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-rw-r--r--README26
1 files changed, 21 insertions, 5 deletions
diff --git a/README b/README
index 182d0c9..a64ac21 100644
--- a/README
+++ b/README
@@ -5,13 +5,23 @@ small size makes it well suited for embedded devices or software
installers that need to decompress files but do not need compression
capabilities. Lunzip is fully compatible with lzip-1.4 or newer.
+If the size of the output buffer is specified with the "--buffer-size"
+option, lunzip uses the decompressed file as dictionary for distances
+beyond the buffer size and is able to decompress any file using as
+little memory as 50 kB, irrespective of the dictionary size used to
+compress the file. Of course, the smaller the output buffer size used in
+relation to the dictionary size, the more accesses to disk are needed
+and the slower the decompression is. This "low memory" mode only works
+when decompressing to a regular file.
+
The lzip file format is designed for long-term data archiving. It is
clean, provides very safe 4 factor integrity checking, and is backed by
the recovery capabilities of lziprecover.
Lunzip uses the same well-defined exit status values used by lzip and
-bzip2, which makes it safer when used in pipes or scripts than
-decompressors returning ambiguous warning values, like gunzip.
+bzip2, which makes it safer than decompressors returning ambiguous
+warning values (like gunzip) when it is used as a back end for tar or
+zutils.
Lunzip replaces every file given in the command line with a decompressed
version of itself. Each decompressed file has the same modification
@@ -35,9 +45,15 @@ two or more compressed files. The result is the concatenation of the
corresponding uncompressed files. Integrity testing of concatenated
compressed files is also supported.
-The amount of memory required by lunzip to decompress a file is only a
-few tens of KiB larger than the dictionary size used to compress that
-file.
+The amount of memory required by lunzip to decompress a file is about
+46 kB larger than the dictionary size used to compress that file, unless
+the "--buffer-size" option is specified.
+
+The ideas embodied in lunzip are due to (at least) the following people:
+Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for
+the definition of Markov chains), G.N.N. Martin (for the definition of
+range encoding), Igor Pavlov (for putting all the above together in
+LZMA), and Julian Seward (for bzip2's CLI).
Copyright (C) 2010, 2011, 2012, 2013 Antonio Diaz Diaz.