[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 1.26 by root, Sat Mar 31 14:20:06 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 = '1.01';
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
…		…
438	=item circular data structures	478	=item circular data structures
439		479
440	Those will be encoded until memory or stackspace runs out.	480	Those will be encoded until memory or stackspace runs out.
441		481
442	=back	482	=back
		483
443		484
444	=head1 COMPARISON	485	=head1 COMPARISON
445		486
446	As already mentioned, this module was created because none of the existing	487	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	488	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	617	(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	618	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	619	to decode or encode properly, so it was impossible to prepare a fair
579	comparison table for that case.	620	comparison table for that case.
580		621
581	=head1 RESOURCE LIMITS
582		622
583	JSON::XS does not impose any limits on the size of JSON texts or Perl	623	=head1 SECURITY CONSIDERATIONS
584	values they represent - if your machine can handle it, JSON::XS will	624
585	encode or decode it. Future versions might optionally impose structure	625	When you are using JSON in a protocol, talking to untrusted potentially
586	depth and memory use resource limits.	626	hostile creatures requires relatively few measures.
		627
		628	First of all, your JSON decoder should be secure, that is, should not have
		629	any buffer overflows. Obviously, this module should ensure that and I am
		630	trying hard on making that true, but you never know.
		631
		632	Second, you need to avoid resource-starving attacks. That means you should
		633	limit the size of JSON texts you accept, or make sure then when your
		634	resources run out, thats just fine (e.g. by using a separate process that
		635	can crash safely). The size of a JSON text in octets or characters is
		636	usually a good indication of the size of the resources required to decode
		637	it into a Perl structure.
		638
		639	Third, JSON::XS recurses using the C stack when decoding objects and
		640	arrays. The C stack is a limited resource: for instance, on my amd64
		641	machine with 8MB of stack size I can decode around 180k nested arrays
		642	but only 14k nested JSON objects. If that is exceeded, the program
		643	crashes. Thats why the default nesting limit is set to 4096. If your
		644	process has a smaller stack, you should adjust this setting accordingly
		645	with the C<max_depth> method.
		646
		647	And last but least, something else could bomb you that I forgot to think
		648	of. In that case, you get to keep the pieces. I am alway sopen for hints,
		649	though...
		650
587		651
588	=head1 BUGS	652	=head1 BUGS
589		653
590	While the goal of this module is to be correct, that unfortunately does	654	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	655	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	656	still relatively early in its development. If you keep reporting bugs they
593	be fixed swiftly, though.	657	will be fixed swiftly, though.
594		658
595	=cut	659	=cut
		660
		661	sub true() { \1 }
		662	sub false() { \0 }
596		663
597	1;	664	1;
598		665
599	=head1 AUTHOR	666	=head1 AUTHOR
600		667

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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 1.26 by root, Sat Mar 31 14:20:06 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 1.26 by root, Sat Mar 31 14:20:06 2007 UTC