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1 | /* gzread.c -- zlib functions for reading gzip files |
2 | * Copyright (C) 2004, 2005, 2010, 2011, 2012 Mark Adler | |
3 | * For conditions of distribution and use, see copyright notice in zlib.h | |
4 | */ | |
5 | ||
6 | #include "gzguts.h" | |
7 | ||
8 | /* Local functions */ | |
9 | local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *)); | |
10 | local int gz_avail OF((gz_statep)); | |
11 | local int gz_look OF((gz_statep)); | |
12 | local int gz_decomp OF((gz_statep)); | |
13 | local int gz_fetch OF((gz_statep)); | |
14 | local int gz_skip OF((gz_statep, z_off64_t)); | |
15 | ||
16 | /* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from | |
17 | state->fd, and update state->eof, state->err, and state->msg as appropriate. | |
18 | This function needs to loop on read(), since read() is not guaranteed to | |
19 | read the number of bytes requested, depending on the type of descriptor. */ | |
20 | local int gz_load(state, buf, len, have) | |
21 | gz_statep state; | |
22 | unsigned char *buf; | |
23 | unsigned len; | |
24 | unsigned *have; | |
25 | { | |
26 | int ret; | |
27 | ||
28 | *have = 0; | |
29 | do { | |
30 | ret = read(state->fd, buf + *have, len - *have); | |
31 | if (ret <= 0) | |
32 | break; | |
33 | *have += ret; | |
34 | } while (*have < len); | |
35 | if (ret < 0) { | |
36 | gz_error(state, Z_ERRNO, zstrerror()); | |
37 | return -1; | |
38 | } | |
39 | if (ret == 0) | |
40 | state->eof = 1; | |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* Load up input buffer and set eof flag if last data loaded -- return -1 on | |
45 | error, 0 otherwise. Note that the eof flag is set when the end of the input | |
46 | file is reached, even though there may be unused data in the buffer. Once | |
47 | that data has been used, no more attempts will be made to read the file. | |
48 | If strm->avail_in != 0, then the current data is moved to the beginning of | |
49 | the input buffer, and then the remainder of the buffer is loaded with the | |
50 | available data from the input file. */ | |
51 | local int gz_avail(state) | |
52 | gz_statep state; | |
53 | { | |
54 | unsigned got; | |
55 | z_streamp strm = &(state->strm); | |
56 | ||
57 | if (state->err != Z_OK && state->err != Z_BUF_ERROR) | |
58 | return -1; | |
59 | if (state->eof == 0) { | |
60 | if (strm->avail_in) { /* copy what's there to the start */ | |
61 | unsigned char *p = state->in, *q = strm->next_in; | |
62 | unsigned n = strm->avail_in; | |
63 | do { | |
64 | *p++ = *q++; | |
65 | } while (--n); | |
66 | } | |
67 | if (gz_load(state, state->in + strm->avail_in, | |
68 | state->size - strm->avail_in, &got) == -1) | |
69 | return -1; | |
70 | strm->avail_in += got; | |
71 | strm->next_in = state->in; | |
72 | } | |
73 | return 0; | |
74 | } | |
75 | ||
76 | /* Look for gzip header, set up for inflate or copy. state->x.have must be 0. | |
77 | If this is the first time in, allocate required memory. state->how will be | |
78 | left unchanged if there is no more input data available, will be set to COPY | |
79 | if there is no gzip header and direct copying will be performed, or it will | |
80 | be set to GZIP for decompression. If direct copying, then leftover input | |
81 | data from the input buffer will be copied to the output buffer. In that | |
82 | case, all further file reads will be directly to either the output buffer or | |
83 | a user buffer. If decompressing, the inflate state will be initialized. | |
84 | gz_look() will return 0 on success or -1 on failure. */ | |
85 | local int gz_look(state) | |
86 | gz_statep state; | |
87 | { | |
88 | z_streamp strm = &(state->strm); | |
89 | ||
90 | /* allocate read buffers and inflate memory */ | |
91 | if (state->size == 0) { | |
92 | /* allocate buffers */ | |
93 | state->in = malloc(state->want); | |
94 | state->out = malloc(state->want << 1); | |
95 | if (state->in == NULL || state->out == NULL) { | |
96 | if (state->out != NULL) | |
97 | free(state->out); | |
98 | if (state->in != NULL) | |
99 | free(state->in); | |
100 | gz_error(state, Z_MEM_ERROR, "out of memory"); | |
101 | return -1; | |
102 | } | |
103 | state->size = state->want; | |
104 | ||
105 | /* allocate inflate memory */ | |
106 | state->strm.zalloc = Z_NULL; | |
107 | state->strm.zfree = Z_NULL; | |
108 | state->strm.opaque = Z_NULL; | |
109 | state->strm.avail_in = 0; | |
110 | state->strm.next_in = Z_NULL; | |
111 | if (inflateInit2(&(state->strm), 15 + 16) != Z_OK) { /* gunzip */ | |
112 | free(state->out); | |
113 | free(state->in); | |
114 | state->size = 0; | |
115 | gz_error(state, Z_MEM_ERROR, "out of memory"); | |
116 | return -1; | |
117 | } | |
118 | } | |
119 | ||
120 | /* get at least the magic bytes in the input buffer */ | |
121 | if (strm->avail_in < 2) { | |
122 | if (gz_avail(state) == -1) | |
123 | return -1; | |
124 | if (strm->avail_in == 0) | |
125 | return 0; | |
126 | } | |
127 | ||
128 | /* look for gzip magic bytes -- if there, do gzip decoding (note: there is | |
129 | a logical dilemma here when considering the case of a partially written | |
130 | gzip file, to wit, if a single 31 byte is written, then we cannot tell | |
131 | whether this is a single-byte file, or just a partially written gzip | |
132 | file -- for here we assume that if a gzip file is being written, then | |
133 | the header will be written in a single operation, so that reading a | |
134 | single byte is sufficient indication that it is not a gzip file) */ | |
135 | if (strm->avail_in > 1 && | |
136 | strm->next_in[0] == 31 && strm->next_in[1] == 139) { | |
137 | inflateReset(strm); | |
138 | state->how = GZIP; | |
139 | state->direct = 0; | |
140 | return 0; | |
141 | } | |
142 | ||
143 | /* no gzip header -- if we were decoding gzip before, then this is trailing | |
144 | garbage. Ignore the trailing garbage and finish. */ | |
145 | if (state->direct == 0) { | |
146 | strm->avail_in = 0; | |
147 | state->eof = 1; | |
148 | state->x.have = 0; | |
149 | return 0; | |
150 | } | |
151 | ||
152 | /* doing raw i/o, copy any leftover input to output -- this assumes that | |
153 | the output buffer is larger than the input buffer, which also assures | |
154 | space for gzungetc() */ | |
155 | state->x.next = state->out; | |
156 | if (strm->avail_in) { | |
157 | memcpy(state->x.next, strm->next_in, strm->avail_in); | |
158 | state->x.have = strm->avail_in; | |
159 | strm->avail_in = 0; | |
160 | } | |
161 | state->how = COPY; | |
162 | state->direct = 1; | |
163 | return 0; | |
164 | } | |
165 | ||
166 | /* Decompress from input to the provided next_out and avail_out in the state. | |
167 | On return, state->x.have and state->x.next point to the just decompressed | |
168 | data. If the gzip stream completes, state->how is reset to LOOK to look for | |
169 | the next gzip stream or raw data, once state->x.have is depleted. Returns 0 | |
170 | on success, -1 on failure. */ | |
171 | local int gz_decomp(state) | |
172 | gz_statep state; | |
173 | { | |
174 | int ret = Z_OK; | |
175 | unsigned had; | |
176 | z_streamp strm = &(state->strm); | |
177 | ||
178 | /* fill output buffer up to end of deflate stream */ | |
179 | had = strm->avail_out; | |
180 | do { | |
181 | /* get more input for inflate() */ | |
182 | if (strm->avail_in == 0 && gz_avail(state) == -1) | |
183 | return -1; | |
184 | if (strm->avail_in == 0) { | |
185 | gz_error(state, Z_BUF_ERROR, "unexpected end of file"); | |
186 | break; | |
187 | } | |
188 | ||
189 | /* decompress and handle errors */ | |
190 | ret = inflate(strm, Z_NO_FLUSH); | |
191 | if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) { | |
192 | gz_error(state, Z_STREAM_ERROR, | |
193 | "internal error: inflate stream corrupt"); | |
194 | return -1; | |
195 | } | |
196 | if (ret == Z_MEM_ERROR) { | |
197 | gz_error(state, Z_MEM_ERROR, "out of memory"); | |
198 | return -1; | |
199 | } | |
200 | if (ret == Z_DATA_ERROR) { /* deflate stream invalid */ | |
201 | gz_error(state, Z_DATA_ERROR, | |
202 | strm->msg == NULL ? "compressed data error" : strm->msg); | |
203 | return -1; | |
204 | } | |
205 | } while (strm->avail_out && ret != Z_STREAM_END); | |
206 | ||
207 | /* update available output */ | |
208 | state->x.have = had - strm->avail_out; | |
209 | state->x.next = strm->next_out - state->x.have; | |
210 | ||
211 | /* if the gzip stream completed successfully, look for another */ | |
212 | if (ret == Z_STREAM_END) | |
213 | state->how = LOOK; | |
214 | ||
215 | /* good decompression */ | |
216 | return 0; | |
217 | } | |
218 | ||
219 | /* Fetch data and put it in the output buffer. Assumes state->x.have is 0. | |
220 | Data is either copied from the input file or decompressed from the input | |
221 | file depending on state->how. If state->how is LOOK, then a gzip header is | |
222 | looked for to determine whether to copy or decompress. Returns -1 on error, | |
223 | otherwise 0. gz_fetch() will leave state->how as COPY or GZIP unless the | |
224 | end of the input file has been reached and all data has been processed. */ | |
225 | local int gz_fetch(state) | |
226 | gz_statep state; | |
227 | { | |
228 | z_streamp strm = &(state->strm); | |
229 | ||
230 | do { | |
231 | switch(state->how) { | |
232 | case LOOK: /* -> LOOK, COPY (only if never GZIP), or GZIP */ | |
233 | if (gz_look(state) == -1) | |
234 | return -1; | |
235 | if (state->how == LOOK) | |
236 | return 0; | |
237 | break; | |
238 | case COPY: /* -> COPY */ | |
239 | if (gz_load(state, state->out, state->size << 1, &(state->x.have)) | |
240 | == -1) | |
241 | return -1; | |
242 | state->x.next = state->out; | |
243 | return 0; | |
244 | case GZIP: /* -> GZIP or LOOK (if end of gzip stream) */ | |
245 | strm->avail_out = state->size << 1; | |
246 | strm->next_out = state->out; | |
247 | if (gz_decomp(state) == -1) | |
248 | return -1; | |
249 | } | |
250 | } while (state->x.have == 0 && (!state->eof || strm->avail_in)); | |
251 | return 0; | |
252 | } | |
253 | ||
254 | /* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */ | |
255 | local int gz_skip(state, len) | |
256 | gz_statep state; | |
257 | z_off64_t len; | |
258 | { | |
259 | unsigned n; | |
260 | ||
261 | /* skip over len bytes or reach end-of-file, whichever comes first */ | |
262 | while (len) | |
263 | /* skip over whatever is in output buffer */ | |
264 | if (state->x.have) { | |
265 | n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > len ? | |
266 | (unsigned)len : state->x.have; | |
267 | state->x.have -= n; | |
268 | state->x.next += n; | |
269 | state->x.pos += n; | |
270 | len -= n; | |
271 | } | |
272 | ||
273 | /* output buffer empty -- return if we're at the end of the input */ | |
274 | else if (state->eof && state->strm.avail_in == 0) | |
275 | break; | |
276 | ||
277 | /* need more data to skip -- load up output buffer */ | |
278 | else { | |
279 | /* get more output, looking for header if required */ | |
280 | if (gz_fetch(state) == -1) | |
281 | return -1; | |
282 | } | |
283 | return 0; | |
284 | } | |
285 | ||
286 | /* -- see zlib.h -- */ | |
287 | int ZEXPORT gzread(file, buf, len) | |
288 | gzFile file; | |
289 | voidp buf; | |
290 | unsigned len; | |
291 | { | |
292 | unsigned got, n; | |
293 | gz_statep state; | |
294 | z_streamp strm; | |
295 | ||
296 | /* get internal structure */ | |
297 | if (file == NULL) | |
298 | return -1; | |
299 | state = (gz_statep)file; | |
300 | strm = &(state->strm); | |
301 | ||
302 | /* check that we're reading and that there's no (serious) error */ | |
303 | if (state->mode != GZ_READ || | |
304 | (state->err != Z_OK && state->err != Z_BUF_ERROR)) | |
305 | return -1; | |
306 | ||
307 | /* since an int is returned, make sure len fits in one, otherwise return | |
308 | with an error (this avoids the flaw in the interface) */ | |
309 | if ((int)len < 0) { | |
310 | gz_error(state, Z_DATA_ERROR, "requested length does not fit in int"); | |
311 | return -1; | |
312 | } | |
313 | ||
314 | /* if len is zero, avoid unnecessary operations */ | |
315 | if (len == 0) | |
316 | return 0; | |
317 | ||
318 | /* process a skip request */ | |
319 | if (state->seek) { | |
320 | state->seek = 0; | |
321 | if (gz_skip(state, state->skip) == -1) | |
322 | return -1; | |
323 | } | |
324 | ||
325 | /* get len bytes to buf, or less than len if at the end */ | |
326 | got = 0; | |
327 | do { | |
328 | /* first just try copying data from the output buffer */ | |
329 | if (state->x.have) { | |
330 | n = state->x.have > len ? len : state->x.have; | |
331 | memcpy(buf, state->x.next, n); | |
332 | state->x.next += n; | |
333 | state->x.have -= n; | |
334 | } | |
335 | ||
336 | /* output buffer empty -- return if we're at the end of the input */ | |
337 | else if (state->eof && strm->avail_in == 0) { | |
338 | state->past = 1; /* tried to read past end */ | |
339 | break; | |
340 | } | |
341 | ||
342 | /* need output data -- for small len or new stream load up our output | |
343 | buffer */ | |
344 | else if (state->how == LOOK || len < (state->size << 1)) { | |
345 | /* get more output, looking for header if required */ | |
346 | if (gz_fetch(state) == -1) | |
347 | return -1; | |
348 | continue; /* no progress yet -- go back to copy above */ | |
349 | /* the copy above assures that we will leave with space in the | |
350 | output buffer, allowing at least one gzungetc() to succeed */ | |
351 | } | |
352 | ||
353 | /* large len -- read directly into user buffer */ | |
354 | else if (state->how == COPY) { /* read directly */ | |
355 | if (gz_load(state, buf, len, &n) == -1) | |
356 | return -1; | |
357 | } | |
358 | ||
359 | /* large len -- decompress directly into user buffer */ | |
360 | else { /* state->how == GZIP */ | |
361 | strm->avail_out = len; | |
362 | strm->next_out = buf; | |
363 | if (gz_decomp(state) == -1) | |
364 | return -1; | |
365 | n = state->x.have; | |
366 | state->x.have = 0; | |
367 | } | |
368 | ||
369 | /* update progress */ | |
370 | len -= n; | |
371 | buf = (char *)buf + n; | |
372 | got += n; | |
373 | state->x.pos += n; | |
374 | } while (len); | |
375 | ||
376 | /* return number of bytes read into user buffer (will fit in int) */ | |
377 | return (int)got; | |
378 | } | |
379 | ||
380 | /* -- see zlib.h -- */ | |
381 | #undef gzgetc | |
382 | int ZEXPORT gzgetc(file) | |
383 | gzFile file; | |
384 | { | |
385 | int ret; | |
386 | unsigned char buf[1]; | |
387 | gz_statep state; | |
388 | ||
389 | /* get internal structure */ | |
390 | if (file == NULL) | |
391 | return -1; | |
392 | state = (gz_statep)file; | |
393 | ||
394 | /* check that we're reading and that there's no (serious) error */ | |
395 | if (state->mode != GZ_READ || | |
396 | (state->err != Z_OK && state->err != Z_BUF_ERROR)) | |
397 | return -1; | |
398 | ||
399 | /* try output buffer (no need to check for skip request) */ | |
400 | if (state->x.have) { | |
401 | state->x.have--; | |
402 | state->x.pos++; | |
403 | return *(state->x.next)++; | |
404 | } | |
405 | ||
406 | /* nothing there -- try gzread() */ | |
407 | ret = gzread(file, buf, 1); | |
408 | return ret < 1 ? -1 : buf[0]; | |
409 | } | |
410 | ||
411 | int ZEXPORT gzgetc_(file) | |
412 | gzFile file; | |
413 | { | |
414 | return gzgetc(file); | |
415 | } | |
416 | ||
417 | /* -- see zlib.h -- */ | |
418 | int ZEXPORT gzungetc(c, file) | |
419 | int c; | |
420 | gzFile file; | |
421 | { | |
422 | gz_statep state; | |
423 | ||
424 | /* get internal structure */ | |
425 | if (file == NULL) | |
426 | return -1; | |
427 | state = (gz_statep)file; | |
428 | ||
429 | /* check that we're reading and that there's no (serious) error */ | |
430 | if (state->mode != GZ_READ || | |
431 | (state->err != Z_OK && state->err != Z_BUF_ERROR)) | |
432 | return -1; | |
433 | ||
434 | /* process a skip request */ | |
435 | if (state->seek) { | |
436 | state->seek = 0; | |
437 | if (gz_skip(state, state->skip) == -1) | |
438 | return -1; | |
439 | } | |
440 | ||
441 | /* can't push EOF */ | |
442 | if (c < 0) | |
443 | return -1; | |
444 | ||
445 | /* if output buffer empty, put byte at end (allows more pushing) */ | |
446 | if (state->x.have == 0) { | |
447 | state->x.have = 1; | |
448 | state->x.next = state->out + (state->size << 1) - 1; | |
449 | state->x.next[0] = c; | |
450 | state->x.pos--; | |
451 | state->past = 0; | |
452 | return c; | |
453 | } | |
454 | ||
455 | /* if no room, give up (must have already done a gzungetc()) */ | |
456 | if (state->x.have == (state->size << 1)) { | |
457 | gz_error(state, Z_DATA_ERROR, "out of room to push characters"); | |
458 | return -1; | |
459 | } | |
460 | ||
461 | /* slide output data if needed and insert byte before existing data */ | |
462 | if (state->x.next == state->out) { | |
463 | unsigned char *src = state->out + state->x.have; | |
464 | unsigned char *dest = state->out + (state->size << 1); | |
465 | while (src > state->out) | |
466 | *--dest = *--src; | |
467 | state->x.next = dest; | |
468 | } | |
469 | state->x.have++; | |
470 | state->x.next--; | |
471 | state->x.next[0] = c; | |
472 | state->x.pos--; | |
473 | state->past = 0; | |
474 | return c; | |
475 | } | |
476 | ||
477 | /* -- see zlib.h -- */ | |
478 | char * ZEXPORT gzgets(file, buf, len) | |
479 | gzFile file; | |
480 | char *buf; | |
481 | int len; | |
482 | { | |
483 | unsigned left, n; | |
484 | char *str; | |
485 | unsigned char *eol; | |
486 | gz_statep state; | |
487 | ||
488 | /* check parameters and get internal structure */ | |
489 | if (file == NULL || buf == NULL || len < 1) | |
490 | return NULL; | |
491 | state = (gz_statep)file; | |
492 | ||
493 | /* check that we're reading and that there's no (serious) error */ | |
494 | if (state->mode != GZ_READ || | |
495 | (state->err != Z_OK && state->err != Z_BUF_ERROR)) | |
496 | return NULL; | |
497 | ||
498 | /* process a skip request */ | |
499 | if (state->seek) { | |
500 | state->seek = 0; | |
501 | if (gz_skip(state, state->skip) == -1) | |
502 | return NULL; | |
503 | } | |
504 | ||
505 | /* copy output bytes up to new line or len - 1, whichever comes first -- | |
506 | append a terminating zero to the string (we don't check for a zero in | |
507 | the contents, let the user worry about that) */ | |
508 | str = buf; | |
509 | left = (unsigned)len - 1; | |
510 | if (left) do { | |
511 | /* assure that something is in the output buffer */ | |
512 | if (state->x.have == 0 && gz_fetch(state) == -1) | |
513 | return NULL; /* error */ | |
514 | if (state->x.have == 0) { /* end of file */ | |
515 | state->past = 1; /* read past end */ | |
516 | break; /* return what we have */ | |
517 | } | |
518 | ||
519 | /* look for end-of-line in current output buffer */ | |
520 | n = state->x.have > left ? left : state->x.have; | |
521 | eol = memchr(state->x.next, '\n', n); | |
522 | if (eol != NULL) | |
523 | n = (unsigned)(eol - state->x.next) + 1; | |
524 | ||
525 | /* copy through end-of-line, or remainder if not found */ | |
526 | memcpy(buf, state->x.next, n); | |
527 | state->x.have -= n; | |
528 | state->x.next += n; | |
529 | state->x.pos += n; | |
530 | left -= n; | |
531 | buf += n; | |
532 | } while (left && eol == NULL); | |
533 | ||
534 | /* return terminated string, or if nothing, end of file */ | |
535 | if (buf == str) | |
536 | return NULL; | |
537 | buf[0] = 0; | |
538 | return str; | |
539 | } | |
540 | ||
541 | /* -- see zlib.h -- */ | |
542 | int ZEXPORT gzdirect(file) | |
543 | gzFile file; | |
544 | { | |
545 | gz_statep state; | |
546 | ||
547 | /* get internal structure */ | |
548 | if (file == NULL) | |
549 | return 0; | |
550 | state = (gz_statep)file; | |
551 | ||
552 | /* if the state is not known, but we can find out, then do so (this is | |
553 | mainly for right after a gzopen() or gzdopen()) */ | |
554 | if (state->mode == GZ_READ && state->how == LOOK && state->x.have == 0) | |
555 | (void)gz_look(state); | |
556 | ||
557 | /* return 1 if transparent, 0 if processing a gzip stream */ | |
558 | return state->direct; | |
559 | } | |
560 | ||
561 | /* -- see zlib.h -- */ | |
562 | int ZEXPORT gzclose_r(file) | |
563 | gzFile file; | |
564 | { | |
565 | int ret, err; | |
566 | gz_statep state; | |
567 | ||
568 | /* get internal structure */ | |
569 | if (file == NULL) | |
570 | return Z_STREAM_ERROR; | |
571 | state = (gz_statep)file; | |
572 | ||
573 | /* check that we're reading */ | |
574 | if (state->mode != GZ_READ) | |
575 | return Z_STREAM_ERROR; | |
576 | ||
577 | /* free memory and close file */ | |
578 | if (state->size) { | |
579 | inflateEnd(&(state->strm)); | |
580 | free(state->out); | |
581 | free(state->in); | |
582 | } | |
583 | err = state->err == Z_BUF_ERROR ? Z_BUF_ERROR : Z_OK; | |
584 | gz_error(state, Z_OK, NULL); | |
585 | free(state->path); | |
586 | ret = close(state->fd); | |
587 | free(state); | |
588 | return ret ? Z_ERRNO : err; | |
589 | } |