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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.20 by root, Sun Mar 25 00:47:42 2007 UTC vs.
Revision 1.43 by root, Sat Jun 23 23:49:29 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
		15	# objToJson and jsonToObj aliases to to_json and from_json
		16	# are exported for compatibility to the JSON module,
		17	# but should not be used in new code.
		18
14	# oo-interface	19	# OO-interface
15		20
16	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
17	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
18	$perl_scalar = $coder->decode ($unicode_json_text);	23	$perl_scalar = $coder->decode ($unicode_json_text);
19		24
…		…
36		41
37	=head2 FEATURES	42	=head2 FEATURES
38		43
39	=over 4	44	=over 4
40		45
41	=item * correct handling of unicode issues	46	=item * correct unicode handling
42		47
43	This module knows how to handle Unicode, and even documents how and when	48	This module knows how to handle Unicode, and even documents how and when
44	it does so.	49	it does so.
45		50
46	=item * round-trip integrity	51	=item * round-trip integrity
47		52
48	When you serialise a perl data structure using only datatypes supported	53	When you serialise a perl data structure using only datatypes supported
49	by JSON, the deserialised data structure is identical on the Perl level.	54	by JSON, the deserialised data structure is identical on the Perl level.
50	(e.g. the string "2.0" doesn't suddenly become "2").	55	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks
		56	like a number).
51		57
52	=item * strict checking of JSON correctness	58	=item * strict checking of JSON correctness
53		59
54	There is no guessing, no generating of illegal JSON texts by default,	60	There is no guessing, no generating of illegal JSON texts by default,
55	and only JSON is accepted as input by default (the latter is a security	61	and only JSON is accepted as input by default (the latter is a security
…		…
66	interface.	72	interface.
67		73
68	=item * reasonably versatile output formats	74	=item * reasonably versatile output formats
69		75
70	You can choose between the most compact guarenteed single-line format	76	You can choose between the most compact guarenteed single-line format
71	possible (nice for simple line-based protocols), a pure-ascii format (for	77	possible (nice for simple line-based protocols), a pure-ascii format
72	when your transport is not 8-bit clean), or a pretty-printed format (for	78	(for when your transport is not 8-bit clean, still supports the whole
73	when you want to read that stuff). Or you can combine those features in	79	unicode range), or a pretty-printed format (for when you want to read that
74	whatever way you like.	80	stuff). Or you can combine those features in whatever way you like.
75		81
76	=back	82	=back
77		83
78	=cut	84	=cut
79		85
80	package JSON::XS;	86	package JSON::XS;
81		87
82	use strict;	88	use strict;
83		89
84	BEGIN {
85	our $VERSION = '0.7';	90	our $VERSION = '1.3';
86	our @ISA = qw(Exporter);	91	our @ISA = qw(Exporter);
87		92
88	our @EXPORT = qw(to_json from_json);	93	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
89	require Exporter;
90		94
91	require XSLoader;	95	use Exporter;
92	XSLoader::load JSON::XS::, $VERSION;	96	use XSLoader;
93	}
94		97
95	=head1 FUNCTIONAL INTERFACE	98	=head1 FUNCTIONAL INTERFACE
96		99
97	The following convinience methods are provided by this module. They are	100	The following convinience methods are provided by this module. They are
98	exported by default:	101	exported by default:
…		…
121		124
122	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	125	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
123		126
124	except being faster.	127	except being faster.
125		128
		129	=item $is_boolean = JSON::XS::is_bool $scalar
		130
		131	Returns true if the passed scalar represents either JSON::XS::true or
		132	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		133	and are used to represent JSON C<true> and C<false> values in Perl.
		134
		135	See MAPPING, below, for more information on how JSON values are mapped to
		136	Perl.
		137
126	=back	138	=back
		139
127		140
128	=head1 OBJECT-ORIENTED INTERFACE	141	=head1 OBJECT-ORIENTED INTERFACE
129		142
130	The object oriented interface lets you configure your own encoding or	143	The object oriented interface lets you configure your own encoding or
131	decoding style, within the limits of supported formats.	144	decoding style, within the limits of supported formats.
…		…
147		160
148	If C<$enable> is true (or missing), then the C<encode> method will not	161	If C<$enable> is true (or missing), then the C<encode> method will not
149	generate characters outside the code range C<0..127> (which is ASCII). Any	162	generate characters outside the code range C<0..127> (which is ASCII). Any
150	unicode characters outside that range will be escaped using either a	163	unicode characters outside that range will be escaped using either a
151	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	164	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
152	as per RFC4627.	165	as per RFC4627. The resulting encoded JSON text can be treated as a native
		166	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		167	or any other superset of ASCII.
153		168
154	If C<$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
155	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
156	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.
157		176
158	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	177	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
159	=> ["\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)
160		202
161	=item $json = $json->utf8 ([$enable])	203	=item $json = $json->utf8 ([$enable])
162		204
163	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
164	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
…		…
277	=> "Hello, World!"	319	=> "Hello, World!"
278		320
279	=item $json = $json->shrink ([$enable])	321	=item $json = $json->shrink ([$enable])
280		322
281	Perl usually over-allocates memory a bit when allocating space for	323	Perl usually over-allocates memory a bit when allocating space for
282	strings. This flag optionally resizes strings generated by either	324	strings. This flag optionally resizes strings generated by either
283	C<encode> or C<decode> to their minimum size possible. This can save	325	C<encode> or C<decode> to their minimum size possible. This can save
284	memory when your JSON texts are either very very long or you have many	326	memory when your JSON texts are either very very long or you have many
285	short strings. It will also try to downgrade any strings to octet-form	327	short strings. It will also try to downgrade any strings to octet-form
286	if possible: perl stores strings internally either in an encoding called	328	if possible: perl stores strings internally either in an encoding called
287	UTF-X or in octet-form. The latter cannot store everything but uses less	329	UTF-X or in octet-form. The latter cannot store everything but uses less
288	space in general.	330	space in general (and some buggy Perl or C code might even rely on that
		331	internal representation being used).
289		332
		333	The actual definition of what shrink does might change in future versions,
		334	but it will always try to save space at the expense of time.
		335
290	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	336	If C<$enable> is true (or missing), the string returned by C<encode> will
291	while all strings generated by C<decode> will also be shrunk-to-fit.	337	be shrunk-to-fit, while all strings generated by C<decode> will also be
		338	shrunk-to-fit.
292		339
293	If C<$enable> is false, then the normal perl allocation algorithms are used.	340	If C<$enable> is false, then the normal perl allocation algorithms are used.
294	If you work with your data, then this is likely to be faster.	341	If you work with your data, then this is likely to be faster.
295		342
296	In the future, this setting might control other things, such as converting	343	In the future, this setting might control other things, such as converting
297	strings that look like integers or floats into integers or floats	344	strings that look like integers or floats into integers or floats
298	internally (there is no difference on the Perl level), saving space.	345	internally (there is no difference on the Perl level), saving space.
		346
		347	=item $json = $json->max_depth ([$maximum_nesting_depth])
		348
		349	Sets the maximum nesting level (default C<512>) accepted while encoding
		350	or decoding. If the JSON text or Perl data structure has an equal or
		351	higher nesting level then this limit, then the encoder and decoder will
		352	stop and croak at that point.
		353
		354	Nesting level is defined by number of hash- or arrayrefs that the encoder
		355	needs to traverse to reach a given point or the number of C<{> or C<[>
		356	characters without their matching closing parenthesis crossed to reach a
		357	given character in a string.
		358
		359	Setting the maximum depth to one disallows any nesting, so that ensures
		360	that the object is only a single hash/object or array.
		361
		362	The argument to C<max_depth> will be rounded up to the next nearest power
		363	of two.
		364
		365	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
299		366
300	=item $json_text = $json->encode ($perl_scalar)	367	=item $json_text = $json->encode ($perl_scalar)
301		368
302	Converts the given Perl data structure (a simple scalar or a reference	369	Converts the given Perl data structure (a simple scalar or a reference
303	to a hash or array) to its JSON representation. Simple scalars will be	370	to a hash or array) to its JSON representation. Simple scalars will be
…		…
313		380
314	JSON numbers and strings become simple Perl scalars. JSON arrays become	381	JSON numbers and strings become simple Perl scalars. JSON arrays become
315	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	382	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
316	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	383	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
317		384
		385	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		386
		387	This works like the C<decode> method, but instead of raising an exception
		388	when there is trailing garbage after the first JSON object, it will
		389	silently stop parsing there and return the number of characters consumed
		390	so far.
		391
		392	This is useful if your JSON texts are not delimited by an outer protocol
		393	(which is not the brightest thing to do in the first place) and you need
		394	to know where the JSON text ends.
		395
		396	JSON::XS->new->decode_prefix ("[1] the tail")
		397	=> ([], 3)
		398
318	=back	399	=back
		400
319		401
320	=head1 MAPPING	402	=head1 MAPPING
321		403
322	This section describes how JSON::XS maps Perl values to JSON values and	404	This section describes how JSON::XS maps Perl values to JSON values and
323	vice versa. These mappings are designed to "do the right thing" in most	405	vice versa. These mappings are designed to "do the right thing" in most
…		…
325	(what you put in comes out as something equivalent).	407	(what you put in comes out as something equivalent).
326		408
327	For the more enlightened: note that in the following descriptions,	409	For the more enlightened: note that in the following descriptions,
328	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	410	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
329	refers to the abstract Perl language itself.	411	refers to the abstract Perl language itself.
		412
330		413
331	=head2 JSON -> PERL	414	=head2 JSON -> PERL
332		415
333	=over 4	416	=over 4
334		417
…		…
355	conversion details, but an integer may take slightly less memory and might	438	conversion details, but an integer may take slightly less memory and might
356	represent more values exactly than (floating point) numbers.	439	represent more values exactly than (floating point) numbers.
357		440
358	=item true, false	441	=item true, false
359		442
360	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	443	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
361	this process. Future versions might represent those values differently,	444	respectively. They are overloaded to act almost exactly like the numbers
362	but they will be guarenteed to act like these integers would normally in	445	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
363	Perl.	446	the C<JSON::XS::is_bool> function.
364		447
365	=item null	448	=item null
366		449
367	A JSON null atom becomes C<undef> in Perl.	450	A JSON null atom becomes C<undef> in Perl.
368		451
369	=back	452	=back
		453
370		454
371	=head2 PERL -> JSON	455	=head2 PERL -> JSON
372		456
373	The mapping from Perl to JSON is slightly more difficult, as Perl is a	457	The mapping from Perl to JSON is slightly more difficult, as Perl is a
374	truly typeless language, so we can only guess which JSON type is meant by	458	truly typeless language, so we can only guess which JSON type is meant by
…		…
377	=over 4	461	=over 4
378		462
379	=item hash references	463	=item hash references
380		464
381	Perl hash references become JSON objects. As there is no inherent ordering	465	Perl hash references become JSON objects. As there is no inherent ordering
382	in hash keys, they will usually be encoded in a pseudo-random order that	466	in hash keys (or JSON objects), they will usually be encoded in a
383	can change between runs of the same program but stays generally the same	467	pseudo-random order that can change between runs of the same program but
384	within a single run of a program. JSON::XS can optionally sort the hash	468	stays generally the same within a single run of a program. JSON::XS can
385	keys (determined by the I<canonical> flag), so the same datastructure	469	optionally sort the hash keys (determined by the I<canonical> flag), so
386	will serialise to the same JSON text (given same settings and version of	470	the same datastructure will serialise to the same JSON text (given same
387	JSON::XS), but this incurs a runtime overhead.	471	settings and version of JSON::XS), but this incurs a runtime overhead
		472	and is only rarely useful, e.g. when you want to compare some JSON text
		473	against another for equality.
388		474
389	=item array references	475	=item array references
390		476
391	Perl array references become JSON arrays.	477	Perl array references become JSON arrays.
		478
		479	=item other references
		480
		481	Other unblessed references are generally not allowed and will cause an
		482	exception to be thrown, except for references to the integers C<0> and
		483	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		484	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		485
		486	to_json [\0,JSON::XS::true] # yields [false,true]
		487
		488	=item JSON::XS::true, JSON::XS::false
		489
		490	These special values become JSON true and JSON false values,
		491	respectively. You cna alos use C<\1> and C<\0> directly if you want.
392		492
393	=item blessed objects	493	=item blessed objects
394		494
395	Blessed objects are not allowed. JSON::XS currently tries to encode their	495	Blessed objects are not allowed. JSON::XS currently tries to encode their
396	underlying representation (hash- or arrayref), but this behaviour might	496	underlying representation (hash- or arrayref), but this behaviour might
…		…
429	$x *= 1; # same thing, the choise is yours.	529	$x *= 1; # same thing, the choise is yours.
430		530
431	You can not currently output JSON booleans or force the type in other,	531	You can not currently output JSON booleans or force the type in other,
432	less obscure, ways. Tell me if you need this capability.	532	less obscure, ways. Tell me if you need this capability.
433		533
434	=item circular data structures
435
436	Those will be encoded until memory or stackspace runs out.
437
438	=back	534	=back
		535
439		536
440	=head1 COMPARISON	537	=head1 COMPARISON
441		538
442	As already mentioned, this module was created because none of the existing	539	As already mentioned, this module was created because none of the existing
443	JSON modules could be made to work correctly. First I will describe the	540	JSON modules could be made to work correctly. First I will describe the
…		…
521		618
522	Does not check input for validity.	619	Does not check input for validity.
523		620
524	=back	621	=back
525		622
		623
		624	=head2 JSON and YAML
		625
		626	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		627	however, a mass hysteria and very far from the truth. In general, there is
		628	no way to configure JSON::XS to output a data structure as valid YAML.
		629
		630	If you really must use JSON::XS to generate YAML, you should use this
		631	algorithm (subject to change in future versions):
		632
		633	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		634	my $yaml = $to_yaml->encode ($ref) . "\n";
		635
		636	This will usually generate JSON texts that also parse as valid
		637	YAML. Please note that YAML has hardcoded limits on (simple) object key
		638	lengths that JSON doesn't have, so you should make sure that your hash
		639	keys are noticably shorter than the 1024 characters YAML allows.
		640
		641	There might be other incompatibilities that I am not aware of. In general
		642	you should not try to generate YAML with a JSON generator or vice versa,
		643	or try to parse JSON with a YAML parser or vice versa: chances are high
		644	that you will run into severe interoperability problems.
		645
		646
526	=head2 SPEED	647	=head2 SPEED
527		648
528	It seems that JSON::XS is surprisingly fast, as shown in the following	649	It seems that JSON::XS is surprisingly fast, as shown in the following
529	tables. They have been generated with the help of the C<eg/bench> program	650	tables. They have been generated with the help of the C<eg/bench> program
530	in the JSON::XS distribution, to make it easy to compare on your own	651	in the JSON::XS distribution, to make it easy to compare on your own
531	system.	652	system.
532		653
533	First comes a comparison between various modules using a very short JSON	654	First comes a comparison between various modules using a very short
534	string:	655	single-line JSON string:
535		656
536	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	657	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		658	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
537		659
538	It shows the number of encodes/decodes per second (JSON::XS uses the	660	It shows the number of encodes/decodes per second (JSON::XS uses
539	functional interface, while JSON::XS/2 uses the OO interface with	661	the functional interface, while JSON::XS/2 uses the OO interface
540	pretty-printing and hashkey sorting enabled). Higher is better:	662	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		663	shrink). Higher is better:
541		664
542	module \| encode \| decode \|	665	module \| encode \| decode \|
543	-----------\|------------\|------------\|	666	-----------\|------------\|------------\|
544	JSON \| 11488.516 \| 7823.035 \|	667	JSON \| 7645.468 \| 4208.613 \|
545	JSON::DWIW \| 94708.054 \| 129094.260 \|	668	JSON::DWIW \| 40721.398 \| 77101.176 \|
546	JSON::PC \| 63884.157 \| 128528.212 \|	669	JSON::PC \| 65948.176 \| 78251.940 \|
547	JSON::Syck \| 34898.677 \| 42096.911 \|	670	JSON::Syck \| 22844.793 \| 26479.192 \|
548	JSON::XS \| 654027.064 \| 396423.669 \|	671	JSON::XS \| 388361.481 \| 199728.762 \|
549	JSON::XS/2 \| 371564.190 \| 371725.613 \|	672	JSON::XS/2 \| 218453.333 \| 192399.266 \|
		673	JSON::XS/3 \| 338250.323 \| 192399.266 \|
		674	Storable \| 15779.925 \| 14169.946 \|
550	-----------+------------+------------+	675	-----------+------------+------------+
551		676
552	That is, JSON::XS is more than six times faster than JSON::DWIW on	677	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
553	encoding, more than three times faster on decoding, and about thirty times	678	about three times faster on decoding, and over fourty times faster
554	faster than JSON, even with pretty-printing and key sorting.	679	than JSON, even with pretty-printing and key sorting. It also compares
		680	favourably to Storable for small amounts of data.
555		681
556	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	682	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
557	search API (http://nanoref.com/yahooapis/mgPdGg):	683	search API (http://nanoref.com/yahooapis/mgPdGg):
558		684
559	module \| encode \| decode \|	685	module \| encode \| decode \|
560	-----------\|------------\|------------\|	686	-----------\|------------\|------------\|
561	JSON \| 273.023 \| 44.674 \|	687	JSON \| 254.685 \| 37.665 \|
562	JSON::DWIW \| 1089.383 \| 1145.704 \|	688	JSON::DWIW \| 843.343 \| 1049.731 \|
563	JSON::PC \| 3097.419 \| 2393.921 \|	689	JSON::PC \| 3602.116 \| 2307.352 \|
564	JSON::Syck \| 514.060 \| 843.053 \|	690	JSON::Syck \| 505.107 \| 787.899 \|
565	JSON::XS \| 6479.668 \| 3636.364 \|	691	JSON::XS \| 5747.196 \| 3690.220 \|
566	JSON::XS/2 \| 3774.221 \| 3599.124 \|	692	JSON::XS/2 \| 3968.121 \| 3676.634 \|
		693	JSON::XS/3 \| 6105.246 \| 3662.508 \|
		694	Storable \| 4417.337 \| 5285.161 \|
567	-----------+------------+------------+	695	-----------+------------+------------+
568		696
569	Again, JSON::XS leads by far.	697	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		698	decodes faster).
570		699
571	On large strings containing lots of high unicode characters, some modules	700	On large strings containing lots of high unicode characters, some modules
572	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	701	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
573	will be broken due to missing (or wrong) unicode handling. Others refuse	702	will be broken due to missing (or wrong) unicode handling. Others refuse
574	to decode or encode properly, so it was impossible to prepare a fair	703	to decode or encode properly, so it was impossible to prepare a fair
575	comparison table for that case.	704	comparison table for that case.
576		705
577	=head1 RESOURCE LIMITS
578		706
579	JSON::XS does not impose any limits on the size of JSON texts or Perl	707	=head1 SECURITY CONSIDERATIONS
580	values they represent - if your machine can handle it, JSON::XS will	708
581	encode or decode it. Future versions might optionally impose structure	709	When you are using JSON in a protocol, talking to untrusted potentially
582	depth and memory use resource limits.	710	hostile creatures requires relatively few measures.
		711
		712	First of all, your JSON decoder should be secure, that is, should not have
		713	any buffer overflows. Obviously, this module should ensure that and I am
		714	trying hard on making that true, but you never know.
		715
		716	Second, you need to avoid resource-starving attacks. That means you should
		717	limit the size of JSON texts you accept, or make sure then when your
		718	resources run out, thats just fine (e.g. by using a separate process that
		719	can crash safely). The size of a JSON text in octets or characters is
		720	usually a good indication of the size of the resources required to decode
		721	it into a Perl structure.
		722
		723	Third, JSON::XS recurses using the C stack when decoding objects and
		724	arrays. The C stack is a limited resource: for instance, on my amd64
		725	machine with 8MB of stack size I can decode around 180k nested arrays but
		726	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		727	to free the temporary). If that is exceeded, the program crashes. to be
		728	conservative, the default nesting limit is set to 512. If your process
		729	has a smaller stack, you should adjust this setting accordingly with the
		730	C<max_depth> method.
		731
		732	And last but least, something else could bomb you that I forgot to think
		733	of. In that case, you get to keep the pieces. I am always open for hints,
		734	though...
		735
		736	If you are using JSON::XS to return packets to consumption
		737	by javascript scripts in a browser you should have a look at
		738	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		739	you are vulnerable to some common attack vectors (which really are browser
		740	design bugs, but it is still you who will have to deal with it, as major
		741	browser developers care only for features, not about doing security
		742	right).
		743
583		744
584	=head1 BUGS	745	=head1 BUGS
585		746
586	While the goal of this module is to be correct, that unfortunately does	747	While the goal of this module is to be correct, that unfortunately does
587	not mean its bug-free, only that I think its design is bug-free. It is	748	not mean its bug-free, only that I think its design is bug-free. It is
588	still very young and not well-tested. If you keep reporting bugs they will	749	still relatively early in its development. If you keep reporting bugs they
589	be fixed swiftly, though.	750	will be fixed swiftly, though.
590		751
591	=cut	752	=cut
		753
		754	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		755	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		756
		757	sub true() { $true }
		758	sub false() { $false }
		759
		760	sub is_bool($) {
		761	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		762	or UNIVERSAL::isa $_[0], "JSON::Literal"
		763	}
		764
		765	XSLoader::load "JSON::XS", $VERSION;
		766
		767	package JSON::XS::Boolean;
		768
		769	use overload
		770	"0+" => sub { ${$_[0]} },
		771	"++" => sub { $_[0] = ${$_[0]} + 1 },
		772	"--" => sub { $_[0] = ${$_[0]} - 1 },
		773	fallback => 1;
592		774
593	1;	775	1;
594		776
595	=head1 AUTHOR	777	=head1 AUTHOR
596		778

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Comparing JSON-XS/XS.pm (file contents): Revision 1.20 by root, Sun Mar 25 00:47:42 2007 UTC vs. Revision 1.43 by root, Sat Jun 23 23:49:29 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.20 by root, Sun Mar 25 00:47:42 2007 UTC vs.
Revision 1.43 by root, Sat Jun 23 23:49:29 2007 UTC