[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 1.47 by root, Mon Jun 25 06:57:42 2007 UTC

…		…
85		85
86	package JSON::XS;	86	package JSON::XS;
87		87
88	use strict;	88	use strict;
89		89
90	BEGIN {
91	our $VERSION = '0.8';	90	our $VERSION = '1.4';
92	our @ISA = qw(Exporter);	91	our @ISA = qw(Exporter);
93		92
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	93	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
95	require Exporter;
96		94
97	require XSLoader;	95	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	96	use XSLoader;
99	}
100		97
101	=head1 FUNCTIONAL INTERFACE	98	=head1 FUNCTIONAL INTERFACE
102		99
103	The following convinience methods are provided by this module. They are	100	The following convinience methods are provided by this module. They are
104	exported by default:	101	exported by default:
…		…
127		124
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	125	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		126
130	except being faster.	127	except being faster.
131		128
		129	=item $is_boolean = JSON::XS::is_bool $scalar
		130
		131	Returns true if the passed scalar represents either JSON::XS::true or
		132	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		133	and are used to represent JSON C<true> and C<false> values in Perl.
		134
		135	See MAPPING, below, for more information on how JSON values are mapped to
		136	Perl.
		137
132	=back	138	=back
		139
133		140
134	=head1 OBJECT-ORIENTED INTERFACE	141	=head1 OBJECT-ORIENTED INTERFACE
135		142
136	The object oriented interface lets you configure your own encoding or	143	The object oriented interface lets you configure your own encoding or
137	decoding style, within the limits of supported formats.	144	decoding style, within the limits of supported formats.
…		…
153		160
154	If C<$enable> is true (or missing), then the C<encode> method will not	161	If C<$enable> is true (or missing), then the C<encode> method will not
155	generate characters outside the code range C<0..127> (which is ASCII). Any	162	generate characters outside the code range C<0..127> (which is ASCII). Any
156	unicode characters outside that range will be escaped using either a	163	unicode characters outside that range will be escaped using either a
157	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	164	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
158	as per RFC4627.	165	as per RFC4627. The resulting encoded JSON text can be treated as a native
		166	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		167	or any other superset of ASCII.
159		168
160	If C<$enable> is false, then the C<encode> method will not escape Unicode	169	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	170	characters unless required by the JSON syntax or other flags. This results
162	and more compact format.	171	in a faster and more compact format.
		172
		173	The main use for this flag is to produce JSON texts that can be
		174	transmitted over a 7-bit channel, as the encoded JSON texts will not
		175	contain any 8 bit characters.
163		176
164	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	177	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
165	=> ["\ud801\udc01"]	178	=> ["\ud801\udc01"]
		179
		180	=item $json = $json->latin1 ([$enable])
		181
		182	If C<$enable> is true (or missing), then the C<encode> method will encode
		183	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
		184	outside the code range C<0..255>. The resulting string can be treated as a
		185	latin1-encoded JSON text or a native unicode string. The C<decode> method
		186	will not be affected in any way by this flag, as C<decode> by default
		187	expects unicode, which is a strict superset of latin1.
		188
		189	If C<$enable> is false, then the C<encode> method will not escape Unicode
		190	characters unless required by the JSON syntax or other flags.
		191
		192	The main use for this flag is efficiently encoding binary data as JSON
		193	text, as most octets will not be escaped, resulting in a smaller encoded
		194	size. The disadvantage is that the resulting JSON text is encoded
		195	in latin1 (and must correctly be treated as such when storing and
		196	transfering), a rare encoding for JSON. It is therefore most useful when
		197	you want to store data structures known to contain binary data efficiently
		198	in files or databases, not when talking to other JSON encoders/decoders.
		199
		200	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
		201	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
166		202
167	=item $json = $json->utf8 ([$enable])	203	=item $json = $json->utf8 ([$enable])
168		204
169	If C<$enable> is true (or missing), then the C<encode> method will encode	205	If C<$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	206	the JSON result into UTF-8, as required by many protocols, while the
…		…
280	resulting in an invalid JSON text:	316	resulting in an invalid JSON text:
281		317
282	JSON::XS->new->allow_nonref->encode ("Hello, World!")	318	JSON::XS->new->allow_nonref->encode ("Hello, World!")
283	=> "Hello, World!"	319	=> "Hello, World!"
284		320
		321	=item $json = $json->allow_blessed ([$enable])
		322
		323	If C<$enable> is true (or missing), then the C<encode> method will not
		324	barf when it encounters a blessed reference. Instead, the value of the
		325	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		326	disabled or no C<to_json> method found) or a representation of the
		327	object (C<convert_blessed> enabled and C<to_json> method found) is being
		328	encoded. Has no effect on C<decode>.
		329
		330	If C<$enable> is false (the default), then C<encode> will throw an
		331	exception when it encounters a blessed object.
		332
		333	=item $json = $json->convert_blessed ([$enable])
		334
		335	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		336	blessed object, will check for the availability of the C<TO_JSON> method
		337	on the object's class. If found, it will be called in scalar context
		338	and the resulting scalar will be encoded instead of the object. If no
		339	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		340	to do.
		341
		342	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		343	returns other blessed objects, those will be handled in the same
		344	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		345	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		346	methods called by the Perl core (== not by the user of the object) are
		347	usually in upper case letters and to avoid collisions with the C<to_json>
		348	function.
		349
		350	This setting does not yet influence C<decode> in any way, but in the
		351	future, global hooks might get installed that influence C<decode> and are
		352	enabled by this setting.
		353
		354	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		355	to do when a blessed object is found.
		356
285	=item $json = $json->shrink ([$enable])	357	=item $json = $json->shrink ([$enable])
286		358
287	Perl usually over-allocates memory a bit when allocating space for	359	Perl usually over-allocates memory a bit when allocating space for
288	strings. This flag optionally resizes strings generated by either	360	strings. This flag optionally resizes strings generated by either
289	C<encode> or C<decode> to their minimum size possible. This can save	361	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	362	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	363	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	364	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	365	UTF-X or in octet-form. The latter cannot store everything but uses less
294	space in general.	366	space in general (and some buggy Perl or C code might even rely on that
		367	internal representation being used).
295		368
		369	The actual definition of what shrink does might change in future versions,
		370	but it will always try to save space at the expense of time.
		371
296	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	372	If C<$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.	373	be shrunk-to-fit, while all strings generated by C<decode> will also be
		374	shrunk-to-fit.
298		375
299	If C<$enable> is false, then the normal perl allocation algorithms are used.	376	If C<$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.	377	If you work with your data, then this is likely to be faster.
301		378
302	In the future, this setting might control other things, such as converting	379	In the future, this setting might control other things, such as converting
303	strings that look like integers or floats into integers or floats	380	strings that look like integers or floats into integers or floats
304	internally (there is no difference on the Perl level), saving space.	381	internally (there is no difference on the Perl level), saving space.
		382
		383	=item $json = $json->max_depth ([$maximum_nesting_depth])
		384
		385	Sets the maximum nesting level (default C<512>) accepted while encoding
		386	or decoding. If the JSON text or Perl data structure has an equal or
		387	higher nesting level then this limit, then the encoder and decoder will
		388	stop and croak at that point.
		389
		390	Nesting level is defined by number of hash- or arrayrefs that the encoder
		391	needs to traverse to reach a given point or the number of C<{> or C<[>
		392	characters without their matching closing parenthesis crossed to reach a
		393	given character in a string.
		394
		395	Setting the maximum depth to one disallows any nesting, so that ensures
		396	that the object is only a single hash/object or array.
		397
		398	The argument to C<max_depth> will be rounded up to the next highest power
		399	of two. If no argument is given, the highest possible setting will be
		400	used, which is rarely useful.
		401
		402	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		403
		404	=item $json = $json->max_size ([$maximum_string_size])
		405
		406	Set the maximum length a JSON text may have (in bytes) where decoding is
		407	being attempted. The default is C<0>, meaning no limit. When C<decode>
		408	is called on a string longer then this number of characters it will not
		409	attempt to decode the string but throw an exception. This setting has no
		410	effect on C<encode> (yet).
		411
		412	The argument to C<max_size> will be rounded up to the next B<highest>
		413	power of two (so may be more than requested). If no argument is given, the
		414	limit check will be deactivated (same as when C<0> is specified).
		415
		416	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
305		417
306	=item $json_text = $json->encode ($perl_scalar)	418	=item $json_text = $json->encode ($perl_scalar)
307		419
308	Converts the given Perl data structure (a simple scalar or a reference	420	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	421	to a hash or array) to its JSON representation. Simple scalars will be
…		…
319		431
320	JSON numbers and strings become simple Perl scalars. JSON arrays become	432	JSON numbers and strings become simple Perl scalars. JSON arrays become
321	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	433	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>.	434	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
323		435
		436	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		437
		438	This works like the C<decode> method, but instead of raising an exception
		439	when there is trailing garbage after the first JSON object, it will
		440	silently stop parsing there and return the number of characters consumed
		441	so far.
		442
		443	This is useful if your JSON texts are not delimited by an outer protocol
		444	(which is not the brightest thing to do in the first place) and you need
		445	to know where the JSON text ends.
		446
		447	JSON::XS->new->decode_prefix ("[1] the tail")
		448	=> ([], 3)
		449
324	=back	450	=back
		451
325		452
326	=head1 MAPPING	453	=head1 MAPPING
327		454
328	This section describes how JSON::XS maps Perl values to JSON values and	455	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	456	vice versa. These mappings are designed to "do the right thing" in most
…		…
331	(what you put in comes out as something equivalent).	458	(what you put in comes out as something equivalent).
332		459
333	For the more enlightened: note that in the following descriptions,	460	For the more enlightened: note that in the following descriptions,
334	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	461	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
335	refers to the abstract Perl language itself.	462	refers to the abstract Perl language itself.
		463
336		464
337	=head2 JSON -> PERL	465	=head2 JSON -> PERL
338		466
339	=over 4	467	=over 4
340		468
…		…
361	conversion details, but an integer may take slightly less memory and might	489	conversion details, but an integer may take slightly less memory and might
362	represent more values exactly than (floating point) numbers.	490	represent more values exactly than (floating point) numbers.
363		491
364	=item true, false	492	=item true, false
365		493
366	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	494	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
367	this process. Future versions might represent those values differently,	495	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	496	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
369	Perl.	497	the C<JSON::XS::is_bool> function.
370		498
371	=item null	499	=item null
372		500
373	A JSON null atom becomes C<undef> in Perl.	501	A JSON null atom becomes C<undef> in Perl.
374		502
375	=back	503	=back
		504
376		505
377	=head2 PERL -> JSON	506	=head2 PERL -> JSON
378		507
379	The mapping from Perl to JSON is slightly more difficult, as Perl is a	508	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	509	truly typeless language, so we can only guess which JSON type is meant by
…		…
383	=over 4	512	=over 4
384		513
385	=item hash references	514	=item hash references
386		515
387	Perl hash references become JSON objects. As there is no inherent ordering	516	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	517	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	518	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	519	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	520	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	521	the same datastructure will serialise to the same JSON text (given same
393	JSON::XS), but this incurs a runtime overhead.	522	settings and version of JSON::XS), but this incurs a runtime overhead
		523	and is only rarely useful, e.g. when you want to compare some JSON text
		524	against another for equality.
394		525
395	=item array references	526	=item array references
396		527
397	Perl array references become JSON arrays.	528	Perl array references become JSON arrays.
		529
		530	=item other references
		531
		532	Other unblessed references are generally not allowed and will cause an
		533	exception to be thrown, except for references to the integers C<0> and
		534	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		535	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		536
		537	to_json [\0,JSON::XS::true] # yields [false,true]
		538
		539	=item JSON::XS::true, JSON::XS::false
		540
		541	These special values become JSON true and JSON false values,
		542	respectively. You cna alos use C<\1> and C<\0> directly if you want.
398		543
399	=item blessed objects	544	=item blessed objects
400		545
401	Blessed objects are not allowed. JSON::XS currently tries to encode their	546	Blessed objects are not allowed. JSON::XS currently tries to encode their
402	underlying representation (hash- or arrayref), but this behaviour might	547	underlying representation (hash- or arrayref), but this behaviour might
…		…
435	$x *= 1; # same thing, the choise is yours.	580	$x *= 1; # same thing, the choise is yours.
436		581
437	You can not currently output JSON booleans or force the type in other,	582	You can not currently output JSON booleans or force the type in other,
438	less obscure, ways. Tell me if you need this capability.	583	less obscure, ways. Tell me if you need this capability.
439		584
440	=item circular data structures
441
442	Those will be encoded until memory or stackspace runs out.
443
444	=back	585	=back
		586
445		587
446	=head1 COMPARISON	588	=head1 COMPARISON
447		589
448	As already mentioned, this module was created because none of the existing	590	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	591	JSON modules could be made to work correctly. First I will describe the
…		…
527		669
528	Does not check input for validity.	670	Does not check input for validity.
529		671
530	=back	672	=back
531		673
		674
		675	=head2 JSON and YAML
		676
		677	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		678	however, a mass hysteria and very far from the truth. In general, there is
		679	no way to configure JSON::XS to output a data structure as valid YAML.
		680
		681	If you really must use JSON::XS to generate YAML, you should use this
		682	algorithm (subject to change in future versions):
		683
		684	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		685	my $yaml = $to_yaml->encode ($ref) . "\n";
		686
		687	This will usually generate JSON texts that also parse as valid
		688	YAML. Please note that YAML has hardcoded limits on (simple) object key
		689	lengths that JSON doesn't have, so you should make sure that your hash
		690	keys are noticably shorter than the 1024 characters YAML allows.
		691
		692	There might be other incompatibilities that I am not aware of. In general
		693	you should not try to generate YAML with a JSON generator or vice versa,
		694	or try to parse JSON with a YAML parser or vice versa: chances are high
		695	that you will run into severe interoperability problems.
		696
		697
532	=head2 SPEED	698	=head2 SPEED
533		699
534	It seems that JSON::XS is surprisingly fast, as shown in the following	700	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	701	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	702	in the JSON::XS distribution, to make it easy to compare on your own
537	system.	703	system.
538		704
539	First comes a comparison between various modules using a very short JSON	705	First comes a comparison between various modules using a very short
540	string:	706	single-line JSON string:
541		707
542	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	708	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		709	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
543		710
544	It shows the number of encodes/decodes per second (JSON::XS uses the	711	It shows the number of encodes/decodes per second (JSON::XS uses
545	functional interface, while JSON::XS/2 uses the OO interface with	712	the functional interface, while JSON::XS/2 uses the OO interface
546	pretty-printing and hashkey sorting enabled). Higher is better:	713	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		714	shrink). Higher is better:
547		715
548	module \| encode \| decode \|	716	module \| encode \| decode \|
549	-----------\|------------\|------------\|	717	-----------\|------------\|------------\|
550	JSON \| 11488.516 \| 7823.035 \|	718	JSON \| 7645.468 \| 4208.613 \|
551	JSON::DWIW \| 94708.054 \| 129094.260 \|	719	JSON::DWIW \| 40721.398 \| 77101.176 \|
552	JSON::PC \| 63884.157 \| 128528.212 \|	720	JSON::PC \| 65948.176 \| 78251.940 \|
553	JSON::Syck \| 34898.677 \| 42096.911 \|	721	JSON::Syck \| 22844.793 \| 26479.192 \|
554	JSON::XS \| 654027.064 \| 396423.669 \|	722	JSON::XS \| 388361.481 \| 199728.762 \|
555	JSON::XS/2 \| 371564.190 \| 371725.613 \|	723	JSON::XS/2 \| 218453.333 \| 192399.266 \|
		724	JSON::XS/3 \| 338250.323 \| 192399.266 \|
		725	Storable \| 15779.925 \| 14169.946 \|
556	-----------+------------+------------+	726	-----------+------------+------------+
557		727
558	That is, JSON::XS is more than six times faster than JSON::DWIW on	728	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	729	about three times faster on decoding, and over fourty times faster
560	faster than JSON, even with pretty-printing and key sorting.	730	than JSON, even with pretty-printing and key sorting. It also compares
		731	favourably to Storable for small amounts of data.
561		732
562	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	733	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
563	search API (http://nanoref.com/yahooapis/mgPdGg):	734	search API (http://nanoref.com/yahooapis/mgPdGg):
564		735
565	module \| encode \| decode \|	736	module \| encode \| decode \|
566	-----------\|------------\|------------\|	737	-----------\|------------\|------------\|
567	JSON \| 273.023 \| 44.674 \|	738	JSON \| 254.685 \| 37.665 \|
568	JSON::DWIW \| 1089.383 \| 1145.704 \|	739	JSON::DWIW \| 843.343 \| 1049.731 \|
569	JSON::PC \| 3097.419 \| 2393.921 \|	740	JSON::PC \| 3602.116 \| 2307.352 \|
570	JSON::Syck \| 514.060 \| 843.053 \|	741	JSON::Syck \| 505.107 \| 787.899 \|
571	JSON::XS \| 6479.668 \| 3636.364 \|	742	JSON::XS \| 5747.196 \| 3690.220 \|
572	JSON::XS/2 \| 3774.221 \| 3599.124 \|	743	JSON::XS/2 \| 3968.121 \| 3676.634 \|
		744	JSON::XS/3 \| 6105.246 \| 3662.508 \|
		745	Storable \| 4417.337 \| 5285.161 \|
573	-----------+------------+------------+	746	-----------+------------+------------+
574		747
575	Again, JSON::XS leads by far.	748	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		749	decodes faster).
576		750
577	On large strings containing lots of high unicode characters, some modules	751	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	752	(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	753	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	754	to decode or encode properly, so it was impossible to prepare a fair
581	comparison table for that case.	755	comparison table for that case.
582		756
583	=head1 RESOURCE LIMITS
584		757
585	JSON::XS does not impose any limits on the size of JSON texts or Perl	758	=head1 SECURITY CONSIDERATIONS
586	values they represent - if your machine can handle it, JSON::XS will	759
587	encode or decode it. Future versions might optionally impose structure	760	When you are using JSON in a protocol, talking to untrusted potentially
588	depth and memory use resource limits.	761	hostile creatures requires relatively few measures.
		762
		763	First of all, your JSON decoder should be secure, that is, should not have
		764	any buffer overflows. Obviously, this module should ensure that and I am
		765	trying hard on making that true, but you never know.
		766
		767	Second, you need to avoid resource-starving attacks. That means you should
		768	limit the size of JSON texts you accept, or make sure then when your
		769	resources run out, thats just fine (e.g. by using a separate process that
		770	can crash safely). The size of a JSON text in octets or characters is
		771	usually a good indication of the size of the resources required to decode
		772	it into a Perl structure. While JSON::XS can check the size of the JSON
		773	text, it might be too late when you already have it in memory, so you
		774	might want to check the size before you accept the string.
		775
		776	Third, JSON::XS recurses using the C stack when decoding objects and
		777	arrays. The C stack is a limited resource: for instance, on my amd64
		778	machine with 8MB of stack size I can decode around 180k nested arrays but
		779	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		780	to free the temporary). If that is exceeded, the program crashes. to be
		781	conservative, the default nesting limit is set to 512. If your process
		782	has a smaller stack, you should adjust this setting accordingly with the
		783	C<max_depth> method.
		784
		785	And last but least, something else could bomb you that I forgot to think
		786	of. In that case, you get to keep the pieces. I am always open for hints,
		787	though...
		788
		789	If you are using JSON::XS to return packets to consumption
		790	by javascript scripts in a browser you should have a look at
		791	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		792	you are vulnerable to some common attack vectors (which really are browser
		793	design bugs, but it is still you who will have to deal with it, as major
		794	browser developers care only for features, not about doing security
		795	right).
		796
589		797
590	=head1 BUGS	798	=head1 BUGS
591		799
592	While the goal of this module is to be correct, that unfortunately does	800	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	801	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	802	still relatively early in its development. If you keep reporting bugs they
595	be fixed swiftly, though.	803	will be fixed swiftly, though.
596		804
597	=cut	805	=cut
		806
		807	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		808	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		809
		810	sub true() { $true }
		811	sub false() { $false }
		812
		813	sub is_bool($) {
		814	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		815	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		816	}
		817
		818	XSLoader::load "JSON::XS", $VERSION;
		819
		820	package JSON::XS::Boolean;
		821
		822	use overload
		823	"0+" => sub { ${$_[0]} },
		824	"++" => sub { $_[0] = ${$_[0]} + 1 },
		825	"--" => sub { $_[0] = ${$_[0]} - 1 },
		826	fallback => 1;
598		827
599	1;	828	1;
600		829
601	=head1 AUTHOR	830	=head1 AUTHOR
602		831

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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 1.47 by root, Mon Jun 25 06:57:42 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 1.47 by root, Mon Jun 25 06:57:42 2007 UTC