From 6b876fb72fd61b2d0a2265c6f6394569bdca3a18 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 May 2017 17:55:05 +0200 Subject: Merging upstream version 1.6. Signed-off-by: Daniel Baumann --- doc/plzip.texi | 64 ++++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 44 insertions(+), 20 deletions(-) (limited to 'doc/plzip.texi') diff --git a/doc/plzip.texi b/doc/plzip.texi index c459cde..5f32f6e 100644 --- a/doc/plzip.texi +++ b/doc/plzip.texi @@ -6,8 +6,8 @@ @finalout @c %**end of header -@set UPDATED 14 May 2016 -@set VERSION 1.5 +@set UPDATED 12 April 2017 +@set VERSION 1.6 @dircategory Data Compression @direntry @@ -48,7 +48,7 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}). @end menu @sp 1 -Copyright @copyright{} 2009-2016 Antonio Diaz Diaz. +Copyright @copyright{} 2009-2017 Antonio Diaz Diaz. This manual is free documentation: you have unlimited permission to copy, distribute and modify it. @@ -90,10 +90,10 @@ including error-checked merging of damaged copies of a file. @item The lzip format is as simple as possible (but not simpler). The lzip -manual provides the code of a simple decompressor along with a detailed -explanation of how it works, so that with the only help of the lzip -manual it would be possible for a digital archaeologist to extract the -data from a lzip file long after quantum computers eventually render +manual provides the source code of a simple decompressor along with a +detailed explanation of how it works, so that with the only help of the +lzip manual it would be possible for a digital archaeologist to extract +the data from a lzip file long after quantum computers eventually render LZMA obsolete. @item @@ -146,6 +146,10 @@ or more compressed files. The result is the concatenation of the corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported. +LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never +have been compressed. Decompressed is used to refer to data which have +undergone the process of decompression. + @node Invoking plzip @chapter Invoking plzip @@ -220,6 +224,20 @@ Force re-compression of files whose name already has the @samp{.lz} or @itemx --keep Keep (don't delete) input files during compression or decompression. +@item -l +@itemx --list +Print the uncompressed size, compressed size and percentage saved of the +specified file(s). Trailing data are ignored. The values produced are +correct even for multimember files. If more than one file is given, a +final line containing the cumulative sizes is printed. With @samp{-v}, +the dictionary size, the number of members in the file, and the amount +of trailing data (if any) are also printed. With @samp{-vv}, the +positions and sizes of each member in multimember files are also +printed. @samp{-lq} can be used to verify quickly (without +decompressing) the structural integrity of the specified files. (Use +@samp{--test} to verify the data integrity). @samp{-alq} additionally +verifies that none of the specified files contain trailing data. + @item -m @var{bytes} @itemx --match-length=@var{bytes} Set the match length limit in bytes. After a match this long is found, @@ -267,8 +285,9 @@ is affected at compression time by the choice of dictionary size limit. Check integrity of the specified file(s), but don't decompress them. This really performs a trial decompression and throws away the result. Use it together with @samp{-v} to see information about the file(s). If -a file fails the test, plzip may be unable to check the rest of the -files. +a file does not exist, can't be opened, or is a terminal, plzip +continues checking the rest of the files. If a file fails the test, +plzip may be unable to check the rest of the files. @item -v @itemx --verbose @@ -469,9 +488,6 @@ times the data size. Default is 136 MiB. For decompression of a regular (seekable) file to another regular file, or for testing of a regular file; the dictionary size. -(Note that regular files with more than 1024 bytes of trailing data are -treated as non-seekable). - @item For testing of a non-seekable file or of standard input; the dictionary size plus up to 5 MiB. @@ -526,20 +542,24 @@ data size for each level: @chapter Extra data appended to the file @cindex trailing data -Sometimes extra data is found appended to a lzip file after the last +Sometimes extra data are found appended to a lzip file after the last member. Such trailing data may be: @itemize @bullet @item Padding added to make the file size a multiple of some block size, for -example when writing to a tape. +example when writing to a tape. It is safe to append any amount of +padding zero bytes to a lzip file. @item -Garbage added by some not totally successful copy operation. +Useful data added by the user; a cryptographically secure hash, a +description of file contents, etc. It is safe to append any amount of +text to a lzip file as long as the text does not begin with the string +"LZIP", and does not contain any zero bytes (null characters). Nonzero +bytes and zero bytes can't be safely mixed in trailing data. @item -Useful data added by the user; a cryptographically secure hash, a -description of file contents, etc. +Garbage added by some not totally successful copy operation. @item Malicious data added to the file in order to make its total size and @@ -554,8 +574,12 @@ integrity information itself. Therefore it can be considered to be below the noise level. @end itemize +Trailing data are in no way part of the lzip file format, but tools +reading lzip files are expected to behave as correctly and usefully as +possible in the presence of trailing data. + Trailing data can be safely ignored in most cases. In some cases, like -that of user-added data, it is expected to be ignored. In those cases +that of user-added data, they are expected to be ignored. In those cases where a file containing trailing data must be rejected, the option @samp{--trailing-error} can be used. @xref{--trailing-error}. @@ -620,8 +644,8 @@ plzip -c /dev/sdc > file.lz @sp 1 @anchor{concat-example} @noindent -Example 6: The right way of concatenating compressed files. -@xref{Trailing data}. +Example 6: The right way of concatenating the decompressed output of two +or more compressed files. @xref{Trailing data}. @example Don't do this -- cgit v1.2.3