/* gzlib.c -- zlib functions common to reading and writing gzip files
* Copyright (C) 2004-2024 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "gzguts.h"
#if defined(_WIN32) && !defined(__BORLANDC__)
# define LSEEK _lseeki64
#else
#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
# define LSEEK lseek64
#else
# define LSEEK lseek
#endif
#endif
#if defined UNDER_CE
/* Map the Windows error number in ERROR to a locale-dependent error message
string and return a pointer to it. Typically, the values for ERROR come
from GetLastError.
The string pointed to shall not be modified by the application, but may be
overwritten by a subsequent call to gz_strwinerror
The gz_strwinerror function does not change the current setting of
GetLastError. */
char ZLIB_INTERNAL *gz_strwinerror(DWORD error) {
static char buf[1024];
wchar_t *msgbuf;
DWORD lasterr = GetLastError();
DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
| FORMAT_MESSAGE_ALLOCATE_BUFFER,
NULL,
error,
0, /* Default language */
(LPVOID)&msgbuf,
0,
NULL);
if (chars != 0) {
/* If there is an \r\n appended, zap it. */
if (chars >= 2
&& msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
chars -= 2;
msgbuf[chars] = 0;
}
if (chars > sizeof (buf) - 1) {
chars = sizeof (buf) - 1;
msgbuf[chars] = 0;
}
wcstombs(buf, msgbuf, chars + 1);
LocalFree(msgbuf);
}
else {
sprintf(buf, "unknown win32 error (%ld)", error);
}
SetLastError(lasterr);
return buf;
}
#endif /* UNDER_CE */
/* Reset gzip file state */
local void gz_reset(gz_statep state) {
state->x.have = 0; /* no output data available */
if (state->mode == GZ_READ) { /* for reading ... */
state->eof = 0; /* not at end of file */
state->past = 0; /* have not read past end yet */
state->how = LOOK; /* look for gzip header */
}
else /* for writing ... */
state->reset = 0; /* no deflateReset pending */
state->seek = 0; /* no seek request pending */
gz_error(state, Z_OK, NULL); /* clear error */
state->x.pos = 0; /* no uncompressed data yet */
state->strm.avail_in = 0; /* no input data yet */
}
/* Open a gzip file either by name or file descriptor. */
local gzFile gz_open(const void *path, int fd, const char *mode) {
gz_statep state;
z_size_t len;
int oflag;
#ifdef O_CLOEXEC
int cloexec = 0;
#endif
#ifdef O_EXCL
int exclusive = 0;
#endif
/* check input */
if (path == NULL)
return NULL;
/* allocate gzFile structure to return */
state = (gz_statep)malloc(sizeof(gz_state));
if (state == NULL)
return NULL;
state->size = 0; /* no buffers allocated yet */
state->want = GZBUFSIZE; /* requested buffer size */
state->msg = NULL; /* no error message yet */
/* interpret mode */
state->mode = GZ_NONE;
state->level = Z_DEFAULT_COMPRESSION;
state->strategy = Z_DEFAULT_STRATEGY;
state->direct = 0;
while (*mode) {
if (*mode >= '0' && *mode <= '9')
state->level = *mode - '0';
else
switch (*mode) {
case 'r':
state->mode = GZ_READ;
break;
#ifndef NO_GZCOMPRESS
case 'w':
state->mode = GZ_WRITE;
break;
case 'a':
state->mode = GZ_APPEND;
break;
#endif
case '+': /* can't read and write at the same time */
free(state);
return NULL;
case 'b': /* ignore -- will request binary anyway */
break;
#ifdef O_CLOEXEC
case 'e':
cloexec = 1;
break;
#endif
#ifdef O_EXCL
case 'x':
exclusive = 1;
break;
#endif
case 'f':
state->strategy = Z_FILTERED;
break;
case 'h':
state->strategy = Z_HUFFMAN_ONLY;
break;
case 'R':
state->strategy = Z_RLE;
break;
case 'F':
state->strategy = Z_FIXED;
break;
case 'T':
state->direct = 1;
break;
default: /* could consider as an error, but just ignore */
;
}
mode++;
}
/* must provide an "r", "w", or "a" */
if (state->mode == GZ_NONE) {
free(state);
return NULL;
}
/* can't force transparent read */
if (state->mode == GZ_READ) {
if (state->direct) {
free(state);
return NULL;
}
state->direct = 1; /* for empty file */
}
/* save the path name for error messages */
#ifdef WIDECHAR
if (fd == -2) {
len = wcstombs(NULL, path, 0);
if (len == (z_size_t)-1)
len = 0;
}
else
#endif
len = strlen((const char *)path);
state->path = (char *)malloc(len + 1);
if (state->path == NULL) {
free(state);
return NULL;
}
#ifdef WIDECHAR
if (fd == -2)
if (len)
wcstombs(state->path, path, len + 1);
else
*(state->path) = 0;
else
#endif
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
(void)snprintf(state->path, len + 1, "%s", (const char *)path);
#else
strcpy(state->path, path);
#endif
/* compute the flags for open() */
oflag =
#ifdef O_LARGEFILE
O_LARGEFILE |
#endif
#ifdef O_BINARY
O_BINARY |
#endif
#ifdef O_CLOEXEC
(cloexec ? O_CLOEXEC : 0) |
#endif
(state->mode == GZ_READ ?
O_RDONLY :
(O_WRONLY | O_CREAT |
#ifdef O_EXCL
(exclusive ? O_EXCL : 0) |
#endif
(state->mode == GZ_WRITE ?
O_TRUNC :
O_APPEND)));
/* open the file with the appropriate flags (or just use fd) */
state->fd = fd > -1 ? fd : (
#ifdef WIDECHAR
fd == -2 ? _wopen(path, oflag, 0666) :
#endif
open((const char *)path, oflag, 0666));
if (state->fd == -1) {
free(state->path);
free(state);
return NULL;
}
if (state->mode == GZ_APPEND) {
LSEEK(state->fd, 0, SEEK_END); /* so gzoffset() is correct */
state->mode = GZ_WRITE; /* simplify later checks */
}
/* save the current position for rewinding (only if reading) */
if (state->mode == GZ_READ) {
state->start = LSEEK(state->fd, 0, SEEK_CUR);
if (state->start == -1) state->start = 0;
}
/* initialize stream */
gz_reset(state);
/* return stream */
return (gzFile)state;
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzopen(const char *path, const char *mode) {
return gz_open(path, -1, mode);
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzopen64(const char *path, const char *mode) {
return gz_open(path, -1, mode);
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzdopen(int fd, const char *mode) {
char *path; /* identifier for error messages */
gzFile gz;
if (fd == -1 || (path = (char *)malloc(7 + 3 * sizeof(int))) == NULL)
return NULL;
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
(void)snprintf(path, 7 + 3 * sizeof(int), "<fd:%d>", fd);
#else
sprintf(path, "<fd:%d>", fd); /* for debugging */
#endif
gz = gz_open(path, fd, mode);
free(path);
return gz;
}
/* -- see zlib.h -- */
#ifdef WIDECHAR
gzFile ZEXPORT gzopen_w(const wchar_t *path, const char *mode) {
return gz_open(path, -2, mode);
}
#endif
/* -- see zlib.h -- */
int ZEXPORT gzbuffer(gzFile file, unsigned size) {
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* make sure we haven't already allocated memory */
if (state->size != 0)
return -1;
/* check and set requested size */
if ((size << 1) < size)
return -1; /* need to be able to double it */
if (size < 8)
size = 8; /* needed to behave well with flushing */
state->want = size;
return 0;
}
/* -- see zlib.h -- */
int ZEXPORT gzrewind(gzFile file) {
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ ||
(state->err != Z_OK && state->err != Z_BUF_ERROR))
return -1;
/* back up and start over */
if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
return -1;
gz_reset(state);
return 0;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gzseek64(gzFile file, z_off64_t offset, int whence) {
unsigned n;
z_off64_t ret;
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* check that there's no error */
if (state->err != Z_OK && state->err != Z_BUF_ERROR)
return -1;
/* can only seek from start or relative to current position */
if (whence != SEEK_SET && whence != SEEK_CUR)
return -1;
/* normalize offset to a SEEK_CUR specification */
if (whence == SEEK_SET)
offset -= state->x.pos;
else if (state->seek)
offset += state->skip;
state->seek = 0;
/* if within raw area while reading, just go there */
if (state->mode == GZ_READ && state->how == COPY &&
state->x.pos + offset >= 0) {
ret = LSEEK(state->fd, offset - (z_off64_t)state->x.have, SEEK_CUR);
if (ret == -1)
return -1;
state->x.have = 0;
state->eof = 0;
state->past = 0;
state->seek = 0;
gz_error(state, Z_OK, NULL);
state->strm.avail_in = 0;
state->x.pos += offset;
return state->x.pos;
}
/* calculate skip amount, rewinding if needed for back seek when reading */
if (offset < 0) {
if (state->mode != GZ_READ) /* writing -- can't go backwards */
return -1;
offset += state->x.pos;
if (offset < 0) /* before start of file! */
return -1;
if (gzrewind(file) == -1) /* rewind, then skip to offset */
return -1;
}
/* if reading, skip what's in output buffer (one less gzgetc() check) */
if (state->mode == GZ_READ) {
n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > offset ?
(unsigned)offset : state->x.have;
state->x.have -= n;
state->x.next += n;
state->x.pos += n;
offset -= n;
}
/* request skip (if not zero) */
if (offset) {
state->seek = 1;
state->skip = offset;
}
return state->x.pos + offset;
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gzseek(gzFile file, z_off_t offset, int whence) {
z_off64_t ret;
ret = gzseek64(file, (z_off64_t)offset, whence);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gztell64(gzFile file) {
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* return position */
return state->x.pos + (state->seek ? state->skip : 0);
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gztell(gzFile file) {
z_off64_t ret;
ret = gztell64(file);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gzoffset64(gzFile file) {
z_off64_t offset;
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* compute and return effective offset in file */
offset = LSEEK(state->fd, 0, SEEK_CUR);
if (offset == -1)
return -1;
if (state->mode == GZ_READ) /* reading */
offset -= state->strm.avail_in; /* don't count buffered input */
return offset;
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gzoffset(gzFile file) {
z_off64_t ret;
ret = gzoffset64(file);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
int ZEXPORT gzeof(gzFile file) {
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return 0;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return 0;
/* return end-of-file state */
return state->mode == GZ_READ ? state->past : 0;
}
/* -- see zlib.h -- */
const char * ZEXPORT gzerror(gzFile file, int *errnum) {
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return NULL;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return NULL;
/* return error information */
if (errnum != NULL)
*errnum = state->err;
return state->err == Z_MEM_ERROR ? "out of memory" :
(state->msg == NULL ? "" : state->msg);
}
/* -- see zlib.h -- */
void ZEXPORT gzclearerr(gzFile file) {
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return;
/* clear error and end-of-file */
if (state->mode == GZ_READ) {
state->eof = 0;
state->past = 0;
}
gz_error(state, Z_OK, NULL);
}
/* Create an error message in allocated memory and set state->err and
state->msg accordingly. Free any previous error message already there. Do
not try to free or allocate space if the error is Z_MEM_ERROR (out of
memory). Simply save the error message as a static string. If there is an
allocation failure constructing the error message, then convert the error to
out of memory. */
void ZLIB_INTERNAL gz_error(gz_statep state, int err, const char *msg) {
/* free previously allocated message and clear */
if (state->msg != NULL) {
if (state->err != Z_MEM_ERROR)
free(state->msg);
state->msg = NULL;
}
/* if fatal, set state->x.have to 0 so that the gzgetc() macro fails */
if (err != Z_OK && err != Z_BUF_ERROR)
state->x.have = 0;
/* set error code, and if no message, then done */
state->err = err;
if (msg == NULL)
return;
/* for an out of memory error, return literal string when requested */
if (err == Z_MEM_ERROR)
return;
/* construct error message with path */
if ((state->msg = (char *)malloc(strlen(state->path) + strlen(msg) + 3)) ==
NULL) {
state->err = Z_MEM_ERROR;
return;
}
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
(void)snprintf(state->msg, strlen(state->path) + strlen(msg) + 3,
"%s%s%s", state->path, ": ", msg);
#else
strcpy(state->msg, state->path);
strcat(state->msg, ": ");
strcat(state->msg, msg);
#endif
}
/* portably return maximum value for an int (when limits.h presumed not
available) -- we need to do this to cover cases where 2's complement not
used, since C standard permits 1's complement and sign-bit representations,
otherwise we could just use ((unsigned)-1) >> 1 */
unsigned ZLIB_INTERNAL gz_intmax(void) {
#ifdef INT_MAX
return INT_MAX;
#else
unsigned p = 1, q;
do {
q = p;
p <<= 1;
p++;
} while (p > q);
return q >> 1;
#endif
}