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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 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
14	# objToJson and jsonToObj are exported for JSON
15	# compatibility, but should not be used in new code.
16
17	# oo-interface	15	# OO-interface
18		16
19	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	17	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
20	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	18	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
21	$perl_scalar = $coder->decode ($unicode_json_text);	19	$perl_scalar = $coder->decode ($unicode_json_text);
22		20
…		…
83		81
84	package JSON::XS;	82	package JSON::XS;
85		83
86	use strict;	84	use strict;
87		85
88	BEGIN {
89	our $VERSION = '0.8';	86	our $VERSION = '1.4';
90	our @ISA = qw(Exporter);	87	our @ISA = qw(Exporter);
91		88
92	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	89	our @EXPORT = qw(to_json from_json);
93	require Exporter;
94		90
95	require XSLoader;	91	use Exporter;
96	XSLoader::load JSON::XS::, $VERSION;	92	use XSLoader;
97	}
98		93
99	=head1 FUNCTIONAL INTERFACE	94	=head1 FUNCTIONAL INTERFACE
100		95
101	The following convinience methods are provided by this module. They are	96	The following convinience methods are provided by this module. They are
102	exported by default:	97	exported by default:
…		…
125		120
126	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	121	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
127		122
128	except being faster.	123	except being faster.
129		124
		125	=item $is_boolean = JSON::XS::is_bool $scalar
		126
		127	Returns true if the passed scalar represents either JSON::XS::true or
		128	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		129	and are used to represent JSON C<true> and C<false> values in Perl.
		130
		131	See MAPPING, below, for more information on how JSON values are mapped to
		132	Perl.
		133
130	=back	134	=back
		135
131		136
132	=head1 OBJECT-ORIENTED INTERFACE	137	=head1 OBJECT-ORIENTED INTERFACE
133		138
134	The object oriented interface lets you configure your own encoding or	139	The object oriented interface lets you configure your own encoding or
135	decoding style, within the limits of supported formats.	140	decoding style, within the limits of supported formats.
…		…
151		156
152	If C<$enable> is true (or missing), then the C<encode> method will not	157	If C<$enable> is true (or missing), then the C<encode> method will not
153	generate characters outside the code range C<0..127> (which is ASCII). Any	158	generate characters outside the code range C<0..127> (which is ASCII). Any
154	unicode characters outside that range will be escaped using either a	159	unicode characters outside that range will be escaped using either a
155	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	160	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
156	as per RFC4627.	161	as per RFC4627. The resulting encoded JSON text can be treated as a native
		162	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		163	or any other superset of ASCII.
157		164
158	If C<$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
159	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
160	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.
161		172
162	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	173	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
163	=> ["\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)
164		198
165	=item $json = $json->utf8 ([$enable])	199	=item $json = $json->utf8 ([$enable])
166		200
167	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
168	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
…		…
278	resulting in an invalid JSON text:	312	resulting in an invalid JSON text:
279		313
280	JSON::XS->new->allow_nonref->encode ("Hello, World!")	314	JSON::XS->new->allow_nonref->encode ("Hello, World!")
281	=> "Hello, World!"	315	=> "Hello, World!"
282		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])
		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, C<decode> will not change the
		365	deserialised hash in any way. This is maximally fast.
		366
		367	Example, convert all JSON objects into the integer 5:
		368
		369	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		370	# returns [5]
		371	$js->decode ('[{}]')
		372	# throw an exception because allow_nonref is not enabled:
		373	$js->decode ('{"a":1, "b":2}');
		374
		375	=item $json = $json->filter_json_single_key_object ([$coderef])
		376
		377	Works like C<filter_json_object>, but is only called for JSON objects
		378	having only a single key.
		379
		380	This C<$coderef> is called before the one specified via
		381	C<filter_json_object>, if any. If it returns something, that will be
		382	inserted into the data structure. If it returns nothing, the callback
		383	from C<filter_json_object> will be called next. If you want to force
		384	insertion of single-key objects even in the presence of a mutating
		385	C<filter_json_object> callback, simply return the passed hash.
		386
		387	As this callback gets called less often then the C<filter_json_object>
		388	one, decoding speed will not usually suffer as much. Therefore, single-key
		389	objects make excellent targets to serialise Perl objects into, especially
		390	as single-key JSON objects are as close to the type-tagged value concept
		391	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		392	support this in any way, so you need to make sure your data never looks
		393	like a serialised Perl hash.
		394
		395	Typical names for the single object key are C<__class_whatever__>, or
		396	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		397	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		398	with real hashes.
		399
		400	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		401	into the corresponding C<< $WIDGET{<id>} >> object:
		402
		403	# return whatever is in $WIDGET{5}:
		404	JSON::XS
		405	->new
		406	->filter_json_single_key_object (sub {
		407	exists $_[0]{__widget__}
		408	? $WIDGET{ $_[0]{__widget__} }
		409	: ()
		410	})
		411	->decode ('{"__widget__": 5')
		412
		413	# this can be used with a TO_JSON method in some "widget" class
		414	# for serialisation to json:
		415	sub WidgetBase::TO_JSON {
		416	my ($self) = @_;
		417
		418	unless ($self->{id}) {
		419	$self->{id} = ..get..some..id..;
		420	$WIDGET{$self->{id}} = $self;
		421	}
		422
		423	{ __widget__ => $self->{id} }
		424	}
		425
283	=item $json = $json->shrink ([$enable])	426	=item $json = $json->shrink ([$enable])
284		427
285	Perl usually over-allocates memory a bit when allocating space for	428	Perl usually over-allocates memory a bit when allocating space for
286	strings. This flag optionally resizes strings generated by either	429	strings. This flag optionally resizes strings generated by either
287	C<encode> or C<decode> to their minimum size possible. This can save	430	C<encode> or C<decode> to their minimum size possible. This can save
288	memory when your JSON texts are either very very long or you have many	431	memory when your JSON texts are either very very long or you have many
289	short strings. It will also try to downgrade any strings to octet-form	432	short strings. It will also try to downgrade any strings to octet-form
290	if possible: perl stores strings internally either in an encoding called	433	if possible: perl stores strings internally either in an encoding called
291	UTF-X or in octet-form. The latter cannot store everything but uses less	434	UTF-X or in octet-form. The latter cannot store everything but uses less
292	space in general.	435	space in general (and some buggy Perl or C code might even rely on that
		436	internal representation being used).
293		437
		438	The actual definition of what shrink does might change in future versions,
		439	but it will always try to save space at the expense of time.
		440
294	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	441	If C<$enable> is true (or missing), the string returned by C<encode> will
295	while all strings generated by C<decode> will also be shrunk-to-fit.	442	be shrunk-to-fit, while all strings generated by C<decode> will also be
		443	shrunk-to-fit.
296		444
297	If C<$enable> is false, then the normal perl allocation algorithms are used.	445	If C<$enable> is false, then the normal perl allocation algorithms are used.
298	If you work with your data, then this is likely to be faster.	446	If you work with your data, then this is likely to be faster.
299		447
300	In the future, this setting might control other things, such as converting	448	In the future, this setting might control other things, such as converting
301	strings that look like integers or floats into integers or floats	449	strings that look like integers or floats into integers or floats
302	internally (there is no difference on the Perl level), saving space.	450	internally (there is no difference on the Perl level), saving space.
		451
		452	=item $json = $json->max_depth ([$maximum_nesting_depth])
		453
		454	Sets the maximum nesting level (default C<512>) accepted while encoding
		455	or decoding. If the JSON text or Perl data structure has an equal or
		456	higher nesting level then this limit, then the encoder and decoder will
		457	stop and croak at that point.
		458
		459	Nesting level is defined by number of hash- or arrayrefs that the encoder
		460	needs to traverse to reach a given point or the number of C<{> or C<[>
		461	characters without their matching closing parenthesis crossed to reach a
		462	given character in a string.
		463
		464	Setting the maximum depth to one disallows any nesting, so that ensures
		465	that the object is only a single hash/object or array.
		466
		467	The argument to C<max_depth> will be rounded up to the next highest power
		468	of two. If no argument is given, the highest possible setting will be
		469	used, which is rarely useful.
		470
		471	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		472
		473	=item $json = $json->max_size ([$maximum_string_size])
		474
		475	Set the maximum length a JSON text may have (in bytes) where decoding is
		476	being attempted. The default is C<0>, meaning no limit. When C<decode>
		477	is called on a string longer then this number of characters it will not
		478	attempt to decode the string but throw an exception. This setting has no
		479	effect on C<encode> (yet).
		480
		481	The argument to C<max_size> will be rounded up to the next B<highest>
		482	power of two (so may be more than requested). If no argument is given, the
		483	limit check will be deactivated (same as when C<0> is specified).
		484
		485	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
303		486
304	=item $json_text = $json->encode ($perl_scalar)	487	=item $json_text = $json->encode ($perl_scalar)
305		488
306	Converts the given Perl data structure (a simple scalar or a reference	489	Converts the given Perl data structure (a simple scalar or a reference
307	to a hash or array) to its JSON representation. Simple scalars will be	490	to a hash or array) to its JSON representation. Simple scalars will be
…		…
317		500
318	JSON numbers and strings become simple Perl scalars. JSON arrays become	501	JSON numbers and strings become simple Perl scalars. JSON arrays become
319	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	502	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
320	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	503	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
321		504
		505	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		506
		507	This works like the C<decode> method, but instead of raising an exception
		508	when there is trailing garbage after the first JSON object, it will
		509	silently stop parsing there and return the number of characters consumed
		510	so far.
		511
		512	This is useful if your JSON texts are not delimited by an outer protocol
		513	(which is not the brightest thing to do in the first place) and you need
		514	to know where the JSON text ends.
		515
		516	JSON::XS->new->decode_prefix ("[1] the tail")
		517	=> ([], 3)
		518
322	=back	519	=back
		520
323		521
324	=head1 MAPPING	522	=head1 MAPPING
325		523
326	This section describes how JSON::XS maps Perl values to JSON values and	524	This section describes how JSON::XS maps Perl values to JSON values and
327	vice versa. These mappings are designed to "do the right thing" in most	525	vice versa. These mappings are designed to "do the right thing" in most
…		…
329	(what you put in comes out as something equivalent).	527	(what you put in comes out as something equivalent).
330		528
331	For the more enlightened: note that in the following descriptions,	529	For the more enlightened: note that in the following descriptions,
332	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	530	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
333	refers to the abstract Perl language itself.	531	refers to the abstract Perl language itself.
		532
334		533
335	=head2 JSON -> PERL	534	=head2 JSON -> PERL
336		535
337	=over 4	536	=over 4
338		537
…		…
359	conversion details, but an integer may take slightly less memory and might	558	conversion details, but an integer may take slightly less memory and might
360	represent more values exactly than (floating point) numbers.	559	represent more values exactly than (floating point) numbers.
361		560
362	=item true, false	561	=item true, false
363		562
364	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	563	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
365	this process. Future versions might represent those values differently,	564	respectively. They are overloaded to act almost exactly like the numbers
366	but they will be guarenteed to act like these integers would normally in	565	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
367	Perl.	566	the C<JSON::XS::is_bool> function.
368		567
369	=item null	568	=item null
370		569
371	A JSON null atom becomes C<undef> in Perl.	570	A JSON null atom becomes C<undef> in Perl.
372		571
373	=back	572	=back
		573
374		574
375	=head2 PERL -> JSON	575	=head2 PERL -> JSON
376		576
377	The mapping from Perl to JSON is slightly more difficult, as Perl is a	577	The mapping from Perl to JSON is slightly more difficult, as Perl is a
378	truly typeless language, so we can only guess which JSON type is meant by	578	truly typeless language, so we can only guess which JSON type is meant by
…		…
381	=over 4	581	=over 4
382		582
383	=item hash references	583	=item hash references
384		584
385	Perl hash references become JSON objects. As there is no inherent ordering	585	Perl hash references become JSON objects. As there is no inherent ordering
386	in hash keys, they will usually be encoded in a pseudo-random order that	586	in hash keys (or JSON objects), they will usually be encoded in a
387	can change between runs of the same program but stays generally the same	587	pseudo-random order that can change between runs of the same program but
388	within a single run of a program. JSON::XS can optionally sort the hash	588	stays generally the same within a single run of a program. JSON::XS can
389	keys (determined by the I<canonical> flag), so the same datastructure	589	optionally sort the hash keys (determined by the I<canonical> flag), so
390	will serialise to the same JSON text (given same settings and version of	590	the same datastructure will serialise to the same JSON text (given same
391	JSON::XS), but this incurs a runtime overhead.	591	settings and version of JSON::XS), but this incurs a runtime overhead
		592	and is only rarely useful, e.g. when you want to compare some JSON text
		593	against another for equality.
392		594
393	=item array references	595	=item array references
394		596
395	Perl array references become JSON arrays.	597	Perl array references become JSON arrays.
		598
		599	=item other references
		600
		601	Other unblessed references are generally not allowed and will cause an
		602	exception to be thrown, except for references to the integers C<0> and
		603	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		604	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		605
		606	to_json [\0,JSON::XS::true] # yields [false,true]
		607
		608	=item JSON::XS::true, JSON::XS::false
		609
		610	These special values become JSON true and JSON false values,
		611	respectively. You cna alos use C<\1> and C<\0> directly if you want.
396		612
397	=item blessed objects	613	=item blessed objects
398		614
399	Blessed objects are not allowed. JSON::XS currently tries to encode their	615	Blessed objects are not allowed. JSON::XS currently tries to encode their
400	underlying representation (hash- or arrayref), but this behaviour might	616	underlying representation (hash- or arrayref), but this behaviour might
…		…
433	$x *= 1; # same thing, the choise is yours.	649	$x *= 1; # same thing, the choise is yours.
434		650
435	You can not currently output JSON booleans or force the type in other,	651	You can not currently output JSON booleans or force the type in other,
436	less obscure, ways. Tell me if you need this capability.	652	less obscure, ways. Tell me if you need this capability.
437		653
438	=item circular data structures
439
440	Those will be encoded until memory or stackspace runs out.
441
442	=back	654	=back
		655
443		656
444	=head1 COMPARISON	657	=head1 COMPARISON
445		658
446	As already mentioned, this module was created because none of the existing	659	As already mentioned, this module was created because none of the existing
447	JSON modules could be made to work correctly. First I will describe the	660	JSON modules could be made to work correctly. First I will describe the
…		…
525		738
526	Does not check input for validity.	739	Does not check input for validity.
527		740
528	=back	741	=back
529		742
		743
		744	=head2 JSON and YAML
		745
		746	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		747	however, a mass hysteria and very far from the truth. In general, there is
		748	no way to configure JSON::XS to output a data structure as valid YAML.
		749
		750	If you really must use JSON::XS to generate YAML, you should use this
		751	algorithm (subject to change in future versions):
		752
		753	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		754	my $yaml = $to_yaml->encode ($ref) . "\n";
		755
		756	This will usually generate JSON texts that also parse as valid
		757	YAML. Please note that YAML has hardcoded limits on (simple) object key
		758	lengths that JSON doesn't have, so you should make sure that your hash
		759	keys are noticably shorter than the 1024 characters YAML allows.
		760
		761	There might be other incompatibilities that I am not aware of. In general
		762	you should not try to generate YAML with a JSON generator or vice versa,
		763	or try to parse JSON with a YAML parser or vice versa: chances are high
		764	that you will run into severe interoperability problems.
		765
		766
530	=head2 SPEED	767	=head2 SPEED
531		768
532	It seems that JSON::XS is surprisingly fast, as shown in the following	769	It seems that JSON::XS is surprisingly fast, as shown in the following
533	tables. They have been generated with the help of the C<eg/bench> program	770	tables. They have been generated with the help of the C<eg/bench> program
534	in the JSON::XS distribution, to make it easy to compare on your own	771	in the JSON::XS distribution, to make it easy to compare on your own
535	system.	772	system.
536		773
537	First comes a comparison between various modules using a very short JSON	774	First comes a comparison between various modules using a very short
538	string:	775	single-line JSON string:
539		776
540	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	777	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		778	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
541		779
542	It shows the number of encodes/decodes per second (JSON::XS uses the	780	It shows the number of encodes/decodes per second (JSON::XS uses
543	functional interface, while JSON::XS/2 uses the OO interface with	781	the functional interface, while JSON::XS/2 uses the OO interface
544	pretty-printing and hashkey sorting enabled). Higher is better:	782	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		783	shrink). Higher is better:
545		784
		785	Storable \| 15779.925 \| 14169.946 \|
		786	-----------+------------+------------+
546	module \| encode \| decode \|	787	module \| encode \| decode \|
547	-----------\|------------\|------------\|	788	-----------\|------------\|------------\|
548	JSON \| 11488.516 \| 7823.035 \|	789	JSON \| 4990.842 \| 4088.813 \|
549	JSON::DWIW \| 94708.054 \| 129094.260 \|	790	JSON::DWIW \| 51653.990 \| 71575.154 \|
550	JSON::PC \| 63884.157 \| 128528.212 \|	791	JSON::PC \| 65948.176 \| 74631.744 \|
551	JSON::Syck \| 34898.677 \| 42096.911 \|	792	JSON::PP \| 8931.652 \| 3817.168 \|
552	JSON::XS \| 654027.064 \| 396423.669 \|	793	JSON::Syck \| 24877.248 \| 27776.848 \|
553	JSON::XS/2 \| 371564.190 \| 371725.613 \|	794	JSON::XS \| 388361.481 \| 227951.304 \|
		795	JSON::XS/2 \| 227951.304 \| 218453.333 \|
		796	JSON::XS/3 \| 338250.323 \| 218453.333 \|
		797	Storable \| 16500.016 \| 135300.129 \|
554	-----------+------------+------------+	798	-----------+------------+------------+
555		799
556	That is, JSON::XS is more than six times faster than JSON::DWIW on	800	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
557	encoding, more than three times faster on decoding, and about thirty times	801	about three times faster on decoding, and over fourty times faster
558	faster than JSON, even with pretty-printing and key sorting.	802	than JSON, even with pretty-printing and key sorting. It also compares
		803	favourably to Storable for small amounts of data.
559		804
560	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	805	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
561	search API (http://nanoref.com/yahooapis/mgPdGg):	806	search API (http://nanoref.com/yahooapis/mgPdGg):
562		807
563	module \| encode \| decode \|	808	module \| encode \| decode \|
564	-----------\|------------\|------------\|	809	-----------\|------------\|------------\|
565	JSON \| 273.023 \| 44.674 \|	810	JSON \| 55.260 \| 34.971 \|
566	JSON::DWIW \| 1089.383 \| 1145.704 \|	811	JSON::DWIW \| 825.228 \| 1082.513 \|
567	JSON::PC \| 3097.419 \| 2393.921 \|	812	JSON::PC \| 3571.444 \| 2394.829 \|
568	JSON::Syck \| 514.060 \| 843.053 \|	813	JSON::PP \| 210.987 \| 32.574 \|
569	JSON::XS \| 6479.668 \| 3636.364 \|	814	JSON::Syck \| 552.551 \| 787.544 \|
570	JSON::XS/2 \| 3774.221 \| 3599.124 \|	815	JSON::XS \| 5780.463 \| 4854.519 \|
		816	JSON::XS/2 \| 3869.998 \| 4798.975 \|
		817	JSON::XS/3 \| 5862.880 \| 4798.975 \|
		818	Storable \| 4445.002 \| 5235.027 \|
571	-----------+------------+------------+	819	-----------+------------+------------+
572		820
573	Again, JSON::XS leads by far.	821	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		822	decodes faster).
574		823
575	On large strings containing lots of high unicode characters, some modules	824	On large strings containing lots of high unicode characters, some modules
576	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	825	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
577	will be broken due to missing (or wrong) unicode handling. Others refuse	826	will be broken due to missing (or wrong) unicode handling. Others refuse
578	to decode or encode properly, so it was impossible to prepare a fair	827	to decode or encode properly, so it was impossible to prepare a fair
579	comparison table for that case.	828	comparison table for that case.
580		829
581	=head1 RESOURCE LIMITS
582		830
583	JSON::XS does not impose any limits on the size of JSON texts or Perl	831	=head1 SECURITY CONSIDERATIONS
584	values they represent - if your machine can handle it, JSON::XS will	832
585	encode or decode it. Future versions might optionally impose structure	833	When you are using JSON in a protocol, talking to untrusted potentially
586	depth and memory use resource limits.	834	hostile creatures requires relatively few measures.
		835
		836	First of all, your JSON decoder should be secure, that is, should not have
		837	any buffer overflows. Obviously, this module should ensure that and I am
		838	trying hard on making that true, but you never know.
		839
		840	Second, you need to avoid resource-starving attacks. That means you should
		841	limit the size of JSON texts you accept, or make sure then when your
		842	resources run out, thats just fine (e.g. by using a separate process that
		843	can crash safely). The size of a JSON text in octets or characters is
		844	usually a good indication of the size of the resources required to decode
		845	it into a Perl structure. While JSON::XS can check the size of the JSON
		846	text, it might be too late when you already have it in memory, so you
		847	might want to check the size before you accept the string.
		848
		849	Third, JSON::XS recurses using the C stack when decoding objects and
		850	arrays. The C stack is a limited resource: for instance, on my amd64
		851	machine with 8MB of stack size I can decode around 180k nested arrays but
		852	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		853	to free the temporary). If that is exceeded, the program crashes. to be
		854	conservative, the default nesting limit is set to 512. If your process
		855	has a smaller stack, you should adjust this setting accordingly with the
		856	C<max_depth> method.
		857
		858	And last but least, something else could bomb you that I forgot to think
		859	of. In that case, you get to keep the pieces. I am always open for hints,
		860	though...
		861
		862	If you are using JSON::XS to return packets to consumption
		863	by javascript scripts in a browser you should have a look at
		864	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		865	you are vulnerable to some common attack vectors (which really are browser
		866	design bugs, but it is still you who will have to deal with it, as major
		867	browser developers care only for features, not about doing security
		868	right).
		869
587		870
588	=head1 BUGS	871	=head1 BUGS
589		872
590	While the goal of this module is to be correct, that unfortunately does	873	While the goal of this module is to be correct, that unfortunately does
591	not mean its bug-free, only that I think its design is bug-free. It is	874	not mean its bug-free, only that I think its design is bug-free. It is
592	still very young and not well-tested. If you keep reporting bugs they will	875	still relatively early in its development. If you keep reporting bugs they
593	be fixed swiftly, though.	876	will be fixed swiftly, though.
594		877
595	=cut	878	=cut
		879
		880	our $true = do { bless \(my $dummy = "1"), "JSON::XS::Boolean" };
		881	our $false = do { bless \(my $dummy = "0"), "JSON::XS::Boolean" };
		882
		883	sub true() { $true }
		884	sub false() { $false }
		885
		886	sub is_bool($) {
		887	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		888	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		889	}
		890
		891	XSLoader::load "JSON::XS", $VERSION;
		892
		893	package JSON::XS::Boolean;
		894
		895	use overload
		896	"0+" => sub { ${$_[0]} },
		897	"++" => sub { $_[0] = ${$_[0]} + 1 },
		898	"--" => sub { $_[0] = ${$_[0]} - 1 },
		899	fallback => 1;
596		900
597	1;	901	1;
598		902
599	=head1 AUTHOR	903	=head1 AUTHOR
600		904

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Comparing JSON-XS/XS.pm (file contents): Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs. Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC