[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 1.32 by root, Thu Apr 12 07:25:29 2007 UTC

…		…
86	package JSON::XS;	86	package JSON::XS;
87		87
88	use strict;	88	use strict;
89		89
90	BEGIN {	90	BEGIN {
91	our $VERSION = '0.8';	91	our $VERSION = '1.12';
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 objToJson jsonToObj);
95	require Exporter;	95	require Exporter;
96		96
…		…
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		129
130	except being faster.	130	except being faster.
131		131
132	=back	132	=back
		133
133		134
134	=head1 OBJECT-ORIENTED INTERFACE	135	=head1 OBJECT-ORIENTED INTERFACE
135		136
136	The object oriented interface lets you configure your own encoding or	137	The object oriented interface lets you configure your own encoding or
137	decoding style, within the limits of supported formats.	138	decoding style, within the limits of supported formats.
…		…
153		154
154	If C<$enable> is true (or missing), then the C<encode> method will not	155	If C<$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	156	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	157	unicode characters outside that range will be escaped using either a
157	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	158	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
158	as per RFC4627.	159	as per RFC4627. The resulting encoded JSON text can be treated as a native
		160	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		161	or any other superset of ASCII.
159		162
160	If C<$enable> is false, then the C<encode> method will not escape Unicode	163	If C<$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	164	characters unless required by the JSON syntax. This results in a faster
162	and more compact format.	165	and more compact format.
163		166
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283	=> "Hello, World!"	286	=> "Hello, World!"
284		287
285	=item $json = $json->shrink ([$enable])	288	=item $json = $json->shrink ([$enable])
286		289
287	Perl usually over-allocates memory a bit when allocating space for	290	Perl usually over-allocates memory a bit when allocating space for
288	strings. This flag optionally resizes strings generated by either	291	strings. This flag optionally resizes strings generated by either
289	C<encode> or C<decode> to their minimum size possible. This can save	292	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	293	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	294	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	295	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	296	UTF-X or in octet-form. The latter cannot store everything but uses less
294	space in general.	297	space in general (and some buggy Perl or C code might even rely on that
		298	internal representation being used).
295		299
		300	The actual definition of what shrink does might change in future versions,
		301	but it will always try to save space at the expense of time.
		302
296	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	303	If C<$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.	304	be shrunk-to-fit, while all strings generated by C<decode> will also be
		305	shrunk-to-fit.
298		306
299	If C<$enable> is false, then the normal perl allocation algorithms are used.	307	If C<$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.	308	If you work with your data, then this is likely to be faster.
301		309
302	In the future, this setting might control other things, such as converting	310	In the future, this setting might control other things, such as converting
303	strings that look like integers or floats into integers or floats	311	strings that look like integers or floats into integers or floats
304	internally (there is no difference on the Perl level), saving space.	312	internally (there is no difference on the Perl level), saving space.
		313
		314	=item $json = $json->max_depth ([$maximum_nesting_depth])
		315
		316	Sets the maximum nesting level (default C<512>) accepted while encoding
		317	or decoding. If the JSON text or Perl data structure has an equal or
		318	higher nesting level then this limit, then the encoder and decoder will
		319	stop and croak at that point.
		320
		321	Nesting level is defined by number of hash- or arrayrefs that the encoder
		322	needs to traverse to reach a given point or the number of C<{> or C<[>
		323	characters without their matching closing parenthesis crossed to reach a
		324	given character in a string.
		325
		326	Setting the maximum depth to one disallows any nesting, so that ensures
		327	that the object is only a single hash/object or array.
		328
		329	The argument to C<max_depth> will be rounded up to the next nearest power
		330	of two.
		331
		332	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
305		333
306	=item $json_text = $json->encode ($perl_scalar)	334	=item $json_text = $json->encode ($perl_scalar)
307		335
308	Converts the given Perl data structure (a simple scalar or a reference	336	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	337	to a hash or array) to its JSON representation. Simple scalars will be
…		…
321	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	349	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>.	350	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
323		351
324	=back	352	=back
325		353
		354
326	=head1 MAPPING	355	=head1 MAPPING
327		356
328	This section describes how JSON::XS maps Perl values to JSON values and	357	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	358	vice versa. These mappings are designed to "do the right thing" in most
330	circumstances automatically, preserving round-tripping characteristics	359	circumstances automatically, preserving round-tripping characteristics
…		…
383	=over 4	412	=over 4
384		413
385	=item hash references	414	=item hash references
386		415
387	Perl hash references become JSON objects. As there is no inherent ordering	416	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	417	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	418	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	419	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	420	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	421	the same datastructure will serialise to the same JSON text (given same
393	JSON::XS), but this incurs a runtime overhead.	422	settings and version of JSON::XS), but this incurs a runtime overhead
		423	and is only rarely useful, e.g. when you want to compare some JSON text
		424	against another for equality.
394		425
395	=item array references	426	=item array references
396		427
397	Perl array references become JSON arrays.	428	Perl array references become JSON arrays.
		429
		430	=item other references
		431
		432	Other unblessed references are generally not allowed and will cause an
		433	exception to be thrown, except for references to the integers C<0> and
		434	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		435	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		436
		437	to_json [\0,JSON::XS::true] # yields [false,true]
398		438
399	=item blessed objects	439	=item blessed objects
400		440
401	Blessed objects are not allowed. JSON::XS currently tries to encode their	441	Blessed objects are not allowed. JSON::XS currently tries to encode their
402	underlying representation (hash- or arrayref), but this behaviour might	442	underlying representation (hash- or arrayref), but this behaviour might
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435	$x *= 1; # same thing, the choise is yours.	475	$x *= 1; # same thing, the choise is yours.
436		476
437	You can not currently output JSON booleans or force the type in other,	477	You can not currently output JSON booleans or force the type in other,
438	less obscure, ways. Tell me if you need this capability.	478	less obscure, ways. Tell me if you need this capability.
439		479
440	=item circular data structures
441
442	Those will be encoded until memory or stackspace runs out.
443
444	=back	480	=back
		481
445		482
446	=head1 COMPARISON	483	=head1 COMPARISON
447		484
448	As already mentioned, this module was created because none of the existing	485	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	486	JSON modules could be made to work correctly. First I will describe the
…		…
578	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	615	(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	616	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	617	to decode or encode properly, so it was impossible to prepare a fair
581	comparison table for that case.	618	comparison table for that case.
582		619
583	=head1 RESOURCE LIMITS
584		620
585	JSON::XS does not impose any limits on the size of JSON texts or Perl	621	=head1 SECURITY CONSIDERATIONS
586	values they represent - if your machine can handle it, JSON::XS will	622
587	encode or decode it. Future versions might optionally impose structure	623	When you are using JSON in a protocol, talking to untrusted potentially
588	depth and memory use resource limits.	624	hostile creatures requires relatively few measures.
		625
		626	First of all, your JSON decoder should be secure, that is, should not have
		627	any buffer overflows. Obviously, this module should ensure that and I am
		628	trying hard on making that true, but you never know.
		629
		630	Second, you need to avoid resource-starving attacks. That means you should
		631	limit the size of JSON texts you accept, or make sure then when your
		632	resources run out, thats just fine (e.g. by using a separate process that
		633	can crash safely). The size of a JSON text in octets or characters is
		634	usually a good indication of the size of the resources required to decode
		635	it into a Perl structure.
		636
		637	Third, JSON::XS recurses using the C stack when decoding objects and
		638	arrays. The C stack is a limited resource: for instance, on my amd64
		639	machine with 8MB of stack size I can decode around 180k nested arrays but
		640	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		641	to free the temporary). If that is exceeded, the program crashes. to be
		642	conservative, the default nesting limit is set to 512. If your process
		643	has a smaller stack, you should adjust this setting accordingly with the
		644	C<max_depth> method.
		645
		646	And last but least, something else could bomb you that I forgot to think
		647	of. In that case, you get to keep the pieces. I am always open for hints,
		648	though...
		649
589		650
590	=head1 BUGS	651	=head1 BUGS
591		652
592	While the goal of this module is to be correct, that unfortunately does	653	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	654	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	655	still relatively early in its development. If you keep reporting bugs they
595	be fixed swiftly, though.	656	will be fixed swiftly, though.
596		657
597	=cut	658	=cut
		659
		660	sub true() { \1 }
		661	sub false() { \0 }
598		662
599	1;	663	1;
600		664
601	=head1 AUTHOR	665	=head1 AUTHOR
602		666

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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 1.32 by root, Thu Apr 12 07:25:29 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.22 by root, Sun Mar 25 02:37:00 2007 UTC vs.
Revision 1.32 by root, Thu Apr 12 07:25:29 2007 UTC