Merging upstream version 1.8.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 82 insertions, 52 deletions

diff --git a/doc/plzip.texi b/doc/plzip.texi
index 44cff75..b5469b9 100644
--- a/doc/plzip.texi
+++ b/doc/plzip.texi
@@ -6,19 +6,19 @@
 @finalout
 @c %**end of header
 
-@set UPDATED 7 February 2018
-@set VERSION 1.7
+@set UPDATED 5 January 2019
+@set VERSION 1.8
 
 @dircategory Data Compression
 @direntry
-* Plzip: (plzip).               Parallel compressor compatible with lzip
+* Plzip: (plzip).               Massively parallel implementation of lzip
 @end direntry
 
 
 @ifnothtml
 @titlepage
 @title Plzip
-@subtitle Parallel compressor compatible with lzip
+@subtitle Massively parallel implementation of lzip
 @subtitle for Plzip version @value{VERSION}, @value{UPDATED}
 @author by Antonio Diaz Diaz
 
@@ -49,7 +49,7 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}).
 @end menu
 
 @sp 1
-Copyright @copyright{} 2009-2018 Antonio Diaz Diaz.
+Copyright @copyright{} 2009-2019 Antonio Diaz Diaz.
 
 This manual is free documentation: you have unlimited permission
 to copy, distribute and modify it.
@@ -59,23 +59,28 @@ to copy, distribute and modify it.
 @chapter Introduction
 @cindex introduction
 
-Plzip is a massively parallel (multi-threaded) lossless data compressor
-based on the lzlib compression library, with a user interface similar to
-the one of lzip, bzip2 or gzip.
+@uref{http://www.nongnu.org/lzip/plzip.html,,Plzip} is a massively parallel
+(multi-threaded) implementation of lzip, fully compatible with lzip 1.4 or
+newer. Plzip uses the lzlib compression library.
+
+@uref{http://www.nongnu.org/lzip/lzip.html,,Lzip} is a lossless data
+compressor with a user interface similar to the one of gzip or bzip2. Lzip
+can compress about as fast as gzip @w{(lzip -0)} or compress most files more
+than bzip2 @w{(lzip -9)}. Decompression speed is intermediate between gzip
+and bzip2. Lzip is better than gzip and bzip2 from a data recovery
+perspective. Lzip has been designed, written and tested with great care to
+replace gzip and bzip2 as the standard general-purpose compressed format for
+unix-like systems.
 
 Plzip can compress/decompress large files on multiprocessor machines
 much faster than lzip, at the cost of a slightly reduced compression
 ratio (0.4 to 2 percent larger compressed files). Note that the number
 of usable threads is limited by file size; on files larger than a few GB
 plzip can use hundreds of processors, but on files of only a few MB
-plzip is no faster than lzip (@pxref{Minimum file sizes}).
-
-Plzip uses the lzip file format; the files produced by plzip are fully
-compatible with lzip-1.4 or newer, and can be rescued with lziprecover.
+plzip is no faster than lzip. @xref{Minimum file sizes}.
 
-The lzip file format is designed for data sharing and long-term
-archiving, taking into account both data integrity and decoder
-availability:
+The lzip file format is designed for data sharing and long-term archiving,
+taking into account both data integrity and decoder availability:
 
 @itemize @bullet
 @item
@@ -107,15 +112,14 @@ repair the nearer it is from the beginning of the file. Therefore, with
 the help of lziprecover, losing an entire archive just because of a
 corrupt byte near the beginning is a thing of the past.
 
-Plzip uses the same well-defined exit status values used by lzip and
-bzip2, which makes it safer than compressors returning ambiguous warning
-values (like gzip) when it is used as a back end for other programs like
-tar or zutils.
+Plzip uses the same well-defined exit status values used by lzip, which
+makes it safer than compressors returning ambiguous warning values (like
+gzip) when it is used as a back end for other programs like tar or zutils.
 
-Plzip will automatically use the smallest possible dictionary size for
-each file without exceeding the given limit. Keep in mind that the
-decompression memory requirement is affected at compression time by the
-choice of dictionary size limit (@pxref{Memory requirements}).
+Plzip will automatically use for each file the largest dictionary size that
+does not exceed neither the file size nor the limit given. Keep in mind that
+the decompression memory requirement is affected at compression time by the
+choice of dictionary size limit. @xref{Memory requirements}.
 
 When compressing, plzip replaces every file given in the command line
 with a compressed version of itself, with the name "original_name.lz".
@@ -130,7 +134,7 @@ file from that of the compressed file as follows:
 
 (De)compressing a file is much like copying or moving it; therefore plzip
 preserves the access and modification dates, permissions, and, when
-possible, ownership of the file just as "cp -p" does. (If the user ID or
+possible, ownership of the file just as @samp{cp -p} does. (If the user ID or
 the group ID can't be duplicated, the file permission bits S_ISUID and
 S_ISGID are cleared).
 
@@ -142,10 +146,10 @@ standard input to standard output. In this case, plzip will decline to
 write compressed output to a terminal, as this would be entirely
 incomprehensible and therefore pointless.
 
-Plzip will correctly decompress a file which is the concatenation of two
-or more compressed files. The result is the concatenation of the
-corresponding decompressed files. Integrity testing of concatenated
-compressed files is also supported.
+Plzip will correctly decompress a file which is the concatenation of two or
+more compressed files. The result is the concatenation of the corresponding
+decompressed files. Integrity testing of concatenated compressed files is
+also supported.
 
 
 @node Output
@@ -225,6 +229,7 @@ Print an informative help message describing the options and exit.
 @item -V
 @itemx --version
 Print the version number of plzip on the standard output and exit.
+This version number should be included in all bug reports.
 
 @anchor{--trailing-error}
 @item -a
@@ -322,12 +327,13 @@ Quiet operation. Suppress all messages.
 @item -s @var{bytes}
 @itemx --dictionary-size=@var{bytes}
 When compressing, set the dictionary size limit in bytes. Plzip will use
-the smallest possible dictionary size for each file without exceeding
-this limit. Valid values range from @w{4 KiB} to @w{512 MiB}. Values 12
-to 29 are interpreted as powers of two, meaning 2^12 to 2^29 bytes. Note
-that dictionary sizes are quantized. If the specified size does not
-match one of the valid sizes, it will be rounded upwards by adding up to
-@w{(@var{bytes} / 8)} to it.
+for each file the largest dictionary size that does not exceed neither
+the file size nor this limit. Valid values range from @w{4 KiB} to
+@w{512 MiB}. Values 12 to 29 are interpreted as powers of two, meaning
+2^12 to 2^29 bytes. Dictionary sizes are quantized so that they can be
+coded in just one byte (@pxref{coded-dict-size}). If the specified size
+does not match one of the valid sizes, it will be rounded upwards by
+adding up to @w{(@var{bytes} / 8)} to it.
 
 For maximum compression you should use a dictionary size limit as large
 as possible, but keep in mind that the decompression memory requirement
@@ -354,18 +360,23 @@ Two or more @samp{-v} options show the progress of (de)compression,
 except for single-member files.
 
 @item -0 .. -9
-Set the compression parameters (dictionary size and match length limit)
-as shown in the table below. The default compression level is @samp{-6}.
-Note that @samp{-9} can be much slower than @samp{-0}. These options
-have no effect when decompressing, testing or listing.
+Compression level. Set the compression parameters (dictionary size and
+match length limit) as shown in the table below. The default compression
+level is @samp{-6}, equivalent to @w{@samp{-s8MiB -m36}}. Note that
+@samp{-9} can be much slower than @samp{-0}. These options have no
+effect when decompressing, testing or listing.
 
 The bidimensional parameter space of LZMA can't be mapped to a linear
 scale optimal for all files. If your files are large, very repetitive,
 etc, you may need to use the @samp{--dictionary-size} and
 @samp{--match-length} options directly to achieve optimal performance.
 
-@multitable {Level} {Dictionary size} {Match length limit}
-@item Level @tab Dictionary size @tab Match length limit
+If several compression levels or @samp{-s} or @samp{-m} options are
+given, the last setting is used. For example @w{@samp{-9 -s64MiB}} is
+equivalent to @w{@samp{-s64MiB -m273}}
+
+@multitable {Level} {Dictionary size (-s)} {Match length limit (-m)}
+@item Level @tab Dictionary size (-s) @tab Match length limit (-m)
 @item -0 @tab 64 KiB @tab  16 bytes
 @item -1 @tab  1 MiB @tab   5 bytes
 @item -2 @tab  1.5 MiB @tab   6 bytes
@@ -388,6 +399,18 @@ bytes are so similar to the magic bytes of a lzip header that they can
 be confused with a corrupt header. Use this option if a file triggers a
 "corrupt header" error and the cause is not indeed a corrupt header.
 
+@item --in-slots=@var{n}
+Number of @w{1 MiB} input packets buffered per worker thread when
+decompressing from non-seekable input. Increasing the number of packets
+may increase decompression speed, but requires more memory. Valid values
+range from 1 to 64. The default value is 4.
+
+@item --out-slots=@var{n}
+Number of @w{1 MiB} output packets buffered per worker thread when
+decompressing to non-seekable output. Increasing the number of packets
+may increase decompression speed, but requires more memory. Valid values
+range from 1 to 1024. The default value is 64.
+
 @end table
 
 Numbers given as arguments to options may be followed by a multiplier
@@ -506,12 +529,13 @@ A four byte string, identifying the lzip format, with the value "LZIP"
 @item VN (version number, 1 byte)
 Just in case something needs to be modified in the future. 1 for now.
 
+@anchor{coded-dict-size}
 @item DS (coded dictionary size, 1 byte)
 The dictionary size is calculated by taking a power of 2 (the base size)
-and substracting from it a fraction between 0/16 and 7/16 of the base
+and subtracting from it a fraction between 0/16 and 7/16 of the base
 size.@*
 Bits 4-0 contain the base 2 logarithm of the base size (12 to 29).@*
-Bits 7-5 contain the numerator of the fraction (0 to 7) to substract
+Bits 7-5 contain the numerator of the fraction (0 to 7) to subtract
 from the base size to obtain the dictionary size.@*
 Example: 0xD3 = 2^19 - 6 * 2^15 = 512 KiB - 6 * 32 KiB = 320 KiB@*
 Valid values for dictionary size range from 4 KiB to 512 MiB.
@@ -546,8 +570,8 @@ facilitates safe recovery of undamaged members from multimember files.
 @chapter Memory required to compress and decompress
 @cindex memory requirements
 
-The amount of memory required @strong{per thread} for decompression or
-testing is approximately the following:
+The amount of memory required @strong{per worker thread} for
+decompression or testing is approximately the following:
 
 @itemize @bullet
 @item
@@ -556,20 +580,23 @@ or for testing of a regular file; the dictionary size.
 
 @item
 For testing of a non-seekable file or of standard input; the dictionary
-size plus up to @w{5 MiB}.
+size plus @w{1 MiB} plus up to the number of @w{1 MiB} input packets
+buffered (4 by default).
 
 @item
 For decompression of a regular file to a non-seekable file or to
-standard output; the dictionary size plus up to @w{32 MiB}.
+standard output; the dictionary size plus up to the number of @w{1 MiB}
+output packets buffered (64 by default).
 
 @item
 For decompression of a non-seekable file or of standard input; the
-dictionary size plus up to @w{35 MiB}.
+dictionary size plus @w{1 MiB} plus up to the number of @w{1 MiB} input
+and output packets buffered (68 by default).
 @end itemize
 
 @noindent
-The amount of memory required @strong{per thread} for compression is
-approximately the following:
+The amount of memory required @strong{per worker thread} for compression
+is approximately the following:
 
 @itemize @bullet
 @item
@@ -696,9 +723,12 @@ where a file containing trailing data must be rejected, the option
 WARNING! Even if plzip is bug-free, other causes may result in a corrupt
 compressed file (bugs in the system libraries, memory errors, etc).
 Therefore, if the data you are going to compress are important, give the
-@samp{--keep} option to plzip and don't remove the original file until
-you verify the compressed file with a command like
-@w{@samp{plzip -cd file.lz | cmp file -}}.
+@samp{--keep} option to plzip and don't remove the original file until you
+verify the compressed file with a command like
+@w{@samp{plzip -cd file.lz | cmp file -}}. Most RAM errors happening during
+compression can only be detected by comparing the compressed file with the
+original because the corruption happens before plzip compresses the RAM
+contents, resulting in a valid compressed file containing wrong data.
 
 @sp 1
 @noindent