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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.36 by root, Wed May 23 22:07:43 2007 UTC vs.
Revision 1.63 by root, Thu Oct 11 23:07:43 2007 UTC

…		…
		1	=encoding utf-8
		2
1	=head1 NAME	3	=head1 NAME
2		4
3	JSON::XS - JSON serialising/deserialising, done correctly and fast	5	JSON::XS - JSON serialising/deserialising, done correctly and fast
		6
		7	JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ
		8	(http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html)
4		9
5	=head1 SYNOPSIS	10	=head1 SYNOPSIS
6		11
7	use JSON::XS;	12	use JSON::XS;
8		13
9	# exported functions, they croak on error	14	# exported functions, they croak on error
10	# and expect/generate UTF-8	15	# and expect/generate UTF-8
11		16
12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	17	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	18	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
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		19
19	# OO-interface	20	# OO-interface
20		21
21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	22	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	23	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
85		86
86	package JSON::XS;	87	package JSON::XS;
87		88
88	use strict;	89	use strict;
89		90
90	BEGIN {
91	our $VERSION = '1.22';	91	our $VERSION = '1.5';
92	our @ISA = qw(Exporter);	92	our @ISA = qw(Exporter);
93		93
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	94	our @EXPORT = qw(to_json from_json);
95	require Exporter;
96		95
97	require XSLoader;	96	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	97	use XSLoader;
99	}
100		98
101	=head1 FUNCTIONAL INTERFACE	99	=head1 FUNCTIONAL INTERFACE
102		100
103	The following convinience methods are provided by this module. They are	101	The following convinience methods are provided by this module. They are
104	exported by default:	102	exported by default:
105		103
106	=over 4	104	=over 4
107		105
108	=item $json_text = to_json $perl_scalar	106	=item $json_text = to_json $perl_scalar
109		107
110	Converts the given Perl data structure (a simple scalar or a reference to	108	Converts the given Perl data structure to a UTF-8 encoded, binary string
111	a hash or array) to a UTF-8 encoded, binary string (that is, the string contains	109	(that is, the string contains octets only). Croaks on error.
112	octets only). Croaks on error.
113		110
114	This function call is functionally identical to:	111	This function call is functionally identical to:
115		112
116	$json_text = JSON::XS->new->utf8->encode ($perl_scalar)	113	$json_text = JSON::XS->new->utf8->encode ($perl_scalar)
117		114
118	except being faster.	115	except being faster.
119		116
120	=item $perl_scalar = from_json $json_text	117	=item $perl_scalar = from_json $json_text
121		118
122	The opposite of C<to_json>: expects an UTF-8 (binary) string and tries to	119	The opposite of C<to_json>: expects an UTF-8 (binary) string and tries
123	parse that as an UTF-8 encoded JSON text, returning the resulting simple	120	to parse that as an UTF-8 encoded JSON text, returning the resulting
124	scalar or reference. Croaks on error.	121	reference. Croaks on error.
125		122
126	This function call is functionally identical to:	123	This function call is functionally identical to:
127		124
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	125	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		126
130	except being faster.	127	except being faster.
131		128
		129	=item $is_boolean = JSON::XS::is_bool $scalar
		130
		131	Returns true if the passed scalar represents either JSON::XS::true or
		132	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		133	and are used to represent JSON C<true> and C<false> values in Perl.
		134
		135	See MAPPING, below, for more information on how JSON values are mapped to
		136	Perl.
		137
132	=back	138	=back
		139
		140
		141	=head1 A FEW NOTES ON UNICODE AND PERL
		142
		143	Since this often leads to confusion, here are a few very clear words on
		144	how Unicode works in Perl, modulo bugs.
		145
		146	=over 4
		147
		148	=item 1. Perl strings can store characters with ordinal values > 255.
		149
		150	This enables you to store unicode characters as single characters in a
		151	Perl string - very natural.
		152
		153	=item 2. Perl does I<not> associate an encoding with your strings.
		154
		155	Unless you force it to, e.g. when matching it against a regex, or printing
		156	the scalar to a file, in which case Perl either interprets your string as
		157	locale-encoded text, octets/binary, or as Unicode, depending on various
		158	settings. In no case is an encoding stored together with your data, it is
		159	I<use> that decides encoding, not any magical metadata.
		160
		161	=item 3. The internal utf-8 flag has no meaning with regards to the
		162	encoding of your string.
		163
		164	Just ignore that flag unless you debug a Perl bug, a module written in
		165	XS or want to dive into the internals of perl. Otherwise it will only
		166	confuse you, as, despite the name, it says nothing about how your string
		167	is encoded. You can have unicode strings with that flag set, with that
		168	flag clear, and you can have binary data with that flag set and that flag
		169	clear. Other possibilities exist, too.
		170
		171	If you didn't know about that flag, just the better, pretend it doesn't
		172	exist.
		173
		174	=item 4. A "Unicode String" is simply a string where each character can be
		175	validly interpreted as a Unicode codepoint.
		176
		177	If you have UTF-8 encoded data, it is no longer a Unicode string, but a
		178	Unicode string encoded in UTF-8, giving you a binary string.
		179
		180	=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string.
		181
		182	Its a fact. Learn to live with it.
		183
		184	=back
		185
		186	I hope this helps :)
133		187
134		188
135	=head1 OBJECT-ORIENTED INTERFACE	189	=head1 OBJECT-ORIENTED INTERFACE
136		190
137	The object oriented interface lets you configure your own encoding or	191	The object oriented interface lets you configure your own encoding or
…		…
276		330
277	Example, space_before and indent disabled, space_after enabled:	331	Example, space_before and indent disabled, space_after enabled:
278		332
279	{"key": "value"}	333	{"key": "value"}
280		334
		335	=item $json = $json->relaxed ([$enable])
		336
		337	If C<$enable> is true (or missing), then C<decode> will accept some
		338	extensions to normal JSON syntax (see below). C<encode> will not be
		339	affected in anyway. I<Be aware that this option makes you accept invalid
		340	JSON texts as if they were valid!>. I suggest only to use this option to
		341	parse application-specific files written by humans (configuration files,
		342	resource files etc.)
		343
		344	If C<$enable> is false (the default), then C<decode> will only accept
		345	valid JSON texts.
		346
		347	Currently accepted extensions are:
		348
		349	=over 4
		350
		351	=item * list items can have an end-comma
		352
		353	JSON I<separates> array elements and key-value pairs with commas. This
		354	can be annoying if you write JSON texts manually and want to be able to
		355	quickly append elements, so this extension accepts comma at the end of
		356	such items not just between them:
		357
		358	[
		359	1,
		360	2, <- this comma not normally allowed
		361	]
		362	{
		363	"k1": "v1",
		364	"k2": "v2", <- this comma not normally allowed
		365	}
		366
		367	=item * shell-style '#'-comments
		368
		369	Whenever JSON allows whitespace, shell-style comments are additionally
		370	allowed. They are terminated by the first carriage-return or line-feed
		371	character, after which more white-space and comments are allowed.
		372
		373	[
		374	1, # this comment not allowed in JSON
		375	# neither this one...
		376	]
		377
		378	=back
		379
281	=item $json = $json->canonical ([$enable])	380	=item $json = $json->canonical ([$enable])
282		381
283	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	382	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
284	by sorting their keys. This is adding a comparatively high overhead.	383	by sorting their keys. This is adding a comparatively high overhead.
285		384
…		…
309	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	408	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
310	resulting in an invalid JSON text:	409	resulting in an invalid JSON text:
311		410
312	JSON::XS->new->allow_nonref->encode ("Hello, World!")	411	JSON::XS->new->allow_nonref->encode ("Hello, World!")
313	=> "Hello, World!"	412	=> "Hello, World!"
		413
		414	=item $json = $json->allow_blessed ([$enable])
		415
		416	If C<$enable> is true (or missing), then the C<encode> method will not
		417	barf when it encounters a blessed reference. Instead, the value of the
		418	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		419	disabled or no C<to_json> method found) or a representation of the
		420	object (C<convert_blessed> enabled and C<to_json> method found) is being
		421	encoded. Has no effect on C<decode>.
		422
		423	If C<$enable> is false (the default), then C<encode> will throw an
		424	exception when it encounters a blessed object.
		425
		426	=item $json = $json->convert_blessed ([$enable])
		427
		428	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		429	blessed object, will check for the availability of the C<TO_JSON> method
		430	on the object's class. If found, it will be called in scalar context
		431	and the resulting scalar will be encoded instead of the object. If no
		432	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		433	to do.
		434
		435	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		436	returns other blessed objects, those will be handled in the same
		437	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		438	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		439	methods called by the Perl core (== not by the user of the object) are
		440	usually in upper case letters and to avoid collisions with the C<to_json>
		441	function.
		442
		443	This setting does not yet influence C<decode> in any way, but in the
		444	future, global hooks might get installed that influence C<decode> and are
		445	enabled by this setting.
		446
		447	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		448	to do when a blessed object is found.
		449
		450	=item $json = $json->filter_json_object ([$coderef->($hashref)])
		451
		452	When C<$coderef> is specified, it will be called from C<decode> each
		453	time it decodes a JSON object. The only argument is a reference to the
		454	newly-created hash. If the code references returns a single scalar (which
		455	need not be a reference), this value (i.e. a copy of that scalar to avoid
		456	aliasing) is inserted into the deserialised data structure. If it returns
		457	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		458	original deserialised hash will be inserted. This setting can slow down
		459	decoding considerably.
		460
		461	When C<$coderef> is omitted or undefined, any existing callback will
		462	be removed and C<decode> will not change the deserialised hash in any
		463	way.
		464
		465	Example, convert all JSON objects into the integer 5:
		466
		467	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		468	# returns [5]
		469	$js->decode ('[{}]')
		470	# throw an exception because allow_nonref is not enabled
		471	# so a lone 5 is not allowed.
		472	$js->decode ('{"a":1, "b":2}');
		473
		474	=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
		475
		476	Works remotely similar to C<filter_json_object>, but is only called for
		477	JSON objects having a single key named C<$key>.
		478
		479	This C<$coderef> is called before the one specified via
		480	C<filter_json_object>, if any. It gets passed the single value in the JSON
		481	object. If it returns a single value, it will be inserted into the data
		482	structure. If it returns nothing (not even C<undef> but the empty list),
		483	the callback from C<filter_json_object> will be called next, as if no
		484	single-key callback were specified.
		485
		486	If C<$coderef> is omitted or undefined, the corresponding callback will be
		487	disabled. There can only ever be one callback for a given key.
		488
		489	As this callback gets called less often then the C<filter_json_object>
		490	one, decoding speed will not usually suffer as much. Therefore, single-key
		491	objects make excellent targets to serialise Perl objects into, especially
		492	as single-key JSON objects are as close to the type-tagged value concept
		493	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		494	support this in any way, so you need to make sure your data never looks
		495	like a serialised Perl hash.
		496
		497	Typical names for the single object key are C<__class_whatever__>, or
		498	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		499	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		500	with real hashes.
		501
		502	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		503	into the corresponding C<< $WIDGET{<id>} >> object:
		504
		505	# return whatever is in $WIDGET{5}:
		506	JSON::XS
		507	->new
		508	->filter_json_single_key_object (__widget__ => sub {
		509	$WIDGET{ $_[0] }
		510	})
		511	->decode ('{"__widget__": 5')
		512
		513	# this can be used with a TO_JSON method in some "widget" class
		514	# for serialisation to json:
		515	sub WidgetBase::TO_JSON {
		516	my ($self) = @_;
		517
		518	unless ($self->{id}) {
		519	$self->{id} = ..get..some..id..;
		520	$WIDGET{$self->{id}} = $self;
		521	}
		522
		523	{ __widget__ => $self->{id} }
		524	}
314		525
315	=item $json = $json->shrink ([$enable])	526	=item $json = $json->shrink ([$enable])
316		527
317	Perl usually over-allocates memory a bit when allocating space for	528	Perl usually over-allocates memory a bit when allocating space for
318	strings. This flag optionally resizes strings generated by either	529	strings. This flag optionally resizes strings generated by either
…		…
351	given character in a string.	562	given character in a string.
352		563
353	Setting the maximum depth to one disallows any nesting, so that ensures	564	Setting the maximum depth to one disallows any nesting, so that ensures
354	that the object is only a single hash/object or array.	565	that the object is only a single hash/object or array.
355		566
356	The argument to C<max_depth> will be rounded up to the next nearest power	567	The argument to C<max_depth> will be rounded up to the next highest power
357	of two.	568	of two. If no argument is given, the highest possible setting will be
		569	used, which is rarely useful.
		570
		571	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		572
		573	=item $json = $json->max_size ([$maximum_string_size])
		574
		575	Set the maximum length a JSON text may have (in bytes) where decoding is
		576	being attempted. The default is C<0>, meaning no limit. When C<decode>
		577	is called on a string longer then this number of characters it will not
		578	attempt to decode the string but throw an exception. This setting has no
		579	effect on C<encode> (yet).
		580
		581	The argument to C<max_size> will be rounded up to the next B<highest>
		582	power of two (so may be more than requested). If no argument is given, the
		583	limit check will be deactivated (same as when C<0> is specified).
358		584
359	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	585	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
360		586
361	=item $json_text = $json->encode ($perl_scalar)	587	=item $json_text = $json->encode ($perl_scalar)
362		588
…		…
402		628
403	For the more enlightened: note that in the following descriptions,	629	For the more enlightened: note that in the following descriptions,
404	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	630	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
405	refers to the abstract Perl language itself.	631	refers to the abstract Perl language itself.
406		632
		633
407	=head2 JSON -> PERL	634	=head2 JSON -> PERL
408		635
409	=over 4	636	=over 4
410		637
411	=item object	638	=item object
…		…
423	are represented by the same codepoints in the Perl string, so no manual	650	are represented by the same codepoints in the Perl string, so no manual
424	decoding is necessary.	651	decoding is necessary.
425		652
426	=item number	653	=item number
427		654
428	A JSON number becomes either an integer or numeric (floating point)	655	A JSON number becomes either an integer, numeric (floating point) or
429	scalar in perl, depending on its range and any fractional parts. On the	656	string scalar in perl, depending on its range and any fractional parts. On
430	Perl level, there is no difference between those as Perl handles all the	657	the Perl level, there is no difference between those as Perl handles all
431	conversion details, but an integer may take slightly less memory and might	658	the conversion details, but an integer may take slightly less memory and
432	represent more values exactly than (floating point) numbers.	659	might represent more values exactly than (floating point) numbers.
		660
		661	If the number consists of digits only, JSON::XS will try to represent
		662	it as an integer value. If that fails, it will try to represent it as
		663	a numeric (floating point) value if that is possible without loss of
		664	precision. Otherwise it will preserve the number as a string value.
		665
		666	Numbers containing a fractional or exponential part will always be
		667	represented as numeric (floating point) values, possibly at a loss of
		668	precision.
		669
		670	This might create round-tripping problems as numbers might become strings,
		671	but as Perl is typeless there is no other way to do it.
433		672
434	=item true, false	673	=item true, false
435		674
436	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	675	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
437	this process. Future versions might represent those values differently,	676	respectively. They are overloaded to act almost exactly like the numbers
438	but they will be guarenteed to act like these integers would normally in	677	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
439	Perl.	678	the C<JSON::XS::is_bool> function.
440		679
441	=item null	680	=item null
442		681
443	A JSON null atom becomes C<undef> in Perl.	682	A JSON null atom becomes C<undef> in Perl.
444		683
445	=back	684	=back
		685
446		686
447	=head2 PERL -> JSON	687	=head2 PERL -> JSON
448		688
449	The mapping from Perl to JSON is slightly more difficult, as Perl is a	689	The mapping from Perl to JSON is slightly more difficult, as Perl is a
450	truly typeless language, so we can only guess which JSON type is meant by	690	truly typeless language, so we can only guess which JSON type is meant by
…		…
475	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	715	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
476	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	716	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
477		717
478	to_json [\0,JSON::XS::true] # yields [false,true]	718	to_json [\0,JSON::XS::true] # yields [false,true]
479		719
		720	=item JSON::XS::true, JSON::XS::false
		721
		722	These special values become JSON true and JSON false values,
		723	respectively. You can also use C<\1> and C<\0> directly if you want.
		724
480	=item blessed objects	725	=item blessed objects
481		726
482	Blessed objects are not allowed. JSON::XS currently tries to encode their	727	Blessed objects are not allowed. JSON::XS currently tries to encode their
483	underlying representation (hash- or arrayref), but this behaviour might	728	underlying representation (hash- or arrayref), but this behaviour might
484	change in future versions.	729	change in future versions.
…		…
605		850
606	Does not check input for validity.	851	Does not check input for validity.
607		852
608	=back	853	=back
609		854
		855
		856	=head2 JSON and YAML
		857
		858	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		859	however, a mass hysteria and very far from the truth. In general, there is
		860	no way to configure JSON::XS to output a data structure as valid YAML.
		861
		862	If you really must use JSON::XS to generate YAML, you should use this
		863	algorithm (subject to change in future versions):
		864
		865	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		866	my $yaml = $to_yaml->encode ($ref) . "\n";
		867
		868	This will usually generate JSON texts that also parse as valid
		869	YAML. Please note that YAML has hardcoded limits on (simple) object key
		870	lengths that JSON doesn't have, so you should make sure that your hash
		871	keys are noticably shorter than the 1024 characters YAML allows.
		872
		873	There might be other incompatibilities that I am not aware of. In general
		874	you should not try to generate YAML with a JSON generator or vice versa,
		875	or try to parse JSON with a YAML parser or vice versa: chances are high
		876	that you will run into severe interoperability problems.
		877
		878
610	=head2 SPEED	879	=head2 SPEED
611		880
612	It seems that JSON::XS is surprisingly fast, as shown in the following	881	It seems that JSON::XS is surprisingly fast, as shown in the following
613	tables. They have been generated with the help of the C<eg/bench> program	882	tables. They have been generated with the help of the C<eg/bench> program
614	in the JSON::XS distribution, to make it easy to compare on your own	883	in the JSON::XS distribution, to make it easy to compare on your own
615	system.	884	system.
616		885
617	First comes a comparison between various modules using a very short JSON	886	First comes a comparison between various modules using a very short
618	string:	887	single-line JSON string:
619		888
620	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	889	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		890	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
621		891
622	It shows the number of encodes/decodes per second (JSON::XS uses the	892	It shows the number of encodes/decodes per second (JSON::XS uses
623	functional interface, while JSON::XS/2 uses the OO interface with	893	the functional interface, while JSON::XS/2 uses the OO interface
624	pretty-printing and hashkey sorting enabled). Higher is better:	894	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		895	shrink). Higher is better:
625		896
		897	Storable \| 15779.925 \| 14169.946 \|
		898	-----------+------------+------------+
626	module \| encode \| decode \|	899	module \| encode \| decode \|
627	-----------\|------------\|------------\|	900	-----------\|------------\|------------\|
628	JSON \| 11488.516 \| 7823.035 \|	901	JSON \| 4990.842 \| 4088.813 \|
629	JSON::DWIW \| 94708.054 \| 129094.260 \|	902	JSON::DWIW \| 51653.990 \| 71575.154 \|
630	JSON::PC \| 63884.157 \| 128528.212 \|	903	JSON::PC \| 65948.176 \| 74631.744 \|
631	JSON::Syck \| 34898.677 \| 42096.911 \|	904	JSON::PP \| 8931.652 \| 3817.168 \|
632	JSON::XS \| 654027.064 \| 396423.669 \|	905	JSON::Syck \| 24877.248 \| 27776.848 \|
633	JSON::XS/2 \| 371564.190 \| 371725.613 \|	906	JSON::XS \| 388361.481 \| 227951.304 \|
		907	JSON::XS/2 \| 227951.304 \| 218453.333 \|
		908	JSON::XS/3 \| 338250.323 \| 218453.333 \|
		909	Storable \| 16500.016 \| 135300.129 \|
634	-----------+------------+------------+	910	-----------+------------+------------+
635		911
636	That is, JSON::XS is more than six times faster than JSON::DWIW on	912	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
637	encoding, more than three times faster on decoding, and about thirty times	913	about three times faster on decoding, and over fourty times faster
638	faster than JSON, even with pretty-printing and key sorting.	914	than JSON, even with pretty-printing and key sorting. It also compares
		915	favourably to Storable for small amounts of data.
639		916
640	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	917	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
641	search API (http://nanoref.com/yahooapis/mgPdGg):	918	search API (http://nanoref.com/yahooapis/mgPdGg):
642		919
643	module \| encode \| decode \|	920	module \| encode \| decode \|
644	-----------\|------------\|------------\|	921	-----------\|------------\|------------\|
645	JSON \| 273.023 \| 44.674 \|	922	JSON \| 55.260 \| 34.971 \|
646	JSON::DWIW \| 1089.383 \| 1145.704 \|	923	JSON::DWIW \| 825.228 \| 1082.513 \|
647	JSON::PC \| 3097.419 \| 2393.921 \|	924	JSON::PC \| 3571.444 \| 2394.829 \|
648	JSON::Syck \| 514.060 \| 843.053 \|	925	JSON::PP \| 210.987 \| 32.574 \|
649	JSON::XS \| 6479.668 \| 3636.364 \|	926	JSON::Syck \| 552.551 \| 787.544 \|
650	JSON::XS/2 \| 3774.221 \| 3599.124 \|	927	JSON::XS \| 5780.463 \| 4854.519 \|
		928	JSON::XS/2 \| 3869.998 \| 4798.975 \|
		929	JSON::XS/3 \| 5862.880 \| 4798.975 \|
		930	Storable \| 4445.002 \| 5235.027 \|
651	-----------+------------+------------+	931	-----------+------------+------------+
652		932
653	Again, JSON::XS leads by far.	933	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		934	decodes faster).
654		935
655	On large strings containing lots of high unicode characters, some modules	936	On large strings containing lots of high unicode characters, some modules
656	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	937	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
657	will be broken due to missing (or wrong) unicode handling. Others refuse	938	will be broken due to missing (or wrong) unicode handling. Others refuse
658	to decode or encode properly, so it was impossible to prepare a fair	939	to decode or encode properly, so it was impossible to prepare a fair
…		…
671	Second, you need to avoid resource-starving attacks. That means you should	952	Second, you need to avoid resource-starving attacks. That means you should
672	limit the size of JSON texts you accept, or make sure then when your	953	limit the size of JSON texts you accept, or make sure then when your
673	resources run out, thats just fine (e.g. by using a separate process that	954	resources run out, thats just fine (e.g. by using a separate process that
674	can crash safely). The size of a JSON text in octets or characters is	955	can crash safely). The size of a JSON text in octets or characters is
675	usually a good indication of the size of the resources required to decode	956	usually a good indication of the size of the resources required to decode
676	it into a Perl structure.	957	it into a Perl structure. While JSON::XS can check the size of the JSON
		958	text, it might be too late when you already have it in memory, so you
		959	might want to check the size before you accept the string.
677		960
678	Third, JSON::XS recurses using the C stack when decoding objects and	961	Third, JSON::XS recurses using the C stack when decoding objects and
679	arrays. The C stack is a limited resource: for instance, on my amd64	962	arrays. The C stack is a limited resource: for instance, on my amd64
680	machine with 8MB of stack size I can decode around 180k nested arrays but	963	machine with 8MB of stack size I can decode around 180k nested arrays but
681	only 14k nested JSON objects (due to perl itself recursing deeply on croak	964	only 14k nested JSON objects (due to perl itself recursing deeply on croak
…		…
686		969
687	And last but least, something else could bomb you that I forgot to think	970	And last but least, something else could bomb you that I forgot to think
688	of. In that case, you get to keep the pieces. I am always open for hints,	971	of. In that case, you get to keep the pieces. I am always open for hints,
689	though...	972	though...
690		973
		974	If you are using JSON::XS to return packets to consumption
		975	by javascript scripts in a browser you should have a look at
		976	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		977	you are vulnerable to some common attack vectors (which really are browser
		978	design bugs, but it is still you who will have to deal with it, as major
		979	browser developers care only for features, not about doing security
		980	right).
		981
691		982
692	=head1 BUGS	983	=head1 BUGS
693		984
694	While the goal of this module is to be correct, that unfortunately does	985	While the goal of this module is to be correct, that unfortunately does
695	not mean its bug-free, only that I think its design is bug-free. It is	986	not mean its bug-free, only that I think its design is bug-free. It is
696	still relatively early in its development. If you keep reporting bugs they	987	still relatively early in its development. If you keep reporting bugs they
697	will be fixed swiftly, though.	988	will be fixed swiftly, though.
698		989
699	=cut	990	=cut
700		991
		992	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		993	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		994
701	sub true() { \1 }	995	sub true() { $true }
702	sub false() { \0 }	996	sub false() { $false }
		997
		998	sub is_bool($) {
		999	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		1000	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		1001	}
		1002
		1003	XSLoader::load "JSON::XS", $VERSION;
		1004
		1005	package JSON::XS::Boolean;
		1006
		1007	use overload
		1008	"0+" => sub { ${$_[0]} },
		1009	"++" => sub { $_[0] = ${$_[0]} + 1 },
		1010	"--" => sub { $_[0] = ${$_[0]} - 1 },
		1011	fallback => 1;
703		1012
704	1;	1013	1;
705		1014
706	=head1 AUTHOR	1015	=head1 AUTHOR
707		1016

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Comparing JSON-XS/XS.pm (file contents): Revision 1.36 by root, Wed May 23 22:07:43 2007 UTC vs. Revision 1.63 by root, Thu Oct 11 23:07:43 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.36 by root, Wed May 23 22:07:43 2007 UTC vs.
Revision 1.63 by root, Thu Oct 11 23:07:43 2007 UTC