[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 1.24 by root, Thu Mar 29 01:27:36 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.
…		…
275	=> "Hello, World!"	284	=> "Hello, World!"
276		285
277	=item $json = $json->shrink ([$enable])	286	=item $json = $json->shrink ([$enable])
278		287
279	Perl usually over-allocates memory a bit when allocating space for	288	Perl usually over-allocates memory a bit when allocating space for
280	strings. This flag optionally resizes strings generated by either	289	strings. This flag optionally resizes strings generated by either
281	C<encode> or C<decode> to their minimum size possible. This can save	290	C<encode> or C<decode> to their minimum size possible. This can save
282	memory when your JSON texts are either very very long or you have many	291	memory when your JSON texts are either very very long or you have many
283	short strings. It will also try to downgrade any strings to octet-form	292	short strings. It will also try to downgrade any strings to octet-form
284	if possible: perl stores strings internally either in an encoding called	293	if possible: perl stores strings internally either in an encoding called
285	UTF-X or in octet-form. The latter cannot store everything but uses less	294	UTF-X or in octet-form. The latter cannot store everything but uses less
286	space in general.	295	space in general (and some buggy Perl or C code might even rely on that
		296	internal representation being used).
287		297
		298	The actual definition of what shrink does might change in future versions,
		299	but it will always try to save space at the expense of time.
		300
288	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	301	If C<$enable> is true (or missing), the string returned by C<encode> will
289	while all strings generated by C<decode> will also be shrunk-to-fit.	302	be shrunk-to-fit, while all strings generated by C<decode> will also be
		303	shrunk-to-fit.
290		304
291	If C<$enable> is false, then the normal perl allocation algorithms are used.	305	If C<$enable> is false, then the normal perl allocation algorithms are used.
292	If you work with your data, then this is likely to be faster.	306	If you work with your data, then this is likely to be faster.
293		307
294	In the future, this setting might control other things, such as converting	308	In the future, this setting might control other things, such as converting
295	strings that look like integers or floats into integers or floats	309	strings that look like integers or floats into integers or floats
296	internally (there is no difference on the Perl level), saving space.	310	internally (there is no difference on the Perl level), saving space.
		311
		312	=item $json = $json->max_depth ([$maximum_nesting_depth])
		313
		314	Sets the maximum nesting level (default C<8192>) accepted while encoding
		315	or decoding. If the JSON text or Perl data structure has an equal or
		316	higher nesting level then this limit, then the encoder and decoder will
		317	stop and croak at that point.
		318
		319	Nesting level is defined by number of hash- or arrayrefs that the encoder
		320	needs to traverse to reach a given point or the number of C<{> or C<[>
		321	characters without their matching closing parenthesis crossed to reach a
		322	given character in a string.
		323
		324	Setting the maximum depth to one disallows any nesting, so that ensures
		325	that the object is only a single hash/object or array.
		326
		327	The argument to C<max_depth> will be rounded up to the next nearest power
		328	of two.
		329
		330	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
297		331
298	=item $json_text = $json->encode ($perl_scalar)	332	=item $json_text = $json->encode ($perl_scalar)
299		333
300	Converts the given Perl data structure (a simple scalar or a reference	334	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	335	to a hash or array) to its JSON representation. Simple scalars will be
…		…
312	JSON numbers and strings become simple Perl scalars. JSON arrays become	346	JSON numbers and strings become simple Perl scalars. JSON arrays become
313	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	347	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>.	348	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
315		349
316	=back	350	=back
		351
317		352
318	=head1 MAPPING	353	=head1 MAPPING
319		354
320	This section describes how JSON::XS maps Perl values to JSON values and	355	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	356	vice versa. These mappings are designed to "do the right thing" in most
…		…
433		468
434	Those will be encoded until memory or stackspace runs out.	469	Those will be encoded until memory or stackspace runs out.
435		470
436	=back	471	=back
437		472
		473
438	=head1 COMPARISON	474	=head1 COMPARISON
439		475
440	As already mentioned, this module was created because none of the existing	476	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	477	JSON modules could be made to work correctly. First I will describe the
442	problems (or pleasures) I encountered with various existing JSON modules,	478	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	563	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	564	in the JSON::XS distribution, to make it easy to compare on your own
529	system.	565	system.
530		566
531	First comes a comparison between various modules using a very short JSON	567	First comes a comparison between various modules using a very short JSON
532	string (83 bytes), showing the number of encodes/decodes per second	568	string:
533	(JSON::XS is the functional interface, while JSON::XS/2 is the OO	569
		570	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}
		571
		572	It shows the number of encodes/decodes per second (JSON::XS uses the
		573	functional interface, while JSON::XS/2 uses the OO interface with
534	interface with pretty-printing and hashkey sorting enabled). Higher is	574	pretty-printing and hashkey sorting enabled). Higher is better:
535	better:
536		575
537	module \| encode \| decode \|	576	module \| encode \| decode \|
538	-----------\|------------\|------------\|	577	-----------\|------------\|------------\|
539	JSON \| 14006 \| 6820 \|	578	JSON \| 11488.516 \| 7823.035 \|
540	JSON::DWIW \| 200937 \| 120386 \|	579	JSON::DWIW \| 94708.054 \| 129094.260 \|
541	JSON::PC \| 85065 \| 129366 \|	580	JSON::PC \| 63884.157 \| 128528.212 \|
542	JSON::Syck \| 59898 \| 44232 \|	581	JSON::Syck \| 34898.677 \| 42096.911 \|
543	JSON::XS \| 1171478 \| 342435 \|	582	JSON::XS \| 654027.064 \| 396423.669 \|
544	JSON::XS/2 \| 730760 \| 328714 \|	583	JSON::XS/2 \| 371564.190 \| 371725.613 \|
545	-----------+------------+------------+	584	-----------+------------+------------+
546		585
547	That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80	586	That is, JSON::XS is more than six times faster than JSON::DWIW on
		587	encoding, more than three times faster on decoding, and about thirty times
548	times faster than JSON, even with pretty-printing and key sorting.	588	faster than JSON, even with pretty-printing and key sorting.
549		589
550	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	590	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
551	search API (http://nanoref.com/yahooapis/mgPdGg):	591	search API (http://nanoref.com/yahooapis/mgPdGg):
552		592
553	module \| encode \| decode \|	593	module \| encode \| decode \|
554	-----------\|------------\|------------\|	594	-----------\|------------\|------------\|
555	JSON \| 673 \| 38 \|	595	JSON \| 273.023 \| 44.674 \|
556	JSON::DWIW \| 5271 \| 770 \|	596	JSON::DWIW \| 1089.383 \| 1145.704 \|
557	JSON::PC \| 9901 \| 2491 \|	597	JSON::PC \| 3097.419 \| 2393.921 \|
558	JSON::Syck \| 2360 \| 786 \|	598	JSON::Syck \| 514.060 \| 843.053 \|
559	JSON::XS \| 37398 \| 3202 \|	599	JSON::XS \| 6479.668 \| 3636.364 \|
560	JSON::XS/2 \| 13765 \| 3153 \|	600	JSON::XS/2 \| 3774.221 \| 3599.124 \|
561	-----------+------------+------------+	601	-----------+------------+------------+
562		602
563	Again, JSON::XS leads by far in the encoding case, while still beating	603	Again, JSON::XS leads by far.
564	every other module in the decoding case.
565		604
566	On large strings containing lots of unicode characters, some modules	605	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	606	(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	607	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	608	to decode or encode properly, so it was impossible to prepare a fair
570	case.	609	comparison table for that case.
571		610
572	=head1 RESOURCE LIMITS
573		611
574	JSON::XS does not impose any limits on the size of JSON texts or Perl	612	=head1 SECURITY CONSIDERATIONS
575	values they represent - if your machine can handle it, JSON::XS will	613
576	encode or decode it. Future versions might optionally impose structure	614	When you are using JSON in a protocol, talking to untrusted potentially
577	depth and memory use resource limits.	615	hostile creatures requires relatively few measures.
		616
		617	First of all, your JSON decoder should be secure, that is, should not have
		618	any buffer overflows. Obviously, this module should ensure that and I am
		619	trying hard on making that true, but you never know.
		620
		621	Second, you need to avoid resource-starving attacks. That means you should
		622	limit the size of JSON texts you accept, or make sure then when your
		623	resources run out, thats just fine (e.g. by using a separate process that
		624	can crash safely). The size of a JSON text in octets or characters is
		625	usually a good indication of the size of the resources required to decode
		626	it into a Perl structure.
		627
		628	Third, JSON::XS recurses using the C stack when decoding objects and
		629	arrays. The C stack is a limited resource: for instance, on my amd64
		630	machine with 8MB of stack size I can decode around 180k nested arrays
		631	but only 14k nested JSON objects. If that is exceeded, the program
		632	crashes. Thats why the default nesting limit is set to 8192. If your
		633	process has a smaller stack, you should adjust this setting accordingly
		634	with the C<max_depth> method.
		635
		636	And last but least, something else could bomb you that I forgot to think
		637	of. In that case, you get to keep the pieces. I am alway sopen for hints,
		638	though...
		639
578		640
579	=head1 BUGS	641	=head1 BUGS
580		642
581	While the goal of this module is to be correct, that unfortunately does	643	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	644	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	645	still relatively early in its development. If you keep reporting bugs they
584	be fixed swiftly, though.	646	will be fixed swiftly, though.
585		647
586	=cut	648	=cut
587		649
588	1;	650	1;
589		651

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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 1.24 by root, Thu Mar 29 01:27:36 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 1.24 by root, Thu Mar 29 01:27:36 2007 UTC