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Comparing JSON-XS/XS.pm (file contents):
Revision 1.43 by root, Sat Jun 23 23:49:29 2007 UTC vs.
Revision 1.49 by root, Sun Jul 1 14:08:03 2007 UTC

… …
9 # exported functions, they croak on error 9 # exported functions, they croak on error
10 # and expect/generate UTF-8 10 # and expect/generate UTF-8
11 11
12 $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; 12 $utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13 $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; 13 $perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
14
15 # objToJson and jsonToObj aliases to to_json and from_json
16 # are exported for compatibility to the JSON module,
17 # but should not be used in new code.
18 14
19 # OO-interface 15 # OO-interface
20 16
21 $coder = JSON::XS->new->ascii->pretty->allow_nonref; 17 $coder = JSON::XS->new->ascii->pretty->allow_nonref;
22 $pretty_printed_unencoded = $coder->encode ($perl_scalar); 18 $pretty_printed_unencoded = $coder->encode ($perl_scalar);
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85 81
86package JSON::XS; 82package JSON::XS;
87 83
88use strict; 84use strict;
89 85
90our $VERSION = '1.3'; 86our $VERSION = '1.4';
91our @ISA = qw(Exporter); 87our @ISA = qw(Exporter);
92 88
93our @EXPORT = qw(to_json from_json objToJson jsonToObj); 89our @EXPORT = qw(to_json from_json);
94 90
95use Exporter; 91use Exporter;
96use XSLoader; 92use XSLoader;
97 93
98=head1 FUNCTIONAL INTERFACE 94=head1 FUNCTIONAL INTERFACE
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315Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, 311Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
316resulting in an invalid JSON text: 312resulting in an invalid JSON text:
317 313
318 JSON::XS->new->allow_nonref->encode ("Hello, World!") 314 JSON::XS->new->allow_nonref->encode ("Hello, World!")
319 => "Hello, World!" 315 => "Hello, World!"
316
317=item $json = $json->allow_blessed ([$enable])
318
319If C<$enable> is true (or missing), then the C<encode> method will not
320barf when it encounters a blessed reference. Instead, the value of the
321B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
322disabled or no C<to_json> method found) or a representation of the
323object (C<convert_blessed> enabled and C<to_json> method found) is being
324encoded. Has no effect on C<decode>.
325
326If C<$enable> is false (the default), then C<encode> will throw an
327exception when it encounters a blessed object.
328
329=item $json = $json->convert_blessed ([$enable])
330
331If C<$enable> is true (or missing), then C<encode>, upon encountering a
332blessed object, will check for the availability of the C<TO_JSON> method
333on the object's class. If found, it will be called in scalar context
334and the resulting scalar will be encoded instead of the object. If no
335C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
336to do.
337
338The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
339returns other blessed objects, those will be handled in the same
340way. C<TO_JSON> must take care of not causing an endless recursion cycle
341(== crash) in this case. The name of C<TO_JSON> was chosen because other
342methods called by the Perl core (== not by the user of the object) are
343usually in upper case letters and to avoid collisions with the C<to_json>
344function.
345
346This setting does not yet influence C<decode> in any way, but in the
347future, global hooks might get installed that influence C<decode> and are
348enabled by this setting.
349
350If C<$enable> is false, then the C<allow_blessed> setting will decide what
351to do when a blessed object is found.
320 352
321=item $json = $json->shrink ([$enable]) 353=item $json = $json->shrink ([$enable])
322 354
323Perl usually over-allocates memory a bit when allocating space for 355Perl usually over-allocates memory a bit when allocating space for
324strings. This flag optionally resizes strings generated by either 356strings. This flag optionally resizes strings generated by either
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357given character in a string. 389given character in a string.
358 390
359Setting the maximum depth to one disallows any nesting, so that ensures 391Setting the maximum depth to one disallows any nesting, so that ensures
360that the object is only a single hash/object or array. 392that the object is only a single hash/object or array.
361 393
362The argument to C<max_depth> will be rounded up to the next nearest power 394The argument to C<max_depth> will be rounded up to the next highest power
363of two. 395of two. If no argument is given, the highest possible setting will be
396used, which is rarely useful.
397
398See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
399
400=item $json = $json->max_size ([$maximum_string_size])
401
402Set the maximum length a JSON text may have (in bytes) where decoding is
403being attempted. The default is C<0>, meaning no limit. When C<decode>
404is called on a string longer then this number of characters it will not
405attempt to decode the string but throw an exception. This setting has no
406effect on C<encode> (yet).
407
408The argument to C<max_size> will be rounded up to the next B<highest>
409power of two (so may be more than requested). If no argument is given, the
410limit check will be deactivated (same as when C<0> is specified).
364 411
365See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 412See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
366 413
367=item $json_text = $json->encode ($perl_scalar) 414=item $json_text = $json->encode ($perl_scalar)
368 415
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660It shows the number of encodes/decodes per second (JSON::XS uses 707It shows the number of encodes/decodes per second (JSON::XS uses
661the functional interface, while JSON::XS/2 uses the OO interface 708the functional interface, while JSON::XS/2 uses the OO interface
662with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables 709with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
663shrink). Higher is better: 710shrink). Higher is better:
664 711
712 Storable | 15779.925 | 14169.946 |
713 -----------+------------+------------+
665 module | encode | decode | 714 module | encode | decode |
666 -----------|------------|------------| 715 -----------|------------|------------|
667 JSON | 7645.468 | 4208.613 | 716 JSON | 4990.842 | 4088.813 |
668 JSON::DWIW | 40721.398 | 77101.176 | 717 JSON::DWIW | 51653.990 | 71575.154 |
669 JSON::PC | 65948.176 | 78251.940 | 718 JSON::PC | 65948.176 | 74631.744 |
670 JSON::Syck | 22844.793 | 26479.192 | 719 JSON::PP | 8931.652 | 3817.168 |
720 JSON::Syck | 24877.248 | 27776.848 |
671 JSON::XS | 388361.481 | 199728.762 | 721 JSON::XS | 388361.481 | 227951.304 |
672 JSON::XS/2 | 218453.333 | 192399.266 | 722 JSON::XS/2 | 227951.304 | 218453.333 |
673 JSON::XS/3 | 338250.323 | 192399.266 | 723 JSON::XS/3 | 338250.323 | 218453.333 |
674 Storable | 15779.925 | 14169.946 | 724 Storable | 16500.016 | 135300.129 |
675 -----------+------------+------------+ 725 -----------+------------+------------+
676 726
677That is, JSON::XS is about five times faster than JSON::DWIW on encoding, 727That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
678about three times faster on decoding, and over fourty times faster 728about three times faster on decoding, and over fourty times faster
679than JSON, even with pretty-printing and key sorting. It also compares 729than JSON, even with pretty-printing and key sorting. It also compares
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682Using a longer test string (roughly 18KB, generated from Yahoo! Locals 732Using a longer test string (roughly 18KB, generated from Yahoo! Locals
683search API (http://nanoref.com/yahooapis/mgPdGg): 733search API (http://nanoref.com/yahooapis/mgPdGg):
684 734
685 module | encode | decode | 735 module | encode | decode |
686 -----------|------------|------------| 736 -----------|------------|------------|
687 JSON | 254.685 | 37.665 | 737 JSON | 55.260 | 34.971 |
688 JSON::DWIW | 843.343 | 1049.731 | 738 JSON::DWIW | 825.228 | 1082.513 |
689 JSON::PC | 3602.116 | 2307.352 | 739 JSON::PC | 3571.444 | 2394.829 |
740 JSON::PP | 210.987 | 32.574 |
690 JSON::Syck | 505.107 | 787.899 | 741 JSON::Syck | 552.551 | 787.544 |
691 JSON::XS | 5747.196 | 3690.220 | 742 JSON::XS | 5780.463 | 4854.519 |
692 JSON::XS/2 | 3968.121 | 3676.634 | 743 JSON::XS/2 | 3869.998 | 4798.975 |
693 JSON::XS/3 | 6105.246 | 3662.508 | 744 JSON::XS/3 | 5862.880 | 4798.975 |
694 Storable | 4417.337 | 5285.161 | 745 Storable | 4445.002 | 5235.027 |
695 -----------+------------+------------+ 746 -----------+------------+------------+
696 747
697Again, JSON::XS leads by far (except for Storable which non-surprisingly 748Again, JSON::XS leads by far (except for Storable which non-surprisingly
698decodes faster). 749decodes faster).
699 750
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716Second, you need to avoid resource-starving attacks. That means you should 767Second, you need to avoid resource-starving attacks. That means you should
717limit the size of JSON texts you accept, or make sure then when your 768limit the size of JSON texts you accept, or make sure then when your
718resources run out, thats just fine (e.g. by using a separate process that 769resources run out, thats just fine (e.g. by using a separate process that
719can crash safely). The size of a JSON text in octets or characters is 770can crash safely). The size of a JSON text in octets or characters is
720usually a good indication of the size of the resources required to decode 771usually a good indication of the size of the resources required to decode
721it into a Perl structure. 772it into a Perl structure. While JSON::XS can check the size of the JSON
773text, it might be too late when you already have it in memory, so you
774might want to check the size before you accept the string.
722 775
723Third, JSON::XS recurses using the C stack when decoding objects and 776Third, JSON::XS recurses using the C stack when decoding objects and
724arrays. The C stack is a limited resource: for instance, on my amd64 777arrays. The C stack is a limited resource: for instance, on my amd64
725machine with 8MB of stack size I can decode around 180k nested arrays but 778machine with 8MB of stack size I can decode around 180k nested arrays but
726only 14k nested JSON objects (due to perl itself recursing deeply on croak 779only 14k nested JSON objects (due to perl itself recursing deeply on croak
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757sub true() { $true } 810sub true() { $true }
758sub false() { $false } 811sub false() { $false }
759 812
760sub is_bool($) { 813sub is_bool($) {
761 UNIVERSAL::isa $_[0], "JSON::XS::Boolean" 814 UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
762 or UNIVERSAL::isa $_[0], "JSON::Literal" 815# or UNIVERSAL::isa $_[0], "JSON::Literal"
763} 816}
764 817
765XSLoader::load "JSON::XS", $VERSION; 818XSLoader::load "JSON::XS", $VERSION;
766 819
767package JSON::XS::Boolean; 820package JSON::XS::Boolean;

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