boost/property_tree/json_parser/detail/write.hpp
// ---------------------------------------------------------------------------- // 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) { typedef typename make_unsigned<Ch>::type UCh; UCh c(*b); // 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 (c == 0x20 || c == 0x21 || (c >= 0x23 && c <= 0x2E) || (c >= 0x30 && c <= 0x5B) || (c >= 0x5D && c <= 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"; unsigned long u = (std::min)(static_cast<unsigned long>( static_cast<UCh>(*b)), 0xFFFFul); unsigned long d1 = u / 4096; u -= d1 * 4096; unsigned long d2 = u / 256; u -= d2 * 256; unsigned long d3 = u / 16; u -= d3 * 16; unsigned long 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