3 Copyright (C) 1999, 2001 Free Software Foundation, Inc.
4 Copyright (C) 1992, 1993 Jean-loup Gailly
6 This file is part of gzip (GNU zip).
8 gzip is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 gzip is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with tar; see the file COPYING. If not, write to
20 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA.
24 Some of the planned features include:
26 - Internationalize by using gettext and setlocale.
28 - Structure the sources so that the compression and decompression code
29 form a library usable by any program, and write both gzip and zip on
30 top of this library. This would ideally be a reentrant (thread safe)
31 library, but this would degrade performance. In the meantime, you can
32 look at the sample program zread.c.
34 The library should have one mode in which compressed data is sent
35 as soon as input is available, instead of waiting for complete
36 blocks. This can be useful for sending compressed data to/from interactive
39 - Make it convenient to define alternative user interfaces (in
40 particular for windowing environments).
42 - Support in-memory compression for arbitrarily large amounts of data
43 (zip currently supports in-memory compression only for a single buffer.)
45 - Map files in memory when possible, this is generally much faster
46 than read/write. (zip currently maps entire files at once, this
47 should be done in chunks to reduce memory usage.)
49 - Add a super-fast compression method, suitable for implementing
50 file systems with transparent compression. One problem is that the
51 best candidate (lzrw1) is patented twice (Waterworth 4,701,745
52 and Gibson & Graybill 5,049,881). The lzrw series of algorithms
53 are available by ftp in ftp.adelaide.edu.au:/pub/compression/lzrw*.
55 - Add a super-tight (but slow) compression method, suitable for long
56 term archives. One problem is that the best versions of arithmetic
57 coding are patented (4,286,256 4,295,125 4,463,342 4,467,317
58 4,633,490 4,652,856 4,891,643 4,905,297 4,935,882 4,973,961
61 Note: I will introduce new compression methods only if they are
62 significantly better in either speed or compression ratio than the
63 existing method(s). So the total number of different methods should
64 reasonably not exceed 3. (The current 9 compression levels are just
65 tuning parameters for a single method, deflation.)
67 - Add optional error correction. One problem is that the current version
68 of ecc cannot recover from inserted or missing bytes. It would be
69 nice to recover from the most common error (transfer of a binary
72 - Add a block size (-b) option to improve error recovery in case of
73 failure of a complete sector. Each block could be extracted
74 independently, but this reduces the compression ratio.
76 For one possible approach to this, please see:
78 http://www.samba.org/netfilter/diary/gzip.rsync.patch
80 - Use a larger window size to deal with some large redundant files that
81 'compress' currently handles better than gzip.
83 - Implement the -e (encrypt) option.
85 Send comments to <bug-gzip@gnu.org>.