1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
|
<!-- HTML header for doxygen 1.8.7-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.8.7"/>
<title>RapidJSON: SAX</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="navtree.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="resize.js"></script>
<script type="text/javascript" src="navtree.js"></script>
<script type="text/javascript">
$(document).ready(initResizable);
$(window).load(resizeHeight);
</script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/search.js"></script>
<script type="text/javascript">
$(document).ready(function() { searchBox.OnSelectItem(0); });
</script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
<link href="doxygenextra.css" rel="stylesheet" type="text/css"/>
</head>
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-63929386-1', 'auto');
ga('send', 'pageview');
</script>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="topbanner"><a href="https://github.com/miloyip/rapidjson" title="RapidJSON GitHub"><i class="githublogo"></i></a></div>
<div id="MSearchBox" class="MSearchBoxInactive">
<span class="left">
<img id="MSearchSelect" src="search/mag_sel.png"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
alt=""/>
<input type="text" id="MSearchField" value="Search" accesskey="S"
onfocus="searchBox.OnSearchFieldFocus(true)"
onblur="searchBox.OnSearchFieldFocus(false)"
onkeyup="searchBox.OnSearchFieldChange(event)"/>
</span><span class="right">
<a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
</span>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.8.7 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
</div><!-- top -->
<div id="side-nav" class="ui-resizable side-nav-resizable">
<div id="nav-tree">
<div id="nav-tree-contents">
<div id="nav-sync" class="sync"></div>
</div>
</div>
<div id="splitbar" style="-moz-user-select:none;"
class="ui-resizable-handle">
</div>
</div>
<script type="text/javascript">
$(document).ready(function(){initNavTree('md_doc_sax.html','');});
</script>
<div id="doc-content">
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Classes</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Namespaces</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark"> </span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark"> </span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark"> </span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark"> </span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark"> </span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(9)"><span class="SelectionMark"> </span>Friends</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(10)"><span class="SelectionMark"> </span>Macros</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(11)"><span class="SelectionMark"> </span>Groups</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(12)"><span class="SelectionMark"> </span>Pages</a></div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div class="header">
<div class="headertitle">
<div class="title">SAX </div> </div>
</div><!--header-->
<div class="contents">
<div class="toc"><h3>Table of Contents</h3>
<ul><li class="level1"><a href="#Reader">Reader</a><ul><li class="level2"><a href="#Handler">Handler</a></li>
<li class="level2"><a href="#GenericReader">GenericReader</a></li>
</ul>
</li>
<li class="level1"><a href="#Writer">Writer</a><ul><li class="level2"><a href="#PrettyWriter">PrettyWriter</a></li>
<li class="level2"><a href="#CompletenessReset">Completeness and Reset</a></li>
<li class="level2"><a href="#CustomDataStructure">Parsing JSON to Custom Data Structure</a></li>
<li class="level2"><a href="#Filtering">Filtering of JSON</a></li>
</ul>
</li>
</ul>
</div>
<div class="textblock"><p>The term "SAX" originated from <a href="http://en.wikipedia.org/wiki/Simple_API_for_XML">Simple API for XML</a>. We borrowed this term for JSON parsing and generation.</p>
<p>In RapidJSON, <code>Reader</code> (typedef of <code>GenericReader<...></code>) is the SAX-style parser for JSON, and <code>Writer</code> (typedef of <code>GenericWriter<...></code>) is the SAX-style generator for JSON.</p>
<h1><a class="anchor" id="Reader"></a>
Reader</h1>
<p><code>Reader</code> parses a JSON from a stream. While it reads characters from the stream, it analyze the characters according to the syntax of JSON, and publish events to a handler.</p>
<p>For example, here is a JSON.</p>
<div class="fragment"><div class="line">{</div>
<div class="line"> <span class="stringliteral">"hello"</span>: <span class="stringliteral">"world"</span>,</div>
<div class="line"> <span class="stringliteral">"t"</span>: true ,</div>
<div class="line"> <span class="stringliteral">"f"</span>: <span class="keyword">false</span>,</div>
<div class="line"> <span class="stringliteral">"n"</span>: null,</div>
<div class="line"> <span class="stringliteral">"i"</span>: 123,</div>
<div class="line"> <span class="stringliteral">"pi"</span>: 3.1416,</div>
<div class="line"> <span class="stringliteral">"a"</span>: [1, 2, 3, 4]</div>
<div class="line">}</div>
</div><!-- fragment --><p>While a <code>Reader</code> parses this JSON, it publishes the following events to the handler sequentially:</p>
<div class="fragment"><div class="line">StartObject()</div>
<div class="line">Key("hello", 5, true)</div>
<div class="line">String("world", 5, true)</div>
<div class="line">Key("t", 1, true)</div>
<div class="line">Bool(true)</div>
<div class="line">Key("f", 1, true)</div>
<div class="line">Bool(false)</div>
<div class="line">Key("n", 1, true)</div>
<div class="line">Null()</div>
<div class="line">Key("i")</div>
<div class="line">UInt(123)</div>
<div class="line">Key("pi")</div>
<div class="line">Double(3.1416)</div>
<div class="line">Key("a")</div>
<div class="line">StartArray()</div>
<div class="line">Uint(1)</div>
<div class="line">Uint(2)</div>
<div class="line">Uint(3)</div>
<div class="line">Uint(4)</div>
<div class="line">EndArray(4)</div>
<div class="line">EndObject(7)</div>
</div><!-- fragment --><p>These events can be easily matched with the JSON, except some event parameters need further explanation. Let's see the <code>simplereader</code> example which produces exactly the same output as above:</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include "<a class="code" href="reader_8h.html">rapidjson/reader.h</a>"</span></div>
<div class="line"><span class="preprocessor">#include <iostream></span></div>
<div class="line"></div>
<div class="line"><span class="keyword">using namespace </span>rapidjson;</div>
<div class="line"><span class="keyword">using namespace </span>std;</div>
<div class="line"></div>
<div class="line"><span class="keyword">struct </span>MyHandler {</div>
<div class="line"> <span class="keywordtype">bool</span> Null() { cout << <span class="stringliteral">"Null()"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Bool(<span class="keywordtype">bool</span> b) { cout << <span class="stringliteral">"Bool("</span> << boolalpha << b << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Int(<span class="keywordtype">int</span> i) { cout << <span class="stringliteral">"Int("</span> << i << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Uint(<span class="keywordtype">unsigned</span> u) { cout << <span class="stringliteral">"Uint("</span> << u << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Int64(int64_t i) { cout << <span class="stringliteral">"Int64("</span> << i << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Uint64(uint64_t u) { cout << <span class="stringliteral">"Uint64("</span> << u << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Double(<span class="keywordtype">double</span> d) { cout << <span class="stringliteral">"Double("</span> << d << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> String(<span class="keyword">const</span> <span class="keywordtype">char</span>* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span> copy) { </div>
<div class="line"> cout << <span class="stringliteral">"String("</span> << str << <span class="stringliteral">", "</span> << length << <span class="stringliteral">", "</span> << boolalpha << copy << <span class="stringliteral">")"</span> << endl;</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordtype">bool</span> StartObject() { cout << <span class="stringliteral">"StartObject()"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> Key(<span class="keyword">const</span> <span class="keywordtype">char</span>* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span> copy) { </div>
<div class="line"> cout << <span class="stringliteral">"Key("</span> << str << <span class="stringliteral">", "</span> << length << <span class="stringliteral">", "</span> << boolalpha << copy << <span class="stringliteral">")"</span> << endl;</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordtype">bool</span> EndObject(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> memberCount) { cout << <span class="stringliteral">"EndObject("</span> << memberCount << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> StartArray() { cout << <span class="stringliteral">"StartArray()"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line"> <span class="keywordtype">bool</span> EndArray(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> elementCount) { cout << <span class="stringliteral">"EndArray("</span> << elementCount << <span class="stringliteral">")"</span> << endl; <span class="keywordflow">return</span> <span class="keyword">true</span>; }</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> main() {</div>
<div class="line"> <span class="keyword">const</span> <span class="keywordtype">char</span> json[] = <span class="stringliteral">" { \"hello\" : \"world\", \"t\" : true , \"f\" : false, \"n\": null, \"i\":123, \"pi\": 3.1416, \"a\":[1, 2, 3, 4] } "</span>;</div>
<div class="line"></div>
<div class="line"> MyHandler handler;</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_generic_reader.html">Reader</a> reader;</div>
<div class="line"> <a class="code" href="structrapidjson_1_1_generic_string_stream.html">StringStream</a> ss(json);</div>
<div class="line"> reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#ac9c540b77de19661f6f45e04b9b0937b">Parse</a>(ss, handler);</div>
<div class="line">}</div>
</div><!-- fragment --><p>Note that, RapidJSON uses template to statically bind the <code>Reader</code> type and the handler type, instead of using class with virtual functions. This paradigm can improve the performance by inlining functions.</p>
<h2><a class="anchor" id="Handler"></a>
Handler</h2>
<p>As the previous example showed, user needs to implement a handler, which consumes the events (function calls) from <code>Reader</code>. The handler must contain the following member functions.</p>
<div class="fragment"><div class="line"><span class="keyword">class </span>Handler {</div>
<div class="line"> <span class="keywordtype">bool</span> Null();</div>
<div class="line"> <span class="keywordtype">bool</span> Bool(<span class="keywordtype">bool</span> b);</div>
<div class="line"> <span class="keywordtype">bool</span> Int(<span class="keywordtype">int</span> i);</div>
<div class="line"> <span class="keywordtype">bool</span> Uint(<span class="keywordtype">unsigned</span> i);</div>
<div class="line"> <span class="keywordtype">bool</span> Int64(int64_t i);</div>
<div class="line"> <span class="keywordtype">bool</span> Uint64(uint64_t i);</div>
<div class="line"> <span class="keywordtype">bool</span> Double(<span class="keywordtype">double</span> d);</div>
<div class="line"> <span class="keywordtype">bool</span> String(<span class="keyword">const</span> Ch* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span> copy);</div>
<div class="line"> <span class="keywordtype">bool</span> StartObject();</div>
<div class="line"> <span class="keywordtype">bool</span> Key(<span class="keyword">const</span> Ch* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span> copy);</div>
<div class="line"> <span class="keywordtype">bool</span> EndObject(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> memberCount);</div>
<div class="line"> <span class="keywordtype">bool</span> StartArray();</div>
<div class="line"> <span class="keywordtype">bool</span> EndArray(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> elementCount);</div>
<div class="line">};</div>
</div><!-- fragment --><p><code>Null()</code> is called when the <code>Reader</code> encounters a JSON null value.</p>
<p><code>Bool(bool)</code> is called when the <code>Reader</code> encounters a JSON true or false value.</p>
<p>When the <code>Reader</code> encounters a JSON number, it chooses a suitable C++ type mapping. And then it calls <em>one</em> function out of <code>Int(int)</code>, <code>Uint(unsigned)</code>, <code>Int64(int64_t)</code>, <code>Uint64(uint64_t)</code> and <code>Double(double)</code>.</p>
<p><code>String(const char* str, SizeType length, bool copy)</code> is called when the <code>Reader</code> encounters a string. The first parameter is pointer to the string. The second parameter is the length of the string (excluding the null terminator). Note that RapidJSON supports null character `'\0'<code>inside a string. If such situation happens,</code>strlen(str) < length<code>. The last</code>copy<code>indicates whether the handler needs to make a copy of the string. For normal parsing,</code>copy = true<code>. Only when *insitu* parsing is used,</code>copy = false`. And beware that, the character type depends on the target encoding, which will be explained later.</p>
<p>When the <code>Reader</code> encounters the beginning of an object, it calls <code>StartObject()</code>. An object in JSON is a set of name-value pairs. If the object contains members it first calls <code>Key()</code> for the name of member, and then calls functions depending on the type of the value. These calls of name-value pairs repeats until calling <code>EndObject(SizeType memberCount)</code>. Note that the <code>memberCount</code> parameter is just an aid for the handler, user may not need this parameter.</p>
<p>Array is similar to object but simpler. At the beginning of an array, the <code>Reader</code> calls <code>BeginArary()</code>. If there is elements, it calls functions according to the types of element. Similarly, in the last call <code>EndArray(SizeType elementCount)</code>, the parameter <code>elementCount</code> is just an aid for the handler.</p>
<p>Every handler functions returns a <code>bool</code>. Normally it should returns <code>true</code>. If the handler encounters an error, it can return <code>false</code> to notify event publisher to stop further processing.</p>
<p>For example, when we parse a JSON with <code>Reader</code> and the handler detected that the JSON does not conform to the required schema, then the handler can return <code>false</code> and let the <code>Reader</code> stop further parsing. And the <code>Reader</code> will be in error state with error code <code>kParseErrorTermination</code>.</p>
<h2><a class="anchor" id="GenericReader"></a>
GenericReader</h2>
<p>As mentioned before, <code>Reader</code> is a typedef of a template class <code>GenericReader</code>:</p>
<div class="fragment"><div class="line"><span class="keyword">namespace </span>rapidjson {</div>
<div class="line"></div>
<div class="line"><span class="keyword">template</span> <<span class="keyword">typename</span> SourceEncoding, <span class="keyword">typename</span> TargetEncoding, <span class="keyword">typename</span> Allocator = MemoryPoolAllocator<> ></div>
<div class="line"><span class="keyword">class </span>GenericReader {</div>
<div class="line"> <span class="comment">// ...</span></div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="keyword">typedef</span> GenericReader<UTF8<>, UTF8<> > <a class="code" href="namespacerapidjson.html#a4eaef42a208413d1f2c8d4655ecec52d">Reader</a>;</div>
<div class="line"></div>
<div class="line">} <span class="comment">// namespace rapidjson</span></div>
</div><!-- fragment --><p>The <code>Reader</code> uses UTF-8 as both source and target encoding. The source encoding means the encoding in the JSON stream. The target encoding means the encoding of the <code>str</code> parameter in <code>String()</code> calls. For example, to parse a UTF-8 stream and outputs UTF-16 string events, you can define a reader by:</p>
<div class="fragment"><div class="line">GenericReader<UTF8<>, UTF16<> > reader;</div>
</div><!-- fragment --><p>Note that, the default character type of <code>UTF16</code> is <code>wchar_t</code>. So this <code>reader</code>needs to call <code>String(const wchar_t*, SizeType, bool)</code> of the handler.</p>
<p>The third template parameter <code>Allocator</code> is the allocator type for internal data structure (actually a stack).</p>
<h2><a class="anchor" id="Parsing"></a>
Parsing</h2>
<p>The one and only one function of <code>Reader</code> is to parse JSON.</p>
<div class="fragment"><div class="line"><span class="keyword">template</span> <<span class="keywordtype">unsigned</span> parseFlags, <span class="keyword">typename</span> InputStream, <span class="keyword">typename</span> Handler></div>
<div class="line"><span class="keywordtype">bool</span> Parse(InputStream& is, Handler& handler);</div>
<div class="line"></div>
<div class="line"><span class="comment">// with parseFlags = kDefaultParseFlags</span></div>
<div class="line"><span class="keyword">template</span> <<span class="keyword">typename</span> InputStream, <span class="keyword">typename</span> Handler></div>
<div class="line"><span class="keywordtype">bool</span> Parse(InputStream& is, Handler& handler);</div>
</div><!-- fragment --><p>If an error occurs during parsing, it will return <code>false</code>. User can also calls <code>bool HasParseEror()</code>, <code>ParseErrorCode GetParseErrorCode()</code> and <code>size_t GetErrorOffset()</code> to obtain the error states. Actually <code>Document</code> uses these <code>Reader</code> functions to obtain parse errors. Please refer to <a class="el" href="md_doc_dom.html">DOM</a> for details about parse error.</p>
<h1><a class="anchor" id="Writer"></a>
Writer</h1>
<p><code>Reader</code> converts (parses) JSON into events. <code>Writer</code> does exactly the opposite. It converts events into JSON.</p>
<p><code>Writer</code> is very easy to use. If your application only need to converts some data into JSON, it may be a good choice to use <code>Writer</code> directly, instead of building a <code>Document</code> and then stringifying it with a <code>Writer</code>.</p>
<p>In <code>simplewriter</code> example, we do exactly the reverse of <code>simplereader</code>.</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include "rapidjson/writer.h"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/stringbuffer.h"</span></div>
<div class="line"><span class="preprocessor">#include <iostream></span></div>
<div class="line"></div>
<div class="line"><span class="keyword">using namespace </span>rapidjson;</div>
<div class="line"><span class="keyword">using namespace </span>std;</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> main() {</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_generic_string_buffer.html">StringBuffer</a> s;</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_writer.html">Writer<StringBuffer></a> writer(s);</div>
<div class="line"></div>
<div class="line"> writer.StartObject();</div>
<div class="line"> writer.Key(<span class="stringliteral">"hello"</span>);</div>
<div class="line"> writer.String(<span class="stringliteral">"world"</span>);</div>
<div class="line"> writer.Key(<span class="stringliteral">"t"</span>);</div>
<div class="line"> writer.Bool(<span class="keyword">true</span>);</div>
<div class="line"> writer.Key(<span class="stringliteral">"f"</span>);</div>
<div class="line"> writer.Bool(<span class="keyword">false</span>);</div>
<div class="line"> writer.Key(<span class="stringliteral">"n"</span>);</div>
<div class="line"> writer.Null();</div>
<div class="line"> writer.Key(<span class="stringliteral">"i"</span>);</div>
<div class="line"> writer.Uint(123);</div>
<div class="line"> writer.Key(<span class="stringliteral">"pi"</span>);</div>
<div class="line"> writer.<a class="code" href="classrapidjson_1_1_writer.html#ad5f042d9c1a8ce5be2d52e18255b4390">Double</a>(3.1416);</div>
<div class="line"> writer.Key(<span class="stringliteral">"a"</span>);</div>
<div class="line"> writer.StartArray();</div>
<div class="line"> <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i = 0; i < 4; i++)</div>
<div class="line"> writer.Uint(i);</div>
<div class="line"> writer.EndArray();</div>
<div class="line"> writer.EndObject();</div>
<div class="line"></div>
<div class="line"> cout << s.GetString() << endl;</div>
<div class="line">}</div>
</div><!-- fragment --><div class="fragment"><div class="line">{<span class="stringliteral">"hello"</span>:<span class="stringliteral">"world"</span>,<span class="stringliteral">"t"</span>:<span class="keyword">true</span>,<span class="stringliteral">"f"</span>:<span class="keyword">false</span>,<span class="stringliteral">"n"</span>:null,<span class="stringliteral">"i"</span>:123,<span class="stringliteral">"pi"</span>:3.1416,<span class="stringliteral">"a"</span>:[0,1,2,3]}</div>
</div><!-- fragment --><p>There are two <code>String()</code> and <code>Key()</code> overloads. One is the same as defined in handler concept with 3 parameters. It can handle string with null characters. Another one is the simpler version used in the above example.</p>
<p>Note that, the example code does not pass any parameters in <code>EndArray()</code> and <code>EndObject()</code>. An <code>SizeType</code> can be passed but it will be simply ignored by <code>Writer</code>.</p>
<p>You may doubt that, why not just using <code>sprintf()</code> or <code>std::stringstream</code> to build a JSON?</p>
<p>There are various reasons:</p><ol type="1">
<li><code>Writer</code> must output a well-formed JSON. If there is incorrect event sequence (e.g. <code>Int()</code> just after <code>StartObject()</code>), it generates assertion fail in debug mode.</li>
<li><code>Writer::String()</code> can handle string escaping (e.g. converting code point <code>U+000A</code> to <code>\n</code>) and Unicode transcoding.</li>
<li><code>Writer</code> handles number output consistently.</li>
<li><code>Writer</code> implements the event handler concept. It can be used to handle events from <code>Reader</code>, <code>Document</code> or other event publisher.</li>
<li><code>Writer</code> can be optimized for different platforms.</li>
</ol>
<p>Anyway, using <code>Writer</code> API is even simpler than generating a JSON by ad hoc methods.</p>
<h2><a class="anchor" id=""></a>
</h2>
<p><code>Writer</code> has a minor design difference to <code>Reader</code>. <code>Writer</code> is a template class, not a typedef. There is no <code>GenericWriter</code>. The following is the declaration.</p>
<div class="fragment"><div class="line"><span class="keyword">namespace </span>rapidjson {</div>
<div class="line"></div>
<div class="line"><span class="keyword">template</span><<span class="keyword">typename</span> OutputStream, <span class="keyword">typename</span> SourceEncoding = UTF8<>, <span class="keyword">typename</span> TargetEncoding = UTF8<>, <span class="keyword">typename</span> Allocator = CrtAllocator<> ></div>
<div class="line"><span class="keyword">class </span>Writer {</div>
<div class="line"><span class="keyword">public</span>:</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_writer.html#ac592904fad01d9d0f29bb0585fb02aa7">Writer</a>(OutputStream& os, Allocator* allocator = 0, <span class="keywordtype">size_t</span> levelDepth = kDefaultLevelDepth)</div>
<div class="line"><span class="comment">// ...</span></div>
<div class="line">};</div>
<div class="line"></div>
<div class="line">} <span class="comment">// namespace rapidjson</span></div>
</div><!-- fragment --><p>The <code>OutputStream</code> template parameter is the type of output stream. It cannot be deduced and must be specified by user.</p>
<p>The <code>SourceEncoding</code> template parameter specifies the encoding to be used in <code>String(const Ch*, ...)</code>.</p>
<p>The <code>TargetEncoding</code> template parameter specifies the encoding in the output stream.</p>
<p>The last one, <code>Allocator</code> is the type of allocator, which is used for allocating internal data structure (a stack).</p>
<p>Besides, the constructor of <code>Writer</code> has a <code>levelDepth</code> parameter. This parameter affects the initial memory allocated for storing information per hierarchy level.</p>
<h2><a class="anchor" id="PrettyWriter"></a>
PrettyWriter</h2>
<p>While the output of <code>Writer</code> is the most condensed JSON without white-spaces, suitable for network transfer or storage, it is not easily readable by human.</p>
<p>Therefore, RapidJSON provides a <code>PrettyWriter</code>, which adds indentation and line feeds in the output.</p>
<p>The usage of <code>PrettyWriter</code> is exactly the same as <code>Writer</code>, expect that <code>PrettyWriter</code> provides a <code>SetIndent(Ch indentChar, unsigned indentCharCount)</code> function. The default is 4 spaces.</p>
<h2><a class="anchor" id="CompletenessReset"></a>
Completeness and Reset</h2>
<p>A <code>Writer</code> can only output a single JSON, which can be any JSON type at the root. Once the singular event for root (e.g. <code>String()</code>), or the last matching <code>EndObject()</code> or <code>EndArray()</code> event, is handled, the output JSON is well-formed and complete. User can detect this state by calling <code>Writer::IsComplete()</code>.</p>
<p>When a JSON is complete, the <code>Writer</code> cannot accept any new events. Otherwise the output will be invalid (i.e. having more than one root). To reuse the <code>Writer</code> object, user can call <code>Writer::Reset(OutputStream& os)</code> to reset all internal states of the <code>Writer</code> with a new output stream.</p>
<h1><a class="anchor" id="Techniques"></a>
Techniques</h1>
<h2><a class="anchor" id="CustomDataStructure"></a>
Parsing JSON to Custom Data Structure</h2>
<p><code>Document</code>'s parsing capability is completely based on <code>Reader</code>. Actually <code>Document</code> is a handler which receives events from a reader to build a DOM during parsing.</p>
<p>User may uses <code>Reader</code> to build other data structures directly. This eliminates building of DOM, thus reducing memory and improving performance.</p>
<p>In the following <code>messagereader</code> example, <code>ParseMessages()</code> parses a JSON which should be an object with key-string pairs.</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include "<a class="code" href="reader_8h.html">rapidjson/reader.h</a>"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/error/en.h"</span></div>
<div class="line"><span class="preprocessor">#include <iostream></span></div>
<div class="line"><span class="preprocessor">#include <string></span></div>
<div class="line"><span class="preprocessor">#include <map></span></div>
<div class="line"></div>
<div class="line"><span class="keyword">using namespace </span>std;</div>
<div class="line"><span class="keyword">using namespace </span>rapidjson;</div>
<div class="line"></div>
<div class="line"><span class="keyword">typedef</span> map<string, string> MessageMap;</div>
<div class="line"></div>
<div class="line"><span class="keyword">struct </span>MessageHandler</div>
<div class="line"> : <span class="keyword">public</span> <a class="code" href="structrapidjson_1_1_base_reader_handler.html">BaseReaderHandler</a><UTF8<>, MessageHandler> {</div>
<div class="line"> MessageHandler() : state_(kExpectObjectStart) {</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordtype">bool</span> StartObject() {</div>
<div class="line"> <span class="keywordflow">switch</span> (state_) {</div>
<div class="line"> <span class="keywordflow">case</span> kExpectObjectStart:</div>
<div class="line"> state_ = kExpectNameOrObjectEnd;</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"> <span class="keywordflow">default</span>:</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"> }</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordtype">bool</span> String(<span class="keyword">const</span> <span class="keywordtype">char</span>* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span>) {</div>
<div class="line"> <span class="keywordflow">switch</span> (state_) {</div>
<div class="line"> <span class="keywordflow">case</span> kExpectNameOrObjectEnd:</div>
<div class="line"> name_ = string(str, length);</div>
<div class="line"> state_ = kExpectValue;</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"> <span class="keywordflow">case</span> kExpectValue:</div>
<div class="line"> messages_.insert(MessageMap::value_type(name_, <span class="keywordtype">string</span>(str, length)));</div>
<div class="line"> state_ = kExpectNameOrObjectEnd;</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"> <span class="keywordflow">default</span>:</div>
<div class="line"> <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"> }</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordtype">bool</span> EndObject(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a>) { <span class="keywordflow">return</span> state_ == kExpectNameOrObjectEnd; }</div>
<div class="line"></div>
<div class="line"> <span class="keywordtype">bool</span> Default() { <span class="keywordflow">return</span> <span class="keyword">false</span>; } <span class="comment">// All other events are invalid.</span></div>
<div class="line"></div>
<div class="line"> MessageMap messages_;</div>
<div class="line"> <span class="keyword">enum</span> State {</div>
<div class="line"> kExpectObjectStart,</div>
<div class="line"> kExpectNameOrObjectEnd,</div>
<div class="line"> kExpectValue,</div>
<div class="line"> }state_;</div>
<div class="line"> std::string name_;</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">void</span> ParseMessages(<span class="keyword">const</span> <span class="keywordtype">char</span>* json, MessageMap& messages) {</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_generic_reader.html">Reader</a> reader;</div>
<div class="line"> MessageHandler handler;</div>
<div class="line"> <a class="code" href="structrapidjson_1_1_generic_string_stream.html">StringStream</a> ss(json);</div>
<div class="line"> <span class="keywordflow">if</span> (reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#ac9c540b77de19661f6f45e04b9b0937b">Parse</a>(ss, handler))</div>
<div class="line"> messages.swap(handler.messages_); <span class="comment">// Only change it if success.</span></div>
<div class="line"> <span class="keywordflow">else</span> {</div>
<div class="line"> <a class="code" href="group___r_a_p_i_d_j_s_o_n___e_r_r_o_r_s.html#ga7d3acf640886b1f2552dc8c4cd6dea60">ParseErrorCode</a> e = reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#a40fd326bad7d7033f096b549cbf159db">GetParseErrorCode</a>();</div>
<div class="line"> <span class="keywordtype">size_t</span> o = reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#ab907a36c410e96154c99797a6a0ce16d">GetErrorOffset</a>();</div>
<div class="line"> cout << <span class="stringliteral">"Error: "</span> << <a class="code" href="group___r_a_p_i_d_j_s_o_n___e_r_r_o_r_s.html#gabdaf1a7a4db30fb0e3d927fdf0fabe79">GetParseError_En</a>(e) << endl;;</div>
<div class="line"> cout << <span class="stringliteral">" at offset "</span> << o << <span class="stringliteral">" near '"</span> << string(json).substr(o, 10) << <span class="stringliteral">"...'"</span> << endl;</div>
<div class="line"> }</div>
<div class="line">}</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">int</span> main() {</div>
<div class="line"> MessageMap messages;</div>
<div class="line"></div>
<div class="line"> <span class="keyword">const</span> <span class="keywordtype">char</span>* json1 = <span class="stringliteral">"{ \"greeting\" : \"Hello!\", \"farewell\" : \"bye-bye!\" }"</span>;</div>
<div class="line"> cout << json1 << endl;</div>
<div class="line"> ParseMessages(json1, messages);</div>
<div class="line"></div>
<div class="line"> <span class="keywordflow">for</span> (MessageMap::const_iterator itr = messages.begin(); itr != messages.end(); ++itr)</div>
<div class="line"> cout << itr->first << <span class="stringliteral">": "</span> << itr->second << endl;</div>
<div class="line"></div>
<div class="line"> cout << endl << <span class="stringliteral">"Parse a JSON with invalid schema."</span> << endl;</div>
<div class="line"> <span class="keyword">const</span> <span class="keywordtype">char</span>* json2 = <span class="stringliteral">"{ \"greeting\" : \"Hello!\", \"farewell\" : \"bye-bye!\", \"foo\" : {} }"</span>;</div>
<div class="line"> cout << json2 << endl;</div>
<div class="line"> ParseMessages(json2, messages);</div>
<div class="line"></div>
<div class="line"> <span class="keywordflow">return</span> 0;</div>
<div class="line">}</div>
</div><!-- fragment --><div class="fragment"><div class="line">{ <span class="stringliteral">"greeting"</span> : <span class="stringliteral">"Hello!"</span>, <span class="stringliteral">"farewell"</span> : <span class="stringliteral">"bye-bye!"</span> }</div>
<div class="line">farewell: bye-bye!</div>
<div class="line">greeting: Hello!</div>
<div class="line"></div>
<div class="line">Parse a JSON with invalid schema.</div>
<div class="line">{ <span class="stringliteral">"greeting"</span> : <span class="stringliteral">"Hello!"</span>, <span class="stringliteral">"farewell"</span> : <span class="stringliteral">"bye-bye!"</span>, <span class="stringliteral">"foo"</span> : {} }</div>
<div class="line">Error: Terminate parsing due to Handler error.</div>
<div class="line"> at offset 59 near <span class="stringliteral">'} }...'</span></div>
</div><!-- fragment --><p>The first JSON (<code>json1</code>) was successfully parsed into <code>MessageMap</code>. Since <code>MessageMap</code> is a <code>std::map</code>, the printing order are sorted by the key. This order is different from the JSON's order.</p>
<p>In the second JSON (<code>json2</code>), <code>foo</code>'s value is an empty object. As it is an object, <code>MessageHandler::StartObject()</code> will be called. However, at that moment <code>state_ = kExpectValue</code>, so that function returns <code>false</code> and cause the parsing process be terminated. The error code is <code>kParseErrorTermination</code>.</p>
<h2><a class="anchor" id="Filtering"></a>
Filtering of JSON</h2>
<p>As mentioned earlier, <code>Writer</code> can handle the events published by <code>Reader</code>. <code>condense</code> example simply set a <code>Writer</code> as handler of a <code>Reader</code>, so it can remove all white-spaces in JSON. <code>pretty</code> example uses the same relationship, but replacing <code>Writer</code> by <code>PrettyWriter</code>. So <code>pretty</code> can be used to reformat a JSON with indentation and line feed.</p>
<p>Actually, we can add intermediate layer(s) to filter the contents of JSON via these SAX-style API. For example, <code>capitalize</code> example capitalize all strings in a JSON.</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include "<a class="code" href="reader_8h.html">rapidjson/reader.h</a>"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/writer.h"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/filereadstream.h"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/filewritestream.h"</span></div>
<div class="line"><span class="preprocessor">#include "rapidjson/error/en.h"</span></div>
<div class="line"><span class="preprocessor">#include <vector></span></div>
<div class="line"><span class="preprocessor">#include <cctype></span></div>
<div class="line"></div>
<div class="line"><span class="keyword">using namespace </span>rapidjson;</div>
<div class="line"></div>
<div class="line"><span class="keyword">template</span><<span class="keyword">typename</span> OutputHandler></div>
<div class="line"><span class="keyword">struct </span>CapitalizeFilter {</div>
<div class="line"> CapitalizeFilter(OutputHandler& out) : out_(out), buffer_() {</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordtype">bool</span> Null() { <span class="keywordflow">return</span> out_.Null(); }</div>
<div class="line"> <span class="keywordtype">bool</span> Bool(<span class="keywordtype">bool</span> b) { <span class="keywordflow">return</span> out_.Bool(b); }</div>
<div class="line"> <span class="keywordtype">bool</span> Int(<span class="keywordtype">int</span> i) { <span class="keywordflow">return</span> out_.Int(i); }</div>
<div class="line"> <span class="keywordtype">bool</span> Uint(<span class="keywordtype">unsigned</span> u) { <span class="keywordflow">return</span> out_.Uint(u); }</div>
<div class="line"> <span class="keywordtype">bool</span> Int64(int64_t i) { <span class="keywordflow">return</span> out_.Int64(i); }</div>
<div class="line"> <span class="keywordtype">bool</span> Uint64(uint64_t u) { <span class="keywordflow">return</span> out_.Uint64(u); }</div>
<div class="line"> <span class="keywordtype">bool</span> Double(<span class="keywordtype">double</span> d) { <span class="keywordflow">return</span> out_.Double(d); }</div>
<div class="line"> <span class="keywordtype">bool</span> String(<span class="keyword">const</span> <span class="keywordtype">char</span>* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span>) { </div>
<div class="line"> buffer_.clear();</div>
<div class="line"> <span class="keywordflow">for</span> (<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> i = 0; i < length; i++)</div>
<div class="line"> buffer_.push_back(std::toupper(str[i]));</div>
<div class="line"> <span class="keywordflow">return</span> out_.String(&buffer_.front(), length, <span class="keyword">true</span>); <span class="comment">// true = output handler need to copy the string</span></div>
<div class="line"> }</div>
<div class="line"> <span class="keywordtype">bool</span> StartObject() { <span class="keywordflow">return</span> out_.StartObject(); }</div>
<div class="line"> <span class="keywordtype">bool</span> Key(<span class="keyword">const</span> <span class="keywordtype">char</span>* str, <a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> length, <span class="keywordtype">bool</span> copy) { <span class="keywordflow">return</span> String(str, length, copy); }</div>
<div class="line"> <span class="keywordtype">bool</span> EndObject(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> memberCount) { <span class="keywordflow">return</span> out_.EndObject(memberCount); }</div>
<div class="line"> <span class="keywordtype">bool</span> StartArray() { <span class="keywordflow">return</span> out_.StartArray(); }</div>
<div class="line"> <span class="keywordtype">bool</span> EndArray(<a class="code" href="namespacerapidjson.html#a44eb33eaa523e36d466b1ced64b85c84">SizeType</a> elementCount) { <span class="keywordflow">return</span> out_.EndArray(elementCount); }</div>
<div class="line"></div>
<div class="line"> OutputHandler& out_;</div>
<div class="line"> std::vector<char> buffer_;</div>
<div class="line">};</div>
<div class="line"></div>
<div class="line"><span class="keywordtype">int</span> main(<span class="keywordtype">int</span>, <span class="keywordtype">char</span>*[]) {</div>
<div class="line"> <span class="comment">// Prepare JSON reader and input stream.</span></div>
<div class="line"> <a class="code" href="classrapidjson_1_1_generic_reader.html">Reader</a> reader;</div>
<div class="line"> <span class="keywordtype">char</span> readBuffer[65536];</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_file_read_stream.html">FileReadStream</a> is(stdin, readBuffer, <span class="keyword">sizeof</span>(readBuffer));</div>
<div class="line"></div>
<div class="line"> <span class="comment">// Prepare JSON writer and output stream.</span></div>
<div class="line"> <span class="keywordtype">char</span> writeBuffer[65536];</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_file_write_stream.html">FileWriteStream</a> os(stdout, writeBuffer, <span class="keyword">sizeof</span>(writeBuffer));</div>
<div class="line"> <a class="code" href="classrapidjson_1_1_writer.html">Writer<FileWriteStream></a> writer(os);</div>
<div class="line"></div>
<div class="line"> <span class="comment">// JSON reader parse from the input stream and let writer generate the output.</span></div>
<div class="line"> CapitalizeFilter<Writer<FileWriteStream> > filter(writer);</div>
<div class="line"> <span class="keywordflow">if</span> (!reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#ac9c540b77de19661f6f45e04b9b0937b">Parse</a>(is, filter)) {</div>
<div class="line"> fprintf(stderr, <span class="stringliteral">"\nError(%u): %s\n"</span>, (<span class="keywordtype">unsigned</span>)reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#ab907a36c410e96154c99797a6a0ce16d">GetErrorOffset</a>(), <a class="code" href="group___r_a_p_i_d_j_s_o_n___e_r_r_o_r_s.html#gabdaf1a7a4db30fb0e3d927fdf0fabe79">GetParseError_En</a>(reader.<a class="code" href="classrapidjson_1_1_generic_reader.html#a40fd326bad7d7033f096b549cbf159db">GetParseErrorCode</a>()));</div>
<div class="line"> <span class="keywordflow">return</span> 1;</div>
<div class="line"> }</div>
<div class="line"></div>
<div class="line"> <span class="keywordflow">return</span> 0;</div>
<div class="line">}</div>
</div><!-- fragment --><p>Note that, it is incorrect to simply capitalize the JSON as a string. For example: </p><div class="fragment"><div class="line">[<span class="stringliteral">"Hello\nWorld"</span>]</div>
</div><!-- fragment --><p>Simply capitalizing the whole JSON would contain incorrect escape character: </p><div class="fragment"><div class="line">[<span class="stringliteral">"HELLO\NWORLD"</span>]</div>
</div><!-- fragment --><p>The correct result by <code>capitalize</code>: </p><div class="fragment"><div class="line">[<span class="stringliteral">"HELLO\nWORLD"</span>]</div>
</div><!-- fragment --><p>More complicated filters can be developed. However, since SAX-style API can only provide information about a single event at a time, user may need to book-keeping the contextual information (e.g. the path from root value, storage of other related values). Some processing may be easier to be implemented in DOM than SAX. </p>
</div></div><!-- contents -->
</div><!-- doc-content -->
<!-- HTML footer for doxygen 1.8.7-->
<!-- start footer part -->
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
<ul>
</ul>
</div>
<script type="text/javascript">
/* * * CONFIGURATION VARIABLES * * */
var disqus_shortname = 'rapidjson-doc';
/* * * DON'T EDIT BELOW THIS LINE * * */
(function() {
var dt = document.createElement('div');
dt.id = "disqus_thread";
(document.getElementsByClassName('contents')[0]).appendChild(dt);
var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js';
(document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
})();
</script>
</body>
</html>
|
