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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs.
Revision 1.27 by root, Tue Apr 3 01:25:40 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
14	# objToJson and jsonToObj are exported for JSON	15	# objToJson and jsonToObj aliases to to_json and from_json
		16	# are exported for compatibility to the JSON module,
15	# compatibility, but should not be used in new code.	17	# but should not be used in new code.
16		18
17	# oo-interface	19	# OO-interface
18		20
19	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
20	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
21	$perl_scalar = $coder->decode ($unicode_json_text);	23	$perl_scalar = $coder->decode ($unicode_json_text);
22		24
…		…
84	package JSON::XS;	86	package JSON::XS;
85		87
86	use strict;	88	use strict;
87		89
88	BEGIN {	90	BEGIN {
89	our $VERSION = '0.8';	91	our $VERSION = '1.02';
90	our @ISA = qw(Exporter);	92	our @ISA = qw(Exporter);
91		93
92	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
93	require Exporter;	95	require Exporter;
94		96
…		…
126	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
127		129
128	except being faster.	130	except being faster.
129		131
130	=back	132	=back
		133
131		134
132	=head1 OBJECT-ORIENTED INTERFACE	135	=head1 OBJECT-ORIENTED INTERFACE
133		136
134	The object oriented interface lets you configure your own encoding or	137	The object oriented interface lets you configure your own encoding or
135	decoding style, within the limits of supported formats.	138	decoding style, within the limits of supported formats.
…		…
281	=> "Hello, World!"	284	=> "Hello, World!"
282		285
283	=item $json = $json->shrink ([$enable])	286	=item $json = $json->shrink ([$enable])
284		287
285	Perl usually over-allocates memory a bit when allocating space for	288	Perl usually over-allocates memory a bit when allocating space for
286	strings. This flag optionally resizes strings generated by either	289	strings. This flag optionally resizes strings generated by either
287	C<encode> or C<decode> to their minimum size possible. This can save	290	C<encode> or C<decode> to their minimum size possible. This can save
288	memory when your JSON texts are either very very long or you have many	291	memory when your JSON texts are either very very long or you have many
289	short strings. It will also try to downgrade any strings to octet-form	292	short strings. It will also try to downgrade any strings to octet-form
290	if possible: perl stores strings internally either in an encoding called	293	if possible: perl stores strings internally either in an encoding called
291	UTF-X or in octet-form. The latter cannot store everything but uses less	294	UTF-X or in octet-form. The latter cannot store everything but uses less
292	space in general.	295	space in general (and some buggy Perl or C code might even rely on that
		296	internal representation being used).
293		297
		298	The actual definition of what shrink does might change in future versions,
		299	but it will always try to save space at the expense of time.
		300
294	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	301	If C<$enable> is true (or missing), the string returned by C<encode> will
295	while all strings generated by C<decode> will also be shrunk-to-fit.	302	be shrunk-to-fit, while all strings generated by C<decode> will also be
		303	shrunk-to-fit.
296		304
297	If C<$enable> is false, then the normal perl allocation algorithms are used.	305	If C<$enable> is false, then the normal perl allocation algorithms are used.
298	If you work with your data, then this is likely to be faster.	306	If you work with your data, then this is likely to be faster.
299		307
300	In the future, this setting might control other things, such as converting	308	In the future, this setting might control other things, such as converting
301	strings that look like integers or floats into integers or floats	309	strings that look like integers or floats into integers or floats
302	internally (there is no difference on the Perl level), saving space.	310	internally (there is no difference on the Perl level), saving space.
		311
		312	=item $json = $json->max_depth ([$maximum_nesting_depth])
		313
		314	Sets the maximum nesting level (default C<4096>) accepted while encoding
		315	or decoding. If the JSON text or Perl data structure has an equal or
		316	higher nesting level then this limit, then the encoder and decoder will
		317	stop and croak at that point.
		318
		319	Nesting level is defined by number of hash- or arrayrefs that the encoder
		320	needs to traverse to reach a given point or the number of C<{> or C<[>
		321	characters without their matching closing parenthesis crossed to reach a
		322	given character in a string.
		323
		324	Setting the maximum depth to one disallows any nesting, so that ensures
		325	that the object is only a single hash/object or array.
		326
		327	The argument to C<max_depth> will be rounded up to the next nearest power
		328	of two.
		329
		330	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
303		331
304	=item $json_text = $json->encode ($perl_scalar)	332	=item $json_text = $json->encode ($perl_scalar)
305		333
306	Converts the given Perl data structure (a simple scalar or a reference	334	Converts the given Perl data structure (a simple scalar or a reference
307	to a hash or array) to its JSON representation. Simple scalars will be	335	to a hash or array) to its JSON representation. Simple scalars will be
…		…
319	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	347	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
320	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	348	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
321		349
322	=back	350	=back
323		351
		352
324	=head1 MAPPING	353	=head1 MAPPING
325		354
326	This section describes how JSON::XS maps Perl values to JSON values and	355	This section describes how JSON::XS maps Perl values to JSON values and
327	vice versa. These mappings are designed to "do the right thing" in most	356	vice versa. These mappings are designed to "do the right thing" in most
328	circumstances automatically, preserving round-tripping characteristics	357	circumstances automatically, preserving round-tripping characteristics
…		…
381	=over 4	410	=over 4
382		411
383	=item hash references	412	=item hash references
384		413
385	Perl hash references become JSON objects. As there is no inherent ordering	414	Perl hash references become JSON objects. As there is no inherent ordering
386	in hash keys, they will usually be encoded in a pseudo-random order that	415	in hash keys (or JSON objects), they will usually be encoded in a
387	can change between runs of the same program but stays generally the same	416	pseudo-random order that can change between runs of the same program but
388	within a single run of a program. JSON::XS can optionally sort the hash	417	stays generally the same within a single run of a program. JSON::XS can
389	keys (determined by the I<canonical> flag), so the same datastructure	418	optionally sort the hash keys (determined by the I<canonical> flag), so
390	will serialise to the same JSON text (given same settings and version of	419	the same datastructure will serialise to the same JSON text (given same
391	JSON::XS), but this incurs a runtime overhead.	420	settings and version of JSON::XS), but this incurs a runtime overhead
		421	and is only rarely useful, e.g. when you want to compare some JSON text
		422	against another for equality.
392		423
393	=item array references	424	=item array references
394		425
395	Perl array references become JSON arrays.	426	Perl array references become JSON arrays.
		427
		428	=item other references
		429
		430	Other unblessed references are generally not allowed and will cause an
		431	exception to be thrown, except for references to the integers C<0> and
		432	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		433	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		434
		435	to_json [\0,JSON::XS::true] # yields [false,true]
396		436
397	=item blessed objects	437	=item blessed objects
398		438
399	Blessed objects are not allowed. JSON::XS currently tries to encode their	439	Blessed objects are not allowed. JSON::XS currently tries to encode their
400	underlying representation (hash- or arrayref), but this behaviour might	440	underlying representation (hash- or arrayref), but this behaviour might
…		…
433	$x *= 1; # same thing, the choise is yours.	473	$x *= 1; # same thing, the choise is yours.
434		474
435	You can not currently output JSON booleans or force the type in other,	475	You can not currently output JSON booleans or force the type in other,
436	less obscure, ways. Tell me if you need this capability.	476	less obscure, ways. Tell me if you need this capability.
437		477
438	=item circular data structures
439
440	Those will be encoded until memory or stackspace runs out.
441
442	=back	478	=back
		479
443		480
444	=head1 COMPARISON	481	=head1 COMPARISON
445		482
446	As already mentioned, this module was created because none of the existing	483	As already mentioned, this module was created because none of the existing
447	JSON modules could be made to work correctly. First I will describe the	484	JSON modules could be made to work correctly. First I will describe the
…		…
576	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	613	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
577	will be broken due to missing (or wrong) unicode handling. Others refuse	614	will be broken due to missing (or wrong) unicode handling. Others refuse
578	to decode or encode properly, so it was impossible to prepare a fair	615	to decode or encode properly, so it was impossible to prepare a fair
579	comparison table for that case.	616	comparison table for that case.
580		617
581	=head1 RESOURCE LIMITS
582		618
583	JSON::XS does not impose any limits on the size of JSON texts or Perl	619	=head1 SECURITY CONSIDERATIONS
584	values they represent - if your machine can handle it, JSON::XS will	620
585	encode or decode it. Future versions might optionally impose structure	621	When you are using JSON in a protocol, talking to untrusted potentially
586	depth and memory use resource limits.	622	hostile creatures requires relatively few measures.
		623
		624	First of all, your JSON decoder should be secure, that is, should not have
		625	any buffer overflows. Obviously, this module should ensure that and I am
		626	trying hard on making that true, but you never know.
		627
		628	Second, you need to avoid resource-starving attacks. That means you should
		629	limit the size of JSON texts you accept, or make sure then when your
		630	resources run out, thats just fine (e.g. by using a separate process that
		631	can crash safely). The size of a JSON text in octets or characters is
		632	usually a good indication of the size of the resources required to decode
		633	it into a Perl structure.
		634
		635	Third, JSON::XS recurses using the C stack when decoding objects and
		636	arrays. The C stack is a limited resource: for instance, on my amd64
		637	machine with 8MB of stack size I can decode around 180k nested arrays
		638	but only 14k nested JSON objects. If that is exceeded, the program
		639	crashes. Thats why the default nesting limit is set to 4096. If your
		640	process has a smaller stack, you should adjust this setting accordingly
		641	with the C<max_depth> method.
		642
		643	And last but least, something else could bomb you that I forgot to think
		644	of. In that case, you get to keep the pieces. I am alway sopen for hints,
		645	though...
		646
587		647
588	=head1 BUGS	648	=head1 BUGS
589		649
590	While the goal of this module is to be correct, that unfortunately does	650	While the goal of this module is to be correct, that unfortunately does
591	not mean its bug-free, only that I think its design is bug-free. It is	651	not mean its bug-free, only that I think its design is bug-free. It is
592	still very young and not well-tested. If you keep reporting bugs they will	652	still relatively early in its development. If you keep reporting bugs they
593	be fixed swiftly, though.	653	will be fixed swiftly, though.
594		654
595	=cut	655	=cut
		656
		657	sub true() { \1 }
		658	sub false() { \0 }
596		659
597	1;	660	1;
598		661
599	=head1 AUTHOR	662	=head1 AUTHOR
600		663

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Comparing JSON-XS/XS.pm (file contents): Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs. Revision 1.27 by root, Tue Apr 3 01:25:40 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs.
Revision 1.27 by root, Tue Apr 3 01:25:40 2007 UTC