't fail if nothing is to be written | |
231 | if (bytes_to_write > 0) | |
232 | { | |
233 | // If the file hasn't been opened for writing, produce error | |
234 | if (!this->is_open() || !(io_mode & std::ios_base::out)) | |
235 | return traits_type::eof(); | |
236 | // If gzipped file won't accept all bytes written to it, fail | |
237 | if (gzwrite(file, this->pbase(), bytes_to_write) != bytes_to_write) | |
238 | return traits_type::eof(); | |
239 | // Reset next pointer to point to pbase on success | |
240 | this->pbump(-bytes_to_write); | |
241 | } | |
242 | } | |
243 | // Write extra character to file if not EOF | |
244 | else if (!traits_type::eq_int_type(c, traits_type::eof())) | |
245 | { | |
246 | // If the file hasn't been opened for writing, produce error | |
247 | if (!this->is_open() || !(io_mode & std::ios_base::out)) | |
248 | return traits_type::eof(); | |
249 | // Impromptu char buffer (allows "unbuffered" output) | |
250 | char_type last_char = traits_type::to_char_type(c); | |
251 | // If gzipped file won't accept this character, fail | |
252 | if (gzwrite(file, &last_char, 1) != 1) | |
253 | return traits_type::eof(); | |
254 | } | |
255 | ||
256 | // If you got here, you have succeeded (even if c was EOF) | |
257 | // The return value should therefore be non-EOF | |
258 | if (traits_type::eq_int_type(c, traits_type::eof())) | |
259 | return traits_type::not_eof(c); | |
260 | else | |
261 | return c; | |
262 | } | |
263 | ||
264 | // Assign new buffer | |
265 | std::streambuf* | |
266 | gzfilebuf::setbuf(char_type* p, | |
267 | std::streamsize n) | |
268 | { | |
269 | // First make sure stuff is sync'ed, for safety | |
270 | if (this->sync() == -1) | |
271 | return NULL; | |
272 | // If buffering is turned off on purpose via setbuf(0,0), still allocate one... | |
273 | // "Unbuffered" only really refers to put [27.8.1.4.10], while get needs at | |
274 | // least a buffer of size 1 (very inefficient though, therefore make it bigger?) | |
275 | // This follows from [27.5.2.4.3]/12 (gptr needs to point at something, it seems) | |
276 | if (!p || !n) | |
277 | { | |
278 | // Replace existing buffer (if any) with small internal buffer | |
279 | this->disable_buffer(); | |
280 | buffer = NULL; | |
281 | buffer_size = 0; | |
282 | own_buffer = true; | |
283 | this->enable_buffer(); | |
284 | } | |
285 | else | |
286 | { | |
287 | // Replace existing buffer (if any) with external buffer | |
288 | this->disable_buffer(); | |
289 | buffer = p; | |
290 | buffer_size = n; | |
291 | own_buffer = false; | |
292 | this->enable_buffer(); | |
293 | } | |
294 | return this; | |
295 | } | |
296 | ||
297 | // Write put area to gzipped file (i.e. ensures that put area is empty) | |
298 | int | |
299 | gzfilebuf::sync() | |
300 | { | |
301 | return traits_type::eq_int_type(this->overflow(), traits_type::eof()) ? -1 : 0; | |
302 | } | |
303 | ||
304 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ | |
305 | ||
306 | // Allocate internal buffer | |
307 | void | |
308 | gzfilebuf::enable_buffer() | |
309 | { | |
310 | // If internal buffer required, allocate one | |
311 | if (own_buffer && !buffer) | |
312 | { | |
313 | // Check for buffered vs. "unbuffered" | |
314 | if (buffer_size > 0) | |
315 | { | |
316 | // Allocate internal buffer | |
317 | buffer = new char_type[buffer_size]; | |
318 | // Get area starts empty and will be expanded by underflow as need arises | |
319 | this->setg(buffer, buffer, buffer); | |
320 | // Setup entire internal buffer as put area. | |
321 | // The one-past-end pointer actually points to the last element of the buffer, | |
322 | // so that overflow(c) can safely add the extra character c to the sequence. | |
323 | // These pointers remain in place for the duration of the buffer | |
324 | this->setp(buffer, buffer + buffer_size - 1); | |
325 | } | |
326 | else | |
327 | { | |
328 | // Even in "unbuffered" case, (small?) get buffer is still required | |
329 | buffer_size = SMALLBUFSIZE; | |
330 | buffer = new char_type[buffer_size]; | |
331 | this->setg(buffer, buffer, buffer); | |
332 | // "Unbuffered" means no put buffer | |
333 | this->setp(0, 0); | |
334 | } | |
335 | } | |
336 | else | |
337 | { | |
338 | // If buffer already allocated, reset buffer pointers just to make sure no | |
339 | // stale chars are lying around | |
340 | this->setg(buffer, buffer, buffer); | |
341 | this->setp(buffer, buffer + buffer_size - 1); | |
342 | } | |
343 | } | |
344 | ||
345 | // Destroy internal buffer | |
346 | void | |
347 | gzfilebuf::disable_buffer() | |
348 | { | |
349 | // If internal buffer exists, deallocate it | |
350 | if (own_buffer && buffer) | |
351 | { | |
352 | // Preserve unbuffered status by zeroing size | |
353 | if (!this->pbase()) | |
354 | buffer_size = 0; | |
355 | delete[] buffer; | |
356 | buffer = NULL; | |
357 | this->setg(0, 0, 0); | |
358 | this->setp(0, 0); | |
359 | } | |
360 | else | |
361 | { | |
362 | // Reset buffer pointers to initial state if external buffer exists | |
363 | this->setg(buffer, buffer, buffer); | |
364 | if (buffer) | |
365 | this->setp(buffer, buffer + buffer_size - 1); | |
366 | else | |
367 | this->setp(0, 0); | |
368 | } | |
369 | } | |
370 | ||
371 | /*****************************************************************************/ | |
372 | ||
373 | // Default constructor initializes stream buffer | |
374 | gzifstream::gzifstream() | |
375 | : std::istream(NULL), sb() | |
376 | { this->init(&sb); } | |
377 | ||
378 | // Initialize stream buffer and open file | |
379 | gzifstream::gzifstream(const char* name, | |
380 | std::ios_base::openmode mode) | |
381 | : std::istream(NULL), sb() | |
382 | { | |
383 | this->init(&sb); | |
384 | this->open(name, mode); | |
385 | } | |
386 | ||
387 | // Initialize stream buffer and attach to file | |
388 | gzifstream::gzifstream(int fd, | |
389 | std::ios_base::openmode mode) | |
390 | : std::istream(NULL), sb() | |
391 | { | |
392 | this->init(&sb); | |
393 | this->attach(fd, mode); | |
394 | } | |
395 | ||
396 | // Open file and go into fail() state if unsuccessful | |
397 | void | |
398 | gzifstream::open(const char* name, | |
399 | std::ios_base::openmode mode) | |
400 | { | |
401 | if (!sb.open(name, mode | std::ios_base::in)) | |
402 | this->setstate(std::ios_base::failbit); | |
403 | else | |
404 | this->clear(); | |
405 | } | |
406 | ||
407 | // Attach to file and go into fail() state if unsuccessful | |
408 | void | |
409 | gzifstream::attach(int fd, | |
410 | std::ios_base::openmode mode) | |
411 | { | |
412 | if (!sb.attach(fd, mode | std::ios_base::in)) | |
413 | this->setstate(std::ios_base::failbit); | |
414 | else | |
415 | this->clear(); | |
416 | } | |
417 | ||
418 | // Close file | |
419 | void | |
420 | gzifstream::close() | |
421 | { | |
422 | if (!sb.close()) | |
423 | this->setstate(std::ios_base::failbit); | |
424 | } | |
425 | ||
426 | /*****************************************************************************/ | |
427 | ||
428 | // Default constructor initializes stream buffer | |
429 | gzofstream::gzofstream() | |
430 | : std::ostream(NULL), sb() | |
431 | { this->init(&sb); } | |
432 | ||
433 | // Initialize stream buffer and open file | |
434 | gzofstream::gzofstream(const char* name, | |
435 | std::ios_base::openmode mode) | |
436 | : std::ostream(NULL), sb() | |
437 | { | |
438 | this->init(&sb); | |
439 | this->open(name, mode); | |
440 | } | |
441 | ||
442 | // Initialize stream buffer and attach to file | |
443 | gzofstream::gzofstream(int fd, | |
444 | std::ios_base::openmode mode) | |
445 | : std::ostream(NULL), sb() | |
446 | { | |
447 | this->init(&sb); | |
448 | this->attach(fd, mode); | |
449 | } | |
450 | ||
451 | // Open file and go into fail() state if unsuccessful | |
452 | void | |
453 | gzofstream::open(const char* name, | |
454 | std::ios_base::openmode mode) | |
455 | { | |
456 | if (!sb.open(name, mode | std::ios_base::out)) | |
457 | this->setstate(std::ios_base::failbit); | |
458 | else | |
459 | this->clear(); | |
460 | } | |
461 | ||
462 | // Attach to file and go into fail() state if unsuccessful | |
463 | void | |
464 | gzofstream::attach(int fd, | |
465 | std::ios_base::openmode mode) | |
466 | { | |
467 | if (!sb.attach(fd, mode | std::ios_base::out)) | |
468 | this->setstate(std::ios_base::failbit); | |
469 | else | |
470 | this->clear(); | |
471 | } | |
472 | ||
473 | // Close file | |
474 | void | |
475 | gzofstream::close() | |
476 | { | |
477 | if (!sb.close()) | |
478 | this->setstate(std::ios_base::failbit); | |
479 | } |