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1 | =head1 NAME |
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2 | |
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3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
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4 | |
1 | =encoding utf-8 |
5 | =encoding utf-8 |
2 | |
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3 | =head1 NAME |
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4 | |
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5 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
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6 | |
6 | |
7 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
7 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
8 | (http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html) |
8 | (http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html) |
9 | |
9 | |
10 | =head1 SYNOPSIS |
10 | =head1 SYNOPSIS |
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37 | primary goal is to be I<correct> and its secondary goal is to be |
37 | primary goal is to be I<correct> and its secondary goal is to be |
38 | I<fast>. To reach the latter goal it was written in C. |
38 | I<fast>. To reach the latter goal it was written in C. |
39 | |
39 | |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
42 | overriden) with no overhead due to emulation (by inheritign constructor |
42 | overridden) with no overhead due to emulation (by inheriting constructor |
43 | and methods). If JSON::XS is not available, it will fall back to the |
43 | and methods). If JSON::XS is not available, it will fall back to the |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
45 | gives you a portable JSON API that can be fast when you need and doesn't |
45 | gives you a portable JSON API that can be fast when you need and doesn't |
46 | require a C compiler when that is a problem. |
46 | require a C compiler when that is a problem. |
47 | |
47 | |
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49 | to write yet another JSON module? While it seems there are many JSON |
49 | to write yet another JSON module? While it seems there are many JSON |
50 | modules, none of them correctly handle all corner cases, and in most cases |
50 | modules, none of them correctly handle all corner cases, and in most cases |
51 | their maintainers are unresponsive, gone missing, or not listening to bug |
51 | their maintainers are unresponsive, gone missing, or not listening to bug |
52 | reports for other reasons. |
52 | reports for other reasons. |
53 | |
53 | |
54 | See COMPARISON, below, for a comparison to some other JSON modules. |
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55 | |
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56 | See MAPPING, below, on how JSON::XS maps perl values to JSON values and |
54 | See MAPPING, below, on how JSON::XS maps perl values to JSON values and |
57 | vice versa. |
55 | vice versa. |
58 | |
56 | |
59 | =head2 FEATURES |
57 | =head2 FEATURES |
60 | |
58 | |
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65 | This module knows how to handle Unicode, documents how and when it does |
63 | This module knows how to handle Unicode, documents how and when it does |
66 | so, and even documents what "correct" means. |
64 | so, and even documents what "correct" means. |
67 | |
65 | |
68 | =item * round-trip integrity |
66 | =item * round-trip integrity |
69 | |
67 | |
70 | When you serialise a perl data structure using only datatypes supported |
68 | When you serialise a perl data structure using only data types supported |
71 | by JSON, the deserialised data structure is identical on the Perl level. |
69 | by JSON, the deserialised data structure is identical on the Perl level. |
72 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
70 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
73 | like a number). There minor I<are> exceptions to this, read the MAPPING |
71 | like a number). There minor I<are> exceptions to this, read the MAPPING |
74 | section below to learn about those. |
72 | section below to learn about those. |
75 | |
73 | |
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84 | Compared to other JSON modules and other serialisers such as Storable, |
82 | Compared to other JSON modules and other serialisers such as Storable, |
85 | this module usually compares favourably in terms of speed, too. |
83 | this module usually compares favourably in terms of speed, too. |
86 | |
84 | |
87 | =item * simple to use |
85 | =item * simple to use |
88 | |
86 | |
89 | This module has both a simple functional interface as well as an objetc |
87 | This module has both a simple functional interface as well as an object |
90 | oriented interface interface. |
88 | oriented interface interface. |
91 | |
89 | |
92 | =item * reasonably versatile output formats |
90 | =item * reasonably versatile output formats |
93 | |
91 | |
94 | You can choose between the most compact guaranteed-single-line format |
92 | You can choose between the most compact guaranteed-single-line format |
95 | possible (nice for simple line-based protocols), a pure-ascii format |
93 | possible (nice for simple line-based protocols), a pure-ASCII format |
96 | (for when your transport is not 8-bit clean, still supports the whole |
94 | (for when your transport is not 8-bit clean, still supports the whole |
97 | Unicode range), or a pretty-printed format (for when you want to read that |
95 | Unicode range), or a pretty-printed format (for when you want to read that |
98 | stuff). Or you can combine those features in whatever way you like. |
96 | stuff). Or you can combine those features in whatever way you like. |
99 | |
97 | |
100 | =back |
98 | =back |
101 | |
99 | |
102 | =cut |
100 | =cut |
103 | |
101 | |
104 | package JSON::XS; |
102 | package JSON::XS; |
105 | |
103 | |
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104 | no warnings; |
106 | use strict; |
105 | use strict; |
107 | |
106 | |
108 | our $VERSION = '2.01'; |
107 | our $VERSION = '2.2222'; |
109 | our @ISA = qw(Exporter); |
108 | our @ISA = qw(Exporter); |
110 | |
109 | |
111 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
110 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
112 | |
111 | |
113 | sub to_json($) { |
112 | sub to_json($) { |
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137 | |
136 | |
138 | This function call is functionally identical to: |
137 | This function call is functionally identical to: |
139 | |
138 | |
140 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
139 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
141 | |
140 | |
142 | except being faster. |
141 | Except being faster. |
143 | |
142 | |
144 | =item $perl_scalar = decode_json $json_text |
143 | =item $perl_scalar = decode_json $json_text |
145 | |
144 | |
146 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
145 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
147 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
146 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
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149 | |
148 | |
150 | This function call is functionally identical to: |
149 | This function call is functionally identical to: |
151 | |
150 | |
152 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
151 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
153 | |
152 | |
154 | except being faster. |
153 | Except being faster. |
155 | |
154 | |
156 | =item $is_boolean = JSON::XS::is_bool $scalar |
155 | =item $is_boolean = JSON::XS::is_bool $scalar |
157 | |
156 | |
158 | Returns true if the passed scalar represents either JSON::XS::true or |
157 | Returns true if the passed scalar represents either JSON::XS::true or |
159 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
158 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
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197 | |
196 | |
198 | If you didn't know about that flag, just the better, pretend it doesn't |
197 | If you didn't know about that flag, just the better, pretend it doesn't |
199 | exist. |
198 | exist. |
200 | |
199 | |
201 | =item 4. A "Unicode String" is simply a string where each character can be |
200 | =item 4. A "Unicode String" is simply a string where each character can be |
202 | validly interpreted as a Unicode codepoint. |
201 | validly interpreted as a Unicode code point. |
203 | |
202 | |
204 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
203 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
205 | Unicode string encoded in UTF-8, giving you a binary string. |
204 | Unicode string encoded in UTF-8, giving you a binary string. |
206 | |
205 | |
207 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
206 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
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245 | |
244 | |
246 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
245 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
247 | characters unless required by the JSON syntax or other flags. This results |
246 | characters unless required by the JSON syntax or other flags. This results |
248 | in a faster and more compact format. |
247 | in a faster and more compact format. |
249 | |
248 | |
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249 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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250 | document. |
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251 | |
250 | The main use for this flag is to produce JSON texts that can be |
252 | The main use for this flag is to produce JSON texts that can be |
251 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
253 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
252 | contain any 8 bit characters. |
254 | contain any 8 bit characters. |
253 | |
255 | |
254 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
256 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
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265 | will not be affected in any way by this flag, as C<decode> by default |
267 | will not be affected in any way by this flag, as C<decode> by default |
266 | expects Unicode, which is a strict superset of latin1. |
268 | expects Unicode, which is a strict superset of latin1. |
267 | |
269 | |
268 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
270 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
269 | characters unless required by the JSON syntax or other flags. |
271 | characters unless required by the JSON syntax or other flags. |
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272 | |
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273 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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274 | document. |
270 | |
275 | |
271 | The main use for this flag is efficiently encoding binary data as JSON |
276 | The main use for this flag is efficiently encoding binary data as JSON |
272 | text, as most octets will not be escaped, resulting in a smaller encoded |
277 | text, as most octets will not be escaped, resulting in a smaller encoded |
273 | size. The disadvantage is that the resulting JSON text is encoded |
278 | size. The disadvantage is that the resulting JSON text is encoded |
274 | in latin1 (and must correctly be treated as such when storing and |
279 | in latin1 (and must correctly be treated as such when storing and |
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293 | |
298 | |
294 | If C<$enable> is false, then the C<encode> method will return the JSON |
299 | If C<$enable> is false, then the C<encode> method will return the JSON |
295 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
300 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
296 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
301 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
297 | to be done yourself, e.g. using the Encode module. |
302 | to be done yourself, e.g. using the Encode module. |
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303 | |
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304 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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305 | document. |
298 | |
306 | |
299 | Example, output UTF-16BE-encoded JSON: |
307 | Example, output UTF-16BE-encoded JSON: |
300 | |
308 | |
301 | use Encode; |
309 | use Encode; |
302 | $jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object); |
310 | $jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object); |
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453 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
461 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
454 | resulting in an invalid JSON text: |
462 | resulting in an invalid JSON text: |
455 | |
463 | |
456 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
464 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
457 | => "Hello, World!" |
465 | => "Hello, World!" |
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466 | |
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467 | =item $json = $json->allow_unknown ([$enable]) |
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468 | |
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469 | =item $enabled = $json->get_allow_unknown |
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470 | |
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471 | If C<$enable> is true (or missing), then C<encode> will I<not> throw an |
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472 | exception when it encounters values it cannot represent in JSON (for |
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473 | example, filehandles) but instead will encode a JSON C<null> value. Note |
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474 | that blessed objects are not included here and are handled separately by |
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475 | c<allow_nonref>. |
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476 | |
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477 | If C<$enable> is false (the default), then C<encode> will throw an |
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478 | exception when it encounters anything it cannot encode as JSON. |
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479 | |
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480 | This option does not affect C<decode> in any way, and it is recommended to |
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481 | leave it off unless you know your communications partner. |
458 | |
482 | |
459 | =item $json = $json->allow_blessed ([$enable]) |
483 | =item $json = $json->allow_blessed ([$enable]) |
460 | |
484 | |
461 | =item $enabled = $json->get_allow_blessed |
485 | =item $enabled = $json->get_allow_blessed |
462 | |
486 | |
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603 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
627 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
604 | |
628 | |
605 | =item $max_depth = $json->get_max_depth |
629 | =item $max_depth = $json->get_max_depth |
606 | |
630 | |
607 | Sets the maximum nesting level (default C<512>) accepted while encoding |
631 | Sets the maximum nesting level (default C<512>) accepted while encoding |
608 | or decoding. If the JSON text or Perl data structure has an equal or |
632 | or decoding. If a higher nesting level is detected in JSON text or a Perl |
609 | higher nesting level then this limit, then the encoder and decoder will |
633 | data structure, then the encoder and decoder will stop and croak at that |
610 | stop and croak at that point. |
634 | point. |
611 | |
635 | |
612 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
636 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
613 | needs to traverse to reach a given point or the number of C<{> or C<[> |
637 | needs to traverse to reach a given point or the number of C<{> or C<[> |
614 | characters without their matching closing parenthesis crossed to reach a |
638 | characters without their matching closing parenthesis crossed to reach a |
615 | given character in a string. |
639 | given character in a string. |
616 | |
640 | |
617 | Setting the maximum depth to one disallows any nesting, so that ensures |
641 | Setting the maximum depth to one disallows any nesting, so that ensures |
618 | that the object is only a single hash/object or array. |
642 | that the object is only a single hash/object or array. |
619 | |
643 | |
620 | The argument to C<max_depth> will be rounded up to the next highest power |
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621 | of two. If no argument is given, the highest possible setting will be |
644 | If no argument is given, the highest possible setting will be used, which |
622 | used, which is rarely useful. |
645 | is rarely useful. |
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646 | |
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647 | Note that nesting is implemented by recursion in C. The default value has |
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648 | been chosen to be as large as typical operating systems allow without |
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649 | crashing. |
623 | |
650 | |
624 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
651 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
625 | |
652 | |
626 | =item $json = $json->max_size ([$maximum_string_size]) |
653 | =item $json = $json->max_size ([$maximum_string_size]) |
627 | |
654 | |
628 | =item $max_size = $json->get_max_size |
655 | =item $max_size = $json->get_max_size |
629 | |
656 | |
630 | Set the maximum length a JSON text may have (in bytes) where decoding is |
657 | Set the maximum length a JSON text may have (in bytes) where decoding is |
631 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
658 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
632 | is called on a string longer then this number of characters it will not |
659 | is called on a string that is longer then this many bytes, it will not |
633 | attempt to decode the string but throw an exception. This setting has no |
660 | attempt to decode the string but throw an exception. This setting has no |
634 | effect on C<encode> (yet). |
661 | effect on C<encode> (yet). |
635 | |
662 | |
636 | The argument to C<max_size> will be rounded up to the next B<highest> |
663 | If no argument is given, the limit check will be deactivated (same as when |
637 | power of two (so may be more than requested). If no argument is given, the |
664 | C<0> is specified). |
638 | limit check will be deactivated (same as when C<0> is specified). |
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639 | |
665 | |
640 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
666 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
641 | |
667 | |
642 | =item $json_text = $json->encode ($perl_scalar) |
668 | =item $json_text = $json->encode ($perl_scalar) |
643 | |
669 | |
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670 | |
696 | |
671 | JSON::XS->new->decode_prefix ("[1] the tail") |
697 | JSON::XS->new->decode_prefix ("[1] the tail") |
672 | => ([], 3) |
698 | => ([], 3) |
673 | |
699 | |
674 | =back |
700 | =back |
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701 | |
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702 | |
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703 | =head1 INCREMENTAL PARSING |
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704 | |
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705 | In some cases, there is the need for incremental parsing of JSON |
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706 | texts. While this module always has to keep both JSON text and resulting |
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707 | Perl data structure in memory at one time, it does allow you to parse a |
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708 | JSON stream incrementally. It does so by accumulating text until it has |
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709 | a full JSON object, which it then can decode. This process is similar to |
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710 | using C<decode_prefix> to see if a full JSON object is available, but |
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711 | is much more efficient (and can be implemented with a minimum of method |
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712 | calls). |
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713 | |
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714 | JSON::XS will only attempt to parse the JSON text once it is sure it |
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715 | has enough text to get a decisive result, using a very simple but |
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716 | truly incremental parser. This means that it sometimes won't stop as |
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717 | early as the full parser, for example, it doesn't detect parenthese |
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718 | mismatches. The only thing it guarantees is that it starts decoding as |
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719 | soon as a syntactically valid JSON text has been seen. This means you need |
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720 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
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721 | parsing in the presence if syntax errors. |
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722 | |
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723 | The following methods implement this incremental parser. |
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724 | |
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725 | =over 4 |
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726 | |
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727 | =item [void, scalar or list context] = $json->incr_parse ([$string]) |
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728 | |
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729 | This is the central parsing function. It can both append new text and |
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730 | extract objects from the stream accumulated so far (both of these |
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731 | functions are optional). |
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732 | |
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733 | If C<$string> is given, then this string is appended to the already |
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734 | existing JSON fragment stored in the C<$json> object. |
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735 | |
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736 | After that, if the function is called in void context, it will simply |
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737 | return without doing anything further. This can be used to add more text |
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738 | in as many chunks as you want. |
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739 | |
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740 | If the method is called in scalar context, then it will try to extract |
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741 | exactly I<one> JSON object. If that is successful, it will return this |
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742 | object, otherwise it will return C<undef>. If there is a parse error, |
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743 | this method will croak just as C<decode> would do (one can then use |
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744 | C<incr_skip> to skip the errornous part). This is the most common way of |
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745 | using the method. |
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746 | |
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747 | And finally, in list context, it will try to extract as many objects |
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748 | from the stream as it can find and return them, or the empty list |
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749 | otherwise. For this to work, there must be no separators between the JSON |
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750 | objects or arrays, instead they must be concatenated back-to-back. If |
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751 | an error occurs, an exception will be raised as in the scalar context |
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752 | case. Note that in this case, any previously-parsed JSON texts will be |
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753 | lost. |
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754 | |
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755 | =item $lvalue_string = $json->incr_text |
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756 | |
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757 | This method returns the currently stored JSON fragment as an lvalue, that |
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758 | is, you can manipulate it. This I<only> works when a preceding call to |
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759 | C<incr_parse> in I<scalar context> successfully returned an object. Under |
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760 | all other circumstances you must not call this function (I mean it. |
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761 | although in simple tests it might actually work, it I<will> fail under |
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762 | real world conditions). As a special exception, you can also call this |
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763 | method before having parsed anything. |
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764 | |
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765 | This function is useful in two cases: a) finding the trailing text after a |
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766 | JSON object or b) parsing multiple JSON objects separated by non-JSON text |
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767 | (such as commas). |
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768 | |
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769 | =item $json->incr_skip |
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770 | |
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771 | This will reset the state of the incremental parser and will remove the |
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772 | parsed text from the input buffer. This is useful after C<incr_parse> |
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773 | died, in which case the input buffer and incremental parser state is left |
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774 | unchanged, to skip the text parsed so far and to reset the parse state. |
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775 | |
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776 | =item $json->incr_reset |
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777 | |
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778 | This completely resets the incremental parser, that is, after this call, |
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779 | it will be as if the parser had never parsed anything. |
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780 | |
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781 | This is useful if you want ot repeatedly parse JSON objects and want to |
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782 | ignore any trailing data, which means you have to reset the parser after |
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783 | each successful decode. |
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784 | |
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785 | =back |
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786 | |
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787 | =head2 LIMITATIONS |
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788 | |
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789 | All options that affect decoding are supported, except |
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790 | C<allow_nonref>. The reason for this is that it cannot be made to |
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791 | work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate |
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792 | them back to back and still decode them perfectly. This does not hold true |
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793 | for JSON numbers, however. |
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794 | |
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795 | For example, is the string C<1> a single JSON number, or is it simply the |
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796 | start of C<12>? Or is C<12> a single JSON number, or the concatenation |
|
|
797 | of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS |
|
|
798 | takes the conservative route and disallows this case. |
|
|
799 | |
|
|
800 | =head2 EXAMPLES |
|
|
801 | |
|
|
802 | Some examples will make all this clearer. First, a simple example that |
|
|
803 | works similarly to C<decode_prefix>: We want to decode the JSON object at |
|
|
804 | the start of a string and identify the portion after the JSON object: |
|
|
805 | |
|
|
806 | my $text = "[1,2,3] hello"; |
|
|
807 | |
|
|
808 | my $json = new JSON::XS; |
|
|
809 | |
|
|
810 | my $obj = $json->incr_parse ($text) |
|
|
811 | or die "expected JSON object or array at beginning of string"; |
|
|
812 | |
|
|
813 | my $tail = $json->incr_text; |
|
|
814 | # $tail now contains " hello" |
|
|
815 | |
|
|
816 | Easy, isn't it? |
|
|
817 | |
|
|
818 | Now for a more complicated example: Imagine a hypothetical protocol where |
|
|
819 | you read some requests from a TCP stream, and each request is a JSON |
|
|
820 | array, without any separation between them (in fact, it is often useful to |
|
|
821 | use newlines as "separators", as these get interpreted as whitespace at |
|
|
822 | the start of the JSON text, which makes it possible to test said protocol |
|
|
823 | with C<telnet>...). |
|
|
824 | |
|
|
825 | Here is how you'd do it (it is trivial to write this in an event-based |
|
|
826 | manner): |
|
|
827 | |
|
|
828 | my $json = new JSON::XS; |
|
|
829 | |
|
|
830 | # read some data from the socket |
|
|
831 | while (sysread $socket, my $buf, 4096) { |
|
|
832 | |
|
|
833 | # split and decode as many requests as possible |
|
|
834 | for my $request ($json->incr_parse ($buf)) { |
|
|
835 | # act on the $request |
|
|
836 | } |
|
|
837 | } |
|
|
838 | |
|
|
839 | Another complicated example: Assume you have a string with JSON objects |
|
|
840 | or arrays, all separated by (optional) comma characters (e.g. C<[1],[2], |
|
|
841 | [3]>). To parse them, we have to skip the commas between the JSON texts, |
|
|
842 | and here is where the lvalue-ness of C<incr_text> comes in useful: |
|
|
843 | |
|
|
844 | my $text = "[1],[2], [3]"; |
|
|
845 | my $json = new JSON::XS; |
|
|
846 | |
|
|
847 | # void context, so no parsing done |
|
|
848 | $json->incr_parse ($text); |
|
|
849 | |
|
|
850 | # now extract as many objects as possible. note the |
|
|
851 | # use of scalar context so incr_text can be called. |
|
|
852 | while (my $obj = $json->incr_parse) { |
|
|
853 | # do something with $obj |
|
|
854 | |
|
|
855 | # now skip the optional comma |
|
|
856 | $json->incr_text =~ s/^ \s* , //x; |
|
|
857 | } |
|
|
858 | |
|
|
859 | Now lets go for a very complex example: Assume that you have a gigantic |
|
|
860 | JSON array-of-objects, many gigabytes in size, and you want to parse it, |
|
|
861 | but you cannot load it into memory fully (this has actually happened in |
|
|
862 | the real world :). |
|
|
863 | |
|
|
864 | Well, you lost, you have to implement your own JSON parser. But JSON::XS |
|
|
865 | can still help you: You implement a (very simple) array parser and let |
|
|
866 | JSON decode the array elements, which are all full JSON objects on their |
|
|
867 | own (this wouldn't work if the array elements could be JSON numbers, for |
|
|
868 | example): |
|
|
869 | |
|
|
870 | my $json = new JSON::XS; |
|
|
871 | |
|
|
872 | # open the monster |
|
|
873 | open my $fh, "<bigfile.json" |
|
|
874 | or die "bigfile: $!"; |
|
|
875 | |
|
|
876 | # first parse the initial "[" |
|
|
877 | for (;;) { |
|
|
878 | sysread $fh, my $buf, 65536 |
|
|
879 | or die "read error: $!"; |
|
|
880 | $json->incr_parse ($buf); # void context, so no parsing |
|
|
881 | |
|
|
882 | # Exit the loop once we found and removed(!) the initial "[". |
|
|
883 | # In essence, we are (ab-)using the $json object as a simple scalar |
|
|
884 | # we append data to. |
|
|
885 | last if $json->incr_text =~ s/^ \s* \[ //x; |
|
|
886 | } |
|
|
887 | |
|
|
888 | # now we have the skipped the initial "[", so continue |
|
|
889 | # parsing all the elements. |
|
|
890 | for (;;) { |
|
|
891 | # in this loop we read data until we got a single JSON object |
|
|
892 | for (;;) { |
|
|
893 | if (my $obj = $json->incr_parse) { |
|
|
894 | # do something with $obj |
|
|
895 | last; |
|
|
896 | } |
|
|
897 | |
|
|
898 | # add more data |
|
|
899 | sysread $fh, my $buf, 65536 |
|
|
900 | or die "read error: $!"; |
|
|
901 | $json->incr_parse ($buf); # void context, so no parsing |
|
|
902 | } |
|
|
903 | |
|
|
904 | # in this loop we read data until we either found and parsed the |
|
|
905 | # separating "," between elements, or the final "]" |
|
|
906 | for (;;) { |
|
|
907 | # first skip whitespace |
|
|
908 | $json->incr_text =~ s/^\s*//; |
|
|
909 | |
|
|
910 | # if we find "]", we are done |
|
|
911 | if ($json->incr_text =~ s/^\]//) { |
|
|
912 | print "finished.\n"; |
|
|
913 | exit; |
|
|
914 | } |
|
|
915 | |
|
|
916 | # if we find ",", we can continue with the next element |
|
|
917 | if ($json->incr_text =~ s/^,//) { |
|
|
918 | last; |
|
|
919 | } |
|
|
920 | |
|
|
921 | # if we find anything else, we have a parse error! |
|
|
922 | if (length $json->incr_text) { |
|
|
923 | die "parse error near ", $json->incr_text; |
|
|
924 | } |
|
|
925 | |
|
|
926 | # else add more data |
|
|
927 | sysread $fh, my $buf, 65536 |
|
|
928 | or die "read error: $!"; |
|
|
929 | $json->incr_parse ($buf); # void context, so no parsing |
|
|
930 | } |
|
|
931 | |
|
|
932 | This is a complex example, but most of the complexity comes from the fact |
|
|
933 | that we are trying to be correct (bear with me if I am wrong, I never ran |
|
|
934 | the above example :). |
|
|
935 | |
675 | |
936 | |
676 | |
937 | |
677 | =head1 MAPPING |
938 | =head1 MAPPING |
678 | |
939 | |
679 | This section describes how JSON::XS maps Perl values to JSON values and |
940 | This section describes how JSON::XS maps Perl values to JSON values and |
… | |
… | |
768 | Other unblessed references are generally not allowed and will cause an |
1029 | Other unblessed references are generally not allowed and will cause an |
769 | exception to be thrown, except for references to the integers C<0> and |
1030 | exception to be thrown, except for references to the integers C<0> and |
770 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
1031 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
771 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
1032 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
772 | |
1033 | |
773 | encode_json [\0,JSON::XS::true] # yields [false,true] |
1034 | encode_json [\0, JSON::XS::true] # yields [false,true] |
774 | |
1035 | |
775 | =item JSON::XS::true, JSON::XS::false |
1036 | =item JSON::XS::true, JSON::XS::false |
776 | |
1037 | |
777 | These special values become JSON true and JSON false values, |
1038 | These special values become JSON true and JSON false values, |
778 | respectively. You can also use C<\1> and C<\0> directly if you want. |
1039 | respectively. You can also use C<\1> and C<\0> directly if you want. |
… | |
… | |
816 | my $x = "3"; # some variable containing a string |
1077 | my $x = "3"; # some variable containing a string |
817 | $x += 0; # numify it, ensuring it will be dumped as a number |
1078 | $x += 0; # numify it, ensuring it will be dumped as a number |
818 | $x *= 1; # same thing, the choice is yours. |
1079 | $x *= 1; # same thing, the choice is yours. |
819 | |
1080 | |
820 | You can not currently force the type in other, less obscure, ways. Tell me |
1081 | You can not currently force the type in other, less obscure, ways. Tell me |
821 | if you need this capability (but don't forget to explain why its needed |
1082 | if you need this capability (but don't forget to explain why it's needed |
822 | :). |
1083 | :). |
823 | |
1084 | |
824 | =back |
1085 | =back |
825 | |
1086 | |
826 | |
1087 | |
… | |
… | |
828 | |
1089 | |
829 | The interested reader might have seen a number of flags that signify |
1090 | The interested reader might have seen a number of flags that signify |
830 | encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be |
1091 | encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be |
831 | some confusion on what these do, so here is a short comparison: |
1092 | some confusion on what these do, so here is a short comparison: |
832 | |
1093 | |
833 | C<utf8> controls wether the JSON text created by C<encode> (and expected |
1094 | C<utf8> controls whether the JSON text created by C<encode> (and expected |
834 | by C<decode>) is UTF-8 encoded or not, while C<latin1> and C<ascii> only |
1095 | by C<decode>) is UTF-8 encoded or not, while C<latin1> and C<ascii> only |
835 | control wether C<encode> escapes character values outside their respective |
1096 | control whether C<encode> escapes character values outside their respective |
836 | codeset range. Neither of these flags conflict with each other, although |
1097 | codeset range. Neither of these flags conflict with each other, although |
837 | some combinations make less sense than others. |
1098 | some combinations make less sense than others. |
838 | |
1099 | |
839 | Care has been taken to make all flags symmetrical with respect to |
1100 | Care has been taken to make all flags symmetrical with respect to |
840 | C<encode> and C<decode>, that is, texts encoded with any combination of |
1101 | C<encode> and C<decode>, that is, texts encoded with any combination of |
… | |
… | |
920 | proper subset of most 8-bit and multibyte encodings in use in the world. |
1181 | proper subset of most 8-bit and multibyte encodings in use in the world. |
921 | |
1182 | |
922 | =back |
1183 | =back |
923 | |
1184 | |
924 | |
1185 | |
925 | =head1 COMPARISON |
|
|
926 | |
|
|
927 | As already mentioned, this module was created because none of the existing |
|
|
928 | JSON modules could be made to work correctly. First I will describe the |
|
|
929 | problems (or pleasures) I encountered with various existing JSON modules, |
|
|
930 | followed by some benchmark values. JSON::XS was designed not to suffer |
|
|
931 | from any of these problems or limitations. |
|
|
932 | |
|
|
933 | =over 4 |
|
|
934 | |
|
|
935 | =item JSON 2.xx |
|
|
936 | |
|
|
937 | A marvellous piece of engineering, this module either uses JSON::XS |
|
|
938 | directly when available (so will be 100% compatible with it, including |
|
|
939 | speed), or it uses JSON::PP, which is basically JSON::XS translated to |
|
|
940 | Pure Perl, which should be 100% compatible with JSON::XS, just a bit |
|
|
941 | slower. |
|
|
942 | |
|
|
943 | You cannot really lose by using this module, especially as it tries very |
|
|
944 | hard to work even with ancient Perl versions, while JSON::XS does not. |
|
|
945 | |
|
|
946 | =item JSON 1.07 |
|
|
947 | |
|
|
948 | Slow (but very portable, as it is written in pure Perl). |
|
|
949 | |
|
|
950 | Undocumented/buggy Unicode handling (how JSON handles Unicode values is |
|
|
951 | undocumented. One can get far by feeding it Unicode strings and doing |
|
|
952 | en-/decoding oneself, but Unicode escapes are not working properly). |
|
|
953 | |
|
|
954 | No round-tripping (strings get clobbered if they look like numbers, e.g. |
|
|
955 | the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will |
|
|
956 | decode into the number 2. |
|
|
957 | |
|
|
958 | =item JSON::PC 0.01 |
|
|
959 | |
|
|
960 | Very fast. |
|
|
961 | |
|
|
962 | Undocumented/buggy Unicode handling. |
|
|
963 | |
|
|
964 | No round-tripping. |
|
|
965 | |
|
|
966 | Has problems handling many Perl values (e.g. regex results and other magic |
|
|
967 | values will make it croak). |
|
|
968 | |
|
|
969 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
|
|
970 | which is not a valid JSON text. |
|
|
971 | |
|
|
972 | Unmaintained (maintainer unresponsive for many months, bugs are not |
|
|
973 | getting fixed). |
|
|
974 | |
|
|
975 | =item JSON::Syck 0.21 |
|
|
976 | |
|
|
977 | Very buggy (often crashes). |
|
|
978 | |
|
|
979 | Very inflexible (no human-readable format supported, format pretty much |
|
|
980 | undocumented. I need at least a format for easy reading by humans and a |
|
|
981 | single-line compact format for use in a protocol, and preferably a way to |
|
|
982 | generate ASCII-only JSON texts). |
|
|
983 | |
|
|
984 | Completely broken (and confusingly documented) Unicode handling (Unicode |
|
|
985 | escapes are not working properly, you need to set ImplicitUnicode to |
|
|
986 | I<different> values on en- and decoding to get symmetric behaviour). |
|
|
987 | |
|
|
988 | No round-tripping (simple cases work, but this depends on whether the scalar |
|
|
989 | value was used in a numeric context or not). |
|
|
990 | |
|
|
991 | Dumping hashes may skip hash values depending on iterator state. |
|
|
992 | |
|
|
993 | Unmaintained (maintainer unresponsive for many months, bugs are not |
|
|
994 | getting fixed). |
|
|
995 | |
|
|
996 | Does not check input for validity (i.e. will accept non-JSON input and |
|
|
997 | return "something" instead of raising an exception. This is a security |
|
|
998 | issue: imagine two banks transferring money between each other using |
|
|
999 | JSON. One bank might parse a given non-JSON request and deduct money, |
|
|
1000 | while the other might reject the transaction with a syntax error. While a |
|
|
1001 | good protocol will at least recover, that is extra unnecessary work and |
|
|
1002 | the transaction will still not succeed). |
|
|
1003 | |
|
|
1004 | =item JSON::DWIW 0.04 |
|
|
1005 | |
|
|
1006 | Very fast. Very natural. Very nice. |
|
|
1007 | |
|
|
1008 | Undocumented Unicode handling (but the best of the pack. Unicode escapes |
|
|
1009 | still don't get parsed properly). |
|
|
1010 | |
|
|
1011 | Very inflexible. |
|
|
1012 | |
|
|
1013 | No round-tripping. |
|
|
1014 | |
|
|
1015 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
|
|
1016 | result in nothing being output) |
|
|
1017 | |
|
|
1018 | Does not check input for validity. |
|
|
1019 | |
|
|
1020 | =back |
|
|
1021 | |
|
|
1022 | |
|
|
1023 | =head2 JSON and YAML |
1186 | =head2 JSON and YAML |
1024 | |
1187 | |
1025 | You often hear that JSON is a subset of YAML. This is, however, a mass |
1188 | You often hear that JSON is a subset of YAML. This is, however, a mass |
1026 | hysteria(*) and very far from the truth. In general, there is no way to |
1189 | hysteria(*) and very far from the truth (as of the time of this writing), |
|
|
1190 | so let me state it clearly: I<in general, there is no way to configure |
1027 | configure JSON::XS to output a data structure as valid YAML that works for |
1191 | JSON::XS to output a data structure as valid YAML> that works in all |
1028 | all cases. |
1192 | cases. |
1029 | |
1193 | |
1030 | If you really must use JSON::XS to generate YAML, you should use this |
1194 | If you really must use JSON::XS to generate YAML, you should use this |
1031 | algorithm (subject to change in future versions): |
1195 | algorithm (subject to change in future versions): |
1032 | |
1196 | |
1033 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
1197 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
… | |
… | |
1036 | This will I<usually> generate JSON texts that also parse as valid |
1200 | This will I<usually> generate JSON texts that also parse as valid |
1037 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1201 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1038 | lengths that JSON doesn't have and also has different and incompatible |
1202 | lengths that JSON doesn't have and also has different and incompatible |
1039 | unicode handling, so you should make sure that your hash keys are |
1203 | unicode handling, so you should make sure that your hash keys are |
1040 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
1204 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
1041 | you do not have codepoints with values outside the Unicode BMP (basic |
1205 | you do not have characters with codepoint values outside the Unicode BMP |
1042 | multilingual page). YAML also does not allow C<\/> sequences in strings |
1206 | (basic multilingual page). YAML also does not allow C<\/> sequences in |
1043 | (which JSON::XS does not I<currently> generate). |
1207 | strings (which JSON::XS does not I<currently> generate, but other JSON |
|
|
1208 | generators might). |
1044 | |
1209 | |
1045 | There might be other incompatibilities that I am not aware of (or the YAML |
1210 | There might be other incompatibilities that I am not aware of (or the YAML |
1046 | specification has been changed yet again - it does so quite often). In |
1211 | specification has been changed yet again - it does so quite often). In |
1047 | general you should not try to generate YAML with a JSON generator or vice |
1212 | general you should not try to generate YAML with a JSON generator or vice |
1048 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
1213 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
… | |
… | |
1051 | |
1216 | |
1052 | =over 4 |
1217 | =over 4 |
1053 | |
1218 | |
1054 | =item (*) |
1219 | =item (*) |
1055 | |
1220 | |
1056 | This is spread actively by the YAML team, however. For many years now they |
1221 | I have been pressured multiple times by Brian Ingerson (one of the |
1057 | claim YAML were a superset of JSON, even when proven otherwise. |
1222 | authors of the YAML specification) to remove this paragraph, despite him |
|
|
1223 | acknowledging that the actual incompatibilities exist. As I was personally |
|
|
1224 | bitten by this "JSON is YAML" lie, I refused and said I will continue to |
|
|
1225 | educate people about these issues, so others do not run into the same |
|
|
1226 | problem again and again. After this, Brian called me a (quote)I<complete |
|
|
1227 | and worthless idiot>(unquote). |
1058 | |
1228 | |
1059 | Even the author of this manpage was at some point accused of providing |
1229 | In my opinion, instead of pressuring and insulting people who actually |
1060 | "incorrect" information, despite the evidence presented (claims ranged |
1230 | clarify issues with YAML and the wrong statements of some of its |
1061 | from "your documentation contains inaccurate and negative statements about |
1231 | proponents, I would kindly suggest reading the JSON spec (which is not |
1062 | YAML" (the only negative comment is this footnote, and it didn't exist |
1232 | that difficult or long) and finally make YAML compatible to it, and |
1063 | back then; the question on which claims were inaccurate was never answered |
1233 | educating users about the changes, instead of spreading lies about the |
1064 | etc.) to "the YAML spec is not up-to-date" (the *real* and supposedly |
1234 | real compatibility for many I<years> and trying to silence people who |
1065 | JSON-compatible spec is apparently not currently publicly available) |
1235 | point out that it isn't true. |
1066 | to actual requests to replace this section by *incorrect* information, |
|
|
1067 | suppressing information about the real problem). |
|
|
1068 | |
|
|
1069 | So whenever you are told that YAML was a superset of JSON, first check |
|
|
1070 | wether it is really true (it might be when you check it, but it certainly |
|
|
1071 | was not true when this was written). I would much prefer if the YAML team |
|
|
1072 | would spent their time on actually making JSON compatibility a truth |
|
|
1073 | (JSON, after all, has a very small and simple specification) instead of |
|
|
1074 | trying to lobby/force people into reporting untruths. |
|
|
1075 | |
1236 | |
1076 | =back |
1237 | =back |
1077 | |
1238 | |
1078 | |
1239 | |
1079 | =head2 SPEED |
1240 | =head2 SPEED |
… | |
… | |
1081 | It seems that JSON::XS is surprisingly fast, as shown in the following |
1242 | It seems that JSON::XS is surprisingly fast, as shown in the following |
1082 | tables. They have been generated with the help of the C<eg/bench> program |
1243 | tables. They have been generated with the help of the C<eg/bench> program |
1083 | in the JSON::XS distribution, to make it easy to compare on your own |
1244 | in the JSON::XS distribution, to make it easy to compare on your own |
1084 | system. |
1245 | system. |
1085 | |
1246 | |
1086 | First comes a comparison between various modules using a very short |
1247 | First comes a comparison between various modules using |
1087 | single-line JSON string: |
1248 | a very short single-line JSON string (also available at |
|
|
1249 | L<http://dist.schmorp.de/misc/json/short.json>). |
1088 | |
1250 | |
1089 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
1251 | {"method": "handleMessage", "params": ["user1", |
1090 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
1252 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
|
|
1253 | true, false]} |
1091 | |
1254 | |
1092 | It shows the number of encodes/decodes per second (JSON::XS uses |
1255 | It shows the number of encodes/decodes per second (JSON::XS uses |
1093 | the functional interface, while JSON::XS/2 uses the OO interface |
1256 | the functional interface, while JSON::XS/2 uses the OO interface |
1094 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1257 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1095 | shrink). Higher is better: |
1258 | shrink). Higher is better: |
… | |
… | |
1111 | about three times faster on decoding, and over forty times faster |
1274 | about three times faster on decoding, and over forty times faster |
1112 | than JSON, even with pretty-printing and key sorting. It also compares |
1275 | than JSON, even with pretty-printing and key sorting. It also compares |
1113 | favourably to Storable for small amounts of data. |
1276 | favourably to Storable for small amounts of data. |
1114 | |
1277 | |
1115 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1278 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1116 | search API (http://nanoref.com/yahooapis/mgPdGg): |
1279 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1117 | |
1280 | |
1118 | module | encode | decode | |
1281 | module | encode | decode | |
1119 | -----------|------------|------------| |
1282 | -----------|------------|------------| |
1120 | JSON 1.x | 55.260 | 34.971 | |
1283 | JSON 1.x | 55.260 | 34.971 | |
1121 | JSON::DWIW | 825.228 | 1082.513 | |
1284 | JSON::DWIW | 825.228 | 1082.513 | |
… | |
… | |
1163 | to free the temporary). If that is exceeded, the program crashes. To be |
1326 | to free the temporary). If that is exceeded, the program crashes. To be |
1164 | conservative, the default nesting limit is set to 512. If your process |
1327 | conservative, the default nesting limit is set to 512. If your process |
1165 | has a smaller stack, you should adjust this setting accordingly with the |
1328 | has a smaller stack, you should adjust this setting accordingly with the |
1166 | C<max_depth> method. |
1329 | C<max_depth> method. |
1167 | |
1330 | |
1168 | And last but least, something else could bomb you that I forgot to think |
1331 | Something else could bomb you, too, that I forgot to think of. In that |
1169 | of. In that case, you get to keep the pieces. I am always open for hints, |
1332 | case, you get to keep the pieces. I am always open for hints, though... |
1170 | though... |
1333 | |
|
|
1334 | Also keep in mind that JSON::XS might leak contents of your Perl data |
|
|
1335 | structures in its error messages, so when you serialise sensitive |
|
|
1336 | information you might want to make sure that exceptions thrown by JSON::XS |
|
|
1337 | will not end up in front of untrusted eyes. |
1171 | |
1338 | |
1172 | If you are using JSON::XS to return packets to consumption |
1339 | If you are using JSON::XS to return packets to consumption |
1173 | by JavaScript scripts in a browser you should have a look at |
1340 | by JavaScript scripts in a browser you should have a look at |
1174 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1341 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1175 | you are vulnerable to some common attack vectors (which really are browser |
1342 | you are vulnerable to some common attack vectors (which really are browser |
… | |
… | |
1181 | =head1 THREADS |
1348 | =head1 THREADS |
1182 | |
1349 | |
1183 | This module is I<not> guaranteed to be thread safe and there are no |
1350 | This module is I<not> guaranteed to be thread safe and there are no |
1184 | plans to change this until Perl gets thread support (as opposed to the |
1351 | plans to change this until Perl gets thread support (as opposed to the |
1185 | horribly slow so-called "threads" which are simply slow and bloated |
1352 | horribly slow so-called "threads" which are simply slow and bloated |
1186 | process simulations - use fork, its I<much> faster, cheaper, better). |
1353 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1187 | |
1354 | |
1188 | (It might actually work, but you have been warned). |
1355 | (It might actually work, but you have been warned). |
1189 | |
1356 | |
1190 | |
1357 | |
1191 | =head1 BUGS |
1358 | =head1 BUGS |
1192 | |
1359 | |
1193 | While the goal of this module is to be correct, that unfortunately does |
1360 | While the goal of this module is to be correct, that unfortunately does |
1194 | not mean its bug-free, only that I think its design is bug-free. It is |
1361 | not mean it's bug-free, only that I think its design is bug-free. If you |
1195 | still relatively early in its development. If you keep reporting bugs they |
1362 | keep reporting bugs they will be fixed swiftly, though. |
1196 | will be fixed swiftly, though. |
|
|
1197 | |
1363 | |
1198 | Please refrain from using rt.cpan.org or any other bug reporting |
1364 | Please refrain from using rt.cpan.org or any other bug reporting |
1199 | service. I put the contact address into my modules for a reason. |
1365 | service. I put the contact address into my modules for a reason. |
1200 | |
1366 | |
1201 | =cut |
1367 | =cut |
… | |
… | |
1221 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
1387 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
1222 | fallback => 1; |
1388 | fallback => 1; |
1223 | |
1389 | |
1224 | 1; |
1390 | 1; |
1225 | |
1391 | |
|
|
1392 | =head1 SEE ALSO |
|
|
1393 | |
|
|
1394 | The F<json_xs> command line utility for quick experiments. |
|
|
1395 | |
1226 | =head1 AUTHOR |
1396 | =head1 AUTHOR |
1227 | |
1397 | |
1228 | Marc Lehmann <schmorp@schmorp.de> |
1398 | Marc Lehmann <schmorp@schmorp.de> |
1229 | http://home.schmorp.de/ |
1399 | http://home.schmorp.de/ |
1230 | |
1400 | |