cannam@89: /* gzlib.c -- zlib functions common to reading and writing gzip files
cannam@89:  * Copyright (C) 2004, 2010, 2011, 2012 Mark Adler
cannam@89:  * For conditions of distribution and use, see copyright notice in zlib.h
cannam@89:  */
cannam@89: 
cannam@89: #include "gzguts.h"
cannam@89: 
cannam@89: #if defined(_WIN32) && !defined(__BORLANDC__)
cannam@89: #  define LSEEK _lseeki64
cannam@89: #else
cannam@89: #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
cannam@89: #  define LSEEK lseek64
cannam@89: #else
cannam@89: #  define LSEEK lseek
cannam@89: #endif
cannam@89: #endif
cannam@89: 
cannam@89: /* Local functions */
cannam@89: local void gz_reset OF((gz_statep));
cannam@89: local gzFile gz_open OF((const void *, int, const char *));
cannam@89: 
cannam@89: #if defined UNDER_CE
cannam@89: 
cannam@89: /* Map the Windows error number in ERROR to a locale-dependent error message
cannam@89:    string and return a pointer to it.  Typically, the values for ERROR come
cannam@89:    from GetLastError.
cannam@89: 
cannam@89:    The string pointed to shall not be modified by the application, but may be
cannam@89:    overwritten by a subsequent call to gz_strwinerror
cannam@89: 
cannam@89:    The gz_strwinerror function does not change the current setting of
cannam@89:    GetLastError. */
cannam@89: char ZLIB_INTERNAL *gz_strwinerror (error)
cannam@89:      DWORD error;
cannam@89: {
cannam@89:     static char buf[1024];
cannam@89: 
cannam@89:     wchar_t *msgbuf;
cannam@89:     DWORD lasterr = GetLastError();
cannam@89:     DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
cannam@89:         | FORMAT_MESSAGE_ALLOCATE_BUFFER,
cannam@89:         NULL,
cannam@89:         error,
cannam@89:         0, /* Default language */
cannam@89:         (LPVOID)&msgbuf,
cannam@89:         0,
cannam@89:         NULL);
cannam@89:     if (chars != 0) {
cannam@89:         /* If there is an \r\n appended, zap it.  */
cannam@89:         if (chars >= 2
cannam@89:             && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
cannam@89:             chars -= 2;
cannam@89:             msgbuf[chars] = 0;
cannam@89:         }
cannam@89: 
cannam@89:         if (chars > sizeof (buf) - 1) {
cannam@89:             chars = sizeof (buf) - 1;
cannam@89:             msgbuf[chars] = 0;
cannam@89:         }
cannam@89: 
cannam@89:         wcstombs(buf, msgbuf, chars + 1);
cannam@89:         LocalFree(msgbuf);
cannam@89:     }
cannam@89:     else {
cannam@89:         sprintf(buf, "unknown win32 error (%ld)", error);
cannam@89:     }
cannam@89: 
cannam@89:     SetLastError(lasterr);
cannam@89:     return buf;
cannam@89: }
cannam@89: 
cannam@89: #endif /* UNDER_CE */
cannam@89: 
cannam@89: /* Reset gzip file state */
cannam@89: local void gz_reset(state)
cannam@89:     gz_statep state;
cannam@89: {
cannam@89:     state->x.have = 0;              /* no output data available */
cannam@89:     if (state->mode == GZ_READ) {   /* for reading ... */
cannam@89:         state->eof = 0;             /* not at end of file */
cannam@89:         state->past = 0;            /* have not read past end yet */
cannam@89:         state->how = LOOK;          /* look for gzip header */
cannam@89:     }
cannam@89:     state->seek = 0;                /* no seek request pending */
cannam@89:     gz_error(state, Z_OK, NULL);    /* clear error */
cannam@89:     state->x.pos = 0;               /* no uncompressed data yet */
cannam@89:     state->strm.avail_in = 0;       /* no input data yet */
cannam@89: }
cannam@89: 
cannam@89: /* Open a gzip file either by name or file descriptor. */
cannam@89: local gzFile gz_open(path, fd, mode)
cannam@89:     const void *path;
cannam@89:     int fd;
cannam@89:     const char *mode;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89:     size_t len;
cannam@89:     int oflag;
cannam@89: #ifdef O_CLOEXEC
cannam@89:     int cloexec = 0;
cannam@89: #endif
cannam@89: #ifdef O_EXCL
cannam@89:     int exclusive = 0;
cannam@89: #endif
cannam@89: 
cannam@89:     /* check input */
cannam@89:     if (path == NULL)
cannam@89:         return NULL;
cannam@89: 
cannam@89:     /* allocate gzFile structure to return */
cannam@89:     state = malloc(sizeof(gz_state));
cannam@89:     if (state == NULL)
cannam@89:         return NULL;
cannam@89:     state->size = 0;            /* no buffers allocated yet */
cannam@89:     state->want = GZBUFSIZE;    /* requested buffer size */
cannam@89:     state->msg = NULL;          /* no error message yet */
cannam@89: 
cannam@89:     /* interpret mode */
cannam@89:     state->mode = GZ_NONE;
cannam@89:     state->level = Z_DEFAULT_COMPRESSION;
cannam@89:     state->strategy = Z_DEFAULT_STRATEGY;
cannam@89:     state->direct = 0;
cannam@89:     while (*mode) {
cannam@89:         if (*mode >= '0' && *mode <= '9')
cannam@89:             state->level = *mode - '0';
cannam@89:         else
cannam@89:             switch (*mode) {
cannam@89:             case 'r':
cannam@89:                 state->mode = GZ_READ;
cannam@89:                 break;
cannam@89: #ifndef NO_GZCOMPRESS
cannam@89:             case 'w':
cannam@89:                 state->mode = GZ_WRITE;
cannam@89:                 break;
cannam@89:             case 'a':
cannam@89:                 state->mode = GZ_APPEND;
cannam@89:                 break;
cannam@89: #endif
cannam@89:             case '+':       /* can't read and write at the same time */
cannam@89:                 free(state);
cannam@89:                 return NULL;
cannam@89:             case 'b':       /* ignore -- will request binary anyway */
cannam@89:                 break;
cannam@89: #ifdef O_CLOEXEC
cannam@89:             case 'e':
cannam@89:                 cloexec = 1;
cannam@89:                 break;
cannam@89: #endif
cannam@89: #ifdef O_EXCL
cannam@89:             case 'x':
cannam@89:                 exclusive = 1;
cannam@89:                 break;
cannam@89: #endif
cannam@89:             case 'f':
cannam@89:                 state->strategy = Z_FILTERED;
cannam@89:                 break;
cannam@89:             case 'h':
cannam@89:                 state->strategy = Z_HUFFMAN_ONLY;
cannam@89:                 break;
cannam@89:             case 'R':
cannam@89:                 state->strategy = Z_RLE;
cannam@89:                 break;
cannam@89:             case 'F':
cannam@89:                 state->strategy = Z_FIXED;
cannam@89:             case 'T':
cannam@89:                 state->direct = 1;
cannam@89:             default:        /* could consider as an error, but just ignore */
cannam@89:                 ;
cannam@89:             }
cannam@89:         mode++;
cannam@89:     }
cannam@89: 
cannam@89:     /* must provide an "r", "w", or "a" */
cannam@89:     if (state->mode == GZ_NONE) {
cannam@89:         free(state);
cannam@89:         return NULL;
cannam@89:     }
cannam@89: 
cannam@89:     /* can't force transparent read */
cannam@89:     if (state->mode == GZ_READ) {
cannam@89:         if (state->direct) {
cannam@89:             free(state);
cannam@89:             return NULL;
cannam@89:         }
cannam@89:         state->direct = 1;      /* for empty file */
cannam@89:     }
cannam@89: 
cannam@89:     /* save the path name for error messages */
cannam@89: #ifdef _WIN32
cannam@89:     if (fd == -2) {
cannam@89:         len = wcstombs(NULL, path, 0);
cannam@89:         if (len == (size_t)-1)
cannam@89:             len = 0;
cannam@89:     }
cannam@89:     else
cannam@89: #endif
cannam@89:         len = strlen(path);
cannam@89:     state->path = malloc(len + 1);
cannam@89:     if (state->path == NULL) {
cannam@89:         free(state);
cannam@89:         return NULL;
cannam@89:     }
cannam@89: #ifdef _WIN32
cannam@89:     if (fd == -2)
cannam@89:         if (len)
cannam@89:             wcstombs(state->path, path, len + 1);
cannam@89:         else
cannam@89:             *(state->path) = 0;
cannam@89:     else
cannam@89: #endif
cannam@89:         strcpy(state->path, path);
cannam@89: 
cannam@89:     /* compute the flags for open() */
cannam@89:     oflag =
cannam@89: #ifdef O_LARGEFILE
cannam@89:         O_LARGEFILE |
cannam@89: #endif
cannam@89: #ifdef O_BINARY
cannam@89:         O_BINARY |
cannam@89: #endif
cannam@89: #ifdef O_CLOEXEC
cannam@89:         (cloexec ? O_CLOEXEC : 0) |
cannam@89: #endif
cannam@89:         (state->mode == GZ_READ ?
cannam@89:          O_RDONLY :
cannam@89:          (O_WRONLY | O_CREAT |
cannam@89: #ifdef O_EXCL
cannam@89:           (exclusive ? O_EXCL : 0) |
cannam@89: #endif
cannam@89:           (state->mode == GZ_WRITE ?
cannam@89:            O_TRUNC :
cannam@89:            O_APPEND)));
cannam@89: 
cannam@89:     /* open the file with the appropriate flags (or just use fd) */
cannam@89:     state->fd = fd > -1 ? fd : (
cannam@89: #ifdef _WIN32
cannam@89:         fd == -2 ? _wopen(path, oflag, 0666) :
cannam@89: #endif
cannam@89:         open(path, oflag, 0666));
cannam@89:     if (state->fd == -1) {
cannam@89:         free(state->path);
cannam@89:         free(state);
cannam@89:         return NULL;
cannam@89:     }
cannam@89:     if (state->mode == GZ_APPEND)
cannam@89:         state->mode = GZ_WRITE;         /* simplify later checks */
cannam@89: 
cannam@89:     /* save the current position for rewinding (only if reading) */
cannam@89:     if (state->mode == GZ_READ) {
cannam@89:         state->start = LSEEK(state->fd, 0, SEEK_CUR);
cannam@89:         if (state->start == -1) state->start = 0;
cannam@89:     }
cannam@89: 
cannam@89:     /* initialize stream */
cannam@89:     gz_reset(state);
cannam@89: 
cannam@89:     /* return stream */
cannam@89:     return (gzFile)state;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: gzFile ZEXPORT gzopen(path, mode)
cannam@89:     const char *path;
cannam@89:     const char *mode;
cannam@89: {
cannam@89:     return gz_open(path, -1, mode);
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: gzFile ZEXPORT gzopen64(path, mode)
cannam@89:     const char *path;
cannam@89:     const char *mode;
cannam@89: {
cannam@89:     return gz_open(path, -1, mode);
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: gzFile ZEXPORT gzdopen(fd, mode)
cannam@89:     int fd;
cannam@89:     const char *mode;
cannam@89: {
cannam@89:     char *path;         /* identifier for error messages */
cannam@89:     gzFile gz;
cannam@89: 
cannam@89:     if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
cannam@89:         return NULL;
cannam@89:     sprintf(path, "<fd:%d>", fd);   /* for debugging */
cannam@89:     gz = gz_open(path, fd, mode);
cannam@89:     free(path);
cannam@89:     return gz;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: #ifdef _WIN32
cannam@89: gzFile ZEXPORT gzopen_w(path, mode)
cannam@89:     const wchar_t *path;
cannam@89:     const char *mode;
cannam@89: {
cannam@89:     return gz_open(path, -2, mode);
cannam@89: }
cannam@89: #endif
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: int ZEXPORT gzbuffer(file, size)
cannam@89:     gzFile file;
cannam@89:     unsigned size;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return -1;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* make sure we haven't already allocated memory */
cannam@89:     if (state->size != 0)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* check and set requested size */
cannam@89:     if (size < 2)
cannam@89:         size = 2;               /* need two bytes to check magic header */
cannam@89:     state->want = size;
cannam@89:     return 0;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: int ZEXPORT gzrewind(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure */
cannam@89:     if (file == NULL)
cannam@89:         return -1;
cannam@89:     state = (gz_statep)file;
cannam@89: 
cannam@89:     /* check that we're reading and that there's no error */
cannam@89:     if (state->mode != GZ_READ ||
cannam@89:             (state->err != Z_OK && state->err != Z_BUF_ERROR))
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* back up and start over */
cannam@89:     if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
cannam@89:         return -1;
cannam@89:     gz_reset(state);
cannam@89:     return 0;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off64_t ZEXPORT gzseek64(file, offset, whence)
cannam@89:     gzFile file;
cannam@89:     z_off64_t offset;
cannam@89:     int whence;
cannam@89: {
cannam@89:     unsigned n;
cannam@89:     z_off64_t ret;
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return -1;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* check that there's no error */
cannam@89:     if (state->err != Z_OK && state->err != Z_BUF_ERROR)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* can only seek from start or relative to current position */
cannam@89:     if (whence != SEEK_SET && whence != SEEK_CUR)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* normalize offset to a SEEK_CUR specification */
cannam@89:     if (whence == SEEK_SET)
cannam@89:         offset -= state->x.pos;
cannam@89:     else if (state->seek)
cannam@89:         offset += state->skip;
cannam@89:     state->seek = 0;
cannam@89: 
cannam@89:     /* if within raw area while reading, just go there */
cannam@89:     if (state->mode == GZ_READ && state->how == COPY &&
cannam@89:             state->x.pos + offset >= 0) {
cannam@89:         ret = LSEEK(state->fd, offset - state->x.have, SEEK_CUR);
cannam@89:         if (ret == -1)
cannam@89:             return -1;
cannam@89:         state->x.have = 0;
cannam@89:         state->eof = 0;
cannam@89:         state->past = 0;
cannam@89:         state->seek = 0;
cannam@89:         gz_error(state, Z_OK, NULL);
cannam@89:         state->strm.avail_in = 0;
cannam@89:         state->x.pos += offset;
cannam@89:         return state->x.pos;
cannam@89:     }
cannam@89: 
cannam@89:     /* calculate skip amount, rewinding if needed for back seek when reading */
cannam@89:     if (offset < 0) {
cannam@89:         if (state->mode != GZ_READ)         /* writing -- can't go backwards */
cannam@89:             return -1;
cannam@89:         offset += state->x.pos;
cannam@89:         if (offset < 0)                     /* before start of file! */
cannam@89:             return -1;
cannam@89:         if (gzrewind(file) == -1)           /* rewind, then skip to offset */
cannam@89:             return -1;
cannam@89:     }
cannam@89: 
cannam@89:     /* if reading, skip what's in output buffer (one less gzgetc() check) */
cannam@89:     if (state->mode == GZ_READ) {
cannam@89:         n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > offset ?
cannam@89:             (unsigned)offset : state->x.have;
cannam@89:         state->x.have -= n;
cannam@89:         state->x.next += n;
cannam@89:         state->x.pos += n;
cannam@89:         offset -= n;
cannam@89:     }
cannam@89: 
cannam@89:     /* request skip (if not zero) */
cannam@89:     if (offset) {
cannam@89:         state->seek = 1;
cannam@89:         state->skip = offset;
cannam@89:     }
cannam@89:     return state->x.pos + offset;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off_t ZEXPORT gzseek(file, offset, whence)
cannam@89:     gzFile file;
cannam@89:     z_off_t offset;
cannam@89:     int whence;
cannam@89: {
cannam@89:     z_off64_t ret;
cannam@89: 
cannam@89:     ret = gzseek64(file, (z_off64_t)offset, whence);
cannam@89:     return ret == (z_off_t)ret ? (z_off_t)ret : -1;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off64_t ZEXPORT gztell64(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return -1;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* return position */
cannam@89:     return state->x.pos + (state->seek ? state->skip : 0);
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off_t ZEXPORT gztell(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     z_off64_t ret;
cannam@89: 
cannam@89:     ret = gztell64(file);
cannam@89:     return ret == (z_off_t)ret ? (z_off_t)ret : -1;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off64_t ZEXPORT gzoffset64(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     z_off64_t offset;
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return -1;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return -1;
cannam@89: 
cannam@89:     /* compute and return effective offset in file */
cannam@89:     offset = LSEEK(state->fd, 0, SEEK_CUR);
cannam@89:     if (offset == -1)
cannam@89:         return -1;
cannam@89:     if (state->mode == GZ_READ)             /* reading */
cannam@89:         offset -= state->strm.avail_in;     /* don't count buffered input */
cannam@89:     return offset;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: z_off_t ZEXPORT gzoffset(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     z_off64_t ret;
cannam@89: 
cannam@89:     ret = gzoffset64(file);
cannam@89:     return ret == (z_off_t)ret ? (z_off_t)ret : -1;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: int ZEXPORT gzeof(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return 0;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return 0;
cannam@89: 
cannam@89:     /* return end-of-file state */
cannam@89:     return state->mode == GZ_READ ? state->past : 0;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: const char * ZEXPORT gzerror(file, errnum)
cannam@89:     gzFile file;
cannam@89:     int *errnum;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return NULL;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return NULL;
cannam@89: 
cannam@89:     /* return error information */
cannam@89:     if (errnum != NULL)
cannam@89:         *errnum = state->err;
cannam@89:     return state->msg == NULL ? "" : state->msg;
cannam@89: }
cannam@89: 
cannam@89: /* -- see zlib.h -- */
cannam@89: void ZEXPORT gzclearerr(file)
cannam@89:     gzFile file;
cannam@89: {
cannam@89:     gz_statep state;
cannam@89: 
cannam@89:     /* get internal structure and check integrity */
cannam@89:     if (file == NULL)
cannam@89:         return;
cannam@89:     state = (gz_statep)file;
cannam@89:     if (state->mode != GZ_READ && state->mode != GZ_WRITE)
cannam@89:         return;
cannam@89: 
cannam@89:     /* clear error and end-of-file */
cannam@89:     if (state->mode == GZ_READ) {
cannam@89:         state->eof = 0;
cannam@89:         state->past = 0;
cannam@89:     }
cannam@89:     gz_error(state, Z_OK, NULL);
cannam@89: }
cannam@89: 
cannam@89: /* Create an error message in allocated memory and set state->err and
cannam@89:    state->msg accordingly.  Free any previous error message already there.  Do
cannam@89:    not try to free or allocate space if the error is Z_MEM_ERROR (out of
cannam@89:    memory).  Simply save the error message as a static string.  If there is an
cannam@89:    allocation failure constructing the error message, then convert the error to
cannam@89:    out of memory. */
cannam@89: void ZLIB_INTERNAL gz_error(state, err, msg)
cannam@89:     gz_statep state;
cannam@89:     int err;
cannam@89:     const char *msg;
cannam@89: {
cannam@89:     /* free previously allocated message and clear */
cannam@89:     if (state->msg != NULL) {
cannam@89:         if (state->err != Z_MEM_ERROR)
cannam@89:             free(state->msg);
cannam@89:         state->msg = NULL;
cannam@89:     }
cannam@89: 
cannam@89:     /* if fatal, set state->x.have to 0 so that the gzgetc() macro fails */
cannam@89:     if (err != Z_OK && err != Z_BUF_ERROR)
cannam@89:         state->x.have = 0;
cannam@89: 
cannam@89:     /* set error code, and if no message, then done */
cannam@89:     state->err = err;
cannam@89:     if (msg == NULL)
cannam@89:         return;
cannam@89: 
cannam@89:     /* for an out of memory error, save as static string */
cannam@89:     if (err == Z_MEM_ERROR) {
cannam@89:         state->msg = (char *)msg;
cannam@89:         return;
cannam@89:     }
cannam@89: 
cannam@89:     /* construct error message with path */
cannam@89:     if ((state->msg = malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
cannam@89:         state->err = Z_MEM_ERROR;
cannam@89:         state->msg = (char *)"out of memory";
cannam@89:         return;
cannam@89:     }
cannam@89:     strcpy(state->msg, state->path);
cannam@89:     strcat(state->msg, ": ");
cannam@89:     strcat(state->msg, msg);
cannam@89:     return;
cannam@89: }
cannam@89: 
cannam@89: #ifndef INT_MAX
cannam@89: /* portably return maximum value for an int (when limits.h presumed not
cannam@89:    available) -- we need to do this to cover cases where 2's complement not
cannam@89:    used, since C standard permits 1's complement and sign-bit representations,
cannam@89:    otherwise we could just use ((unsigned)-1) >> 1 */
cannam@89: unsigned ZLIB_INTERNAL gz_intmax()
cannam@89: {
cannam@89:     unsigned p, q;
cannam@89: 
cannam@89:     p = 1;
cannam@89:     do {
cannam@89:         q = p;
cannam@89:         p <<= 1;
cannam@89:         p++;
cannam@89:     } while (p > q);
cannam@89:     return q >> 1;
cannam@89: }
cannam@89: #endif