text: //------------------------------------------------------------------------------
  /*
      This file is part of rippled: https://github.com/ripple/rippled
      Copyright (c) 2012, 2013 Ripple Labs Inc.
  
      Permission to use, copy, modify, and/or distribute this software for any
      purpose  with  or without fee is hereby granted, provided that the above
      copyright notice and this permission notice appear in all copies.
  
      THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
      MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
      ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
      WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
      ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
      OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
  //==============================================================================
  
  #ifndef RIPPLE_JSON_JSON_WRITER_H_INCLUDED
  #define RIPPLE_JSON_JSON_WRITER_H_INCLUDED
  
  #include <ripple/json/json_forwards.h>
  #include <ripple/json/json_value.h>
  #include <ostream>
  #include <vector>
  
  namespace Json {
  
  class Value;
  
  /** \brief Abstract class for writers.
   */
  class WriterBase
  {
  public:
      virtual ~WriterBase()
      {
      }
      virtual std::string
      write(const Value& root) = 0;
  };
  
  /** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format
   * without formatting (not human friendly).
   *
   * The JSON document is written in a single line. It is not intended for 'human'
   * consumption, but may be useful to support feature such as RPC where bandwith
   * is limited. \sa Reader, Value
   */
  
  class FastWriter : public WriterBase
  {
  public:
      FastWriter() = default;
      virtual ~FastWriter()
      {
      }
  
  public:  // overridden from Writer
      std::string
      write(const Value& root) override;
  
  private:
      void
      writeValue(const Value& value);
  
      std::string document_;
  };
  
  /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
   * human friendly way.
   *
   * The rules for line break and indent are as follow:
   * - Object value:
   *     - if empty then print {} without indent and line break
   *     - if not empty the print '{', line break & indent, print one value per
   * line and then unindent and line break and print '}'.
   * - Array value:
   *     - if empty then print [] without indent and line break
   *     - if the array contains no object value, empty array or some other value
   * types, and all the values fit on one lines, then print the array on a single
   * line.
   *     - otherwise, it the values do not fit on one line, or the array contains
   *       object or non empty array, then print one value per line.
   *
   * \sa Reader, Value
   */
  class StyledWriter : public WriterBase
  {
  public:
      StyledWriter();
      virtual ~StyledWriter()
      {
      }
  
  public:  // overridden from Writer
      /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a>
       * format. \param root Value to serialize. \return String containing the
       * JSON document that represents the root value.
       */
      std::string
      write(const Value& root) override;
  
  private:
      void
      writeValue(const Value& value);
      void
      writeArrayValue(const Value& value);
      bool
      isMultineArray(const Value& value);
      void
      pushValue(std::string const& value);
      void
      writeIndent();
      void
      writeWithIndent(std::string const& value);
      void
      indent();
      void
      unindent();
  
      using ChildValues = std::vector<std::string>;
  
      ChildValues childValues_;
      std::string document_;
      std::string indentString_;
      int rightMargin_;
      int indentSize_;
      bool addChildValues_;
  };
  
  /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
   human friendly way, to a stream rather than to a string.
   *
   * The rules for line break and indent are as follow:
   * - Object value:
   *     - if empty then print {} without indent and line break
   *     - if not empty the print '{', line break & indent, print one value per
   line
   *       and then unindent and line break and print '}'.
   * - Array value:
   *     - if empty then print [] without indent and line break
   *     - if the array contains no object value, empty array or some other value
   types,
   *       and all the values fit on one lines, then print the array on a single
   line.
   *     - otherwise, it the values do not fit on one line, or the array contains
   *       object or non empty array, then print one value per line.
   *
   * \param indentation Each level will be indented by this amount extra.
   * \sa Reader, Value
   */
  class StyledStreamWriter
  {
  public:
      StyledStreamWriter(std::string indentation = "\t");
      ~StyledStreamWriter()
      {
      }
  
  public:
      /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a>
       * format. \param out Stream to write to. (Can be ostringstream, e.g.)
       * \param root Value to serialize.
       * \note There is no point in deriving from Writer, since write() should not
       * return a value.
       */
      void
      write(std::ostream& out, const Value& root);
  
  private:
      void
      writeValue(const Value& value);
      void
      writeArrayValue(const Value& value);
      bool
      isMultineArray(const Value& value);
      void
      pushValue(std::string const& value);
      void
      writeIndent();
      void
      writeWithIndent(std::string const& value);
      void
      indent();
      void
      unindent();
  
      using ChildValues = std::vector<std::string>;
  
      ChildValues childValues_;
      std::ostream* document_;
      std::string indentString_;
      int rightMargin_;
      std::string indentation_;
      bool addChildValues_;
  };
  
  std::string
  valueToString(Int value);
  std::string
  valueToString(UInt value);
  std::string
  valueToString(double value);
  std::string
  valueToString(bool value);
  std::string
  valueToQuotedString(const char* value);
  
  /// \brief Output using the StyledStreamWriter.
  /// \see Json::operator>>()
  std::ostream&
  operator<<(std::ostream&, const Value& root);
  
  //------------------------------------------------------------------------------
  
  // Helpers for stream
  namespace detail {
  
  template <class Write>
  void
  write_string(Write const& write, std::string const& s)
  {
      write(s.data(), s.size());
  }
  
  template <class Write>
  void
  write_value(Write const& write, Value const& value)
  {
      switch (value.type())
      {
          case nullValue:
              write("null", 4);
              break;
  
          case intValue:
              write_string(write, valueToString(value.asInt()));
              break;
  
          case uintValue:
              write_string(write, valueToString(value.asUInt()));
              break;
  
          case realValue:
              write_string(write, valueToString(value.asDouble()));
              break;
  
          case stringValue:
              write_string(write, valueToQuotedString(value.asCString()));
              break;
  
          case booleanValue:
              write_string(write, valueToString(value.asBool()));
              break;
  
          case arrayValue: {
              write("[", 1);
              int const size = value.size();
              for (int index = 0; index < size; ++index)
              {
                  if (index > 0)
                      write(",", 1);
                  write_value(write, value[index]);
              }
              write("]", 1);
              break;
          }
  
          case objectValue: {
              Value::Members const members = value.getMemberNames();
              write("{", 1);
              for (auto it = members.begin(); it != members.end(); ++it)
              {
                  std::string const& name = *it;
                  if (it != members.begin())
                      write(",", 1);
  
                  write_string(write, valueToQuotedString(name.c_str()));
                  write(":", 1);
                  write_value(write, value[name]);
              }
              write("}", 1);
              break;
          }
      }
  }
  
  }  // namespace detail
  
  /** Stream compact JSON to the specified function.
  
      @param jv The Json::Value to write
      @param write Invocable with signature void(void const*, std::size_t) that
                   is called when output should be written to the stream.
  */
  template <class Write>
  void
  stream(Json::Value const& jv, Write const& write)
  {
      detail::write_value(write, jv);
      write("\n", 1);
  }
  
  /** Decorator for streaming out compact json
  
      Use
  
          Json::Value jv;
          out << Json::Compact{jv}
  
      to write a single-line, compact version of `jv` to the stream, rather
      than the styled format that comes from undecorated streaming.
  */
  class Compact
  {
      Json::Value jv_;
  
  public:
      /** Wrap a Json::Value for compact streaming
  
          @param jv The Json::Value to stream
  
          @note For now, we do not support wrapping lvalues to avoid
                potentially costly copies. If we find a need, we can consider
                adding support for compact lvalue streaming in the future.
      */
      Compact(Json::Value&& jv) : jv_{std::move(jv)}
      {
      }
  
      friend std::ostream&
      operator<<(std::ostream& o, Compact const& cJv)
      {
          detail::write_value(
              [&o](void const* data, std::size_t n) {
                  o.write(static_cast<char const*>(data), n);
              },
              cJv.jv_);
          return o;
      }
  };
  
  }  // namespace Json
  
  #endif  // JSON_WRITER_H_INCLUDED
  