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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.22 by root, Sun Mar 25 02:37:00 2007 UTC vs.
Revision 1.55 by root, Mon Jul 23 22:57:40 2007 UTC

…		…
9	# exported functions, they croak on error	9	# exported functions, they croak on error
10	# and expect/generate UTF-8	10	# and expect/generate UTF-8
11		11
12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	13	$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		14
19	# OO-interface	15	# OO-interface
20		16
21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	17	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	18	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
…		…
85		81
86	package JSON::XS;	82	package JSON::XS;
87		83
88	use strict;	84	use strict;
89		85
90	BEGIN {
91	our $VERSION = '0.8';	86	our $VERSION = '1.42';
92	our @ISA = qw(Exporter);	87	our @ISA = qw(Exporter);
93		88
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	89	our @EXPORT = qw(to_json from_json);
95	require Exporter;
96		90
97	require XSLoader;	91	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	92	use XSLoader;
99	}
100		93
101	=head1 FUNCTIONAL INTERFACE	94	=head1 FUNCTIONAL INTERFACE
102		95
103	The following convinience methods are provided by this module. They are	96	The following convinience methods are provided by this module. They are
104	exported by default:	97	exported by default:
…		…
127		120
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	121	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		122
130	except being faster.	123	except being faster.
131		124
		125	=item $is_boolean = JSON::XS::is_bool $scalar
		126
		127	Returns true if the passed scalar represents either JSON::XS::true or
		128	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		129	and are used to represent JSON C<true> and C<false> values in Perl.
		130
		131	See MAPPING, below, for more information on how JSON values are mapped to
		132	Perl.
		133
132	=back	134	=back
		135
133		136
134	=head1 OBJECT-ORIENTED INTERFACE	137	=head1 OBJECT-ORIENTED INTERFACE
135		138
136	The object oriented interface lets you configure your own encoding or	139	The object oriented interface lets you configure your own encoding or
137	decoding style, within the limits of supported formats.	140	decoding style, within the limits of supported formats.
…		…
153		156
154	If C<$enable> is true (or missing), then the C<encode> method will not	157	If C<$enable> is true (or missing), then the C<encode> method will not
155	generate characters outside the code range C<0..127> (which is ASCII). Any	158	generate characters outside the code range C<0..127> (which is ASCII). Any
156	unicode characters outside that range will be escaped using either a	159	unicode characters outside that range will be escaped using either a
157	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	160	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
158	as per RFC4627.	161	as per RFC4627. The resulting encoded JSON text can be treated as a native
		162	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		163	or any other superset of ASCII.
159		164
160	If C<$enable> is false, then the C<encode> method will not escape Unicode	165	If C<$enable> is false, then the C<encode> method will not escape Unicode
161	characters unless required by the JSON syntax. This results in a faster	166	characters unless required by the JSON syntax or other flags. This results
162	and more compact format.	167	in a faster and more compact format.
		168
		169	The main use for this flag is to produce JSON texts that can be
		170	transmitted over a 7-bit channel, as the encoded JSON texts will not
		171	contain any 8 bit characters.
163		172
164	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	173	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
165	=> ["\ud801\udc01"]	174	=> ["\ud801\udc01"]
		175
		176	=item $json = $json->latin1 ([$enable])
		177
		178	If C<$enable> is true (or missing), then the C<encode> method will encode
		179	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
		180	outside the code range C<0..255>. The resulting string can be treated as a
		181	latin1-encoded JSON text or a native unicode string. The C<decode> method
		182	will not be affected in any way by this flag, as C<decode> by default
		183	expects unicode, which is a strict superset of latin1.
		184
		185	If C<$enable> is false, then the C<encode> method will not escape Unicode
		186	characters unless required by the JSON syntax or other flags.
		187
		188	The main use for this flag is efficiently encoding binary data as JSON
		189	text, as most octets will not be escaped, resulting in a smaller encoded
		190	size. The disadvantage is that the resulting JSON text is encoded
		191	in latin1 (and must correctly be treated as such when storing and
		192	transfering), a rare encoding for JSON. It is therefore most useful when
		193	you want to store data structures known to contain binary data efficiently
		194	in files or databases, not when talking to other JSON encoders/decoders.
		195
		196	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
		197	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
166		198
167	=item $json = $json->utf8 ([$enable])	199	=item $json = $json->utf8 ([$enable])
168		200
169	If C<$enable> is true (or missing), then the C<encode> method will encode	201	If C<$enable> is true (or missing), then the C<encode> method will encode
170	the JSON result into UTF-8, as required by many protocols, while the	202	the JSON result into UTF-8, as required by many protocols, while the
…		…
280	resulting in an invalid JSON text:	312	resulting in an invalid JSON text:
281		313
282	JSON::XS->new->allow_nonref->encode ("Hello, World!")	314	JSON::XS->new->allow_nonref->encode ("Hello, World!")
283	=> "Hello, World!"	315	=> "Hello, World!"
284		316
		317	=item $json = $json->allow_blessed ([$enable])
		318
		319	If C<$enable> is true (or missing), then the C<encode> method will not
		320	barf when it encounters a blessed reference. Instead, the value of the
		321	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		322	disabled or no C<to_json> method found) or a representation of the
		323	object (C<convert_blessed> enabled and C<to_json> method found) is being
		324	encoded. Has no effect on C<decode>.
		325
		326	If C<$enable> is false (the default), then C<encode> will throw an
		327	exception when it encounters a blessed object.
		328
		329	=item $json = $json->convert_blessed ([$enable])
		330
		331	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		332	blessed object, will check for the availability of the C<TO_JSON> method
		333	on the object's class. If found, it will be called in scalar context
		334	and the resulting scalar will be encoded instead of the object. If no
		335	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		336	to do.
		337
		338	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		339	returns other blessed objects, those will be handled in the same
		340	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		341	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		342	methods called by the Perl core (== not by the user of the object) are
		343	usually in upper case letters and to avoid collisions with the C<to_json>
		344	function.
		345
		346	This setting does not yet influence C<decode> in any way, but in the
		347	future, global hooks might get installed that influence C<decode> and are
		348	enabled by this setting.
		349
		350	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		351	to do when a blessed object is found.
		352
		353	=item $json = $json->filter_json_object ([$coderef->($hashref)])
		354
		355	When C<$coderef> is specified, it will be called from C<decode> each
		356	time it decodes a JSON object. The only argument is a reference to the
		357	newly-created hash. If the code references returns a single scalar (which
		358	need not be a reference), this value (i.e. a copy of that scalar to avoid
		359	aliasing) is inserted into the deserialised data structure. If it returns
		360	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		361	original deserialised hash will be inserted. This setting can slow down
		362	decoding considerably.
		363
		364	When C<$coderef> is omitted or undefined, any existing callback will
		365	be removed and C<decode> will not change the deserialised hash in any
		366	way.
		367
		368	Example, convert all JSON objects into the integer 5:
		369
		370	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		371	# returns [5]
		372	$js->decode ('[{}]')
		373	# throw an exception because allow_nonref is not enabled
		374	# so a lone 5 is not allowed.
		375	$js->decode ('{"a":1, "b":2}');
		376
		377	=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
		378
		379	Works remotely similar to C<filter_json_object>, but is only called for
		380	JSON objects having a single key named C<$key>.
		381
		382	This C<$coderef> is called before the one specified via
		383	C<filter_json_object>, if any. It gets passed the single value in the JSON
		384	object. If it returns a single value, it will be inserted into the data
		385	structure. If it returns nothing (not even C<undef> but the empty list),
		386	the callback from C<filter_json_object> will be called next, as if no
		387	single-key callback were specified.
		388
		389	If C<$coderef> is omitted or undefined, the corresponding callback will be
		390	disabled. There can only ever be one callback for a given key.
		391
		392	As this callback gets called less often then the C<filter_json_object>
		393	one, decoding speed will not usually suffer as much. Therefore, single-key
		394	objects make excellent targets to serialise Perl objects into, especially
		395	as single-key JSON objects are as close to the type-tagged value concept
		396	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		397	support this in any way, so you need to make sure your data never looks
		398	like a serialised Perl hash.
		399
		400	Typical names for the single object key are C<__class_whatever__>, or
		401	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		402	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		403	with real hashes.
		404
		405	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		406	into the corresponding C<< $WIDGET{<id>} >> object:
		407
		408	# return whatever is in $WIDGET{5}:
		409	JSON::XS
		410	->new
		411	->filter_json_single_key_object (__widget__ => sub {
		412	$WIDGET{ $_[0] }
		413	})
		414	->decode ('{"__widget__": 5')
		415
		416	# this can be used with a TO_JSON method in some "widget" class
		417	# for serialisation to json:
		418	sub WidgetBase::TO_JSON {
		419	my ($self) = @_;
		420
		421	unless ($self->{id}) {
		422	$self->{id} = ..get..some..id..;
		423	$WIDGET{$self->{id}} = $self;
		424	}
		425
		426	{ __widget__ => $self->{id} }
		427	}
		428
285	=item $json = $json->shrink ([$enable])	429	=item $json = $json->shrink ([$enable])
286		430
287	Perl usually over-allocates memory a bit when allocating space for	431	Perl usually over-allocates memory a bit when allocating space for
288	strings. This flag optionally resizes strings generated by either	432	strings. This flag optionally resizes strings generated by either
289	C<encode> or C<decode> to their minimum size possible. This can save	433	C<encode> or C<decode> to their minimum size possible. This can save
290	memory when your JSON texts are either very very long or you have many	434	memory when your JSON texts are either very very long or you have many
291	short strings. It will also try to downgrade any strings to octet-form	435	short strings. It will also try to downgrade any strings to octet-form
292	if possible: perl stores strings internally either in an encoding called	436	if possible: perl stores strings internally either in an encoding called
293	UTF-X or in octet-form. The latter cannot store everything but uses less	437	UTF-X or in octet-form. The latter cannot store everything but uses less
294	space in general.	438	space in general (and some buggy Perl or C code might even rely on that
		439	internal representation being used).
295		440
		441	The actual definition of what shrink does might change in future versions,
		442	but it will always try to save space at the expense of time.
		443
296	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	444	If C<$enable> is true (or missing), the string returned by C<encode> will
297	while all strings generated by C<decode> will also be shrunk-to-fit.	445	be shrunk-to-fit, while all strings generated by C<decode> will also be
		446	shrunk-to-fit.
298		447
299	If C<$enable> is false, then the normal perl allocation algorithms are used.	448	If C<$enable> is false, then the normal perl allocation algorithms are used.
300	If you work with your data, then this is likely to be faster.	449	If you work with your data, then this is likely to be faster.
301		450
302	In the future, this setting might control other things, such as converting	451	In the future, this setting might control other things, such as converting
303	strings that look like integers or floats into integers or floats	452	strings that look like integers or floats into integers or floats
304	internally (there is no difference on the Perl level), saving space.	453	internally (there is no difference on the Perl level), saving space.
		454
		455	=item $json = $json->max_depth ([$maximum_nesting_depth])
		456
		457	Sets the maximum nesting level (default C<512>) accepted while encoding
		458	or decoding. If the JSON text or Perl data structure has an equal or
		459	higher nesting level then this limit, then the encoder and decoder will
		460	stop and croak at that point.
		461
		462	Nesting level is defined by number of hash- or arrayrefs that the encoder
		463	needs to traverse to reach a given point or the number of C<{> or C<[>
		464	characters without their matching closing parenthesis crossed to reach a
		465	given character in a string.
		466
		467	Setting the maximum depth to one disallows any nesting, so that ensures
		468	that the object is only a single hash/object or array.
		469
		470	The argument to C<max_depth> will be rounded up to the next highest power
		471	of two. If no argument is given, the highest possible setting will be
		472	used, which is rarely useful.
		473
		474	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		475
		476	=item $json = $json->max_size ([$maximum_string_size])
		477
		478	Set the maximum length a JSON text may have (in bytes) where decoding is
		479	being attempted. The default is C<0>, meaning no limit. When C<decode>
		480	is called on a string longer then this number of characters it will not
		481	attempt to decode the string but throw an exception. This setting has no
		482	effect on C<encode> (yet).
		483
		484	The argument to C<max_size> will be rounded up to the next B<highest>
		485	power of two (so may be more than requested). If no argument is given, the
		486	limit check will be deactivated (same as when C<0> is specified).
		487
		488	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
305		489
306	=item $json_text = $json->encode ($perl_scalar)	490	=item $json_text = $json->encode ($perl_scalar)
307		491
308	Converts the given Perl data structure (a simple scalar or a reference	492	Converts the given Perl data structure (a simple scalar or a reference
309	to a hash or array) to its JSON representation. Simple scalars will be	493	to a hash or array) to its JSON representation. Simple scalars will be
…		…
319		503
320	JSON numbers and strings become simple Perl scalars. JSON arrays become	504	JSON numbers and strings become simple Perl scalars. JSON arrays become
321	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	505	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
322	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	506	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
323		507
		508	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		509
		510	This works like the C<decode> method, but instead of raising an exception
		511	when there is trailing garbage after the first JSON object, it will
		512	silently stop parsing there and return the number of characters consumed
		513	so far.
		514
		515	This is useful if your JSON texts are not delimited by an outer protocol
		516	(which is not the brightest thing to do in the first place) and you need
		517	to know where the JSON text ends.
		518
		519	JSON::XS->new->decode_prefix ("[1] the tail")
		520	=> ([], 3)
		521
324	=back	522	=back
		523
325		524
326	=head1 MAPPING	525	=head1 MAPPING
327		526
328	This section describes how JSON::XS maps Perl values to JSON values and	527	This section describes how JSON::XS maps Perl values to JSON values and
329	vice versa. These mappings are designed to "do the right thing" in most	528	vice versa. These mappings are designed to "do the right thing" in most
…		…
331	(what you put in comes out as something equivalent).	530	(what you put in comes out as something equivalent).
332		531
333	For the more enlightened: note that in the following descriptions,	532	For the more enlightened: note that in the following descriptions,
334	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	533	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
335	refers to the abstract Perl language itself.	534	refers to the abstract Perl language itself.
		535
336		536
337	=head2 JSON -> PERL	537	=head2 JSON -> PERL
338		538
339	=over 4	539	=over 4
340		540
…		…
361	conversion details, but an integer may take slightly less memory and might	561	conversion details, but an integer may take slightly less memory and might
362	represent more values exactly than (floating point) numbers.	562	represent more values exactly than (floating point) numbers.
363		563
364	=item true, false	564	=item true, false
365		565
366	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	566	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
367	this process. Future versions might represent those values differently,	567	respectively. They are overloaded to act almost exactly like the numbers
368	but they will be guarenteed to act like these integers would normally in	568	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
369	Perl.	569	the C<JSON::XS::is_bool> function.
370		570
371	=item null	571	=item null
372		572
373	A JSON null atom becomes C<undef> in Perl.	573	A JSON null atom becomes C<undef> in Perl.
374		574
375	=back	575	=back
		576
376		577
377	=head2 PERL -> JSON	578	=head2 PERL -> JSON
378		579
379	The mapping from Perl to JSON is slightly more difficult, as Perl is a	580	The mapping from Perl to JSON is slightly more difficult, as Perl is a
380	truly typeless language, so we can only guess which JSON type is meant by	581	truly typeless language, so we can only guess which JSON type is meant by
…		…
383	=over 4	584	=over 4
384		585
385	=item hash references	586	=item hash references
386		587
387	Perl hash references become JSON objects. As there is no inherent ordering	588	Perl hash references become JSON objects. As there is no inherent ordering
388	in hash keys, they will usually be encoded in a pseudo-random order that	589	in hash keys (or JSON objects), they will usually be encoded in a
389	can change between runs of the same program but stays generally the same	590	pseudo-random order that can change between runs of the same program but
390	within a single run of a program. JSON::XS can optionally sort the hash	591	stays generally the same within a single run of a program. JSON::XS can
391	keys (determined by the I<canonical> flag), so the same datastructure	592	optionally sort the hash keys (determined by the I<canonical> flag), so
392	will serialise to the same JSON text (given same settings and version of	593	the same datastructure will serialise to the same JSON text (given same
393	JSON::XS), but this incurs a runtime overhead.	594	settings and version of JSON::XS), but this incurs a runtime overhead
		595	and is only rarely useful, e.g. when you want to compare some JSON text
		596	against another for equality.
394		597
395	=item array references	598	=item array references
396		599
397	Perl array references become JSON arrays.	600	Perl array references become JSON arrays.
		601
		602	=item other references
		603
		604	Other unblessed references are generally not allowed and will cause an
		605	exception to be thrown, except for references to the integers C<0> and
		606	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		607	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		608
		609	to_json [\0,JSON::XS::true] # yields [false,true]
		610
		611	=item JSON::XS::true, JSON::XS::false
		612
		613	These special values become JSON true and JSON false values,
		614	respectively. You cna alos use C<\1> and C<\0> directly if you want.
398		615
399	=item blessed objects	616	=item blessed objects
400		617
401	Blessed objects are not allowed. JSON::XS currently tries to encode their	618	Blessed objects are not allowed. JSON::XS currently tries to encode their
402	underlying representation (hash- or arrayref), but this behaviour might	619	underlying representation (hash- or arrayref), but this behaviour might
…		…
435	$x *= 1; # same thing, the choise is yours.	652	$x *= 1; # same thing, the choise is yours.
436		653
437	You can not currently output JSON booleans or force the type in other,	654	You can not currently output JSON booleans or force the type in other,
438	less obscure, ways. Tell me if you need this capability.	655	less obscure, ways. Tell me if you need this capability.
439		656
440	=item circular data structures
441
442	Those will be encoded until memory or stackspace runs out.
443
444	=back	657	=back
		658
445		659
446	=head1 COMPARISON	660	=head1 COMPARISON
447		661
448	As already mentioned, this module was created because none of the existing	662	As already mentioned, this module was created because none of the existing
449	JSON modules could be made to work correctly. First I will describe the	663	JSON modules could be made to work correctly. First I will describe the
…		…
527		741
528	Does not check input for validity.	742	Does not check input for validity.
529		743
530	=back	744	=back
531		745
		746
		747	=head2 JSON and YAML
		748
		749	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		750	however, a mass hysteria and very far from the truth. In general, there is
		751	no way to configure JSON::XS to output a data structure as valid YAML.
		752
		753	If you really must use JSON::XS to generate YAML, you should use this
		754	algorithm (subject to change in future versions):
		755
		756	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		757	my $yaml = $to_yaml->encode ($ref) . "\n";
		758
		759	This will usually generate JSON texts that also parse as valid
		760	YAML. Please note that YAML has hardcoded limits on (simple) object key
		761	lengths that JSON doesn't have, so you should make sure that your hash
		762	keys are noticably shorter than the 1024 characters YAML allows.
		763
		764	There might be other incompatibilities that I am not aware of. In general
		765	you should not try to generate YAML with a JSON generator or vice versa,
		766	or try to parse JSON with a YAML parser or vice versa: chances are high
		767	that you will run into severe interoperability problems.
		768
		769
532	=head2 SPEED	770	=head2 SPEED
533		771
534	It seems that JSON::XS is surprisingly fast, as shown in the following	772	It seems that JSON::XS is surprisingly fast, as shown in the following
535	tables. They have been generated with the help of the C<eg/bench> program	773	tables. They have been generated with the help of the C<eg/bench> program
536	in the JSON::XS distribution, to make it easy to compare on your own	774	in the JSON::XS distribution, to make it easy to compare on your own
537	system.	775	system.
538		776
539	First comes a comparison between various modules using a very short JSON	777	First comes a comparison between various modules using a very short
540	string:	778	single-line JSON string:
541		779
542	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	780	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		781	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
543		782
544	It shows the number of encodes/decodes per second (JSON::XS uses the	783	It shows the number of encodes/decodes per second (JSON::XS uses
545	functional interface, while JSON::XS/2 uses the OO interface with	784	the functional interface, while JSON::XS/2 uses the OO interface
546	pretty-printing and hashkey sorting enabled). Higher is better:	785	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		786	shrink). Higher is better:
547		787
		788	Storable \| 15779.925 \| 14169.946 \|
		789	-----------+------------+------------+
548	module \| encode \| decode \|	790	module \| encode \| decode \|
549	-----------\|------------\|------------\|	791	-----------\|------------\|------------\|
550	JSON \| 11488.516 \| 7823.035 \|	792	JSON \| 4990.842 \| 4088.813 \|
551	JSON::DWIW \| 94708.054 \| 129094.260 \|	793	JSON::DWIW \| 51653.990 \| 71575.154 \|
552	JSON::PC \| 63884.157 \| 128528.212 \|	794	JSON::PC \| 65948.176 \| 74631.744 \|
553	JSON::Syck \| 34898.677 \| 42096.911 \|	795	JSON::PP \| 8931.652 \| 3817.168 \|
554	JSON::XS \| 654027.064 \| 396423.669 \|	796	JSON::Syck \| 24877.248 \| 27776.848 \|
555	JSON::XS/2 \| 371564.190 \| 371725.613 \|	797	JSON::XS \| 388361.481 \| 227951.304 \|
		798	JSON::XS/2 \| 227951.304 \| 218453.333 \|
		799	JSON::XS/3 \| 338250.323 \| 218453.333 \|
		800	Storable \| 16500.016 \| 135300.129 \|
556	-----------+------------+------------+	801	-----------+------------+------------+
557		802
558	That is, JSON::XS is more than six times faster than JSON::DWIW on	803	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
559	encoding, more than three times faster on decoding, and about thirty times	804	about three times faster on decoding, and over fourty times faster
560	faster than JSON, even with pretty-printing and key sorting.	805	than JSON, even with pretty-printing and key sorting. It also compares
		806	favourably to Storable for small amounts of data.
561		807
562	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	808	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
563	search API (http://nanoref.com/yahooapis/mgPdGg):	809	search API (http://nanoref.com/yahooapis/mgPdGg):
564		810
565	module \| encode \| decode \|	811	module \| encode \| decode \|
566	-----------\|------------\|------------\|	812	-----------\|------------\|------------\|
567	JSON \| 273.023 \| 44.674 \|	813	JSON \| 55.260 \| 34.971 \|
568	JSON::DWIW \| 1089.383 \| 1145.704 \|	814	JSON::DWIW \| 825.228 \| 1082.513 \|
569	JSON::PC \| 3097.419 \| 2393.921 \|	815	JSON::PC \| 3571.444 \| 2394.829 \|
570	JSON::Syck \| 514.060 \| 843.053 \|	816	JSON::PP \| 210.987 \| 32.574 \|
571	JSON::XS \| 6479.668 \| 3636.364 \|	817	JSON::Syck \| 552.551 \| 787.544 \|
572	JSON::XS/2 \| 3774.221 \| 3599.124 \|	818	JSON::XS \| 5780.463 \| 4854.519 \|
		819	JSON::XS/2 \| 3869.998 \| 4798.975 \|
		820	JSON::XS/3 \| 5862.880 \| 4798.975 \|
		821	Storable \| 4445.002 \| 5235.027 \|
573	-----------+------------+------------+	822	-----------+------------+------------+
574		823
575	Again, JSON::XS leads by far.	824	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		825	decodes faster).
576		826
577	On large strings containing lots of high unicode characters, some modules	827	On large strings containing lots of high unicode characters, some modules
578	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	828	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
579	will be broken due to missing (or wrong) unicode handling. Others refuse	829	will be broken due to missing (or wrong) unicode handling. Others refuse
580	to decode or encode properly, so it was impossible to prepare a fair	830	to decode or encode properly, so it was impossible to prepare a fair
581	comparison table for that case.	831	comparison table for that case.
582		832
583	=head1 RESOURCE LIMITS
584		833
585	JSON::XS does not impose any limits on the size of JSON texts or Perl	834	=head1 SECURITY CONSIDERATIONS
586	values they represent - if your machine can handle it, JSON::XS will	835
587	encode or decode it. Future versions might optionally impose structure	836	When you are using JSON in a protocol, talking to untrusted potentially
588	depth and memory use resource limits.	837	hostile creatures requires relatively few measures.
		838
		839	First of all, your JSON decoder should be secure, that is, should not have
		840	any buffer overflows. Obviously, this module should ensure that and I am
		841	trying hard on making that true, but you never know.
		842
		843	Second, you need to avoid resource-starving attacks. That means you should
		844	limit the size of JSON texts you accept, or make sure then when your
		845	resources run out, thats just fine (e.g. by using a separate process that
		846	can crash safely). The size of a JSON text in octets or characters is
		847	usually a good indication of the size of the resources required to decode
		848	it into a Perl structure. While JSON::XS can check the size of the JSON
		849	text, it might be too late when you already have it in memory, so you
		850	might want to check the size before you accept the string.
		851
		852	Third, JSON::XS recurses using the C stack when decoding objects and
		853	arrays. The C stack is a limited resource: for instance, on my amd64
		854	machine with 8MB of stack size I can decode around 180k nested arrays but
		855	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		856	to free the temporary). If that is exceeded, the program crashes. to be
		857	conservative, the default nesting limit is set to 512. If your process
		858	has a smaller stack, you should adjust this setting accordingly with the
		859	C<max_depth> method.
		860
		861	And last but least, something else could bomb you that I forgot to think
		862	of. In that case, you get to keep the pieces. I am always open for hints,
		863	though...
		864
		865	If you are using JSON::XS to return packets to consumption
		866	by javascript scripts in a browser you should have a look at
		867	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		868	you are vulnerable to some common attack vectors (which really are browser
		869	design bugs, but it is still you who will have to deal with it, as major
		870	browser developers care only for features, not about doing security
		871	right).
		872
589		873
590	=head1 BUGS	874	=head1 BUGS
591		875
592	While the goal of this module is to be correct, that unfortunately does	876	While the goal of this module is to be correct, that unfortunately does
593	not mean its bug-free, only that I think its design is bug-free. It is	877	not mean its bug-free, only that I think its design is bug-free. It is
594	still very young and not well-tested. If you keep reporting bugs they will	878	still relatively early in its development. If you keep reporting bugs they
595	be fixed swiftly, though.	879	will be fixed swiftly, though.
596		880
597	=cut	881	=cut
		882
		883	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		884	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		885
		886	sub true() { $true }
		887	sub false() { $false }
		888
		889	sub is_bool($) {
		890	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		891	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		892	}
		893
		894	XSLoader::load "JSON::XS", $VERSION;
		895
		896	package JSON::XS::Boolean;
		897
		898	use overload
		899	"0+" => sub { ${$_[0]} },
		900	"++" => sub { $_[0] = ${$_[0]} + 1 },
		901	"--" => sub { $_[0] = ${$_[0]} - 1 },
		902	fallback => 1;
598		903
599	1;	904	1;
600		905
601	=head1 AUTHOR	906	=head1 AUTHOR
602		907

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Comparing JSON-XS/XS.pm (file contents): Revision 1.22 by root, Sun Mar 25 02:37:00 2007 UTC vs. Revision 1.55 by root, Mon Jul 23 22:57:40 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.22 by root, Sun Mar 25 02:37:00 2007 UTC vs.
Revision 1.55 by root, Mon Jul 23 22:57:40 2007 UTC