1 /* gzlib.c -- zlib functions common to reading and writing gzip files
2 * Copyright (C) 2004, 2010 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
8 #if defined(_WIN32) && !defined(__BORLANDC__)
9 # define LSEEK _lseeki64
10 #elif defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
11 # define LSEEK lseek64
17 local void gz_reset OF((gz_statep));
18 local gzFile gz_open OF((const char *, int, const char *));
22 /* Map the Windows error number in ERROR to a locale-dependent error message
23 string and return a pointer to it. Typically, the values for ERROR come
26 The string pointed to shall not be modified by the application, but may be
27 overwritten by a subsequent call to gz_strwinerror
29 The gz_strwinerror function does not change the current setting of
31 char ZLIB_INTERNAL *gz_strwinerror (error)
34 static char buf[1024];
37 DWORD lasterr = GetLastError();
38 DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
39 | FORMAT_MESSAGE_ALLOCATE_BUFFER,
42 0, /* Default language */
47 /* If there is an \r\n appended, zap it. */
49 && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
54 if (chars > sizeof (buf) - 1) {
55 chars = sizeof (buf) - 1;
59 wcstombs(buf, msgbuf, chars + 1);
63 sprintf(buf, "unknown win32 error (%ld)", error);
66 SetLastError(lasterr);
72 /* Reset gzip file state */
73 local void gz_reset(state)
76 if (state->mode == GZ_READ) { /* for reading ... */
77 state->have = 0; /* no output data available */
78 state->eof = 0; /* not at end of file */
79 state->how = LOOK; /* look for gzip header */
80 state->direct = 1; /* default for empty file */
82 state->seek = 0; /* no seek request pending */
83 gz_error(state, Z_OK, NULL); /* clear error */
84 state->pos = 0; /* no uncompressed data yet */
85 state->strm.avail_in = 0; /* no input data yet */
88 /* Open a gzip file either by name or file descriptor. */
89 local gzFile gz_open(path, fd, mode)
96 /* allocate gzFile structure to return */
97 state = malloc(sizeof(gz_state));
100 state->size = 0; /* no buffers allocated yet */
101 state->want = GZBUFSIZE; /* requested buffer size */
102 state->msg = NULL; /* no error message yet */
105 state->mode = GZ_NONE;
106 state->level = Z_DEFAULT_COMPRESSION;
107 state->strategy = Z_DEFAULT_STRATEGY;
109 if (*mode >= '0' && *mode <= '9')
110 state->level = *mode - '0';
114 state->mode = GZ_READ;
116 #ifndef NO_GZCOMPRESS
118 state->mode = GZ_WRITE;
121 state->mode = GZ_APPEND;
124 case '+': /* can't read and write at the same time */
127 case 'b': /* ignore -- will request binary anyway */
130 state->strategy = Z_FILTERED;
133 state->strategy = Z_HUFFMAN_ONLY;
136 state->strategy = Z_RLE;
139 state->strategy = Z_FIXED;
140 default: /* could consider as an error, but just ignore */
146 /* must provide an "r", "w", or "a" */
147 if (state->mode == GZ_NONE) {
152 /* save the path name for error messages */
153 state->path = malloc(strlen(path) + 1);
154 if (state->path == NULL) {
158 strcpy(state->path, path);
160 /* open the file with the appropriate mode (or just use fd) */
161 state->fd = fd != -1 ? fd :
169 (state->mode == GZ_READ ?
171 (O_WRONLY | O_CREAT | (
172 state->mode == GZ_WRITE ?
176 if (state->fd == -1) {
181 if (state->mode == GZ_APPEND)
182 state->mode = GZ_WRITE; /* simplify later checks */
184 /* save the current position for rewinding (only if reading) */
185 if (state->mode == GZ_READ) {
186 state->start = LSEEK(state->fd, 0, SEEK_CUR);
187 if (state->start == -1) state->start = 0;
190 /* initialize stream */
194 return (gzFile)state;
197 /* -- see zlib.h -- */
198 gzFile ZEXPORT gzopen(path, mode)
202 return gz_open(path, -1, mode);
205 /* -- see zlib.h -- */
206 gzFile ZEXPORT gzopen64(path, mode)
210 return gz_open(path, -1, mode);
213 /* -- see zlib.h -- */
214 gzFile ZEXPORT gzdopen(fd, mode)
218 char *path; /* identifier for error messages */
221 if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
223 sprintf(path, "<fd:%d>", fd); /* for debugging */
224 gz = gz_open(path, fd, mode);
229 /* -- see zlib.h -- */
230 int ZEXPORT gzbuffer(file, size)
236 /* get internal structure and check integrity */
239 state = (gz_statep)file;
240 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
243 /* make sure we haven't already allocated memory */
244 if (state->size != 0)
247 /* check and set requested size */
254 /* -- see zlib.h -- */
255 int ZEXPORT gzrewind(file)
260 /* get internal structure */
263 state = (gz_statep)file;
265 /* check that we're reading and that there's no error */
266 if (state->mode != GZ_READ || state->err != Z_OK)
269 /* back up and start over */
270 if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
276 /* -- see zlib.h -- */
277 z_off64_t ZEXPORT gzseek64(file, offset, whence)
286 /* get internal structure and check integrity */
289 state = (gz_statep)file;
290 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
293 /* check that there's no error */
294 if (state->err != Z_OK)
297 /* can only seek from start or relative to current position */
298 if (whence != SEEK_SET && whence != SEEK_CUR)
301 /* normalize offset to a SEEK_CUR specification */
302 if (whence == SEEK_SET)
303 offset -= state->pos;
304 else if (state->seek)
305 offset += state->skip;
308 /* if within raw area while reading, just go there */
309 if (state->mode == GZ_READ && state->how == COPY &&
310 state->pos + offset >= state->raw) {
311 ret = LSEEK(state->fd, offset - state->have, SEEK_CUR);
317 gz_error(state, Z_OK, NULL);
318 state->strm.avail_in = 0;
319 state->pos += offset;
323 /* calculate skip amount, rewinding if needed for back seek when reading */
325 if (state->mode != GZ_READ) /* writing -- can't go backwards */
327 offset += state->pos;
328 if (offset < 0) /* before start of file! */
330 if (gzrewind(file) == -1) /* rewind, then skip to offset */
334 /* if reading, skip what's in output buffer (one less gzgetc() check) */
335 if (state->mode == GZ_READ) {
336 n = GT_OFF(state->have) || (z_off64_t)state->have > offset ?
337 (unsigned)offset : state->have;
344 /* request skip (if not zero) */
347 state->skip = offset;
349 return state->pos + offset;
352 /* -- see zlib.h -- */
353 z_off_t ZEXPORT gzseek(file, offset, whence)
360 ret = gzseek64(file, (z_off64_t)offset, whence);
361 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
364 /* -- see zlib.h -- */
365 z_off64_t ZEXPORT gztell64(file)
370 /* get internal structure and check integrity */
373 state = (gz_statep)file;
374 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
377 /* return position */
378 return state->pos + (state->seek ? state->skip : 0);
381 /* -- see zlib.h -- */
382 z_off_t ZEXPORT gztell(file)
387 ret = gztell64(file);
388 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
391 /* -- see zlib.h -- */
392 z_off64_t ZEXPORT gzoffset64(file)
398 /* get internal structure and check integrity */
401 state = (gz_statep)file;
402 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
405 /* compute and return effective offset in file */
406 offset = LSEEK(state->fd, 0, SEEK_CUR);
409 if (state->mode == GZ_READ) /* reading */
410 offset -= state->strm.avail_in; /* don't count buffered input */
414 /* -- see zlib.h -- */
415 z_off_t ZEXPORT gzoffset(file)
420 ret = gzoffset64(file);
421 return ret == (z_off_t)ret ? (z_off_t)ret : -1;
424 /* -- see zlib.h -- */
425 int ZEXPORT gzeof(file)
430 /* get internal structure and check integrity */
433 state = (gz_statep)file;
434 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
437 /* return end-of-file state */
438 return state->mode == GZ_READ ?
439 (state->eof && state->strm.avail_in == 0 && state->have == 0) : 0;
442 /* -- see zlib.h -- */
443 const char * ZEXPORT gzerror(file, errnum)
449 /* get internal structure and check integrity */
452 state = (gz_statep)file;
453 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
456 /* return error information */
458 *errnum = state->err;
459 return state->msg == NULL ? "" : state->msg;
462 /* -- see zlib.h -- */
463 void ZEXPORT gzclearerr(file)
468 /* get internal structure and check integrity */
471 state = (gz_statep)file;
472 if (state->mode != GZ_READ && state->mode != GZ_WRITE)
475 /* clear error and end-of-file */
476 if (state->mode == GZ_READ)
478 gz_error(state, Z_OK, NULL);
481 /* Create an error message in allocated memory and set state->err and
482 state->msg accordingly. Free any previous error message already there. Do
483 not try to free or allocate space if the error is Z_MEM_ERROR (out of
484 memory). Simply save the error message as a static string. If there is an
485 allocation failure constructing the error message, then convert the error to
487 void ZLIB_INTERNAL gz_error(state, err, msg)
492 /* free previously allocated message and clear */
493 if (state->msg != NULL) {
494 if (state->err != Z_MEM_ERROR)
499 /* set error code, and if no message, then done */
504 /* for an out of memory error, save as static string */
505 if (err == Z_MEM_ERROR) {
506 state->msg = (char *)msg;
510 /* construct error message with path */
511 if ((state->msg = malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
512 state->err = Z_MEM_ERROR;
513 state->msg = (char *)"out of memory";
516 strcpy(state->msg, state->path);
517 strcat(state->msg, ": ");
518 strcat(state->msg, msg);
523 /* portably return maximum value for an int (when limits.h presumed not
524 available) -- we need to do this to cover cases where 2's complement not
525 used, since C standard permits 1's complement and sign-bit representations,
526 otherwise we could just use ((unsigned)-1) >> 1 */
527 unsigned ZLIB_INTERNAL gz_intmax()