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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs.
Revision 1.44 by root, Mon Jun 25 04:08:17 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	BEGIN {	88	use strict;
		89
83	$VERSION = '0.31';	90	our $VERSION = '1.4';
84	@ISA = qw(Exporter);	91	our @ISA = qw(Exporter);
85		92
86	@EXPORT = qw(to_json from_json);	93	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
87	require Exporter;
88		94
89	require XSLoader;	95	use Exporter;
90	XSLoader::load JSON::XS::, $VERSION;	96	use XSLoader;
91	}
92		97
93	=head1 FUNCTIONAL INTERFACE	98	=head1 FUNCTIONAL INTERFACE
94		99
95	The following convinience methods are provided by this module. They are	100	The following convinience methods are provided by this module. They are
96	exported by default:	101	exported by default:
…		…
119		124
120	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	125	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
121		126
122	except being faster.	127	except being faster.
123		128
		129	=item $is_boolean = JSON::XS::is_bool $scalar
		130
		131	Returns true if the passed scalar represents either JSON::XS::true or
		132	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		133	and are used to represent JSON C<true> and C<false> values in Perl.
		134
		135	See MAPPING, below, for more information on how JSON values are mapped to
		136	Perl.
		137
124	=back	138	=back
		139
125		140
126	=head1 OBJECT-ORIENTED INTERFACE	141	=head1 OBJECT-ORIENTED INTERFACE
127		142
128	The object oriented interface lets you configure your own encoding or	143	The object oriented interface lets you configure your own encoding or
129	decoding style, within the limits of supported formats.	144	decoding style, within the limits of supported formats.
…		…
145		160
146	If C<$enable> is true (or missing), then the C<encode> method will not	161	If C<$enable> is true (or missing), then the C<encode> method will not
147	generate characters outside the code range C<0..127> (which is ASCII). Any	162	generate characters outside the code range C<0..127> (which is ASCII). Any
148	unicode characters outside that range will be escaped using either a	163	unicode characters outside that range will be escaped using either a
149	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	164	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
150	as per RFC4627.	165	as per RFC4627. The resulting encoded JSON text can be treated as a native
		166	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		167	or any other superset of ASCII.
151		168
152	If C<$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
153	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
154	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.
155		176
156	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	177	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
157	=> ["\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)
158		202
159	=item $json = $json->utf8 ([$enable])	203	=item $json = $json->utf8 ([$enable])
160		204
161	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
162	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
…		…
272	resulting in an invalid JSON text:	316	resulting in an invalid JSON text:
273		317
274	JSON::XS->new->allow_nonref->encode ("Hello, World!")	318	JSON::XS->new->allow_nonref->encode ("Hello, World!")
275	=> "Hello, World!"	319	=> "Hello, World!"
276		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<$enable> is true (or missing), then C<encode>, upon encountering a
		336	blessed object, will check for the availability of the C<TO_JSON> method
		337	on the object's class. If found, it will be called in scalar context
		338	and the resulting scalar will be encoded instead of the object. If no
		339	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		340	to do.
		341
		342	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		343	returns other blessed objects, those will be handled in the same
		344	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		345	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		346	methods called by the Perl core (== not the user of the object) are
		347	usually in upper case letters and to avoid collisions with the C<to_json>
		348	function.
		349
		350	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		351	to do when a blessed object is found.
		352
277	=item $json = $json->shrink ([$enable])	353	=item $json = $json->shrink ([$enable])
278		354
279	Perl usually over-allocates memory a bit when allocating space for	355	Perl usually over-allocates memory a bit when allocating space for
280	strings. This flag optionally resizes strings generated by either	356	strings. This flag optionally resizes strings generated by either
281	C<encode> or C<decode> to their minimum size possible. This can save	357	C<encode> or C<decode> to their minimum size possible. This can save
282	memory when your JSON texts are either very very long or you have many	358	memory when your JSON texts are either very very long or you have many
283	short strings. It will also try to downgrade any strings to octet-form	359	short strings. It will also try to downgrade any strings to octet-form
284	if possible: perl stores strings internally either in an encoding called	360	if possible: perl stores strings internally either in an encoding called
285	UTF-X or in octet-form. The latter cannot store everything but uses less	361	UTF-X or in octet-form. The latter cannot store everything but uses less
286	space in general.	362	space in general (and some buggy Perl or C code might even rely on that
		363	internal representation being used).
287		364
		365	The actual definition of what shrink does might change in future versions,
		366	but it will always try to save space at the expense of time.
		367
288	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	368	If C<$enable> is true (or missing), the string returned by C<encode> will
289	while all strings generated by C<decode> will also be shrunk-to-fit.	369	be shrunk-to-fit, while all strings generated by C<decode> will also be
		370	shrunk-to-fit.
290		371
291	If C<$enable> is false, then the normal perl allocation algorithms are used.	372	If C<$enable> is false, then the normal perl allocation algorithms are used.
292	If you work with your data, then this is likely to be faster.	373	If you work with your data, then this is likely to be faster.
293		374
294	In the future, this setting might control other things, such as converting	375	In the future, this setting might control other things, such as converting
295	strings that look like integers or floats into integers or floats	376	strings that look like integers or floats into integers or floats
296	internally (there is no difference on the Perl level), saving space.	377	internally (there is no difference on the Perl level), saving space.
		378
		379	=item $json = $json->max_depth ([$maximum_nesting_depth])
		380
		381	Sets the maximum nesting level (default C<512>) accepted while encoding
		382	or decoding. If the JSON text or Perl data structure has an equal or
		383	higher nesting level then this limit, then the encoder and decoder will
		384	stop and croak at that point.
		385
		386	Nesting level is defined by number of hash- or arrayrefs that the encoder
		387	needs to traverse to reach a given point or the number of C<{> or C<[>
		388	characters without their matching closing parenthesis crossed to reach a
		389	given character in a string.
		390
		391	Setting the maximum depth to one disallows any nesting, so that ensures
		392	that the object is only a single hash/object or array.
		393
		394	The argument to C<max_depth> will be rounded up to the next nearest power
		395	of two.
		396
		397	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
297		398
298	=item $json_text = $json->encode ($perl_scalar)	399	=item $json_text = $json->encode ($perl_scalar)
299		400
300	Converts the given Perl data structure (a simple scalar or a reference	401	Converts the given Perl data structure (a simple scalar or a reference
301	to a hash or array) to its JSON representation. Simple scalars will be	402	to a hash or array) to its JSON representation. Simple scalars will be
…		…
311		412
312	JSON numbers and strings become simple Perl scalars. JSON arrays become	413	JSON numbers and strings become simple Perl scalars. JSON arrays become
313	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	414	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
314	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	415	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
315		416
		417	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		418
		419	This works like the C<decode> method, but instead of raising an exception
		420	when there is trailing garbage after the first JSON object, it will
		421	silently stop parsing there and return the number of characters consumed
		422	so far.
		423
		424	This is useful if your JSON texts are not delimited by an outer protocol
		425	(which is not the brightest thing to do in the first place) and you need
		426	to know where the JSON text ends.
		427
		428	JSON::XS->new->decode_prefix ("[1] the tail")
		429	=> ([], 3)
		430
316	=back	431	=back
		432
317		433
318	=head1 MAPPING	434	=head1 MAPPING
319		435
320	This section describes how JSON::XS maps Perl values to JSON values and	436	This section describes how JSON::XS maps Perl values to JSON values and
321	vice versa. These mappings are designed to "do the right thing" in most	437	vice versa. These mappings are designed to "do the right thing" in most
…		…
323	(what you put in comes out as something equivalent).	439	(what you put in comes out as something equivalent).
324		440
325	For the more enlightened: note that in the following descriptions,	441	For the more enlightened: note that in the following descriptions,
326	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	442	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
327	refers to the abstract Perl language itself.	443	refers to the abstract Perl language itself.
		444
328		445
329	=head2 JSON -> PERL	446	=head2 JSON -> PERL
330		447
331	=over 4	448	=over 4
332		449
…		…
353	conversion details, but an integer may take slightly less memory and might	470	conversion details, but an integer may take slightly less memory and might
354	represent more values exactly than (floating point) numbers.	471	represent more values exactly than (floating point) numbers.
355		472
356	=item true, false	473	=item true, false
357		474
358	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	475	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
359	this process. Future versions might represent those values differently,	476	respectively. They are overloaded to act almost exactly like the numbers
360	but they will be guarenteed to act like these integers would normally in	477	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
361	Perl.	478	the C<JSON::XS::is_bool> function.
362		479
363	=item null	480	=item null
364		481
365	A JSON null atom becomes C<undef> in Perl.	482	A JSON null atom becomes C<undef> in Perl.
366		483
367	=back	484	=back
		485
368		486
369	=head2 PERL -> JSON	487	=head2 PERL -> JSON
370		488
371	The mapping from Perl to JSON is slightly more difficult, as Perl is a	489	The mapping from Perl to JSON is slightly more difficult, as Perl is a
372	truly typeless language, so we can only guess which JSON type is meant by	490	truly typeless language, so we can only guess which JSON type is meant by
…		…
375	=over 4	493	=over 4
376		494
377	=item hash references	495	=item hash references
378		496
379	Perl hash references become JSON objects. As there is no inherent ordering	497	Perl hash references become JSON objects. As there is no inherent ordering
380	in hash keys, they will usually be encoded in a pseudo-random order that	498	in hash keys (or JSON objects), they will usually be encoded in a
381	can change between runs of the same program but stays generally the same	499	pseudo-random order that can change between runs of the same program but
382	within a single run of a program. JSON::XS can optionally sort the hash	500	stays generally the same within a single run of a program. JSON::XS can
383	keys (determined by the I<canonical> flag), so the same datastructure	501	optionally sort the hash keys (determined by the I<canonical> flag), so
384	will serialise to the same JSON text (given same settings and version of	502	the same datastructure will serialise to the same JSON text (given same
385	JSON::XS), but this incurs a runtime overhead.	503	settings and version of JSON::XS), but this incurs a runtime overhead
		504	and is only rarely useful, e.g. when you want to compare some JSON text
		505	against another for equality.
386		506
387	=item array references	507	=item array references
388		508
389	Perl array references become JSON arrays.	509	Perl array references become JSON arrays.
		510
		511	=item other references
		512
		513	Other unblessed references are generally not allowed and will cause an
		514	exception to be thrown, except for references to the integers C<0> and
		515	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		516	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		517
		518	to_json [\0,JSON::XS::true] # yields [false,true]
		519
		520	=item JSON::XS::true, JSON::XS::false
		521
		522	These special values become JSON true and JSON false values,
		523	respectively. You cna alos use C<\1> and C<\0> directly if you want.
390		524
391	=item blessed objects	525	=item blessed objects
392		526
393	Blessed objects are not allowed. JSON::XS currently tries to encode their	527	Blessed objects are not allowed. JSON::XS currently tries to encode their
394	underlying representation (hash- or arrayref), but this behaviour might	528	underlying representation (hash- or arrayref), but this behaviour might
…		…
427	$x *= 1; # same thing, the choise is yours.	561	$x *= 1; # same thing, the choise is yours.
428		562
429	You can not currently output JSON booleans or force the type in other,	563	You can not currently output JSON booleans or force the type in other,
430	less obscure, ways. Tell me if you need this capability.	564	less obscure, ways. Tell me if you need this capability.
431		565
432	=item circular data structures
433
434	Those will be encoded until memory or stackspace runs out.
435
436	=back	566	=back
		567
437		568
438	=head1 COMPARISON	569	=head1 COMPARISON
439		570
440	As already mentioned, this module was created because none of the existing	571	As already mentioned, this module was created because none of the existing
441	JSON modules could be made to work correctly. First I will describe the	572	JSON modules could be made to work correctly. First I will describe the
…		…
519		650
520	Does not check input for validity.	651	Does not check input for validity.
521		652
522	=back	653	=back
523		654
		655
		656	=head2 JSON and YAML
		657
		658	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		659	however, a mass hysteria and very far from the truth. In general, there is
		660	no way to configure JSON::XS to output a data structure as valid YAML.
		661
		662	If you really must use JSON::XS to generate YAML, you should use this
		663	algorithm (subject to change in future versions):
		664
		665	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		666	my $yaml = $to_yaml->encode ($ref) . "\n";
		667
		668	This will usually generate JSON texts that also parse as valid
		669	YAML. Please note that YAML has hardcoded limits on (simple) object key
		670	lengths that JSON doesn't have, so you should make sure that your hash
		671	keys are noticably shorter than the 1024 characters YAML allows.
		672
		673	There might be other incompatibilities that I am not aware of. In general
		674	you should not try to generate YAML with a JSON generator or vice versa,
		675	or try to parse JSON with a YAML parser or vice versa: chances are high
		676	that you will run into severe interoperability problems.
		677
		678
524	=head2 SPEED	679	=head2 SPEED
525		680
526	It seems that JSON::XS is surprisingly fast, as shown in the following	681	It seems that JSON::XS is surprisingly fast, as shown in the following
527	tables. They have been generated with the help of the C<eg/bench> program	682	tables. They have been generated with the help of the C<eg/bench> program
528	in the JSON::XS distribution, to make it easy to compare on your own	683	in the JSON::XS distribution, to make it easy to compare on your own
529	system.	684	system.
530		685
531	First comes a comparison between various modules using a very short JSON	686	First comes a comparison between various modules using a very short
532	string (83 bytes), showing the number of encodes/decodes per second	687	single-line JSON string:
		688
		689	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		690	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
		691
		692	It shows the number of encodes/decodes per second (JSON::XS uses
533	(JSON::XS is the functional interface, while JSON::XS/2 is the OO	693	the functional interface, while JSON::XS/2 uses the OO interface
534	interface with pretty-printing and hashkey sorting enabled). Higher is	694	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
535	better:	695	shrink). Higher is better:
536		696
537	module \| encode \| decode \|	697	module \| encode \| decode \|
538	-----------\|------------\|------------\|	698	-----------\|------------\|------------\|
539	JSON \| 14006 \| 6820 \|	699	JSON \| 7645.468 \| 4208.613 \|
540	JSON::DWIW \| 200937 \| 120386 \|	700	JSON::DWIW \| 40721.398 \| 77101.176 \|
541	JSON::PC \| 85065 \| 129366 \|	701	JSON::PC \| 65948.176 \| 78251.940 \|
542	JSON::Syck \| 59898 \| 44232 \|	702	JSON::Syck \| 22844.793 \| 26479.192 \|
543	JSON::XS \| 1171478 \| 342435 \|	703	JSON::XS \| 388361.481 \| 199728.762 \|
544	JSON::XS/2 \| 730760 \| 328714 \|	704	JSON::XS/2 \| 218453.333 \| 192399.266 \|
		705	JSON::XS/3 \| 338250.323 \| 192399.266 \|
		706	Storable \| 15779.925 \| 14169.946 \|
545	-----------+------------+------------+	707	-----------+------------+------------+
546		708
547	That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80	709	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
		710	about three times faster on decoding, and over fourty times faster
548	times faster than JSON, even with pretty-printing and key sorting.	711	than JSON, even with pretty-printing and key sorting. It also compares
		712	favourably to Storable for small amounts of data.
549		713
550	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	714	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
551	search API (http://nanoref.com/yahooapis/mgPdGg):	715	search API (http://nanoref.com/yahooapis/mgPdGg):
552		716
553	module \| encode \| decode \|	717	module \| encode \| decode \|
554	-----------\|------------\|------------\|	718	-----------\|------------\|------------\|
555	JSON \| 673 \| 38 \|	719	JSON \| 254.685 \| 37.665 \|
556	JSON::DWIW \| 5271 \| 770 \|	720	JSON::DWIW \| 843.343 \| 1049.731 \|
557	JSON::PC \| 9901 \| 2491 \|	721	JSON::PC \| 3602.116 \| 2307.352 \|
558	JSON::Syck \| 2360 \| 786 \|	722	JSON::Syck \| 505.107 \| 787.899 \|
559	JSON::XS \| 37398 \| 3202 \|	723	JSON::XS \| 5747.196 \| 3690.220 \|
560	JSON::XS/2 \| 13765 \| 3153 \|	724	JSON::XS/2 \| 3968.121 \| 3676.634 \|
		725	JSON::XS/3 \| 6105.246 \| 3662.508 \|
		726	Storable \| 4417.337 \| 5285.161 \|
561	-----------+------------+------------+	727	-----------+------------+------------+
562		728
563	Again, JSON::XS leads by far in the encoding case, while still beating	729	Again, JSON::XS leads by far (except for Storable which non-surprisingly
564	every other module in the decoding case.	730	decodes faster).
565		731
566	On large strings containing lots of unicode characters, some modules	732	On large strings containing lots of high unicode characters, some modules
567	(such as JSON::PC) decode faster than JSON::XS, but the result will be	733	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
568	broken due to missing unicode handling. Others refuse to decode or encode	734	will be broken due to missing (or wrong) unicode handling. Others refuse
569	properly, so it was impossible to prepare a fair comparison table for that	735	to decode or encode properly, so it was impossible to prepare a fair
570	case.	736	comparison table for that case.
571		737
572	=head1 RESOURCE LIMITS
573		738
574	JSON::XS does not impose any limits on the size of JSON texts or Perl	739	=head1 SECURITY CONSIDERATIONS
575	values they represent - if your machine can handle it, JSON::XS will	740
576	encode or decode it. Future versions might optionally impose structure	741	When you are using JSON in a protocol, talking to untrusted potentially
577	depth and memory use resource limits.	742	hostile creatures requires relatively few measures.
		743
		744	First of all, your JSON decoder should be secure, that is, should not have
		745	any buffer overflows. Obviously, this module should ensure that and I am
		746	trying hard on making that true, but you never know.
		747
		748	Second, you need to avoid resource-starving attacks. That means you should
		749	limit the size of JSON texts you accept, or make sure then when your
		750	resources run out, thats just fine (e.g. by using a separate process that
		751	can crash safely). The size of a JSON text in octets or characters is
		752	usually a good indication of the size of the resources required to decode
		753	it into a Perl structure.
		754
		755	Third, JSON::XS recurses using the C stack when decoding objects and
		756	arrays. The C stack is a limited resource: for instance, on my amd64
		757	machine with 8MB of stack size I can decode around 180k nested arrays but
		758	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		759	to free the temporary). If that is exceeded, the program crashes. to be
		760	conservative, the default nesting limit is set to 512. If your process
		761	has a smaller stack, you should adjust this setting accordingly with the
		762	C<max_depth> method.
		763
		764	And last but least, something else could bomb you that I forgot to think
		765	of. In that case, you get to keep the pieces. I am always open for hints,
		766	though...
		767
		768	If you are using JSON::XS to return packets to consumption
		769	by javascript scripts in a browser you should have a look at
		770	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		771	you are vulnerable to some common attack vectors (which really are browser
		772	design bugs, but it is still you who will have to deal with it, as major
		773	browser developers care only for features, not about doing security
		774	right).
		775
578		776
579	=head1 BUGS	777	=head1 BUGS
580		778
581	While the goal of this module is to be correct, that unfortunately does	779	While the goal of this module is to be correct, that unfortunately does
582	not mean its bug-free, only that I think its design is bug-free. It is	780	not mean its bug-free, only that I think its design is bug-free. It is
583	still very young and not well-tested. If you keep reporting bugs they will	781	still relatively early in its development. If you keep reporting bugs they
584	be fixed swiftly, though.	782	will be fixed swiftly, though.
585		783
586	=cut	784	=cut
		785
		786	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		787	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		788
		789	sub true() { $true }
		790	sub false() { $false }
		791
		792	sub is_bool($) {
		793	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		794	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		795	}
		796
		797	XSLoader::load "JSON::XS", $VERSION;
		798
		799	package JSON::XS::Boolean;
		800
		801	use overload
		802	"0+" => sub { ${$_[0]} },
		803	"++" => sub { $_[0] = ${$_[0]} + 1 },
		804	"--" => sub { $_[0] = ${$_[0]} - 1 },
		805	fallback => 1;
587		806
588	1;	807	1;
589		808
590	=head1 AUTHOR	809	=head1 AUTHOR
591		810

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Comparing JSON-XS/XS.pm (file contents): Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs. Revision 1.44 by root, Mon Jun 25 04:08:17 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.16 by root, Sat Mar 24 02:23:51 2007 UTC vs.
Revision 1.44 by root, Mon Jun 25 04:08:17 2007 UTC