[ViewVC] Diff of: cvs/Compress-LZF/LZF.pm

Comparing Compress-LZF/LZF.pm (file contents):
Revision 1.2 by root, Thu Sep 27 19:51:24 2001 UTC vs.
Revision 1.35 by root, Mon Jun 29 23:51:28 2015 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	Compress::LZF - extremely leight-weight Lev-Zimpel-Free compression	3	Compress::LZF - extremely light-weight Lempel-Ziv-Free compression
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	# import compress/decompress functions	7	# import compress/decompress functions
8	use Compress::LZF;	8	use Compress::LZF;
23	LZF is an extremely fast (not that much slower than a pure memcpy)	23	LZF is an extremely fast (not that much slower than a pure memcpy)
24	compression algorithm. It is ideal for applications where you want to save	24	compression algorithm. It is ideal for applications where you want to save
25	I<some> space but not at the cost of speed. It is ideal for repetitive	25	I<some> space but not at the cost of speed. It is ideal for repetitive
26	data as well. The module is self-contained and very small (no large	26	data as well. The module is self-contained and very small (no large
27	library to be pulled in). It is also free, so there should be no problems	27	library to be pulled in). It is also free, so there should be no problems
28	incoporating this module into commercial programs.	28	incorporating this module into commercial programs.
29		29
30	I have no idea wether any patents in any countries apply to this	30	I have no idea wether any patents in any countries apply to this
31	algorithm, but at the moment it is believed that it is free from any	31	algorithm, but at the moment it is believed that it is free from any
32	patents.	32	patents.
33		33
34	=head1 FUNCTIONS	34	=head1 FUNCTIONS
35		35
		36	=over 4
		37
36	=head2 $compressed = compress $uncompressed	38	=item $compressed = compress $uncompressed
		39
		40	=item $compressed = compress_best $uncompressed
37		41
38	Try to compress the given string as quickly and as much as possible. In	42	Try to compress the given string as quickly and as much as possible. In
39	the worst case, the string can enlarge by 1 byte, but that should be the	43	the worst case, the string can enlarge by 1 byte, but that should be the
40	absolute exception. You can expect a 45% compression ratio on large,	44	absolute exception. You can expect a 45% compression ratio on large,
41	binary strings.	45	binary strings.
42		46
		47	The C<compress_best> function uses a different algorithm that is slower
		48	but usually achieves better compression.
		49
43	=head2 $decompressed = decompress $compressed	50	=item $decompressed = decompress $compressed
44		51
45	Uncompress the string (compressed by C<compress>) and return the original	52	Uncompress the string (compressed by C<compress>) and return the original
46	data. Decompression errors can result in either broken data (there is no	53	data. Decompression errors can result in either broken data (there is no
47	checksum kept) or a runtime error.	54	checksum kept) or a runtime error.
48		55
49	=head2 $serialized = sfreeze $value (simplified freeze)	56	=item $serialized = sfreeze $value (simplified freeze)
		57
		58	=item $serialized = sfreeze_best $value
50		59
51	Often there is the need to serialize data into a string. This function does that, by using the Storable	60	Often there is the need to serialize data into a string. This function does that, by using the Storable
52	module. It does the following transforms:	61	module. It does the following transforms:
53		62
		63	undef (the perl undefined value)
		64	=> a special cookie (undef'ness is being preserved)
54	IV, NV, PV (i.e. a _plain_ perl scalar):	65	IV, NV, PV (i.e. a _plain_ perl scalar):
55	=> stays as is when it contains normal text/numbers	66	=> stays as is when it contains normal text/numbers
56	=> gets serialized into a string	67	=> gets serialized into a string
57	RV, undef, other funny objects (magical ones for example):	68	RV, undef, other funny objects (magical ones for example):
58	=> data structure is freeze'd into a string.	69	=> data structure is freeze'd into a string.
59		70
60	That is, it tries to leave "normal", human-readable data untouched but	71	That is, it tries to leave "normal", human-readable data untouched but
61	still serializes complex data structures into strings.	72	still serializes complex data structures into strings. The idea is to keep
62		73	readability as high as possible, and in cases readability can't be helped
63	The idea of all these C<sfreeze> functions is to keep readability as high	74	anyways, it tries to compress the string.
64	as possible, and in cases readability can't be helped anyways, it tries to
65	compress the string.
66		75
67	The C<sfreeze> functions will enlarge the original data one byte at most	76	The C<sfreeze> functions will enlarge the original data one byte at most
68	and will only load the Storable method when neccessary.	77	and will only load the Storable method when neccessary.
69		78
		79	The C<sfreeze_best> function uses a different algorithm that is slower
		80	but usually achieves better compression.
		81
70	=head2 $serialized = sfreeze_c $value (sfreeze and compress)	82	=item $serialized = sfreeze_c $value (sfreeze and compress)
		83
		84	=item $serialized = sfreeze_c_best $value
71		85
72	Similar to C<sfreeze>, but always tries to C<c>ompress the resulting	86	Similar to C<sfreeze>, but always tries to C<c>ompress the resulting
73	string. This still leaves most small objects (most numbers) untouched.	87	string. This still leaves most small objects (most numbers) untouched.
74		88
		89	The C<sfreeze_c> function uses a different algorithm that is slower
		90	but usually achieves better compression.
		91
75	=head2 $serialized = sfreeze_cr $value (sfreeze and compress references)	92	=item $serialized = sfreeze_cr $value (sfreeze and compress references)
		93
		94	=item $serialized = sfreeze_cr_best $value
76		95
77	Similar to C<sfreeze>, but tries to C<c>ompress the resulting string	96	Similar to C<sfreeze>, but tries to C<c>ompress the resulting string
78	unless it's a "simple" string. References for example are not "simple" and	97	unless it's a "simple" string. References for example are not "simple" and
79	as such are being compressed.	98	as such are being compressed.
80		99
		100	The C<sfreeze_cr_best> function uses a different algorithm that is slower
		101	but usually achieves better compression.
		102
81	=head2 $original_data = sthaw $serialized	103	=item $original_data = sthaw $serialized
82		104
83	Recreate the original object from it's serialized representation. This	105	Recreate the original object from it's serialized representation. This
84	function automatically detects all the different sfreeze formats.	106	function automatically detects all the different sfreeze formats.
		107
		108	=item Compress::LZF::set_serializer $package, $freeze, $thaw
		109
		110	Set the serialize module and functions to use. The default is "Storable",
		111	"Storable::net_mstore" and "Storable::mretrieve", which should be fine for
		112	most purposes.
		113
		114	=back
		115
		116	=head1 SUPPORT FOR THE PERL MULTICORE SPECIFICATION
		117
		118	This module supports the perl multicore specification
		119	(L<http://perlmulticore.schmorp.de/>) for all compression (> 2000 octets) and
		120	decompression (> 4000 octets) functions.
85		121
86	=head1 SEE ALSO	122	=head1 SEE ALSO
87		123
88	Other Compress::* modules, especially Compress::LZV1 (an older, less	124	Other Compress::* modules, especially Compress::LZV1 (an older, less
89	speedy module that guarentees only 1 byte overhead worst case) and	125	speedy module that guarentees only 1 byte overhead worst case) and
…		…
92	http://liblzf.plan9.de/	128	http://liblzf.plan9.de/
93		129
94	=head1 AUTHOR	130	=head1 AUTHOR
95		131
96	This perl extension and the underlying liblzf were written by Marc Lehmann	132	This perl extension and the underlying liblzf were written by Marc Lehmann
97	<pcg@goof.com> (See also http://liblzf.plan9.de/).	133	<schmorp@schmorp.de> (See also http://liblzf.plan9.de/).
98		134
99	=head1 BUGS	135	=head1 BUGS
100		136
101	=cut	137	=cut
102		138
103	package Compress::LZF;	139	package Compress::LZF;
104		140
105	require Exporter;	141	require Exporter;
106	require DynaLoader;	142	require DynaLoader;
107		143
108	$VERSION = 0.1;	144	$VERSION = 3.8;
109	@ISA = qw/Exporter DynaLoader/;	145	@ISA = qw/Exporter DynaLoader/;
110	%EXPORT_TAGS = (	146	%EXPORT_TAGS = (
111	freeze => [qw(sfreeze sfreeze_cr sfreeze_c sthaw)],	147	freeze => [qw(sfreeze sfreeze_best sfreeze_cr sfreeze_cr_best sfreeze_c sfreeze_c_best sthaw)],
112	compress => [qw(compress decompress)],	148	compress => [qw(compress compress_best decompress)],
113	);	149	);
114		150
115	Exporter::export_tags('compress');	151	Exporter::export_tags('compress');
116	Exporter::export_ok_tags('freeze');	152	Exporter::export_ok_tags('freeze');
117		153

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Comparing Compress-LZF/LZF.pm (file contents): Revision 1.2 by root, Thu Sep 27 19:51:24 2001 UTC vs. Revision 1.35 by root, Mon Jun 29 23:51:28 2015 UTC

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Comparing Compress-LZF/LZF.pm (file contents):
Revision 1.2 by root, Thu Sep 27 19:51:24 2001 UTC vs.
Revision 1.35 by root, Mon Jun 29 23:51:28 2015 UTC