[ViewVC] Diff of: cvs/JSON-XS/XS.pm

Comparing JSON-XS/XS.pm (file contents):
Revision 1.17 by root, Sat Mar 24 19:42:14 2007 UTC vs.
Revision 1.23 by root, Sun Mar 25 21:19:13 2007 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use JSON::XS;	7	use JSON::XS;
8		8
9	# exported functions, croak on error	9	# exported functions, they croak on error
		10	# and expect/generate UTF-8
10		11
11	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
12	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
13		14
		15	# objToJson and jsonToObj aliases to to_json and from_json
		16	# are exported for compatibility to the JSON module,
		17	# but should not be used in new code.
		18
14	# oo-interface	19	# OO-interface
15		20
16	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
17	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
18	$perl_scalar = $coder->decode ($unicode_json_text);	23	$perl_scalar = $coder->decode ($unicode_json_text);
19		24
…		…
36		41
37	=head2 FEATURES	42	=head2 FEATURES
38		43
39	=over 4	44	=over 4
40		45
41	=item * correct handling of unicode issues	46	=item * correct unicode handling
42		47
43	This module knows how to handle Unicode, and even documents how and when	48	This module knows how to handle Unicode, and even documents how and when
44	it does so.	49	it does so.
45		50
46	=item * round-trip integrity	51	=item * round-trip integrity
47		52
48	When you serialise a perl data structure using only datatypes supported	53	When you serialise a perl data structure using only datatypes supported
49	by JSON, the deserialised data structure is identical on the Perl level.	54	by JSON, the deserialised data structure is identical on the Perl level.
50	(e.g. the string "2.0" doesn't suddenly become "2").	55	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks
		56	like a number).
51		57
52	=item * strict checking of JSON correctness	58	=item * strict checking of JSON correctness
53		59
54	There is no guessing, no generating of illegal JSON texts by default,	60	There is no guessing, no generating of illegal JSON texts by default,
55	and only JSON is accepted as input by default (the latter is a security	61	and only JSON is accepted as input by default (the latter is a security
…		…
66	interface.	72	interface.
67		73
68	=item * reasonably versatile output formats	74	=item * reasonably versatile output formats
69		75
70	You can choose between the most compact guarenteed single-line format	76	You can choose between the most compact guarenteed single-line format
71	possible (nice for simple line-based protocols), a pure-ascii format (for	77	possible (nice for simple line-based protocols), a pure-ascii format
72	when your transport is not 8-bit clean), or a pretty-printed format (for	78	(for when your transport is not 8-bit clean, still supports the whole
73	when you want to read that stuff). Or you can combine those features in	79	unicode range), or a pretty-printed format (for when you want to read that
74	whatever way you like.	80	stuff). Or you can combine those features in whatever way you like.
75		81
76	=back	82	=back
77		83
78	=cut	84	=cut
79		85
80	package JSON::XS;	86	package JSON::XS;
81		87
		88	use strict;
		89
82	BEGIN {	90	BEGIN {
83	$VERSION = '0.5';	91	our $VERSION = '0.8';
84	@ISA = qw(Exporter);	92	our @ISA = qw(Exporter);
85		93
86	@EXPORT = qw(to_json from_json);	94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
87	require Exporter;	95	require Exporter;
88		96
89	require XSLoader;	97	require XSLoader;
90	XSLoader::load JSON::XS::, $VERSION;	98	XSLoader::load JSON::XS::, $VERSION;
91	}	99	}
…		…
120	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
121		129
122	except being faster.	130	except being faster.
123		131
124	=back	132	=back
		133
125		134
126	=head1 OBJECT-ORIENTED INTERFACE	135	=head1 OBJECT-ORIENTED INTERFACE
127		136
128	The object oriented interface lets you configure your own encoding or	137	The object oriented interface lets you configure your own encoding or
129	decoding style, within the limits of supported formats.	138	decoding style, within the limits of supported formats.
…		…
293		302
294	In the future, this setting might control other things, such as converting	303	In the future, this setting might control other things, such as converting
295	strings that look like integers or floats into integers or floats	304	strings that look like integers or floats into integers or floats
296	internally (there is no difference on the Perl level), saving space.	305	internally (there is no difference on the Perl level), saving space.
297		306
		307	=item $json = $json->max_depth ([$maximum_nesting_depth])
		308
		309	Sets the maximum nesting level (default C<8192>) accepted while encoding
		310	or decoding. If the JSON text or Perl data structure has an equal or
		311	higher nesting level then this limit, then the encoder and decoder will
		312	stop and croak at that point.
		313
		314	Nesting level is defined by number of hash- or arrayrefs that the encoder
		315	needs to traverse to reach a given point or the number of C<{> or C<[>
		316	characters without their matching closing parenthesis crossed to reach a
		317	given character in a string.
		318
		319	Setting the maximum depth to one disallows any nesting, so that ensures
		320	that the object is only a single hash/object or array.
		321
		322	The argument to C<max_depth> will be rounded up to the next nearest power
		323	of two.
		324
		325	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		326
298	=item $json_text = $json->encode ($perl_scalar)	327	=item $json_text = $json->encode ($perl_scalar)
299		328
300	Converts the given Perl data structure (a simple scalar or a reference	329	Converts the given Perl data structure (a simple scalar or a reference
301	to a hash or array) to its JSON representation. Simple scalars will be	330	to a hash or array) to its JSON representation. Simple scalars will be
302	converted into JSON string or number sequences, while references to arrays	331	converted into JSON string or number sequences, while references to arrays
…		…
312	JSON numbers and strings become simple Perl scalars. JSON arrays become	341	JSON numbers and strings become simple Perl scalars. JSON arrays become
313	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	342	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
314	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	343	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
315		344
316	=back	345	=back
		346
317		347
318	=head1 MAPPING	348	=head1 MAPPING
319		349
320	This section describes how JSON::XS maps Perl values to JSON values and	350	This section describes how JSON::XS maps Perl values to JSON values and
321	vice versa. These mappings are designed to "do the right thing" in most	351	vice versa. These mappings are designed to "do the right thing" in most
…		…
433		463
434	Those will be encoded until memory or stackspace runs out.	464	Those will be encoded until memory or stackspace runs out.
435		465
436	=back	466	=back
437		467
		468
438	=head1 COMPARISON	469	=head1 COMPARISON
439		470
440	As already mentioned, this module was created because none of the existing	471	As already mentioned, this module was created because none of the existing
441	JSON modules could be made to work correctly. First I will describe the	472	JSON modules could be made to work correctly. First I will describe the
442	problems (or pleasures) I encountered with various existing JSON modules,	473	problems (or pleasures) I encountered with various existing JSON modules,
…		…
527	tables. They have been generated with the help of the C<eg/bench> program	558	tables. They have been generated with the help of the C<eg/bench> program
528	in the JSON::XS distribution, to make it easy to compare on your own	559	in the JSON::XS distribution, to make it easy to compare on your own
529	system.	560	system.
530		561
531	First comes a comparison between various modules using a very short JSON	562	First comes a comparison between various modules using a very short JSON
532	string (83 bytes), showing the number of encodes/decodes per second	563	string:
533	(JSON::XS is the functional interface, while JSON::XS/2 is the OO	564
		565	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}
		566
		567	It shows the number of encodes/decodes per second (JSON::XS uses the
		568	functional interface, while JSON::XS/2 uses the OO interface with
534	interface with pretty-printing and hashkey sorting enabled). Higher is	569	pretty-printing and hashkey sorting enabled). Higher is better:
535	better:
536		570
537	module \| encode \| decode \|	571	module \| encode \| decode \|
538	-----------\|------------\|------------\|	572	-----------\|------------\|------------\|
539	JSON \| 14006 \| 6820 \|	573	JSON \| 11488.516 \| 7823.035 \|
540	JSON::DWIW \| 200937 \| 120386 \|	574	JSON::DWIW \| 94708.054 \| 129094.260 \|
541	JSON::PC \| 85065 \| 129366 \|	575	JSON::PC \| 63884.157 \| 128528.212 \|
542	JSON::Syck \| 59898 \| 44232 \|	576	JSON::Syck \| 34898.677 \| 42096.911 \|
543	JSON::XS \| 1171478 \| 342435 \|	577	JSON::XS \| 654027.064 \| 396423.669 \|
544	JSON::XS/2 \| 730760 \| 328714 \|	578	JSON::XS/2 \| 371564.190 \| 371725.613 \|
545	-----------+------------+------------+	579	-----------+------------+------------+
546		580
547	That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80	581	That is, JSON::XS is more than six times faster than JSON::DWIW on
		582	encoding, more than three times faster on decoding, and about thirty times
548	times faster than JSON, even with pretty-printing and key sorting.	583	faster than JSON, even with pretty-printing and key sorting.
549		584
550	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	585	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
551	search API (http://nanoref.com/yahooapis/mgPdGg):	586	search API (http://nanoref.com/yahooapis/mgPdGg):
552		587
553	module \| encode \| decode \|	588	module \| encode \| decode \|
554	-----------\|------------\|------------\|	589	-----------\|------------\|------------\|
555	JSON \| 673 \| 38 \|	590	JSON \| 273.023 \| 44.674 \|
556	JSON::DWIW \| 5271 \| 770 \|	591	JSON::DWIW \| 1089.383 \| 1145.704 \|
557	JSON::PC \| 9901 \| 2491 \|	592	JSON::PC \| 3097.419 \| 2393.921 \|
558	JSON::Syck \| 2360 \| 786 \|	593	JSON::Syck \| 514.060 \| 843.053 \|
559	JSON::XS \| 37398 \| 3202 \|	594	JSON::XS \| 6479.668 \| 3636.364 \|
560	JSON::XS/2 \| 13765 \| 3153 \|	595	JSON::XS/2 \| 3774.221 \| 3599.124 \|
561	-----------+------------+------------+	596	-----------+------------+------------+
562		597
563	Again, JSON::XS leads by far in the encoding case, while still beating	598	Again, JSON::XS leads by far.
564	every other module in the decoding case.
565		599
566	On large strings containing lots of unicode characters, some modules	600	On large strings containing lots of high unicode characters, some modules
567	(such as JSON::PC) decode faster than JSON::XS, but the result will be	601	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
568	broken due to missing unicode handling. Others refuse to decode or encode	602	will be broken due to missing (or wrong) unicode handling. Others refuse
569	properly, so it was impossible to prepare a fair comparison table for that	603	to decode or encode properly, so it was impossible to prepare a fair
570	case.	604	comparison table for that case.
571		605
572	=head1 RESOURCE LIMITS
573		606
574	JSON::XS does not impose any limits on the size of JSON texts or Perl	607	=head1 SECURITY CONSIDERATIONS
575	values they represent - if your machine can handle it, JSON::XS will	608
576	encode or decode it. Future versions might optionally impose structure	609	When you are using JSON in a protocol, talking to untrusted potentially
577	depth and memory use resource limits.	610	hostile creatures requires relatively few measures.
		611
		612	First of all, your JSON decoder should be secure, that is, should not have
		613	any buffer overflows. Obviously, this module should ensure that and I am
		614	trying hard on making that true, but you never know.
		615
		616	Second, you need to avoid resource-starving attacks. That means you should
		617	limit the size of JSON texts you accept, or make sure then when your
		618	resources run out, thats just fine (e.g. by using a separate process that
		619	can crash safely). The size of a JSON text in octets or characters is
		620	usually a good indication of the size of the resources required to decode
		621	it into a Perl structure.
		622
		623	Third, JSON::XS recurses using the C stack when decoding objects and
		624	arrays. The C stack is a limited resource: for instance, on my amd64
		625	machine with 8MB of stack size I can decode around 180k nested arrays
		626	but only 14k nested JSON objects. If that is exceeded, the program
		627	crashes. Thats why the default nesting limit is set to 8192. If your
		628	process has a smaller stack, you should adjust this setting accordingly
		629	with the C<max_depth> method.
		630
		631	And last but least, something else could bomb you that I forgot to think
		632	of. In that case, you get to keep the pieces. I am alway sopen for hints,
		633	though...
		634
578		635
579	=head1 BUGS	636	=head1 BUGS
580		637
581	While the goal of this module is to be correct, that unfortunately does	638	While the goal of this module is to be correct, that unfortunately does
582	not mean its bug-free, only that I think its design is bug-free. It is	639	not mean its bug-free, only that I think its design is bug-free. It is
583	still very young and not well-tested. If you keep reporting bugs they will	640	still relatively early in its development. If you keep reporting bugs they
584	be fixed swiftly, though.	641	will be fixed swiftly, though.
585		642
586	=cut	643	=cut
587		644
588	1;	645	1;
589		646

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Comparing JSON-XS/XS.pm (file contents): Revision 1.17 by root, Sat Mar 24 19:42:14 2007 UTC vs. Revision 1.23 by root, Sun Mar 25 21:19:13 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.17 by root, Sat Mar 24 19:42:14 2007 UTC vs.
Revision 1.23 by root, Sun Mar 25 21:19:13 2007 UTC