text: // Copyright (c) 2018 X-CASH Project, Derived from 2014-2018, The Monero Project
  // 
  // All rights reserved.
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  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  // 
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  // 
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  // 
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  // 
  // Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
  
  /*! \file json_archive.h
   *
   * \brief JSON archive
   */
  
  #pragma once
  
  #include "serialization.h"
  #include <cassert>
  #include <iostream>
  #include <iomanip>
  
  /*! \struct json_archive_base
   *
   * \brief the base class of json archive type
   *
   * \detailed contains the basic logic for serializing a json archive
   */
  template <class Stream, bool IsSaving>
  struct json_archive_base
  {
    typedef Stream stream_type;
    typedef json_archive_base<Stream, IsSaving> base_type;
    typedef boost::mpl::bool_<IsSaving> is_saving;
  
    typedef const char *variant_tag_type;
  
    json_archive_base(stream_type &s, bool indent = false)
    : stream_(s), indent_(indent), object_begin(false), depth_(0) { }
  
    void tag(const char *tag) {
      if (!object_begin)
        stream_ << ", ";
      make_indent();
      stream_ << '"' << tag << "\": ";
      object_begin = false;
    }
  
    void begin_object()
    {
      stream_ << "{";
      ++depth_;
      object_begin = true;
    }
  
    void end_object()
    {
      --depth_;
      make_indent();
      stream_ << "}";
    }
  
    void begin_variant() { begin_object(); }
    void end_variant() { end_object(); }
    Stream &stream() { return stream_; }
  
  protected:
    void make_indent()
    {
      if (indent_)
      {
        stream_ << '\n' << std::string(2 * depth_, ' ');
      }
    }
  
  protected:
    stream_type &stream_;
    bool indent_;
    bool object_begin;
    size_t depth_;
  };
  
  
  /*! \struct json_archive
   * 
   * \brief a archive using the JSON standard
   *
   * \detailed only supports being written to
   */
  template <bool W>
  struct json_archive;
  
  template <>
  struct json_archive<true> : public json_archive_base<std::ostream, true>
  {
    json_archive(stream_type &s, bool indent = false) : base_type(s, indent) { }
  
    template<typename T>
    static auto promote_to_printable_integer_type(T v) -> decltype(+v)
    {
      // Unary operator '+' performs integral promotion on type T [expr.unary.op].
      // If T is signed or unsigned char, it's promoted to int and printed as number.
      return +v;
    }
  
    template <class T>
    void serialize_int(T v)
    {
      stream_ << std::dec << promote_to_printable_integer_type(v);
    }
  
    void serialize_blob(void *buf, size_t len, const char *delimiter="\"") {
      begin_string(delimiter);
      for (size_t i = 0; i < len; i++) {
        unsigned char c = ((unsigned char *)buf)[i];
        stream_ << std::hex << std::setw(2) << std::setfill('0') << (int)c;
      }
      end_string(delimiter);
    }
  
    template <class T>
    void serialize_varint(T &v)
    {
      stream_ << std::dec << promote_to_printable_integer_type(v);
    }
  
    void begin_string(const char *delimiter="\"")
    {
      stream_ << delimiter;
    }
  
    void end_string(const char *delimiter="\"")
    {
      stream_ << delimiter;
    }
  
    void begin_array(size_t s=0)
    {
      inner_array_size_ = s;
      ++depth_;
      stream_ << "[ ";
    }
  
    void delimit_array()
    {
      stream_ << ", ";
    }
  
    void end_array()
    {
      --depth_;
      if (0 < inner_array_size_)
      {
        make_indent();
      }
      stream_ << "]";
    }
  
    void write_variant_tag(const char *t)
    {
      tag(t);
    }
  
  private:
    size_t inner_array_size_;
  };
  