CP/M/CPM_CDROM.iso/beehive/compress/crunch28.arc/CRUNCH28.DOC

Text File | 1991-07-16 | 12KB | 252 lines

                         CRUNCH and UNCR
                           Version 2.8

             Copyright (c) 1987 by Steven Greenberg
   This Version Released with the Permission of the Author by
                          Gene Pizzetta
                           May 5, 1991


CRUNCH and UNCR are basic file compression and decompression
tools for ZCPR3 and CP/M.  A number options allow these utilities
to serve as hard disk backup and restoral tools, and make CRUNCH
a convenient tool for creating of archival libraries.  UNCR
handles crunched, squeezed, and LZH-encoded files.

Under ZSDOS and ZDDOS file date stamps are embedded in the
crunched file and then restored to disk when the file is
uncrunched.  In addition, the source file's date stamp is
transferred to the crunched file's on-disk date stamp so the
create and modify dates can be checked without uncrunching it.

CRUNCH USAGE:

     CRUNCH {dir:}afn.aft {dir:} {[text]} {/options}

UNCR USAGE:

     UNCR {dir:}afn.aft {dir:} {/options}

All command line parameters are optional, except the source
filename, which may be ambiguous.  The output filename is
generated automatically.

The two DIR specifications, the first for the source file and the
second for the destination file, may be in DU (drive and user)
form or, if running under ZCPR3, named directories.  If no drive
or user is given, the current default directory is assumed.
Under ZCPR3 all 32 user areas are available, but only the first
16 users are accessible under vanilla CP/M.

"[text]" is an optional text string (CRUNCH only) that can be
used to identify the file.  The text string must be enclosed with
square brackets.  During uncrunching UNCR will print on the
screen any text string contained in the crunched file.

OPTIONS:  The option list must be preceded by a slash and contain
no embedded spaces.

     A    Archive mode (CRUNCH only).  The only files crunched
          (or copied) are those that have been modified since
          they were last backed up, based on the archive
          attribute.  After each source file is crunched, its
          attribute will be changed to archived.  This option
          allows CRUNCH to be used as an simple archival backup
          tool.

     C    Confirm mode.  Same as I.

     E    Erase existing files without asking.  Suppresses the
          prompt "Erase existing file (Y/[N])?" when a file of
          the same name is found in the destination directory.
          Instead existing files will be erased and overwritten
          without notice.

     I    Inspect mode.  Allows choosing the files to be
          processed interactively.  Each filename is displayed,
          one at a time, alphabetically, and can be tagged for
          processing, untagged if tagged previously, or skipped.
          Processing begins after selection is completed.  This
          mode works similarly to the SWEEP and NSWP tagging
          concept.

     O    Overwrite mode.  Same as E.

     Q    Quiet mode.  Suppresses continuous console output
          during the processing of a file.  Only the input and
          output filenames and sizes in kilobytes will be
          displayed.  Normally this mode uses only one screen
          line for each file, so it allows the display of as many
          as 24 filename pairs at one time.  This mode is also
          desirable for printing or other slow terminals because
          they will slow down file processing.

     S    Include system files.  Allows system (hidden) files to
          be found and processed.  Normally system files are
          ignored.

     T    Tag mode.  Same as I.

All command line options can be set as the default mode of
operation (see "Configuration", below).  The command line option
will then toggle to the non-default mode.  The current effect of
the command line options is always correctly reflected by the
usage screen, which can be accessed by "CRUNCH //" or "UNCR //".

DETAILS:  CRUNCH and UNCR cannot handle more than 512 matching
files.  When system files are being ignored, such files do not
count toward this file limit.  In archive (option A) mode,
however, archived files still count, even though they will not be
processed, because this mode works internally by "tagging" all
files which do have their archive attribute set.  That method can
be useful, however, because if inspect mode (options I or T) is
also selected, all filenames are presented as if inspect mode had
been selected alone, except unarchived files will already be
tagged.  It is then possible to tag any archived files that you
might want to include, or to untag any pre-tagged unarchived
files you might want to skip.

Pressing ^C will abort either program immediately.  It may be
issued anytime the programs are running.  The partial output file
will be closed and erased, so zero-length files or files in an
unknown condition will not be left on the disk.  Although
probably of limited usefulness, ^S will pause the programs and
any key (except ^C) will resume operation.  Pressing ^C after a
^S will abort the program, but a partial file will not be erased.

While crunching or uncrunching a file (unless in quiet mode) a
full running progress report is displayed, including the number
of input and output records, the compression ratio, the number of
codes assigned, and the number of codes reassigned.  Although
some of this information has limited usefulness, it is amusing to
watch.

OUTPUT FILENAMES:  The CRUNCH destination file will have the same
name as the crunched file, except that the middle letter of the
filetype will be changed to "Z".  If the source file's filetype
already has a "Z" as the middle letter, then the last two letters
of the filetype will be changed to "ZZ"  If the source file's
filetype already ends in "ZZ", or if its filetype is blank, then
"ZZZ" will be used as the filetype of the crunched file.  Files
with filetypes of "ZZZ" cannot be crunched.  When a file is
uncrunched by UNCR, its original filename and filetype will be
restored.

DIRECT COPYING:  If CRUNCH creates a file larger than the
original, this file will be automatically erased and replaced
with a direct copy of the original.  If the original is already
crunched or squeezed, or if the filetype matches a type on the
filetype exclusion list, such as .LBR or .ARK, no attempt will be
made to compress it.  Instead, a straight copy operation will be
substituted.  Thus all specified files will be transferred in the
most efficient manner, facilitating the use of CRUNCH for the
creation of LBR's or as a backup utility.  Similarly, UNCR will
either uncrunch or direct-copy all specified files for full
restoration.

If the source and destination directories are the same, then
direct copying is inhibited.  In this case, CRUNCH will ask the
user whether he wants to keep a crunched file, if it is larger
than the original.

LZH DECODING AND UNSQUEEZING:  UNCR also uncrunches LZH-encoded
files and unsqueezes as an added convenience.  The file's format
will be recognized automatically and the appropriate method will
be used.

EXCLUSION LIST OVERRIDE:  While it is useful to have CRUNCH skip
attempts to compress certain filetypes when doing bulk transfers,
there may be instances where you want to crunch, for instance, a
LBR file.  (As distributed, excluded filetypes are ARC, ARK, LBR,
and FOR.)  To make that possible, CRUNCH will ignore the filetype
exclusion list if a filename is fully specified.  The exclusion
list will be used, however, whenever one or more wildcard
characters ("?" or "*") appear in the filename.

SPANNING DISKETTES:  If an output disk fills during a wildcard
operation, the last (partial) file will be deleted and the user
will be prompted to change disks.  Operation will then continue,
starting  with that last file.  If the source and destination
drives are the same, however, then the prompt to change diskettes
will not be given, since changing the output diskette will remove
the input disk from which the program is reading.

UNCR WILDCARD LIMITATIONS:  Normally when UNCR is given a "*.*"
wildcard specification, it transfers all files from one drive
and/or user area to another, uncrunching crunched files,
unsqueezing squeezed files, and copying the rest.  If your intent
is to only process crunched files, you must issue a file
specification with a filetype of "?Z?".

When the source and destination directories are the same,
however, a file specification of "*.*" will be automatically
converted to "*.?Z?".  A side-effect is that squeezed and LZH-
encoded files will not be uncompressed unless a specific "*.?Q?"
or "*.?Y?" file specification is given.

FILE DATE STAMPS:  When running under ZSDOS or ZDDOS, CRUNCH will
store the date and time stamp of the source file in the header of
the crunched file.  In addition, it will transfer the source
file's date stamp to the crunched file's on-disk date stamp.
Since crunching is used primarily for archival storage and the
crunched file will not be modified in place, this latter feature
allows you to check the original date stamp of the file without
uncrunching it.  The access date of the crunched file will be the
date it was crunched, until you type it with ZLT or uncrunch it.

When UNCR uncrunches a file, it looks for a date stamp in the
header and, if it finds one, it restores the file's original
create and modify dates to the uncrunched file.  This restoral
works equally well with files crunched by CR23D.  If there is no
date stamp in the header of the crunched file, UNCR will transfer
the crunched file's on-disk date stamp to the uncrunched file, so
at least you will not lose whatever date stamp you have.  As with
CRUNCH, the access date will be the date the file is uncrunched.
The original access date is stored in the header by CRUNCH, but
it will not be restored.

If the source file has no modify date, a non-standard condition,
the modify date of the output file will be filled in from the
create date.  A blank create date will be transferred as is.

TELENET AND PC-PURSUIT SUPPORT:  CRUNCH monitors its output for a
sequence that would put Telenet or PC-Pursuit into command mode
and abort a file transfer.  If this sequence is detected, CRUNCH
inserts the CRUNCH null code to prevent disaster.

CONFIGURATION:  All the modes of operation set by command line
options can be configured as default modes.  In that case the
corresponding command line option will toggle to the non-default
mode.  (The current effect of the command line options will
always be reflected by the usage screen.)  In addition, CRUNCH
contains a list of filetypes that will be ignored during wildcard
operations.  Up to 10 filetypes can be entered in the list.
There are also specific options that are only effective under
TurboDos or vanilla CP/M.

Configuration for both CRUNCH and UNCR is accomplished using the
accompanying CRUNCHnn.CFG file and ZCNFG, which is available from
most Z-Nodes and RCP/M's.  The name of the configuration file
should not be changed.  More complete instructions are included
on the configuration help screens.

+---------------------------------------------------------------+
| The source code, as well as any object code created from it,  |
| are copyright (c) 1987 by Steven Greenberg.  It may be repro- |
| duced for non-profit use only.  Public release of modifica-   |
| tions is strictly prohibited without the expressed consent of |
| the author.                                                   |
+---------------------------------------------------------------+

This version was released with the permission of the original
author.  Please report any bugs to:

     Gene Pizzetta
     481 Revere St.
     Revere, MA 02151

     Voice:  [phone]
     Newton Centre Z-Node:  [phone]
     Ladera Z-Node Central:  [phone]