[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 1.32 by root, Thu Apr 12 07:25:29 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 = '1.12';
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.
…		…
151		154
152	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
153	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
154	unicode characters outside that range will be escaped using either a	157	unicode characters outside that range will be escaped using either a
155	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	158	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
156	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.
157		162
158	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
159	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
160	and more compact format.	165	and more compact format.
161		166
…		…
281	=> "Hello, World!"	286	=> "Hello, World!"
282		287
283	=item $json = $json->shrink ([$enable])	288	=item $json = $json->shrink ([$enable])
284		289
285	Perl usually over-allocates memory a bit when allocating space for	290	Perl usually over-allocates memory a bit when allocating space for
286	strings. This flag optionally resizes strings generated by either	291	strings. This flag optionally resizes strings generated by either
287	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
288	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
289	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
290	if possible: perl stores strings internally either in an encoding called	295	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	296	UTF-X or in octet-form. The latter cannot store everything but uses less
292	space in general.	297	space in general (and some buggy Perl or C code might even rely on that
		298	internal representation being used).
293		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
294	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
295	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.
296		306
297	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.
298	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.
299		309
300	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
301	strings that look like integers or floats into integers or floats	311	strings that look like integers or floats into integers or floats
302	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.
303		333
304	=item $json_text = $json->encode ($perl_scalar)	334	=item $json_text = $json->encode ($perl_scalar)
305		335
306	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
307	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
…		…
319	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	349	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>.	350	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
321		351
322	=back	352	=back
323		353
		354
324	=head1 MAPPING	355	=head1 MAPPING
325		356
326	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
327	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
328	circumstances automatically, preserving round-tripping characteristics	359	circumstances automatically, preserving round-tripping characteristics
…		…
381	=over 4	412	=over 4
382		413
383	=item hash references	414	=item hash references
384		415
385	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
386	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
387	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
388	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
389	keys (determined by the I<canonical> flag), so the same datastructure	420	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	421	the same datastructure will serialise to the same JSON text (given same
391	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.
392		425
393	=item array references	426	=item array references
394		427
395	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]
396		438
397	=item blessed objects	439	=item blessed objects
398		440
399	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
400	underlying representation (hash- or arrayref), but this behaviour might	442	underlying representation (hash- or arrayref), but this behaviour might
…		…
433	$x *= 1; # same thing, the choise is yours.	475	$x *= 1; # same thing, the choise is yours.
434		476
435	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,
436	less obscure, ways. Tell me if you need this capability.	478	less obscure, ways. Tell me if you need this capability.
437		479
438	=item circular data structures
439
440	Those will be encoded until memory or stackspace runs out.
441
442	=back	480	=back
		481
443		482
444	=head1 COMPARISON	483	=head1 COMPARISON
445		484
446	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
447	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
…		…
576	(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
577	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
578	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
579	comparison table for that case.	618	comparison table for that case.
580		619
581	=head1 RESOURCE LIMITS
582		620
583	JSON::XS does not impose any limits on the size of JSON texts or Perl	621	=head1 SECURITY CONSIDERATIONS
584	values they represent - if your machine can handle it, JSON::XS will	622
585	encode or decode it. Future versions might optionally impose structure	623	When you are using JSON in a protocol, talking to untrusted potentially
586	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
587		650
588	=head1 BUGS	651	=head1 BUGS
589		652
590	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
591	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
592	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
593	be fixed swiftly, though.	656	will be fixed swiftly, though.
594		657
595	=cut	658	=cut
		659
		660	sub true() { \1 }
		661	sub false() { \0 }
596		662
597	1;	663	1;
598		664
599	=head1 AUTHOR	665	=head1 AUTHOR
600		666

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing JSON-XS/XS.pm (file contents): Revision 1.21 by root, Sun Mar 25 02:32:40 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 1.21 by root, Sun Mar 25 02:32:40 2007 UTC vs.
Revision 1.32 by root, Thu Apr 12 07:25:29 2007 UTC