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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.29 by root, Mon Apr 9 05:09:57 2007 UTC vs.
Revision 1.62 by root, Thu Oct 11 22:52:52 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 = '1.11';	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:
…		…
126	This function call is functionally identical to:	124	This function call is functionally identical to:
127		125
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	126	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		127
130	except being faster.	128	except being faster.
		129
		130	=item $is_boolean = JSON::XS::is_bool $scalar
		131
		132	Returns true if the passed scalar represents either JSON::XS::true or
		133	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		134	and are used to represent JSON C<true> and C<false> values in Perl.
		135
		136	See MAPPING, below, for more information on how JSON values are mapped to
		137	Perl.
131		138
132	=back	139	=back
133		140
134		141
135	=head1 OBJECT-ORIENTED INTERFACE	142	=head1 OBJECT-ORIENTED INTERFACE
…		…
154		161
155	If C<$enable> is true (or missing), then the C<encode> method will not	162	If C<$enable> is true (or missing), then the C<encode> method will not
156	generate characters outside the code range C<0..127> (which is ASCII). Any	163	generate characters outside the code range C<0..127> (which is ASCII). Any
157	unicode characters outside that range will be escaped using either a	164	unicode characters outside that range will be escaped using either a
158	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	165	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
159	as per RFC4627.	166	as per RFC4627. The resulting encoded JSON text can be treated as a native
		167	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		168	or any other superset of ASCII.
160		169
161	If C<$enable> is false, then the C<encode> method will not escape Unicode	170	If C<$enable> is false, then the C<encode> method will not escape Unicode
162	characters unless required by the JSON syntax. This results in a faster	171	characters unless required by the JSON syntax or other flags. This results
163	and more compact format.	172	in a faster and more compact format.
		173
		174	The main use for this flag is to produce JSON texts that can be
		175	transmitted over a 7-bit channel, as the encoded JSON texts will not
		176	contain any 8 bit characters.
164		177
165	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	178	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
166	=> ["\ud801\udc01"]	179	=> ["\ud801\udc01"]
		180
		181	=item $json = $json->latin1 ([$enable])
		182
		183	If C<$enable> is true (or missing), then the C<encode> method will encode
		184	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
		185	outside the code range C<0..255>. The resulting string can be treated as a
		186	latin1-encoded JSON text or a native unicode string. The C<decode> method
		187	will not be affected in any way by this flag, as C<decode> by default
		188	expects unicode, which is a strict superset of latin1.
		189
		190	If C<$enable> is false, then the C<encode> method will not escape Unicode
		191	characters unless required by the JSON syntax or other flags.
		192
		193	The main use for this flag is efficiently encoding binary data as JSON
		194	text, as most octets will not be escaped, resulting in a smaller encoded
		195	size. The disadvantage is that the resulting JSON text is encoded
		196	in latin1 (and must correctly be treated as such when storing and
		197	transfering), a rare encoding for JSON. It is therefore most useful when
		198	you want to store data structures known to contain binary data efficiently
		199	in files or databases, not when talking to other JSON encoders/decoders.
		200
		201	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
		202	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
167		203
168	=item $json = $json->utf8 ([$enable])	204	=item $json = $json->utf8 ([$enable])
169		205
170	If C<$enable> is true (or missing), then the C<encode> method will encode	206	If C<$enable> is true (or missing), then the C<encode> method will encode
171	the JSON result into UTF-8, as required by many protocols, while the	207	the JSON result into UTF-8, as required by many protocols, while the
…		…
247		283
248	Example, space_before and indent disabled, space_after enabled:	284	Example, space_before and indent disabled, space_after enabled:
249		285
250	{"key": "value"}	286	{"key": "value"}
251		287
		288	=item $json = $json->relaxed ([$enable])
		289
		290	If C<$enable> is true (or missing), then C<decode> will accept some
		291	extensions to normal JSON syntax (see below). C<encode> will not be
		292	affected in anyway. I<Be aware that this option makes you accept invalid
		293	JSON texts as if they were valid!>. I suggest only to use this option to
		294	parse application-specific files written by humans (configuration files,
		295	resource files etc.)
		296
		297	If C<$enable> is false (the default), then C<decode> will only accept
		298	valid JSON texts.
		299
		300	Currently accepted extensions are:
		301
		302	=over 4
		303
		304	=item * list items can have an end-comma
		305
		306	JSON I<separates> array elements and key-value pairs with commas. This
		307	can be annoying if you write JSON texts manually and want to be able to
		308	quickly append elements, so this extension accepts comma at the end of
		309	such items not just between them:
		310
		311	[
		312	1,
		313	2, <- this comma not normally allowed
		314	]
		315	{
		316	"k1": "v1",
		317	"k2": "v2", <- this comma not normally allowed
		318	}
		319
		320	=item * shell-style '#'-comments
		321
		322	Whenever JSON allows whitespace, shell-style comments are additionally
		323	allowed. They are terminated by the first carriage-return or line-feed
		324	character, after which more white-space and comments are allowed.
		325
		326	[
		327	1, # this comment not allowed in JSON
		328	# neither this one...
		329	]
		330
		331	=back
		332
252	=item $json = $json->canonical ([$enable])	333	=item $json = $json->canonical ([$enable])
253		334
254	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	335	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
255	by sorting their keys. This is adding a comparatively high overhead.	336	by sorting their keys. This is adding a comparatively high overhead.
256		337
…		…
280	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	361	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
281	resulting in an invalid JSON text:	362	resulting in an invalid JSON text:
282		363
283	JSON::XS->new->allow_nonref->encode ("Hello, World!")	364	JSON::XS->new->allow_nonref->encode ("Hello, World!")
284	=> "Hello, World!"	365	=> "Hello, World!"
		366
		367	=item $json = $json->allow_blessed ([$enable])
		368
		369	If C<$enable> is true (or missing), then the C<encode> method will not
		370	barf when it encounters a blessed reference. Instead, the value of the
		371	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		372	disabled or no C<to_json> method found) or a representation of the
		373	object (C<convert_blessed> enabled and C<to_json> method found) is being
		374	encoded. Has no effect on C<decode>.
		375
		376	If C<$enable> is false (the default), then C<encode> will throw an
		377	exception when it encounters a blessed object.
		378
		379	=item $json = $json->convert_blessed ([$enable])
		380
		381	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		382	blessed object, will check for the availability of the C<TO_JSON> method
		383	on the object's class. If found, it will be called in scalar context
		384	and the resulting scalar will be encoded instead of the object. If no
		385	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		386	to do.
		387
		388	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		389	returns other blessed objects, those will be handled in the same
		390	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		391	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		392	methods called by the Perl core (== not by the user of the object) are
		393	usually in upper case letters and to avoid collisions with the C<to_json>
		394	function.
		395
		396	This setting does not yet influence C<decode> in any way, but in the
		397	future, global hooks might get installed that influence C<decode> and are
		398	enabled by this setting.
		399
		400	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		401	to do when a blessed object is found.
		402
		403	=item $json = $json->filter_json_object ([$coderef->($hashref)])
		404
		405	When C<$coderef> is specified, it will be called from C<decode> each
		406	time it decodes a JSON object. The only argument is a reference to the
		407	newly-created hash. If the code references returns a single scalar (which
		408	need not be a reference), this value (i.e. a copy of that scalar to avoid
		409	aliasing) is inserted into the deserialised data structure. If it returns
		410	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		411	original deserialised hash will be inserted. This setting can slow down
		412	decoding considerably.
		413
		414	When C<$coderef> is omitted or undefined, any existing callback will
		415	be removed and C<decode> will not change the deserialised hash in any
		416	way.
		417
		418	Example, convert all JSON objects into the integer 5:
		419
		420	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		421	# returns [5]
		422	$js->decode ('[{}]')
		423	# throw an exception because allow_nonref is not enabled
		424	# so a lone 5 is not allowed.
		425	$js->decode ('{"a":1, "b":2}');
		426
		427	=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
		428
		429	Works remotely similar to C<filter_json_object>, but is only called for
		430	JSON objects having a single key named C<$key>.
		431
		432	This C<$coderef> is called before the one specified via
		433	C<filter_json_object>, if any. It gets passed the single value in the JSON
		434	object. If it returns a single value, it will be inserted into the data
		435	structure. If it returns nothing (not even C<undef> but the empty list),
		436	the callback from C<filter_json_object> will be called next, as if no
		437	single-key callback were specified.
		438
		439	If C<$coderef> is omitted or undefined, the corresponding callback will be
		440	disabled. There can only ever be one callback for a given key.
		441
		442	As this callback gets called less often then the C<filter_json_object>
		443	one, decoding speed will not usually suffer as much. Therefore, single-key
		444	objects make excellent targets to serialise Perl objects into, especially
		445	as single-key JSON objects are as close to the type-tagged value concept
		446	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		447	support this in any way, so you need to make sure your data never looks
		448	like a serialised Perl hash.
		449
		450	Typical names for the single object key are C<__class_whatever__>, or
		451	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		452	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		453	with real hashes.
		454
		455	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		456	into the corresponding C<< $WIDGET{<id>} >> object:
		457
		458	# return whatever is in $WIDGET{5}:
		459	JSON::XS
		460	->new
		461	->filter_json_single_key_object (__widget__ => sub {
		462	$WIDGET{ $_[0] }
		463	})
		464	->decode ('{"__widget__": 5')
		465
		466	# this can be used with a TO_JSON method in some "widget" class
		467	# for serialisation to json:
		468	sub WidgetBase::TO_JSON {
		469	my ($self) = @_;
		470
		471	unless ($self->{id}) {
		472	$self->{id} = ..get..some..id..;
		473	$WIDGET{$self->{id}} = $self;
		474	}
		475
		476	{ __widget__ => $self->{id} }
		477	}
285		478
286	=item $json = $json->shrink ([$enable])	479	=item $json = $json->shrink ([$enable])
287		480
288	Perl usually over-allocates memory a bit when allocating space for	481	Perl usually over-allocates memory a bit when allocating space for
289	strings. This flag optionally resizes strings generated by either	482	strings. This flag optionally resizes strings generated by either
…		…
322	given character in a string.	515	given character in a string.
323		516
324	Setting the maximum depth to one disallows any nesting, so that ensures	517	Setting the maximum depth to one disallows any nesting, so that ensures
325	that the object is only a single hash/object or array.	518	that the object is only a single hash/object or array.
326		519
327	The argument to C<max_depth> will be rounded up to the next nearest power	520	The argument to C<max_depth> will be rounded up to the next highest power
328	of two.	521	of two. If no argument is given, the highest possible setting will be
		522	used, which is rarely useful.
		523
		524	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		525
		526	=item $json = $json->max_size ([$maximum_string_size])
		527
		528	Set the maximum length a JSON text may have (in bytes) where decoding is
		529	being attempted. The default is C<0>, meaning no limit. When C<decode>
		530	is called on a string longer then this number of characters it will not
		531	attempt to decode the string but throw an exception. This setting has no
		532	effect on C<encode> (yet).
		533
		534	The argument to C<max_size> will be rounded up to the next B<highest>
		535	power of two (so may be more than requested). If no argument is given, the
		536	limit check will be deactivated (same as when C<0> is specified).
329		537
330	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	538	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
331		539
332	=item $json_text = $json->encode ($perl_scalar)	540	=item $json_text = $json->encode ($perl_scalar)
333		541
…		…
345		553
346	JSON numbers and strings become simple Perl scalars. JSON arrays become	554	JSON numbers and strings become simple Perl scalars. JSON arrays become
347	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	555	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
348	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	556	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
349		557
		558	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		559
		560	This works like the C<decode> method, but instead of raising an exception
		561	when there is trailing garbage after the first JSON object, it will
		562	silently stop parsing there and return the number of characters consumed
		563	so far.
		564
		565	This is useful if your JSON texts are not delimited by an outer protocol
		566	(which is not the brightest thing to do in the first place) and you need
		567	to know where the JSON text ends.
		568
		569	JSON::XS->new->decode_prefix ("[1] the tail")
		570	=> ([], 3)
		571
350	=back	572	=back
351		573
352		574
353	=head1 MAPPING	575	=head1 MAPPING
354		576
…		…
359		581
360	For the more enlightened: note that in the following descriptions,	582	For the more enlightened: note that in the following descriptions,
361	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	583	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
362	refers to the abstract Perl language itself.	584	refers to the abstract Perl language itself.
363		585
		586
364	=head2 JSON -> PERL	587	=head2 JSON -> PERL
365		588
366	=over 4	589	=over 4
367		590
368	=item object	591	=item object
…		…
380	are represented by the same codepoints in the Perl string, so no manual	603	are represented by the same codepoints in the Perl string, so no manual
381	decoding is necessary.	604	decoding is necessary.
382		605
383	=item number	606	=item number
384		607
385	A JSON number becomes either an integer or numeric (floating point)	608	A JSON number becomes either an integer, numeric (floating point) or
386	scalar in perl, depending on its range and any fractional parts. On the	609	string scalar in perl, depending on its range and any fractional parts. On
387	Perl level, there is no difference between those as Perl handles all the	610	the Perl level, there is no difference between those as Perl handles all
388	conversion details, but an integer may take slightly less memory and might	611	the conversion details, but an integer may take slightly less memory and
389	represent more values exactly than (floating point) numbers.	612	might represent more values exactly than (floating point) numbers.
		613
		614	If the number consists of digits only, JSON::XS will try to represent
		615	it as an integer value. If that fails, it will try to represent it as
		616	a numeric (floating point) value if that is possible without loss of
		617	precision. Otherwise it will preserve the number as a string value.
		618
		619	Numbers containing a fractional or exponential part will always be
		620	represented as numeric (floating point) values, possibly at a loss of
		621	precision.
		622
		623	This might create round-tripping problems as numbers might become strings,
		624	but as Perl is typeless there is no other way to do it.
390		625
391	=item true, false	626	=item true, false
392		627
393	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	628	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
394	this process. Future versions might represent those values differently,	629	respectively. They are overloaded to act almost exactly like the numbers
395	but they will be guarenteed to act like these integers would normally in	630	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
396	Perl.	631	the C<JSON::XS::is_bool> function.
397		632
398	=item null	633	=item null
399		634
400	A JSON null atom becomes C<undef> in Perl.	635	A JSON null atom becomes C<undef> in Perl.
401		636
402	=back	637	=back
		638
403		639
404	=head2 PERL -> JSON	640	=head2 PERL -> JSON
405		641
406	The mapping from Perl to JSON is slightly more difficult, as Perl is a	642	The mapping from Perl to JSON is slightly more difficult, as Perl is a
407	truly typeless language, so we can only guess which JSON type is meant by	643	truly typeless language, so we can only guess which JSON type is meant by
…		…
432	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	668	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
433	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	669	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
434		670
435	to_json [\0,JSON::XS::true] # yields [false,true]	671	to_json [\0,JSON::XS::true] # yields [false,true]
436		672
		673	=item JSON::XS::true, JSON::XS::false
		674
		675	These special values become JSON true and JSON false values,
		676	respectively. You can also use C<\1> and C<\0> directly if you want.
		677
437	=item blessed objects	678	=item blessed objects
438		679
439	Blessed objects are not allowed. JSON::XS currently tries to encode their	680	Blessed objects are not allowed. JSON::XS currently tries to encode their
440	underlying representation (hash- or arrayref), but this behaviour might	681	underlying representation (hash- or arrayref), but this behaviour might
441	change in future versions.	682	change in future versions.
…		…
562		803
563	Does not check input for validity.	804	Does not check input for validity.
564		805
565	=back	806	=back
566		807
		808
		809	=head2 JSON and YAML
		810
		811	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		812	however, a mass hysteria and very far from the truth. In general, there is
		813	no way to configure JSON::XS to output a data structure as valid YAML.
		814
		815	If you really must use JSON::XS to generate YAML, you should use this
		816	algorithm (subject to change in future versions):
		817
		818	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		819	my $yaml = $to_yaml->encode ($ref) . "\n";
		820
		821	This will usually generate JSON texts that also parse as valid
		822	YAML. Please note that YAML has hardcoded limits on (simple) object key
		823	lengths that JSON doesn't have, so you should make sure that your hash
		824	keys are noticably shorter than the 1024 characters YAML allows.
		825
		826	There might be other incompatibilities that I am not aware of. In general
		827	you should not try to generate YAML with a JSON generator or vice versa,
		828	or try to parse JSON with a YAML parser or vice versa: chances are high
		829	that you will run into severe interoperability problems.
		830
		831
567	=head2 SPEED	832	=head2 SPEED
568		833
569	It seems that JSON::XS is surprisingly fast, as shown in the following	834	It seems that JSON::XS is surprisingly fast, as shown in the following
570	tables. They have been generated with the help of the C<eg/bench> program	835	tables. They have been generated with the help of the C<eg/bench> program
571	in the JSON::XS distribution, to make it easy to compare on your own	836	in the JSON::XS distribution, to make it easy to compare on your own
572	system.	837	system.
573		838
574	First comes a comparison between various modules using a very short JSON	839	First comes a comparison between various modules using a very short
575	string:	840	single-line JSON string:
576		841
577	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	842	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		843	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
578		844
579	It shows the number of encodes/decodes per second (JSON::XS uses the	845	It shows the number of encodes/decodes per second (JSON::XS uses
580	functional interface, while JSON::XS/2 uses the OO interface with	846	the functional interface, while JSON::XS/2 uses the OO interface
581	pretty-printing and hashkey sorting enabled). Higher is better:	847	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		848	shrink). Higher is better:
582		849
		850	Storable \| 15779.925 \| 14169.946 \|
		851	-----------+------------+------------+
583	module \| encode \| decode \|	852	module \| encode \| decode \|
584	-----------\|------------\|------------\|	853	-----------\|------------\|------------\|
585	JSON \| 11488.516 \| 7823.035 \|	854	JSON \| 4990.842 \| 4088.813 \|
586	JSON::DWIW \| 94708.054 \| 129094.260 \|	855	JSON::DWIW \| 51653.990 \| 71575.154 \|
587	JSON::PC \| 63884.157 \| 128528.212 \|	856	JSON::PC \| 65948.176 \| 74631.744 \|
588	JSON::Syck \| 34898.677 \| 42096.911 \|	857	JSON::PP \| 8931.652 \| 3817.168 \|
589	JSON::XS \| 654027.064 \| 396423.669 \|	858	JSON::Syck \| 24877.248 \| 27776.848 \|
590	JSON::XS/2 \| 371564.190 \| 371725.613 \|	859	JSON::XS \| 388361.481 \| 227951.304 \|
		860	JSON::XS/2 \| 227951.304 \| 218453.333 \|
		861	JSON::XS/3 \| 338250.323 \| 218453.333 \|
		862	Storable \| 16500.016 \| 135300.129 \|
591	-----------+------------+------------+	863	-----------+------------+------------+
592		864
593	That is, JSON::XS is more than six times faster than JSON::DWIW on	865	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
594	encoding, more than three times faster on decoding, and about thirty times	866	about three times faster on decoding, and over fourty times faster
595	faster than JSON, even with pretty-printing and key sorting.	867	than JSON, even with pretty-printing and key sorting. It also compares
		868	favourably to Storable for small amounts of data.
596		869
597	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	870	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
598	search API (http://nanoref.com/yahooapis/mgPdGg):	871	search API (http://nanoref.com/yahooapis/mgPdGg):
599		872
600	module \| encode \| decode \|	873	module \| encode \| decode \|
601	-----------\|------------\|------------\|	874	-----------\|------------\|------------\|
602	JSON \| 273.023 \| 44.674 \|	875	JSON \| 55.260 \| 34.971 \|
603	JSON::DWIW \| 1089.383 \| 1145.704 \|	876	JSON::DWIW \| 825.228 \| 1082.513 \|
604	JSON::PC \| 3097.419 \| 2393.921 \|	877	JSON::PC \| 3571.444 \| 2394.829 \|
605	JSON::Syck \| 514.060 \| 843.053 \|	878	JSON::PP \| 210.987 \| 32.574 \|
606	JSON::XS \| 6479.668 \| 3636.364 \|	879	JSON::Syck \| 552.551 \| 787.544 \|
607	JSON::XS/2 \| 3774.221 \| 3599.124 \|	880	JSON::XS \| 5780.463 \| 4854.519 \|
		881	JSON::XS/2 \| 3869.998 \| 4798.975 \|
		882	JSON::XS/3 \| 5862.880 \| 4798.975 \|
		883	Storable \| 4445.002 \| 5235.027 \|
608	-----------+------------+------------+	884	-----------+------------+------------+
609		885
610	Again, JSON::XS leads by far.	886	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		887	decodes faster).
611		888
612	On large strings containing lots of high unicode characters, some modules	889	On large strings containing lots of high unicode characters, some modules
613	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	890	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
614	will be broken due to missing (or wrong) unicode handling. Others refuse	891	will be broken due to missing (or wrong) unicode handling. Others refuse
615	to decode or encode properly, so it was impossible to prepare a fair	892	to decode or encode properly, so it was impossible to prepare a fair
…		…
628	Second, you need to avoid resource-starving attacks. That means you should	905	Second, you need to avoid resource-starving attacks. That means you should
629	limit the size of JSON texts you accept, or make sure then when your	906	limit the size of JSON texts you accept, or make sure then when your
630	resources run out, thats just fine (e.g. by using a separate process that	907	resources run out, thats just fine (e.g. by using a separate process that
631	can crash safely). The size of a JSON text in octets or characters is	908	can crash safely). The size of a JSON text in octets or characters is
632	usually a good indication of the size of the resources required to decode	909	usually a good indication of the size of the resources required to decode
633	it into a Perl structure.	910	it into a Perl structure. While JSON::XS can check the size of the JSON
		911	text, it might be too late when you already have it in memory, so you
		912	might want to check the size before you accept the string.
634		913
635	Third, JSON::XS recurses using the C stack when decoding objects and	914	Third, JSON::XS recurses using the C stack when decoding objects and
636	arrays. The C stack is a limited resource: for instance, on my amd64	915	arrays. The C stack is a limited resource: for instance, on my amd64
637	machine with 8MB of stack size I can decode around 180k nested arrays but	916	machine with 8MB of stack size I can decode around 180k nested arrays but
638	only 14k nested JSON objects (due to perl itself recursing deeply on croak	917	only 14k nested JSON objects (due to perl itself recursing deeply on croak
…		…
640	conservative, the default nesting limit is set to 512. If your process	919	conservative, the default nesting limit is set to 512. If your process
641	has a smaller stack, you should adjust this setting accordingly with the	920	has a smaller stack, you should adjust this setting accordingly with the
642	C<max_depth> method.	921	C<max_depth> method.
643		922
644	And last but least, something else could bomb you that I forgot to think	923	And last but least, something else could bomb you that I forgot to think
645	of. In that case, you get to keep the pieces. I am alway sopen for hints,	924	of. In that case, you get to keep the pieces. I am always open for hints,
646	though...	925	though...
		926
		927	If you are using JSON::XS to return packets to consumption
		928	by javascript scripts in a browser you should have a look at
		929	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		930	you are vulnerable to some common attack vectors (which really are browser
		931	design bugs, but it is still you who will have to deal with it, as major
		932	browser developers care only for features, not about doing security
		933	right).
647		934
648		935
649	=head1 BUGS	936	=head1 BUGS
650		937
651	While the goal of this module is to be correct, that unfortunately does	938	While the goal of this module is to be correct, that unfortunately does
…		…
653	still relatively early in its development. If you keep reporting bugs they	940	still relatively early in its development. If you keep reporting bugs they
654	will be fixed swiftly, though.	941	will be fixed swiftly, though.
655		942
656	=cut	943	=cut
657		944
		945	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		946	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		947
658	sub true() { \1 }	948	sub true() { $true }
659	sub false() { \0 }	949	sub false() { $false }
		950
		951	sub is_bool($) {
		952	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		953	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		954	}
		955
		956	XSLoader::load "JSON::XS", $VERSION;
		957
		958	package JSON::XS::Boolean;
		959
		960	use overload
		961	"0+" => sub { ${$_[0]} },
		962	"++" => sub { $_[0] = ${$_[0]} + 1 },
		963	"--" => sub { $_[0] = ${$_[0]} - 1 },
		964	fallback => 1;
660		965
661	1;	966	1;
662		967
663	=head1 AUTHOR	968	=head1 AUTHOR
664		969

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Comparing JSON-XS/XS.pm (file contents): Revision 1.29 by root, Mon Apr 9 05:09:57 2007 UTC vs. Revision 1.62 by root, Thu Oct 11 22:52:52 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.29 by root, Mon Apr 9 05:09:57 2007 UTC vs.
Revision 1.62 by root, Thu Oct 11 22:52:52 2007 UTC