Attachment 27629 Details for Bug 46787 – file.diff

[patch] file.diff

file.diff (text/plain), 4.08 KB, created by Gary W. Swearingen on 2003-01-05 18:20:04 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Gary W. Swearingen

Created: 2003-01-05 18:20:04 UTC

Size: 4.08 KB

patch

obsolete

>--- /tmp/compress..orig.1	Sun Jan  5 06:33:35 2003
>+++ /tmp/compress.1	Sun Jan  5 10:02:14 2003
>@@ -54,17 +54,17 @@
> .Sh DESCRIPTION
> The
> .Nm
>-utility reduces the size of the named files using adaptive Lempel-Ziv coding.
>+utility attempts to reduce the size of the 
>+named files using adaptive Lempel-Ziv coding.
> Each
> .Ar file
> is renamed to the same name plus the extension
> .Dq .Z .
>-As many of the modification time, access time, file flags, file mode,
>-user ID, and group ID as allowed by permissions are retained in the
>-new file.
>-If compression would not reduce the size of a
>+If attempted compression would not reduce the size of a
> .Ar file ,
>-the file is ignored.
>+or if the filename ends with
>+.Dq .Z ,
>+the file is not compressed.  Exceptions are discussed below.
> .Pp
> The
> .Nm uncompress
>@@ -72,38 +72,53 @@
> files by deleting the
> .Dq .Z
> extension.
>+If a specified filename doesn't end with
>+.Dq .Z ,
>+one will be assumed unless a file with the extended filename does not
>+exist, in which case the named file will be removed (because of a bug).
> .Pp
> If renaming the files would cause files to be overwritten and the standard
> input device is a terminal, the user is prompted (on the standard error
> output) for confirmation.
> If prompting is not possible or confirmation is not received, the files
> are not overwritten.
>+As many of the file attributes (modification time, access time,
>+file flags, file mode, user ID, and group ID) as allowed by 
>+file permissions are retained in the new file.
> .Pp
> If no files are specified or a
> .Ar file
> argument is a single dash
> .Pq Sq Fl ,
> the standard input is compressed or uncompressed to the standard output.
>-If either the input and output files are not regular files, the checks for
>+If either the input and output are not regular files, the checks for
> reduction in size and file overwriting are not performed, the input file is
>-not removed, and the attributes of the input file are not retained.
>+not removed, and the attributes of the input file
>+are not retained in the output.
> .Pp
> The options are as follows:
>-.Bl -tag -width indent
>-.It Fl b
>-Specify the
>-.Ar bits
>-code limit (see below).
>+.Bl -tag -width ".Fl b Ar bits"
>+.It Fl b Ar bits
>+The code size (see below) is limited to
>+.Ar bits ,
>+which must be in the range 9..16.
>+The default is 16.
> .It Fl c
> Compressed or uncompressed output is written to the standard output.
>-No files are modified.
>+Compression is attempted even if the results will be larger than the
>+original.
>+No files are modified.  The
>+.Fl v
>+flag is ignored.
> .It Fl f
>-Force compression of
>-.Ar file ,
>-even if it is not actually reduced in size.
>-Additionally, files are overwritten without prompting for confirmation.
>+Files are overwritten without prompting for confirmation.
>+For compression, proceed even if the
>+results will be larger than the original.
> .It Fl v
>-Print the percentage reduction of each file.
>+The size reduction of each file is printed as a percentage to
>+the standard output.  Ignored for uncompressiong or if the
>+.Fl c
>+flag is also used.
> .El
> .Pp
> The
>@@ -112,21 +127,14 @@
> Common substrings in the file are first replaced by 9-bit codes 257 and up.
> When code 512 is reached, the algorithm switches to 10-bit codes and
> continues to use more bits until the
>-limit specified by the
>-.Fl b
>-flag is reached (the default is 16).
>-.Ar Bits
>-must be between 9 and 16.
>-.Pp
>-After the
>-.Ar bits
>-limit is reached,
>-.Nm
>-periodically checks the compression ratio.
>+code size limit (see
>+.Fl b )
>+is reached.
>+Then the compression ratio is periodically checked.
> If it is increasing,
> .Nm
>-continues to use the existing code dictionary.
>-However, if the compression ratio decreases,
>+continues to use the existing code dictionary;
>+but if the compression ratio is decreasing,
> .Nm
> discards the table of substrings and rebuilds it from scratch.  This allows
> the algorithm to adapt to the next "block" of the file.
>@@ -187,3 +195,9 @@
> .Nm
> command appeared in
> .Bx 4.3 .
>+.Sh BUGS
>+For uncompression, if a specified filename doesn't end with
>+.Dq .Z
>+and a file with the filename extended with
>+.Dq .Z 
>+does not exist, the named file will be removed.

Actions: View | Diff

Attachments on bug 46787: 27629