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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs.
Revision 1.31 by root, Wed Apr 11 12:23:02 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 = '0.31';	91	our $VERSION = '1.12';
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<512>) 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
…		…
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
317		351
		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
322	circumstances automatically, preserving round-tripping characteristics	357	circumstances automatically, preserving round-tripping characteristics
…		…
375	=over 4	410	=over 4
376		411
377	=item hash references	412	=item hash references
378		413
379	Perl hash references become JSON objects. As there is no inherent ordering	414	Perl hash references become JSON objects. As there is no inherent ordering
380	in hash keys, they will usually be encoded in a pseudo-random order that	415	in hash keys (or JSON objects), they will usually be encoded in a
381	can change between runs of the same program but stays generally the same	416	pseudo-random order that can change between runs of the same program but
382	within a single run of a program. JSON::XS can optionally sort the hash	417	stays generally the same within a single run of a program. JSON::XS can
383	keys (determined by the I<canonical> flag), so the same datastructure	418	optionally sort the hash keys (determined by the I<canonical> flag), so
384	will serialise to the same JSON text (given same settings and version of	419	the same datastructure will serialise to the same JSON text (given same
385	JSON::XS), but this incurs a runtime overhead.	420	settings and version of JSON::XS), but this incurs a runtime overhead
		421	and is only rarely useful, e.g. when you want to compare some JSON text
		422	against another for equality.
386		423
387	=item array references	424	=item array references
388		425
389	Perl array references become JSON arrays.	426	Perl array references become JSON arrays.
		427
		428	=item other references
		429
		430	Other unblessed references are generally not allowed and will cause an
		431	exception to be thrown, except for references to the integers C<0> and
		432	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		433	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		434
		435	to_json [\0,JSON::XS::true] # yields [false,true]
390		436
391	=item blessed objects	437	=item blessed objects
392		438
393	Blessed objects are not allowed. JSON::XS currently tries to encode their	439	Blessed objects are not allowed. JSON::XS currently tries to encode their
394	underlying representation (hash- or arrayref), but this behaviour might	440	underlying representation (hash- or arrayref), but this behaviour might
…		…
427	$x *= 1; # same thing, the choise is yours.	473	$x *= 1; # same thing, the choise is yours.
428		474
429	You can not currently output JSON booleans or force the type in other,	475	You can not currently output JSON booleans or force the type in other,
430	less obscure, ways. Tell me if you need this capability.	476	less obscure, ways. Tell me if you need this capability.
431		477
432	=item circular data structures
433
434	Those will be encoded until memory or stackspace runs out.
435
436	=back	478	=back
		479
437		480
438	=head1 COMPARISON	481	=head1 COMPARISON
439		482
440	As already mentioned, this module was created because none of the existing	483	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	484	JSON modules could be made to work correctly. First I will describe the
…		…
527	tables. They have been generated with the help of the C<eg/bench> program	570	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	571	in the JSON::XS distribution, to make it easy to compare on your own
529	system.	572	system.
530		573
531	First comes a comparison between various modules using a very short JSON	574	First comes a comparison between various modules using a very short JSON
532	string (83 bytes), showing the number of encodes/decodes per second	575	string:
533	(JSON::XS is the functional interface, while JSON::XS/2 is the OO	576
		577	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}
		578
		579	It shows the number of encodes/decodes per second (JSON::XS uses the
		580	functional interface, while JSON::XS/2 uses the OO interface with
534	interface with pretty-printing and hashkey sorting enabled). Higher is	581	pretty-printing and hashkey sorting enabled). Higher is better:
535	better:
536		582
537	module \| encode \| decode \|	583	module \| encode \| decode \|
538	-----------\|------------\|------------\|	584	-----------\|------------\|------------\|
539	JSON \| 14006 \| 6820 \|	585	JSON \| 11488.516 \| 7823.035 \|
540	JSON::DWIW \| 200937 \| 120386 \|	586	JSON::DWIW \| 94708.054 \| 129094.260 \|
541	JSON::PC \| 85065 \| 129366 \|	587	JSON::PC \| 63884.157 \| 128528.212 \|
542	JSON::Syck \| 59898 \| 44232 \|	588	JSON::Syck \| 34898.677 \| 42096.911 \|
543	JSON::XS \| 1171478 \| 342435 \|	589	JSON::XS \| 654027.064 \| 396423.669 \|
544	JSON::XS/2 \| 730760 \| 328714 \|	590	JSON::XS/2 \| 371564.190 \| 371725.613 \|
545	-----------+------------+------------+	591	-----------+------------+------------+
546		592
547	That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80	593	That is, JSON::XS is more than six times faster than JSON::DWIW on
		594	encoding, more than three times faster on decoding, and about thirty times
548	times faster than JSON, even with pretty-printing and key sorting.	595	faster than JSON, even with pretty-printing and key sorting.
549		596
550	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	597	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
551	search API (http://nanoref.com/yahooapis/mgPdGg):	598	search API (http://nanoref.com/yahooapis/mgPdGg):
552		599
553	module \| encode \| decode \|	600	module \| encode \| decode \|
554	-----------\|------------\|------------\|	601	-----------\|------------\|------------\|
555	JSON \| 673 \| 38 \|	602	JSON \| 273.023 \| 44.674 \|
556	JSON::DWIW \| 5271 \| 770 \|	603	JSON::DWIW \| 1089.383 \| 1145.704 \|
557	JSON::PC \| 9901 \| 2491 \|	604	JSON::PC \| 3097.419 \| 2393.921 \|
558	JSON::Syck \| 2360 \| 786 \|	605	JSON::Syck \| 514.060 \| 843.053 \|
559	JSON::XS \| 37398 \| 3202 \|	606	JSON::XS \| 6479.668 \| 3636.364 \|
560	JSON::XS/2 \| 13765 \| 3153 \|	607	JSON::XS/2 \| 3774.221 \| 3599.124 \|
561	-----------+------------+------------+	608	-----------+------------+------------+
562		609
563	Again, JSON::XS leads by far in the encoding case, while still beating	610	Again, JSON::XS leads by far.
564	every other module in the decoding case.
565		611
566	On large strings containing lots of unicode characters, some modules	612	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	613	(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	614	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	615	to decode or encode properly, so it was impossible to prepare a fair
570	case.	616	comparison table for that case.
571		617
572	=head1 RESOURCE LIMITS
573		618
574	JSON::XS does not impose any limits on the size of JSON texts or Perl	619	=head1 SECURITY CONSIDERATIONS
575	values they represent - if your machine can handle it, JSON::XS will	620
576	encode or decode it. Future versions might optionally impose structure	621	When you are using JSON in a protocol, talking to untrusted potentially
577	depth and memory use resource limits.	622	hostile creatures requires relatively few measures.
		623
		624	First of all, your JSON decoder should be secure, that is, should not have
		625	any buffer overflows. Obviously, this module should ensure that and I am
		626	trying hard on making that true, but you never know.
		627
		628	Second, you need to avoid resource-starving attacks. That means you should
		629	limit the size of JSON texts you accept, or make sure then when your
		630	resources run out, thats just fine (e.g. by using a separate process that
		631	can crash safely). The size of a JSON text in octets or characters is
		632	usually a good indication of the size of the resources required to decode
		633	it into a Perl structure.
		634
		635	Third, JSON::XS recurses using the C stack when decoding objects and
		636	arrays. The C stack is a limited resource: for instance, on my amd64
		637	machine with 8MB of stack size I can decode around 180k nested arrays but
		638	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		639	to free the temporary). If that is exceeded, the program crashes. to be
		640	conservative, the default nesting limit is set to 512. If your process
		641	has a smaller stack, you should adjust this setting accordingly with the
		642	C<max_depth> method.
		643
		644	And last but least, something else could bomb you that I forgot to think
		645	of. In that case, you get to keep the pieces. I am always open for hints,
		646	though...
		647
578		648
579	=head1 BUGS	649	=head1 BUGS
580		650
581	While the goal of this module is to be correct, that unfortunately does	651	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	652	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	653	still relatively early in its development. If you keep reporting bugs they
584	be fixed swiftly, though.	654	will be fixed swiftly, though.
585		655
586	=cut	656	=cut
		657
		658	sub true() { \1 }
		659	sub false() { \0 }
587		660
588	1;	661	1;
589		662
590	=head1 AUTHOR	663	=head1 AUTHOR
591		664

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Comparing JSON-XS/XS.pm (file contents): Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs. Revision 1.31 by root, Wed Apr 11 12:23:02 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs.
Revision 1.31 by root, Wed Apr 11 12:23:02 2007 UTC