Merging upstream version 1.22.

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

1 files changed, 50 insertions, 46 deletions

diff --git a/README b/README
index 92d9793..b618e36 100644
--- a/README
+++ b/README
@@ -3,8 +3,9 @@ Description
 Lziprecover is a data recovery tool and decompressor for files in the lzip
 compressed data format (.lz). Lziprecover is able to repair slightly damaged
 files, produce a correct file by merging the good parts of two or more
-damaged copies, extract data from damaged files, decompress files and test
-integrity of files.
+damaged copies, reproduce a missing (zeroed) sector using a reference file,
+extract data from damaged files, decompress files, and test integrity of
+files.
 
 Lziprecover can remove the damaged members from multimember files, for
 example multimember tar.lz archives.
@@ -22,68 +23,71 @@ The lzip file format is designed for data sharing and long-term archiving,
 taking into account both data integrity and decoder availability:
 
    * The lzip format provides very safe integrity checking and some data
-     recovery means. The lziprecover program can repair bit flip errors
-     (one of the most common forms of data corruption) in lzip files,
-     and provides data recovery capabilities, including error-checked
-     merging of damaged copies of a file.
-
-   * The lzip format is as simple as possible (but not simpler). The
-     lzip 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.
+     recovery means. The program lziprecover can repair bit flip errors
+     (one of the most common forms of data corruption) in lzip files, and
+     provides data recovery capabilities, including error-checked merging
+     of damaged copies of a file.
+
+   * The lzip format is as simple as possible (but not simpler). The lzip
+     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.
 
    * Additionally the lzip reference implementation is copylefted, which
      guarantees that it will remain free forever.
 
-A nice feature of the lzip format is that a corrupt byte is easier to
-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.
+A nice feature of the lzip format is that a corrupt byte is easier to 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.
 
-For compressible data, multiple lzip-compressed copies have a better
-chance of surviving intact than one uncompressed copy using the same
-amount of storage space.
+Compression may be good for long-term archiving. For compressible data,
+multiple compressed copies may provide redundancy in a more useful form and
+may have a better chance of surviving intact than one uncompressed copy
+using the same amount of storage space. This is specially true if the format
+provides recovery capabilities like those of lziprecover, which is able to
+find and combine the good parts of several damaged copies.
 
-Lziprecover is able to recover or decompress files produced by any of
-the compressors in the lzip family; lzip, plzip, minilzip/lzlib, clzip
-and pdlzip.
+Lziprecover is able to recover or decompress files produced by any of the
+compressors in the lzip family; lzip, plzip, minilzip/lzlib, clzip, and
+pdlzip.
 
-If the cause of file corruption is damaged media, the combination
-GNU ddrescue + lziprecover is the best option for recovering data from
-multiple damaged copies.
+If the cause of file corruption is a damaged medium, the combination
+GNU ddrescue + lziprecover is the recommended option for recovering data
+from damaged lzip files.
 
-If a file is too damaged for lziprecover to repair it, all the
-recoverable data in all members of the file can be extracted in one step
-with the '-D' option.
+If a file is too damaged for lziprecover to repair it, all the recoverable
+data in all members of the file can be extracted in one step with the
+command 'lziprecover -cd -i file.lz > file'.
 
 When recovering data, lziprecover takes as arguments the names of the
 damaged files and writes zero or more recovered files depending on the
-operation selected and whether the recovery succeeded or not. The
-damaged files themselves are kept unchanged.
+operation selected and whether the recovery succeeded or not. The damaged
+files themselves are kept unchanged.
 
-When decompressing or testing file integrity, lziprecover behaves like
-lzip or lunzip.
+When decompressing or testing file integrity, lziprecover behaves like lzip
+or lunzip.
 
-To give you an idea of its possibilities, when merging two copies, each
-of them with one damaged area affecting 1 percent of the copy, the
-probability of obtaining a correct file is about 98 percent. With three
-such copies the probability rises to 99.97 percent. For large files (a
-few MB) with small errors (one sector damaged per copy), the probability
-approaches 100 percent even with only two copies. (Supposing that the
-errors are randomly located inside each copy).
+To give you an idea of its possibilities, when merging two copies, each of
+them with one damaged area affecting 1 percent of the copy, the probability
+of obtaining a correct file is about 98 percent. With three such copies the
+probability rises to 99.97 percent. For large files (a few MB) with small
+errors (one sector damaged per copy), the probability approaches 100 percent
+even with only two copies. (Supposing that the errors are randomly located
+inside each copy).
 
-The lziprecover package also includes unzcrash, a program written to
-test robustness to decompression of corrupted data, inspired by
-unzcrash.c from Julian Seward's bzip2. Type 'make unzcrash' in the
-lziprecover source directory to build it. Then try 'unzcrash --help'.
+The lziprecover package also includes unzcrash, a program written to test
+robustness to decompression of corrupted data, inspired by unzcrash.c from
+Julian Seward's bzip2. Type 'make unzcrash' in the lziprecover source
+directory to build it. Then try 'unzcrash --help'.
 
 
-Copyright (C) 2009-2019 Antonio Diaz Diaz.
+Copyright (C) 2009-2021 Antonio Diaz Diaz.
 
 This file is free documentation: you have unlimited permission to copy,
-distribute and modify it.
+distribute, and modify it.
 
 The file Makefile.in is a data file used by configure to produce the
 Makefile. It has the same copyright owner and permissions that configure