1 /* gzlib.c -- zlib functions common to reading and writing gzip files
2 * Copyright (C) 2004, 2010, 2011, 2012, 2013 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
11 #if defined(_WIN32) && !defined(__BORLANDC__)
12 # define LSEEK _lseeki64
14 #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
15 # define LSEEK lseek64
22 local void gz_reset OF((gz_statep));
23 local gzFile gz_open OF((const void *, int, const char *));
27 /* Map the Windows error number in ERROR to a locale-dependent error message
28 string and return a pointer to it. Typically, the values for ERROR come
31 The string pointed to shall not be modified by the application, but may be
32 overwritten by a subsequent call to gz_strwinerror
34 The gz_strwinerror function does not change the current setting of
36 char ZLIB_INTERNAL *gz_strwinerror (error)
39 static char buf[1024];
42 DWORD lasterr = GetLastError();
43 DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
44 | FORMAT_MESSAGE_ALLOCATE_BUFFER,
47 0, /* Default language */
52 /* If there is an \r\n appended, zap it. */
54 && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
59 if (chars > sizeof (buf) - 1) {
60 chars = sizeof (buf) - 1;
64 wcstombs(buf, msgbuf, chars + 1);
68 sprintf(buf, "unknown win32 error (%ld)", error);
71 SetLastError(lasterr);
77 /* Reset gzip file state */
78 local void gz_reset(state)
81 state->x.have = 0; /* no output data available */
82 if (state->mode == GZ_READ) { /* for reading ... */
83 state->eof = 0; /* not at end of file */
84 state->past = 0; /* have not read past end yet */
85 state->how = LOOK; /* look for gzip header */
87 state->seek = 0; /* no seek request pending */
88 gz_error(state, Z_OK, NULL); /* clear error */
89 state->x.pos = 0; /* no uncompressed data yet */
90 state->strm.avail_in = 0; /* no input data yet */
93 /* Open a gzip file either by name or file descriptor. */
94 local gzFile gz_open(path, fd, mode)
113 /* allocate gzFile structure to return */
114 state = (gz_statep)malloc(sizeof(gz_state));
117 state->size = 0; /* no buffers allocated yet */
118 state->want = GZBUFSIZE; /* requested buffer size */
119 state->msg = NULL; /* no error message yet */
122 state->mode = GZ_NONE;
123 state->level = Z_DEFAULT_COMPRESSION;
124 state->strategy = Z_DEFAULT_STRATEGY;
127 if (*mode >= '0' && *mode <= '9')
128 state->level = *mode - '0';
132 state->mode = GZ_READ;
134 #ifndef NO_GZCOMPRESS
136 state->mode = GZ_WRITE;
139 state->mode = GZ_APPEND;
142 case '+': /* can't read and write at the same time */
145 case 'b': /* ignore -- will request binary anyway */
158 state->strategy = Z_FILTERED;
161 state->strategy = Z_HUFFMAN_ONLY;
164 state->strategy = Z_RLE;
167 state->strategy = Z_FIXED;
172 default: /* could consider as an error, but just ignore */
178 /* must provide an "r", "w", or "a" */
179 if (state->mode == GZ_NONE) {
184 /* can't force transparent read */
185 if (state->mode == GZ_READ) {
190 state->direct = 1; /* for empty file */
193 /* save the path name for error messages */
196 len = wcstombs(NULL, path, 0);
197 if (len == (size_t)-1)
202 len = strlen((const char *)path);
203 state->path = (char *)malloc(len + 1);
204 if (state->path == NULL) {
211 wcstombs(state->path, path, len + 1);
216 #if !defined(NO_snprintf) && !defined(NO_vsnprintf)
217 snprintf(state->path, len + 1, "%s", (const char *)path);
219 strcpy(state->path, path);
222 /* compute the flags for open() */
231 (cloexec ? O_CLOEXEC : 0) |
233 (state->mode == GZ_READ ?
235 (O_WRONLY | O_CREAT |
237 (exclusive ? O_EXCL : 0) |
239 (state->mode == GZ_WRITE ?
243 /* open the file with the appropriate flags (or just use fd) */
244 state->fd = fd > -1 ? fd : (
246 fd == -2 ? _wopen(path, oflag, 0666) :
248 open((const char *)path, oflag, 0666));
249 if (state->fd == -1) {
254 if (state->mode == GZ_APPEND)
255 state->mode = GZ_WRITE; /* simplify later checks */
257 /* save the current position for rewinding (only if reading) */
258 if (state->mode == GZ_READ) {
259 state->start = LSEEK(state->fd, 0, SEEK_CUR);
260 if (state->start == -1) state->start = 0;
263 /* initialize stream */
267 return (gzFile)state;
270 /* -- see zlib.h -- */
271 gzFile ZEXPORT gzopen(path, mode)
275 return gz_open(path, -1, mode);
278 /* -- see zlib.h -- */
279 gzFile ZEXPORT gzopen64(path, mode)
283 return gz_open(path, -1, mode);
286 /* -- see zlib.h -- */
287 gzFile ZEXPORT gzdopen(fd, mode)
291 char *path; /* identifier for error messages */
294 if (fd == -1 || (path = (char *)malloc(7 + 3 * sizeof(int))) == NULL)
296 #if !defined(NO_snprintf) && !defined(NO_vsnprintf)
297 snprintf(path, 7 + 3 * sizeof(int), "<fd:%d>", fd); /* for debugging */
299 sprintf(path, "<fd:%d>", fd); /* for debugging */
301 gz = gz_open(path, fd, mode);
306 /* -- see zlib.h -- */
308 gzFile ZEXPORT gzopen_w(path, mode)
312 return gz_open(path, -2, mode);
316 /* -- see zlib.h -- */
317 int ZEXPORT gzbuffer(file, size)
323 /* get internal structure and check integrity */
326 state = (gz_statep)file;
327 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
330 /* make sure we haven't already allocated memory */
331 if (state->size != 0)
334 /* check and set requested size */
336 size = 2; /* need two bytes to check magic header */
341 /* -- see zlib.h -- */
342 int ZEXPORT gzrewind(file)
347 /* get internal structure */
350 state = (gz_statep)file;
352 /* check that we're reading and that there's no error */
353 if (state->mode != GZ_READ ||
354 (state->err != Z_OK && state->err != Z_BUF_ERROR))
357 /* back up and start over */
358 if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
364 /* -- see zlib.h -- */
365 z_off64_t ZEXPORT gzseek64(file, offset, whence)
374 /* get internal structure and check integrity */
377 state = (gz_statep)file;
378 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
381 /* check that there's no error */
382 if (state->err != Z_OK && state->err != Z_BUF_ERROR)
385 /* can only seek from start or relative to current position */
386 if (whence != SEEK_SET && whence != SEEK_CUR)
389 /* normalize offset to a SEEK_CUR specification */
390 if (whence == SEEK_SET)
391 offset -= state->x.pos;
392 else if (state->seek)
393 offset += state->skip;
396 /* if within raw area while reading, just go there */
397 if (state->mode == GZ_READ && state->how == COPY &&
398 state->x.pos + offset >= 0) {
399 ret = LSEEK(state->fd, offset - state->x.have, SEEK_CUR);
406 gz_error(state, Z_OK, NULL);
407 state->strm.avail_in = 0;
408 state->x.pos += offset;
412 /* calculate skip amount, rewinding if needed for back seek when reading */
414 if (state->mode != GZ_READ) /* writing -- can't go backwards */
416 offset += state->x.pos;
417 if (offset < 0) /* before start of file! */
419 if (gzrewind(file) == -1) /* rewind, then skip to offset */
423 /* if reading, skip what's in output buffer (one less gzgetc() check) */
424 if (state->mode == GZ_READ) {
425 n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > offset ?
426 (unsigned)offset : state->x.have;
433 /* request skip (if not zero) */
436 state->skip = offset;
438 return state->x.pos + offset;
441 /* -- see zlib.h -- */
442 z_off_t ZEXPORT gzseek(file, offset, whence)
449 ret = gzseek64(file, (z_off64_t)offset, whence);
450 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
453 /* -- see zlib.h -- */
454 z_off64_t ZEXPORT gztell64(file)
459 /* get internal structure and check integrity */
462 state = (gz_statep)file;
463 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
466 /* return position */
467 return state->x.pos + (state->seek ? state->skip : 0);
470 /* -- see zlib.h -- */
471 z_off_t ZEXPORT gztell(file)
476 ret = gztell64(file);
477 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
480 /* -- see zlib.h -- */
481 z_off64_t ZEXPORT gzoffset64(file)
487 /* get internal structure and check integrity */
490 state = (gz_statep)file;
491 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
494 /* compute and return effective offset in file */
495 offset = LSEEK(state->fd, 0, SEEK_CUR);
498 if (state->mode == GZ_READ) /* reading */
499 offset -= state->strm.avail_in; /* don't count buffered input */
503 /* -- see zlib.h -- */
504 z_off_t ZEXPORT gzoffset(file)
509 ret = gzoffset64(file);
510 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
513 /* -- see zlib.h -- */
514 int ZEXPORT gzeof(file)
519 /* get internal structure and check integrity */
522 state = (gz_statep)file;
523 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
526 /* return end-of-file state */
527 return state->mode == GZ_READ ? state->past : 0;
530 /* -- see zlib.h -- */
531 const char * ZEXPORT gzerror(file, errnum)
537 /* get internal structure and check integrity */
540 state = (gz_statep)file;
541 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
544 /* return error information */
546 *errnum = state->err;
547 return state->err == Z_MEM_ERROR ? "out of memory" :
548 (state->msg == NULL ? "" : state->msg);
551 /* -- see zlib.h -- */
552 void ZEXPORT gzclearerr(file)
557 /* get internal structure and check integrity */
560 state = (gz_statep)file;
561 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
564 /* clear error and end-of-file */
565 if (state->mode == GZ_READ) {
569 gz_error(state, Z_OK, NULL);
572 /* Create an error message in allocated memory and set state->err and
573 state->msg accordingly. Free any previous error message already there. Do
574 not try to free or allocate space if the error is Z_MEM_ERROR (out of
575 memory). Simply save the error message as a static string. If there is an
576 allocation failure constructing the error message, then convert the error to
578 void ZLIB_INTERNAL gz_error(state, err, msg)
583 /* free previously allocated message and clear */
584 if (state->msg != NULL) {
585 if (state->err != Z_MEM_ERROR)
590 /* if fatal, set state->x.have to 0 so that the gzgetc() macro fails */
591 if (err != Z_OK && err != Z_BUF_ERROR)
594 /* set error code, and if no message, then done */
599 /* for an out of memory error, return literal string when requested */
600 if (err == Z_MEM_ERROR)
603 /* construct error message with path */
604 if ((state->msg = (char *)malloc(strlen(state->path) + strlen(msg) + 3)) ==
606 state->err = Z_MEM_ERROR;
609 #if !defined(NO_snprintf) && !defined(NO_vsnprintf)
610 snprintf(state->msg, strlen(state->path) + strlen(msg) + 3,
611 "%s%s%s", state->path, ": ", msg);
613 strcpy(state->msg, state->path);
614 strcat(state->msg, ": ");
615 strcat(state->msg, msg);
621 /* portably return maximum value for an int (when limits.h presumed not
622 available) -- we need to do this to cover cases where 2's complement not
623 used, since C standard permits 1's complement and sign-bit representations,
624 otherwise we could just use ((unsigned)-1) >> 1 */
625 unsigned ZLIB_INTERNAL gz_intmax()