1 /* gzread.c contains minimal changes required to be compiled with zlibWrapper:
2 * - gz_statep was converted to union to work with -Wstrict-aliasing=1 */
4 /* gzread.c -- zlib functions for reading gzip files
5 * Copyright (C) 2004, 2005, 2010, 2011, 2012, 2013, 2016 Mark Adler
6 * For conditions of distribution and use, see https://www.zlib.net/zlib_license.html
11 /* fix for Visual Studio, which doesn't support ssize_t type.
12 * see https://github.com/facebook/zstd/issues/1800#issuecomment-545945050 */
13 #if defined(_MSC_VER) && !defined(ssize_t)
15 typedef SSIZE_T ssize_t;
20 local int gz_load _Z_OF((gz_statep, unsigned char *, unsigned, unsigned *));
21 local int gz_avail _Z_OF((gz_statep));
22 local int gz_look _Z_OF((gz_statep));
23 local int gz_decomp _Z_OF((gz_statep));
24 local int gz_fetch _Z_OF((gz_statep));
25 local int gz_skip _Z_OF((gz_statep, z_off64_t));
26 local z_size_t gz_read _Z_OF((gz_statep, voidp, z_size_t));
28 /* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from
29 state.state->fd, and update state.state->eof, state.state->err, and state.state->msg as appropriate.
30 This function needs to loop on read(), since read() is not guaranteed to
31 read the number of bytes requested, depending on the type of descriptor. */
32 local int gz_load(state, buf, len, have)
39 unsigned get, max = ((unsigned)-1 >> 2) + 1;
46 ret = read(state.state->fd, buf + *have, get);
49 *have += (unsigned)ret;
50 } while (*have < len);
52 gz_error(state, Z_ERRNO, zstrerror());
60 /* Load up input buffer and set eof flag if last data loaded -- return -1 on
61 error, 0 otherwise. Note that the eof flag is set when the end of the input
62 file is reached, even though there may be unused data in the buffer. Once
63 that data has been used, no more attempts will be made to read the file.
64 If strm->avail_in != 0, then the current data is moved to the beginning of
65 the input buffer, and then the remainder of the buffer is loaded with the
66 available data from the input file. */
67 local int gz_avail(state)
71 z_streamp strm = &(state.state->strm);
73 if (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR)
75 if (state.state->eof == 0) {
76 if (strm->avail_in) { /* copy what's there to the start */
77 unsigned char *p = state.state->in;
78 unsigned const char *q = strm->next_in;
79 unsigned n = strm->avail_in;
84 if (gz_load(state, state.state->in + strm->avail_in,
85 state.state->size - strm->avail_in, &got) == -1)
87 strm->avail_in += got;
88 strm->next_in = state.state->in;
93 /* Look for gzip header, set up for inflate or copy. state.state->x.have must be 0.
94 If this is the first time in, allocate required memory. state.state->how will be
95 left unchanged if there is no more input data available, will be set to COPY
96 if there is no gzip header and direct copying will be performed, or it will
97 be set to GZIP for decompression. If direct copying, then leftover input
98 data from the input buffer will be copied to the output buffer. In that
99 case, all further file reads will be directly to either the output buffer or
100 a user buffer. If decompressing, the inflate state will be initialized.
101 gz_look() will return 0 on success or -1 on failure. */
102 local int gz_look(state)
105 z_streamp strm = &(state.state->strm);
107 /* allocate read buffers and inflate memory */
108 if (state.state->size == 0) {
109 /* allocate buffers */
110 state.state->in = (unsigned char *)malloc(state.state->want);
111 state.state->out = (unsigned char *)malloc(state.state->want << 1);
112 if (state.state->in == NULL || state.state->out == NULL) {
113 free(state.state->out);
114 free(state.state->in);
115 gz_error(state, Z_MEM_ERROR, "out of memory");
118 state.state->size = state.state->want;
120 /* allocate inflate memory */
121 state.state->strm.zalloc = Z_NULL;
122 state.state->strm.zfree = Z_NULL;
123 state.state->strm.opaque = Z_NULL;
124 state.state->strm.avail_in = 0;
125 state.state->strm.next_in = Z_NULL;
126 if (inflateInit2(&(state.state->strm), 15 + 16) != Z_OK) { /* gunzip */
127 free(state.state->out);
128 free(state.state->in);
129 state.state->size = 0;
130 gz_error(state, Z_MEM_ERROR, "out of memory");
135 /* get at least the magic bytes in the input buffer */
136 if (strm->avail_in < 2) {
137 if (gz_avail(state) == -1)
139 if (strm->avail_in == 0)
143 /* look for gzip magic bytes -- if there, do gzip decoding (note: there is
144 a logical dilemma here when considering the case of a partially written
145 gzip file, to wit, if a single 31 byte is written, then we cannot tell
146 whether this is a single-byte file, or just a partially written gzip
147 file -- for here we assume that if a gzip file is being written, then
148 the header will be written in a single operation, so that reading a
149 single byte is sufficient indication that it is not a gzip file) */
150 if (strm->avail_in > 1 &&
151 ((strm->next_in[0] == 31 && strm->next_in[1] == 139) /* gz header */
152 || (strm->next_in[0] == 40 && strm->next_in[1] == 181))) { /* zstd header */
154 state.state->how = GZIP;
155 state.state->direct = 0;
159 /* no gzip header -- if we were decoding gzip before, then this is trailing
160 garbage. Ignore the trailing garbage and finish. */
161 if (state.state->direct == 0) {
163 state.state->eof = 1;
164 state.state->x.have = 0;
168 /* doing raw i/o, copy any leftover input to output -- this assumes that
169 the output buffer is larger than the input buffer, which also assures
170 space for gzungetc() */
171 state.state->x.next = state.state->out;
172 if (strm->avail_in) {
173 memcpy(state.state->x.next, strm->next_in, strm->avail_in);
174 state.state->x.have = strm->avail_in;
177 state.state->how = COPY;
178 state.state->direct = 1;
182 /* Decompress from input to the provided next_out and avail_out in the state.
183 On return, state.state->x.have and state.state->x.next point to the just decompressed
184 data. If the gzip stream completes, state.state->how is reset to LOOK to look for
185 the next gzip stream or raw data, once state.state->x.have is depleted. Returns 0
186 on success, -1 on failure. */
187 local int gz_decomp(state)
192 z_streamp strm = &(state.state->strm);
194 /* fill output buffer up to end of deflate stream */
195 had = strm->avail_out;
197 /* get more input for inflate() */
198 if (strm->avail_in == 0 && gz_avail(state) == -1)
200 if (strm->avail_in == 0) {
201 gz_error(state, Z_BUF_ERROR, "unexpected end of file");
205 /* decompress and handle errors */
206 ret = inflate(strm, Z_NO_FLUSH);
207 if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
208 gz_error(state, Z_STREAM_ERROR,
209 "internal error: inflate stream corrupt");
212 if (ret == Z_MEM_ERROR) {
213 gz_error(state, Z_MEM_ERROR, "out of memory");
216 if (ret == Z_DATA_ERROR) { /* deflate stream invalid */
217 gz_error(state, Z_DATA_ERROR,
218 strm->msg == NULL ? "compressed data error" : strm->msg);
221 } while (strm->avail_out && ret != Z_STREAM_END);
223 /* update available output */
224 state.state->x.have = had - strm->avail_out;
225 state.state->x.next = strm->next_out - state.state->x.have;
227 /* if the gzip stream completed successfully, look for another */
228 if (ret == Z_STREAM_END)
229 state.state->how = LOOK;
231 /* good decompression */
235 /* Fetch data and put it in the output buffer. Assumes state.state->x.have is 0.
236 Data is either copied from the input file or decompressed from the input
237 file depending on state.state->how. If state.state->how is LOOK, then a gzip header is
238 looked for to determine whether to copy or decompress. Returns -1 on error,
239 otherwise 0. gz_fetch() will leave state.state->how as COPY or GZIP unless the
240 end of the input file has been reached and all data has been processed. */
241 local int gz_fetch(state)
244 z_streamp strm = &(state.state->strm);
247 switch(state.state->how) {
248 case LOOK: /* -> LOOK, COPY (only if never GZIP), or GZIP */
249 if (gz_look(state) == -1)
251 if (state.state->how == LOOK)
254 case COPY: /* -> COPY */
255 if (gz_load(state, state.state->out, state.state->size << 1, &(state.state->x.have))
258 state.state->x.next = state.state->out;
260 case GZIP: /* -> GZIP or LOOK (if end of gzip stream) */
261 strm->avail_out = state.state->size << 1;
262 strm->next_out = state.state->out;
263 if (gz_decomp(state) == -1)
266 } while (state.state->x.have == 0 && (!state.state->eof || strm->avail_in));
270 /* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */
271 local int gz_skip(state, len)
277 /* skip over len bytes or reach end-of-file, whichever comes first */
279 /* skip over whatever is in output buffer */
280 if (state.state->x.have) {
281 n = GT_OFF(state.state->x.have) || (z_off64_t)state.state->x.have > len ?
282 (unsigned)len : state.state->x.have;
283 state.state->x.have -= n;
284 state.state->x.next += n;
285 state.state->x.pos += n;
289 /* output buffer empty -- return if we're at the end of the input */
290 else if (state.state->eof && state.state->strm.avail_in == 0)
293 /* need more data to skip -- load up output buffer */
295 /* get more output, looking for header if required */
296 if (gz_fetch(state) == -1)
302 /* Read len bytes into buf from file, or less than len up to the end of the
303 input. Return the number of bytes read. If zero is returned, either the
304 end of file was reached, or there was an error. state.state->err must be
305 consulted in that case to determine which. */
306 local z_size_t gz_read(state, buf, len)
314 /* if len is zero, avoid unnecessary operations */
318 /* process a skip request */
319 if (state.state->seek) {
320 state.state->seek = 0;
321 if (gz_skip(state, state.state->skip) == -1)
325 /* get len bytes to buf, or less than len if at the end */
328 /* set n to the maximum amount of len that fits in an unsigned int */
333 /* first just try copying data from the output buffer */
334 if (state.state->x.have) {
335 if (state.state->x.have < n)
336 n = state.state->x.have;
337 memcpy(buf, state.state->x.next, n);
338 state.state->x.next += n;
339 state.state->x.have -= n;
342 /* output buffer empty -- return if we're at the end of the input */
343 else if (state.state->eof && state.state->strm.avail_in == 0) {
344 state.state->past = 1; /* tried to read past end */
348 /* need output data -- for small len or new stream load up our output
350 else if (state.state->how == LOOK || n < (state.state->size << 1)) {
351 /* get more output, looking for header if required */
352 if (gz_fetch(state) == -1)
354 continue; /* no progress yet -- go back to copy above */
355 /* the copy above assures that we will leave with space in the
356 output buffer, allowing at least one gzungetc() to succeed */
359 /* large len -- read directly into user buffer */
360 else if (state.state->how == COPY) { /* read directly */
361 if (gz_load(state, (unsigned char *)buf, n, &n) == -1)
365 /* large len -- decompress directly into user buffer */
366 else { /* state.state->how == GZIP */
367 state.state->strm.avail_out = n;
368 state.state->strm.next_out = (unsigned char *)buf;
369 if (gz_decomp(state) == -1)
371 n = state.state->x.have;
372 state.state->x.have = 0;
375 /* update progress */
377 buf = (char *)buf + n;
379 state.state->x.pos += n;
382 /* return number of bytes read into user buffer */
386 /* -- see zlib.h -- */
387 int ZEXPORT gzread(file, buf, len)
394 /* get internal structure */
399 /* check that we're reading and that there's no (serious) error */
400 if (state.state->mode != GZ_READ ||
401 (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR))
404 /* since an int is returned, make sure len fits in one, otherwise return
405 with an error (this avoids a flaw in the interface) */
407 gz_error(state, Z_STREAM_ERROR, "request does not fit in an int");
411 /* read len or fewer bytes to buf */
412 len = (unsigned)gz_read(state, buf, len);
414 /* check for an error */
415 if (len == 0 && state.state->err != Z_OK && state.state->err != Z_BUF_ERROR)
418 /* return the number of bytes read (this is assured to fit in an int) */
422 /* -- see zlib.h -- */
423 z_size_t ZEXPORT gzfread(buf, size, nitems, file)
432 /* get internal structure */
437 /* check that we're reading and that there's no (serious) error */
438 if (state.state->mode != GZ_READ ||
439 (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR))
442 /* compute bytes to read -- error on overflow */
444 if (size && len / size != nitems) {
445 gz_error(state, Z_STREAM_ERROR, "request does not fit in a size_t");
449 /* read len or fewer bytes to buf, return the number of full items read */
450 return len ? gz_read(state, buf, len) / size : 0;
453 /* -- see zlib.h -- */
454 #if ZLIB_VERNUM >= 0x1261
462 #if ZLIB_VERNUM == 0x1260
466 #if ZLIB_VERNUM <= 0x1250
467 ZEXTERN int ZEXPORT gzgetc _Z_OF((gzFile file));
468 ZEXTERN int ZEXPORT gzgetc_ _Z_OF((gzFile file));
471 int ZEXPORT gzgetc(file)
475 unsigned char buf[1];
478 /* get internal structure */
483 /* check that we're reading and that there's no (serious) error */
484 if (state.state->mode != GZ_READ ||
485 (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR))
488 /* try output buffer (no need to check for skip request) */
489 if (state.state->x.have) {
490 state.state->x.have--;
491 state.state->x.pos++;
492 return *(state.state->x.next)++;
495 /* nothing there -- try gz_read() */
496 ret = (int)gz_read(state, buf, 1);
497 return ret < 1 ? -1 : buf[0];
500 int ZEXPORT gzgetc_(file)
506 /* -- see zlib.h -- */
507 int ZEXPORT gzungetc(c, file)
513 /* get internal structure */
518 /* check that we're reading and that there's no (serious) error */
519 if (state.state->mode != GZ_READ ||
520 (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR))
523 /* process a skip request */
524 if (state.state->seek) {
525 state.state->seek = 0;
526 if (gz_skip(state, state.state->skip) == -1)
534 /* if output buffer empty, put byte at end (allows more pushing) */
535 if (state.state->x.have == 0) {
536 state.state->x.have = 1;
537 state.state->x.next = state.state->out + (state.state->size << 1) - 1;
538 state.state->x.next[0] = (unsigned char)c;
539 state.state->x.pos--;
540 state.state->past = 0;
544 /* if no room, give up (must have already done a gzungetc()) */
545 if (state.state->x.have == (state.state->size << 1)) {
546 gz_error(state, Z_DATA_ERROR, "out of room to push characters");
550 /* slide output data if needed and insert byte before existing data */
551 if (state.state->x.next == state.state->out) {
552 unsigned char *src = state.state->out + state.state->x.have;
553 unsigned char *dest = state.state->out + (state.state->size << 1);
554 while (src > state.state->out)
556 state.state->x.next = dest;
558 state.state->x.have++;
559 state.state->x.next--;
560 state.state->x.next[0] = (unsigned char)c;
561 state.state->x.pos--;
562 state.state->past = 0;
566 /* -- see zlib.h -- */
567 char * ZEXPORT gzgets(file, buf, len)
577 /* check parameters and get internal structure */
578 if (file == NULL || buf == NULL || len < 1)
582 /* check that we're reading and that there's no (serious) error */
583 if (state.state->mode != GZ_READ ||
584 (state.state->err != Z_OK && state.state->err != Z_BUF_ERROR))
587 /* process a skip request */
588 if (state.state->seek) {
589 state.state->seek = 0;
590 if (gz_skip(state, state.state->skip) == -1)
594 /* copy output bytes up to new line or len - 1, whichever comes first --
595 append a terminating zero to the string (we don't check for a zero in
596 the contents, let the user worry about that) */
598 left = (unsigned)len - 1;
600 /* assure that something is in the output buffer */
601 if (state.state->x.have == 0 && gz_fetch(state) == -1)
602 return NULL; /* error */
603 if (state.state->x.have == 0) { /* end of file */
604 state.state->past = 1; /* read past end */
605 break; /* return what we have */
608 /* look for end-of-line in current output buffer */
609 n = state.state->x.have > left ? left : state.state->x.have;
610 eol = (unsigned char *)memchr(state.state->x.next, '\n', n);
612 n = (unsigned)(eol - state.state->x.next) + 1;
614 /* copy through end-of-line, or remainder if not found */
615 memcpy(buf, state.state->x.next, n);
616 state.state->x.have -= n;
617 state.state->x.next += n;
618 state.state->x.pos += n;
621 } while (left && eol == NULL);
623 /* return terminated string, or if nothing, end of file */
630 /* -- see zlib.h -- */
631 int ZEXPORT gzdirect(file)
636 /* get internal structure */
641 /* if the state is not known, but we can find out, then do so (this is
642 mainly for right after a gzopen() or gzdopen()) */
643 if (state.state->mode == GZ_READ && state.state->how == LOOK && state.state->x.have == 0)
644 (void)gz_look(state);
646 /* return 1 if transparent, 0 if processing a gzip stream */
647 return state.state->direct;
650 /* -- see zlib.h -- */
651 int ZEXPORT gzclose_r(file)
657 /* get internal structure */
659 return Z_STREAM_ERROR;
662 /* check that we're reading */
663 if (state.state->mode != GZ_READ)
664 return Z_STREAM_ERROR;
666 /* free memory and close file */
667 if (state.state->size) {
668 inflateEnd(&(state.state->strm));
669 free(state.state->out);
670 free(state.state->in);
672 err = state.state->err == Z_BUF_ERROR ? Z_BUF_ERROR : Z_OK;
673 gz_error(state, Z_OK, NULL);
674 free(state.state->path);
675 ret = close(state.state->fd);
677 return ret ? Z_ERRNO : err;