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