gzip.c

zip格式压缩解压缩源码及演示 先用VC编译czip_source目录内程序,之后拷贝debug目录内zipdll.dll和zipdll.lib到czip_demo目录再编译此目录内程序即可得到演示程

#ifdef NO_MULTIPLE_DOTS
    fprintf(stderr, "NO_MULTIPLE_DOTS ");
#endif
#ifdef NO_CHOWN
    fprintf(stderr, "NO_CHOWN ");
#endif
#ifdef PROTO
    fprintf(stderr, "PROTO ");
#endif
#ifdef ASMV
    fprintf(stderr, "ASMV ");
#endif
#ifdef DEBUG
    fprintf(stderr, "DEBUG ");
#endif
#ifdef DYN_ALLOC
    fprintf(stderr, "DYN_ALLOC ");
#endif
#ifdef MAXSEG_64K
    fprintf(stderr, "MAXSEG_64K");
#endif
    fprintf(stderr, "\n");
}


/* ========================================================================
 * Compress or decompress stdin
 */
local void treat_stdin()
{
    if (!force && !list &&
	isatty(fileno((FILE *)(decompress ? stdin : stdout)))) {
	/* Do not send compressed data to the terminal or read it from
	 * the terminal. We get here when user invoked the program
	 * without parameters, so be helpful. According to the GNU standards:
	 *
	 *   If there is one behavior you think is most useful when the output
	 *   is to a terminal, and another that you think is most useful when
	 *   the output is a file or a pipe, then it is usually best to make
	 *   the default behavior the one that is useful with output to a
	 *   terminal, and have an option for the other behavior.
	 *
	 * Here we use the --force option to get the other behavior.
	 */
	fprintf(stderr,
    "%s: compressed data not %s a terminal. Use -f to force %scompression.\n",
		progname, decompress ? "read from" : "written to",
		decompress ? "de" : "");
	fprintf(stderr,"For help, type: %s -h\n", progname);
	do_exit(ERROR);
    }

    if (decompress || !ascii) {
	SET_BINARY_MODE(fileno(stdin));
    }
    if (!test && !list && (!decompress || !ascii)) {
	SET_BINARY_MODE(fileno(stdout));
    }
    strcpy(ifname, "stdin");
    strcpy(ofname, "stdout");

    /* Get the time stamp on the input file. */
    time_stamp = 0; /* time unknown by default */

#ifndef NO_STDIN_FSTAT
    if (list || !no_time) {
	if (fstat(fileno(stdin), &istat) != 0) {
	    error("fstat(stdin)");
	}
# ifdef NO_PIPE_TIMESTAMP
	if (S_ISREG(istat.st_mode))
# endif
	    time_stamp = istat.st_mtime;
#endif /* NO_STDIN_FSTAT */
    }
    ifile_size = -1L; /* convention for unknown size */

    clear_bufs(); /* clear input and output buffers */
    to_stdout = 1;
    part_nb = 0;

    if (decompress) {
	method = get_method(ifd);
	if (method < 0) {
	    do_exit(exit_code); /* error message already emitted */
	}
    }
    if (list) {
        do_list(ifd, method);
        return;
    }

    /* Actually do the compression/decompression. Loop over zipped members.
     */
    for (;;) {
	if ((*work)(fileno(stdin), fileno(stdout)) != OK) return;

	if (!decompress || last_member || inptr == insize) break;
	/* end of file */

	method = get_method(ifd);
	if (method < 0) return; /* error message already emitted */
	bytes_out = 0;            /* required for length check */
    }

    if (verbose) {
	if (test) {
	    fprintf(stderr, " OK\n");

	} else if (!decompress) {
	    display_ratio(bytes_in-(bytes_out-header_bytes), bytes_in, stderr);
	    fprintf(stderr, "\n");
#ifdef DISPLAY_STDIN_RATIO
	} else {
	    display_ratio(bytes_out-(bytes_in-header_bytes), bytes_out,stderr);
	    fprintf(stderr, "\n");
#endif
	}
    }
}

/* ========================================================================
 * Compress or decompress the given file
 */
local void treat_file(iname)
    char *iname;
{
    /* Accept "-" as synonym for stdin */
    if (strequ(iname, "-")) {
	int cflag = to_stdout;
	treat_stdin();
	to_stdout = cflag;
	return;
    }

    /* Check if the input file is present, set ifname and istat: */
    if (get_istat(iname, &istat) != OK) return;

    /* If the input name is that of a directory, recurse or ignore: */
    if (S_ISDIR(istat.st_mode)) {
#ifndef NO_DIR
	if (recursive) {
	    struct stat st;
	    st = istat;
	    treat_dir(iname);
	    /* Warning: ifname is now garbage */
#  ifndef NO_UTIME
	    reset_times (iname, &st);
#  endif
	} else
#endif
	WARN((stderr,"%s: %s is a directory -- ignored\n", progname, ifname));
	return;
    }
    if (!S_ISREG(istat.st_mode)) {
	WARN((stderr,
	      "%s: %s is not a directory or a regular file - ignored\n",
	      progname, ifname));
	return;
    }
    if (istat.st_nlink > 1 && !to_stdout && !force) {
	WARN((stderr, "%s: %s has %d other link%c -- unchanged\n",
	      progname, ifname,
	      (int)istat.st_nlink - 1, istat.st_nlink > 2 ? 's' : ' '));
	return;
    }

    ifile_size = istat.st_size;
    time_stamp = no_time && !list ? 0 : istat.st_mtime;

    /* Generate output file name. For -r and (-t or -l), skip files
     * without a valid gzip suffix (check done in make_ofname).
     */
    if (to_stdout && !list && !test) {
	strcpy(ofname, "stdout");

    } else if (make_ofname() != OK) {
	return;
    }

    /* Open the input file and determine compression method. The mode
     * parameter is ignored but required by some systems (VMS) and forbidden
     * on other systems (MacOS).
     */
    ifd = OPEN(ifname, ascii && !decompress ? O_RDONLY : O_RDONLY | O_BINARY,
	       RW_USER);
    if (ifd == -1) {
	fprintf(stderr, "%s: ", progname);
	perror(ifname);
	exit_code = ERROR;
	return;
    }
    clear_bufs(); /* clear input and output buffers */
    part_nb = 0;

    if (decompress) {
	method = get_method(ifd); /* updates ofname if original given */
	if (method < 0) {
	    close(ifd);
	    return;               /* error message already emitted */
	}
    }
    if (list) {
        do_list(ifd, method);
        close(ifd);
        return;
    }

    /* If compressing to a file, check if ofname is not ambiguous
     * because the operating system truncates names. Otherwise, generate
     * a new ofname and save the original name in the compressed file.
     */
    if (to_stdout) {
	ofd = fileno(stdout);
	/* keep remove_ofname as zero */
    } else {
	if (create_outfile() != OK) return;

	if (!decompress && save_orig_name && !verbose && !quiet) {
	    fprintf(stderr, "%s: %s compressed to %s\n",
		    progname, ifname, ofname);
	}
    }
    /* Keep the name even if not truncated except with --no-name: */
    if (!save_orig_name) save_orig_name = !no_name;

    if (verbose) {
	fprintf(stderr, "%s:\t%s", ifname, (int)strlen(ifname) >= 15 ? 
		"" : ((int)strlen(ifname) >= 7 ? "\t" : "\t\t"));
    }

    /* Actually do the compression/decompression. Loop over zipped members.
     */
    for (;;) {
	if ((*work)(ifd, ofd) != OK) {
	    method = -1; /* force cleanup */
	    break;
	}
	if (!decompress || last_member || inptr == insize) break;
	/* end of file */

	method = get_method(ifd);
	if (method < 0) break;    /* error message already emitted */
	bytes_out = 0;            /* required for length check */
    }

    close(ifd);
    if (!to_stdout && close(ofd)) {
	write_error();
    }
    if (method == -1) {
	if (!to_stdout) unlink (ofname);
	return;
    }
    /* Display statistics */
    if(verbose) {
	if (test) {
	    fprintf(stderr, " OK");
	} else if (decompress) {
	    display_ratio(bytes_out-(bytes_in-header_bytes), bytes_out,stderr);
	} else {
	    display_ratio(bytes_in-(bytes_out-header_bytes), bytes_in, stderr);
	}
	if (!test && !to_stdout) {
	    fprintf(stderr, " -- replaced with %s", ofname);
	}
	fprintf(stderr, "\n");
    }
    /* Copy modes, times, ownership, and remove the input file */
    if (!to_stdout) {
	copy_stat(&istat);
    }
}

/* ========================================================================
 * Create the output file. Return OK or ERROR.
 * Try several times if necessary to avoid truncating the z_suffix. For
 * example, do not create a compressed file of name "1234567890123."
 * Sets save_orig_name to true if the file name has been truncated.
 * IN assertions: the input file has already been open (ifd is set) and
 *   ofname has already been updated if there was an original name.
 * OUT assertions: ifd and ofd are closed in case of error.
 */
local int create_outfile()
{
    struct stat	ostat; /* stat for ofname */
    int flags = O_WRONLY | O_CREAT | O_EXCL | O_BINARY;

    if (ascii && decompress) {
	flags &= ~O_BINARY; /* force ascii text mode */
    }
    for (;;) {
	/* Make sure that ofname is not an existing file */
	if (check_ofname() != OK) {
	    close(ifd);
	    return ERROR;
	}
	/* Create the output file */
	remove_ofname = 1;
	ofd = OPEN(ofname, flags, RW_USER);
	if (ofd == -1) {
	    perror(ofname);
	    close(ifd);
	    exit_code = ERROR;
	    return ERROR;
	}

	/* Check for name truncation on new file (1234567890123.gz) */
#ifdef NO_FSTAT
	if (stat(ofname, &ostat) != 0) {
#else
	if (fstat(ofd, &ostat) != 0) {
#endif
	    fprintf(stderr, "%s: ", progname);
	    perror(ofname);
	    close(ifd); close(ofd);
	    unlink(ofname);
	    exit_code = ERROR;
	    return ERROR;
	}
	if (!name_too_long(ofname, &ostat)) return OK;

	if (decompress) {
	    /* name might be too long if an original name was saved */
	    WARN((stderr, "%s: %s: warning, name truncated\n",
		  progname, ofname));
	    return OK;
	}
	close(ofd);
	unlink(ofname);
#ifdef NO_MULTIPLE_DOTS
	/* Should never happen, see check_ofname() */
	fprintf(stderr, "%s: %s: name too long\n", progname, ofname);
	do_exit(ERROR);
#endif
	shorten_name(ofname);
    }
}

/* ========================================================================
 * Use lstat if available, except for -c or -f. Use stat otherwise.
 * This allows links when not removing the original file.
 */
local int do_stat(name, sbuf)
    char *name;
    struct stat *sbuf;
{
    errno = 0;
#if (defined(S_IFLNK) || defined (S_ISLNK)) && !defined(NO_SYMLINK)
    if (!to_stdout && !force) {
	return lstat(name, sbuf);
    }
#endif
    return stat(name, sbuf);
}

/* ========================================================================
 * Return a pointer to the 'z' suffix of a file name, or NULL. For all
 * systems, ".gz", ".z", ".Z", ".taz", ".tgz", "-gz", "-z" and "_z" are
 * accepted suffixes, in addition to the value of the --suffix option.
 * ".tgz" is a useful convention for tar.z files on systems limited
 * to 3 characters extensions. On such systems, ".?z" and ".??z" are
 * also accepted suffixes. For Unix, we do not want to accept any
 * .??z suffix as indicating a compressed file; some people use .xyz
 * to denote volume data.
 *   On systems allowing multiple versions of the same file (such as VMS),
 * this function removes any version suffix in the given name.
 */
local char *get_suffix(name)
    char *name;
{
    int nlen, slen;
    char suffix[MAX_SUFFIX+3]; /* last chars of name, forced to lower case */
    static char *known_suffixes[] =
       {z_suffix, ".gz", ".z", ".taz", ".tgz", "-gz", "-z", "_z",
#ifdef MAX_EXT_CHARS
          "z",
#endif
          NULL};
    char **suf = known_suffixes;

    if (strequ(z_suffix, "z")) suf++; /* check long suffixes first */

#ifdef SUFFIX_SEP
    /* strip a version number from the file name */
    {
	char *v = strrchr(name, SUFFIX_SEP);
 	if (v != NULL) *v = '\0';
    }
#endif
    nlen = strlen(name);
    if (nlen <= MAX_SUFFIX+2) {
        strcpy(suffix, name);
    } else {
        strcpy(suffix, name+nlen-MAX_SUFFIX-2);
    }
    strlwr(suffix);
    slen = strlen(suffix);