| 1 | TODO file for gzip.
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| 2 |
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| 3 | Some of the planned features include:
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| 4 |
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| 5 | - Remove some of the old porting cruft, since we no longer support
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| 6 | PRIMOS etc. any more.
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| 7 |
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| 8 | - Separate out the shell scripts like gzexe into a new little package;
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| 9 | these scripts are less used and less reliable and should be optional.
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| 10 |
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| 11 | - Internationalize by using gettext and setlocale.
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| 12 |
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| 13 | - Structure the sources so that the compression and decompression code
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| 14 | form a library usable by any program, and write both gzip and zip on
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| 15 | top of this library. This would ideally be a reentrant (thread safe)
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| 16 | library, but this would degrade performance. In the meantime, you can
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| 17 | look at the sample program zread.c.
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| 18 |
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| 19 | The library should have one mode in which compressed data is sent
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| 20 | as soon as input is available, instead of waiting for complete
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| 21 | blocks. This can be useful for sending compressed data to/from interactive
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| 22 | programs.
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| 23 |
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| 24 | - Make it convenient to define alternative user interfaces (in
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| 25 | particular for windowing environments).
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| 26 |
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| 27 | - Support in-memory compression for arbitrarily large amounts of data
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| 28 | (zip currently supports in-memory compression only for a single buffer.)
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| 29 |
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| 30 | - Map files in memory when possible, this is generally much faster
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| 31 | than read/write. (zip currently maps entire files at once, this
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| 32 | should be done in chunks to reduce memory usage.)
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| 33 |
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| 34 | - Add a super-fast compression method, suitable for implementing
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| 35 | file systems with transparent compression. One problem is that the
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| 36 | best candidate (lzrw1) is patented twice (Waterworth 4,701,745
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| 37 | and Gibson & Graybill 5,049,881). The lzrw series of algorithms
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| 38 | are available by ftp in ftp.adelaide.edu.au:/pub/compression/lzrw*.
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| 39 |
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| 40 | - Add a super-tight (but slow) compression method, suitable for long
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| 41 | term archives. One problem is that the best versions of arithmetic
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| 42 | coding are patented (4,286,256 4,295,125 4,463,342 4,467,317
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| 43 | 4,633,490 4,652,856 4,891,643 4,905,297 4,935,882 4,973,961
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| 44 | 5,023,611 5,025,258).
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| 45 |
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| 46 | Note: I will introduce new compression methods only if they are
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| 47 | significantly better in either speed or compression ratio than the
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| 48 | existing method(s). So the total number of different methods should
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| 49 | reasonably not exceed 3. (The current 9 compression levels are just
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| 50 | tuning parameters for a single method, deflation.)
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| 51 |
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| 52 | - Add optional error correction. One problem is that the current version
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| 53 | of ecc cannot recover from inserted or missing bytes. It would be
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| 54 | nice to recover from the most common error (transfer of a binary
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| 55 | file in ascii mode).
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| 56 |
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| 57 | - Add a block size (-b) option to improve error recovery in case of
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| 58 | failure of a complete sector. Each block could be extracted
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| 59 | independently, but this reduces the compression ratio.
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| 60 |
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| 61 | For one possible approach to this, please see:
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| 62 |
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| 63 | http://www.samba.org/netfilter/diary/gzip.rsync.patch
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| 64 |
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| 65 | - Use a larger window size to deal with some large redundant files that
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| 66 | 'compress' currently handles better than gzip.
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| 67 |
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| 68 | - Implement the -e (encrypt) option.
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| 69 |
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| 70 | Send comments to <bug-gzip@gnu.org>.
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| 71 |
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| 72 |
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| 73 | ========================================================================
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| 74 |
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| 75 | Copyright (C) 1999, 2001, 2006 Free Software Foundation, Inc.
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| 76 | Copyright (C) 1992, 1993 Jean-loup Gailly
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| 77 |
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| 78 | Permission is granted to copy, distribute and/or modify this document
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| 79 | under the terms of the GNU Free Documentation License, Version 1.2 or
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| 80 | any later version published by the Free Software Foundation; with no
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| 81 | Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
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| 82 | Texts. A copy of the license is included in the ``GNU Free
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| 83 | Documentation License'' file as part of this distribution.
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