[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 1.23 by root, Sun Mar 25 21:19:13 2007 UTC

…		…
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.
…		…
301		302
302	In the future, this setting might control other things, such as converting	303	In the future, this setting might control other things, such as converting
303	strings that look like integers or floats into integers or floats	304	strings that look like integers or floats into integers or floats
304	internally (there is no difference on the Perl level), saving space.	305	internally (there is no difference on the Perl level), saving space.
305		306
		307	=item $json = $json->max_depth ([$maximum_nesting_depth])
		308
		309	Sets the maximum nesting level (default C<8192>) accepted while encoding
		310	or decoding. If the JSON text or Perl data structure has an equal or
		311	higher nesting level then this limit, then the encoder and decoder will
		312	stop and croak at that point.
		313
		314	Nesting level is defined by number of hash- or arrayrefs that the encoder
		315	needs to traverse to reach a given point or the number of C<{> or C<[>
		316	characters without their matching closing parenthesis crossed to reach a
		317	given character in a string.
		318
		319	Setting the maximum depth to one disallows any nesting, so that ensures
		320	that the object is only a single hash/object or array.
		321
		322	The argument to C<max_depth> will be rounded up to the next nearest power
		323	of two.
		324
		325	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		326
306	=item $json_text = $json->encode ($perl_scalar)	327	=item $json_text = $json->encode ($perl_scalar)
307		328
308	Converts the given Perl data structure (a simple scalar or a reference	329	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	330	to a hash or array) to its JSON representation. Simple scalars will be
310	converted into JSON string or number sequences, while references to arrays	331	converted into JSON string or number sequences, while references to arrays
…		…
320	JSON numbers and strings become simple Perl scalars. JSON arrays become	341	JSON numbers and strings become simple Perl scalars. JSON arrays become
321	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	342	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>.	343	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
323		344
324	=back	345	=back
		346
325		347
326	=head1 MAPPING	348	=head1 MAPPING
327		349
328	This section describes how JSON::XS maps Perl values to JSON values and	350	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	351	vice versa. These mappings are designed to "do the right thing" in most
…		…
440	=item circular data structures	462	=item circular data structures
441		463
442	Those will be encoded until memory or stackspace runs out.	464	Those will be encoded until memory or stackspace runs out.
443		465
444	=back	466	=back
		467
445		468
446	=head1 COMPARISON	469	=head1 COMPARISON
447		470
448	As already mentioned, this module was created because none of the existing	471	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	472	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	601	(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	602	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	603	to decode or encode properly, so it was impossible to prepare a fair
581	comparison table for that case.	604	comparison table for that case.
582		605
583	=head1 RESOURCE LIMITS
584		606
585	JSON::XS does not impose any limits on the size of JSON texts or Perl	607	=head1 SECURITY CONSIDERATIONS
586	values they represent - if your machine can handle it, JSON::XS will	608
587	encode or decode it. Future versions might optionally impose structure	609	When you are using JSON in a protocol, talking to untrusted potentially
588	depth and memory use resource limits.	610	hostile creatures requires relatively few measures.
		611
		612	First of all, your JSON decoder should be secure, that is, should not have
		613	any buffer overflows. Obviously, this module should ensure that and I am
		614	trying hard on making that true, but you never know.
		615
		616	Second, you need to avoid resource-starving attacks. That means you should
		617	limit the size of JSON texts you accept, or make sure then when your
		618	resources run out, thats just fine (e.g. by using a separate process that
		619	can crash safely). The size of a JSON text in octets or characters is
		620	usually a good indication of the size of the resources required to decode
		621	it into a Perl structure.
		622
		623	Third, JSON::XS recurses using the C stack when decoding objects and
		624	arrays. The C stack is a limited resource: for instance, on my amd64
		625	machine with 8MB of stack size I can decode around 180k nested arrays
		626	but only 14k nested JSON objects. If that is exceeded, the program
		627	crashes. Thats why the default nesting limit is set to 8192. If your
		628	process has a smaller stack, you should adjust this setting accordingly
		629	with the C<max_depth> method.
		630
		631	And last but least, something else could bomb you that I forgot to think
		632	of. In that case, you get to keep the pieces. I am alway sopen for hints,
		633	though...
		634
589		635
590	=head1 BUGS	636	=head1 BUGS
591		637
592	While the goal of this module is to be correct, that unfortunately does	638	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	639	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	640	still relatively early in its development. If you keep reporting bugs they
595	be fixed swiftly, though.	641	will be fixed swiftly, though.
596		642
597	=cut	643	=cut
598		644
599	1;	645	1;
600		646

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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 1.23 by root, Sun Mar 25 21:19:13 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 1.23 by root, Sun Mar 25 21:19:13 2007 UTC