summaryrefslogtreecommitdiff
path: root/boost/property_tree/detail/json_parser_write.hpp
blob: b52c8eac6f316e5c3b42029c87068544d1ccf94c (plain)
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
// ----------------------------------------------------------------------------
// Copyright (C) 2002-2006 Marcin Kalicinski
//
// Distributed under the Boost Software License, Version 1.0. 
// (See accompanying file LICENSE_1_0.txt or copy at 
// http://www.boost.org/LICENSE_1_0.txt)
//
// For more information, see www.boost.org
// ----------------------------------------------------------------------------
#ifndef BOOST_PROPERTY_TREE_DETAIL_JSON_PARSER_WRITE_HPP_INCLUDED
#define BOOST_PROPERTY_TREE_DETAIL_JSON_PARSER_WRITE_HPP_INCLUDED

#include <boost/property_tree/ptree.hpp>
#include <boost/next_prior.hpp>
#include <boost/type_traits/make_unsigned.hpp>
#include <string>
#include <ostream>
#include <iomanip>

namespace boost { namespace property_tree { namespace json_parser
{

    // Create necessary escape sequences from illegal characters
    template<class Ch>
    std::basic_string<Ch> create_escapes(const std::basic_string<Ch> &s)
    {
        std::basic_string<Ch> result;
        typename std::basic_string<Ch>::const_iterator b = s.begin();
        typename std::basic_string<Ch>::const_iterator e = s.end();
        while (b != e)
        {
            // This assumes an ASCII superset. But so does everything in PTree.
            // We escape everything outside ASCII, because this code can't
            // handle high unicode characters.
            if (*b == 0x20 || *b == 0x21 || (*b >= 0x23 && *b <= 0x2E) ||
                (*b >= 0x30 && *b <= 0x5B) || (*b >= 0x5D && *b <= 0xFF))
                result += *b;
            else if (*b == Ch('\b')) result += Ch('\\'), result += Ch('b');
            else if (*b == Ch('\f')) result += Ch('\\'), result += Ch('f');
            else if (*b == Ch('\n')) result += Ch('\\'), result += Ch('n');
            else if (*b == Ch('\r')) result += Ch('\\'), result += Ch('r');
            else if (*b == Ch('\t')) result += Ch('\\'), result += Ch('t');
            else if (*b == Ch('/')) result += Ch('\\'), result += Ch('/');
            else if (*b == Ch('"'))  result += Ch('\\'), result += Ch('"');
            else if (*b == Ch('\\')) result += Ch('\\'), result += Ch('\\');
            else
            {
                const char *hexdigits = "0123456789ABCDEF";
                typedef typename make_unsigned<Ch>::type UCh;
                unsigned long u = (std::min)(static_cast<unsigned long>(
                                                 static_cast<UCh>(*b)),
                                             0xFFFFul);
                int d1 = u / 4096; u -= d1 * 4096;
                int d2 = u / 256; u -= d2 * 256;
                int d3 = u / 16; u -= d3 * 16;
                int d4 = u;
                result += Ch('\\'); result += Ch('u');
                result += Ch(hexdigits[d1]); result += Ch(hexdigits[d2]);
                result += Ch(hexdigits[d3]); result += Ch(hexdigits[d4]);
            }
            ++b;
        }
        return result;
    }

    template<class Ptree>
    void write_json_helper(std::basic_ostream<typename Ptree::key_type::value_type> &stream, 
                           const Ptree &pt,
                           int indent, bool pretty)
    {

        typedef typename Ptree::key_type::value_type Ch;
        typedef typename std::basic_string<Ch> Str;

        // Value or object or array
        if (indent > 0 && pt.empty())
        {
            // Write value
            Str data = create_escapes(pt.template get_value<Str>());
            stream << Ch('"') << data << Ch('"');

        }
        else if (indent > 0 && pt.count(Str()) == pt.size())
        {
            // Write array
            stream << Ch('[');
            if (pretty) stream << Ch('\n');
            typename Ptree::const_iterator it = pt.begin();
            for (; it != pt.end(); ++it)
            {
                if (pretty) stream << Str(4 * (indent + 1), Ch(' '));
                write_json_helper(stream, it->second, indent + 1, pretty);
                if (boost::next(it) != pt.end())
                    stream << Ch(',');
                if (pretty) stream << Ch('\n');
            }
            if (pretty) stream << Str(4 * indent, Ch(' '));
            stream << Ch(']');

        }
        else
        {
            // Write object
            stream << Ch('{');
            if (pretty) stream << Ch('\n');
            typename Ptree::const_iterator it = pt.begin();
            for (; it != pt.end(); ++it)
            {
                if (pretty) stream << Str(4 * (indent + 1), Ch(' '));
                stream << Ch('"') << create_escapes(it->first) << Ch('"') << Ch(':');
                if (pretty) stream << Ch(' ');
                write_json_helper(stream, it->second, indent + 1, pretty);
                if (boost::next(it) != pt.end())
                    stream << Ch(',');
                if (pretty) stream << Ch('\n');
            }
            if (pretty) stream << Str(4 * indent, Ch(' '));
            stream << Ch('}');
        }

    }

    // Verify if ptree does not contain information that cannot be written to json
    template<class Ptree>
    bool verify_json(const Ptree &pt, int depth)
    {

        typedef typename Ptree::key_type::value_type Ch;
        typedef typename std::basic_string<Ch> Str;

        // Root ptree cannot have data
        if (depth == 0 && !pt.template get_value<Str>().empty())
            return false;
        
        // Ptree cannot have both children and data
        if (!pt.template get_value<Str>().empty() && !pt.empty())
            return false;

        // Check children
        typename Ptree::const_iterator it = pt.begin();
        for (; it != pt.end(); ++it)
            if (!verify_json(it->second, depth + 1))
                return false;

        // Success
        return true;

    }
    
    // Write ptree to json stream
    template<class Ptree>
    void write_json_internal(std::basic_ostream<typename Ptree::key_type::value_type> &stream, 
                             const Ptree &pt,
                             const std::string &filename,
                             bool pretty)
    {
        if (!verify_json(pt, 0))
            BOOST_PROPERTY_TREE_THROW(json_parser_error("ptree contains data that cannot be represented in JSON format", filename, 0));
        write_json_helper(stream, pt, 0, pretty);
        stream << std::endl;
        if (!stream.good())
            BOOST_PROPERTY_TREE_THROW(json_parser_error("write error", filename, 0));
    }

} } }

#endif