writer.h revision f59fb0e83fd0a4b41700d3f5eebdc8d21b173c2e 
1// Copyright 2007-2010 Baptiste Lepilleur
2// Distributed under MIT license, or public domain if desired and
3// recognized in your jurisdiction.
4// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
5
6#ifndef JSON_WRITER_H_INCLUDED
7# define JSON_WRITER_H_INCLUDED
8
9#if !defined(JSON_IS_AMALGAMATION)
10# include "value.h"
11#endif // if !defined(JSON_IS_AMALGAMATION)
12# include <vector>
13# include <string>
14
15namespace Json {
16
17   class Value;
18
19   /** \brief Abstract class for writers.
20    */
21   class JSON_API Writer
22   {
23   public:
24      virtual ~Writer();
25
26      virtual std::string write( const Value &root ) = 0;
27   };
28
29   /** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format without formatting (not human friendly).
30    *
31    * The JSON document is written in a single line. It is not intended for 'human' consumption,
32    * but may be usefull to support feature such as RPC where bandwith is limited.
33    * \sa Reader, Value
34    */
35   class JSON_API FastWriter : public Writer
36   {
37   public:
38      FastWriter();
39      virtual ~FastWriter(){}
40
41      void enableYAMLCompatibility();
42
43   public: // overridden from Writer
44      virtual std::string write( const Value &root );
45
46   private:
47      void writeValue( const Value &value );
48
49      std::string document_;
50      bool yamlCompatiblityEnabled_;
51   };
52
53   /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way.
54    *
55    * The rules for line break and indent are as follow:
56    * - Object value:
57    *     - if empty then print {} without indent and line break
58    *     - if not empty the print '{', line break & indent, print one value per line
59    *       and then unindent and line break and print '}'.
60    * - Array value:
61    *     - if empty then print [] without indent and line break
62    *     - if the array contains no object value, empty array or some other value types,
63    *       and all the values fit on one lines, then print the array on a single line.
64    *     - otherwise, it the values do not fit on one line, or the array contains
65    *       object or non empty array, then print one value per line.
66    *
67    * If the Value have comments then they are outputed according to their #CommentPlacement.
68    *
69    * \sa Reader, Value, Value::setComment()
70    */
71   class JSON_API StyledWriter: public Writer
72   {
73   public:
74      StyledWriter();
75      virtual ~StyledWriter(){}
76
77   public: // overridden from Writer
78      /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
79       * \param root Value to serialize.
80       * \return String containing the JSON document that represents the root value.
81       */
82      virtual std::string write( const Value &root );
83
84   private:
85      void writeValue( const Value &value );
86      void writeArrayValue( const Value &value );
87      bool isMultineArray( const Value &value );
88      void pushValue( const std::string &value );
89      void writeIndent();
90      void writeWithIndent( const std::string &value );
91      void indent();
92      void unindent();
93      void writeCommentBeforeValue( const Value &root );
94      void writeCommentAfterValueOnSameLine( const Value &root );
95      bool hasCommentForValue( const Value &value );
96      static std::string normalizeEOL( const std::string &text );
97
98      typedef std::vector<std::string> ChildValues;
99
100      ChildValues childValues_;
101      std::string document_;
102      std::string indentString_;
103      int rightMargin_;
104      int indentSize_;
105      bool addChildValues_;
106   };
107
108   /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way,
109        to a stream rather than to a string.
110    *
111    * The rules for line break and indent are as follow:
112    * - Object value:
113    *     - if empty then print {} without indent and line break
114    *     - if not empty the print '{', line break & indent, print one value per line
115    *       and then unindent and line break and print '}'.
116    * - Array value:
117    *     - if empty then print [] without indent and line break
118    *     - if the array contains no object value, empty array or some other value types,
119    *       and all the values fit on one lines, then print the array on a single line.
120    *     - otherwise, it the values do not fit on one line, or the array contains
121    *       object or non empty array, then print one value per line.
122    *
123    * If the Value have comments then they are outputed according to their #CommentPlacement.
124    *
125    * \param indentation Each level will be indented by this amount extra.
126    * \sa Reader, Value, Value::setComment()
127    */
128   class JSON_API StyledStreamWriter
129   {
130   public:
131      StyledStreamWriter( std::string indentation="\t" );
132      ~StyledStreamWriter(){}
133
134   public:
135      /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
136       * \param out Stream to write to. (Can be ostringstream, e.g.)
137       * \param root Value to serialize.
138       * \note There is no point in deriving from Writer, since write() should not return a value.
139       */
140      void write( std::ostream &out, const Value &root );
141
142   private:
143      void writeValue( const Value &value );
144      void writeArrayValue( const Value &value );
145      bool isMultineArray( const Value &value );
146      void pushValue( const std::string &value );
147      void writeIndent();
148      void writeWithIndent( const std::string &value );
149      void indent();
150      void unindent();
151      void writeCommentBeforeValue( const Value &root );
152      void writeCommentAfterValueOnSameLine( const Value &root );
153      bool hasCommentForValue( const Value &value );
154      static std::string normalizeEOL( const std::string &text );
155
156      typedef std::vector<std::string> ChildValues;
157
158      ChildValues childValues_;
159      std::ostream* document_;
160      std::string indentString_;
161      int rightMargin_;
162      std::string indentation_;
163      bool addChildValues_;
164   };
165
166# if defined(JSON_HAS_INT64)
167   std::string JSON_API valueToString( Int value );
168   std::string JSON_API valueToString( UInt value );
169# endif // if defined(JSON_HAS_INT64)
170   std::string JSON_API valueToString( LargestInt value );
171   std::string JSON_API valueToString( LargestUInt value );
172   std::string JSON_API valueToString( double value );
173   std::string JSON_API valueToString( bool value );
174   std::string JSON_API valueToQuotedString( const char *value );
175
176   /// \brief Output using the StyledStreamWriter.
177   /// \see Json::operator>>()
178   std::ostream& operator<<( std::ostream&, const Value &root );
179
180} // namespace Json
181
182
183
184#endif // JSON_WRITER_H_INCLUDED
185