File indexing completed on 2024-04-21 03:48:30

 /* gzlib.c -- zlib functions common to reading and writing gzip files
  * Copyright (C) 2004, 2010, 2011, 2012, 2013 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
 
 /* Local functions */
 local void gz_reset OF((gz_statep));
 local gzFile gz_open OF((const void *, int, const char *));
 
 #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 (error)
      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(state)
     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 */
     }
     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(path, fd, mode)
     const void *path;
     int fd;
     const char *mode;
 {
     gz_statep state;
     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 _WIN32
     if (fd == -2) {
         len = wcstombs(NULL, path, 0);
         if (len == (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 _WIN32
     if (fd == -2)
         if (len)
             wcstombs(state->path, path, len + 1);
         else
             *(state->path) = 0;
     else
 #endif
 #if !defined(NO_snprintf) && !defined(NO_vsnprintf)
         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 _WIN32
         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)
         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(path, mode)
     const char *path;
     const char *mode;
 {
     return gz_open(path, -1, mode);
 }
 
 /* -- see zlib.h -- */
 gzFile ZEXPORT gzopen64(path, mode)
     const char *path;
     const char *mode;
 {
     return gz_open(path, -1, mode);
 }
 
 /* -- see zlib.h -- */
 gzFile ZEXPORT gzdopen(fd, mode)
     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)
     snprintf(path, 7 + 3 * sizeof(int), "<fd:%d>", fd); /* for debugging */
 #else
     sprintf(path, "<fd:%d>", fd);   /* for debugging */
 #endif
     gz = gz_open(path, fd, mode);
     free(path);
     return gz;
 }
 
 /* -- see zlib.h -- */
 #ifdef _WIN32
 gzFile ZEXPORT gzopen_w(path, mode)
     const wchar_t *path;
     const char *mode;
 {
     return gz_open(path, -2, mode);
 }
 #endif
 
 /* -- see zlib.h -- */
 int ZEXPORT gzbuffer(file, size)
     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 < 2)
         size = 2;               /* need two bytes to check magic header */
     state->want = size;
     return 0;
 }
 
 /* -- see zlib.h -- */
 int ZEXPORT gzrewind(file)
     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(file, offset, whence)
     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 - 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(file, offset, whence)
     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(file)
     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(file)
     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(file)
     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(file)
     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(file)
     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(file, errnum)
     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(file)
     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(state, err, msg)
     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)
     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
     return;
 }
 
 #ifndef INT_MAX
 /* 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()
 {
     unsigned p, q;
 
     p = 1;
     do {
         q = p;
         p <<= 1;
         p++;
     } while (p > q);
     return q >> 1;
 }
 #endif