binary_archive.h

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// Copyright (c) 2014-2019, The Monero Project
//
// All rights reserved.
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// 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.
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// 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.
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//    used to endorse or promote products derived from this software without specific
//    prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers

#pragma once
 
#include <cassert>
#include <iostream>
#include <iterator>
#include <boost/type_traits/make_unsigned.hpp>
 
#include "common/varint.h"
#include "warnings.h"
 
/* I have no clue what these lines means */
PUSH_WARNINGS
DISABLE_VS_WARNINGS(4244)
 
//TODO: fix size_t warning in x32 platform
 

template <class Stream, bool IsSaving>
struct binary_archive_base
{
    typedef Stream stream_type;
    typedef binary_archive_base<Stream, IsSaving> base_type;
    typedef boost::mpl::bool_<IsSaving> is_saving;
 
    typedef uint8_t variant_tag_type;
 
    explicit binary_archive_base(stream_type &s) : stream_(s) { }
 
    /* definition of standard API functions */
    void tag(const char *) { }
    void begin_object() { }
    void end_object() { }
    void begin_variant() { }
    void end_variant() { }
    /* I just want to leave a comment saying how this line really shows
       flaws in the ownership model of many OOP languages, that is all. */
    stream_type &stream() { return stream_; }
 
protected:
    stream_type &stream_;
};
 
/* \struct binary_archive
 *
 * \brief the actually binary archive type
 *
 * \detailed The boolean template argument /a W is the is_saving
 * parameter for binary_archive_base.
 *
 * The is_saving parameter says whether the archive is being read from
 * (false) or written to (true)
 */
template <bool W>
struct binary_archive;
 
 
template <>
struct binary_archive<false> : public binary_archive_base<std::istream, false>
{
 
    explicit binary_archive(stream_type &s) : base_type(s) {
      stream_type::pos_type pos = stream_.tellg();
      stream_.seekg(0, std::ios_base::end);
      eof_pos_ = stream_.tellg();
      stream_.seekg(pos);
    }
 
    template <class T>
    void serialize_int(T &v)
    {
      serialize_uint(*(typename boost::make_unsigned<T>::type *)&v);
    }

    template <class T>
    void serialize_uint(T &v, size_t width = sizeof(T))
    {
      T ret = 0;
      unsigned shift = 0;
      for (size_t i = 0; i < width; i++) {
        //std::cerr << "tell: " << stream_.tellg() << " value: " << ret << std::endl;
        char c;
        stream_.get(c);
        T b = (unsigned char)c;
        ret += (b << shift);    // can this be changed to OR, i think it can.
        shift += 8;
      }
      v = ret;
    }
 
    void serialize_blob(void *buf, size_t len, const char *delimiter="")
    {
      stream_.read((char *)buf, len);
    }
 
    void serialize_string(std::string str, const char *delimiter="")
    {
      stream_.read((char *)str.c_str(), str.size());
    }
 
    template <class T>
    void serialize_varint(T &v)
    {
      serialize_uvarint(*(typename boost::make_unsigned<T>::type *)(&v));
    }
 
    template <class T>
    void serialize_uvarint(T &v)
    {
      typedef std::istreambuf_iterator<char> it;
      if (tools::read_varint(it(stream_), it(), v) < 0)
        stream_.setstate(std::ios_base::failbit);
    }
 
    void begin_array(size_t &s)
    {
      serialize_varint(s);
    }
 
    void begin_array() { }
    void delimit_array() { }
    void end_array() { }
 
    void begin_string(const char *delimiter /*="\""*/) { }
    void end_string(const char *delimiter   /*="\""*/) { }
 
    void read_variant_tag(variant_tag_type &t) {
      serialize_int(t);
    }
 
    size_t remaining_bytes() {
      if (!stream_.good())
        return 0;
      //std::cerr << "tell: " << stream_.tellg() << std::endl;
      assert(stream_.tellg() <= eof_pos_);
      return eof_pos_ - stream_.tellg();
    }
protected:
    std::streamoff eof_pos_;
};
 
template <>
struct binary_archive<true> : public binary_archive_base<std::ostream, true>
{
    explicit binary_archive(stream_type &s) : base_type(s) { }
 
    template <class T>
    void serialize_int(T v)
    {
      serialize_uint(static_cast<typename boost::make_unsigned<T>::type>(v));
    }
    template <class T>
    void serialize_uint(T v)
    {
      for (size_t i = 0; i < sizeof(T); i++) {
        stream_.put((char)(v & 0xff));
        if (1 < sizeof(T)) v >>= 8;
      }
    }
 
    void serialize_blob(void *buf, size_t len, const char *delimiter="")
    {
      stream_.write((char *)buf, len);
    }
 
    void serialize_string(std::string str, const char *delimiter="")
    {
      stream_.write((char *)str.c_str(), str.size());
    }
 
    template <class T>
    void serialize_varint(T &v)
    {
      serialize_uvarint(*(typename boost::make_unsigned<T>::type *)(&v));
    }
 
    template <class T>
    void serialize_uvarint(T &v)
    {
      typedef std::ostreambuf_iterator<char> it;
      tools::write_varint(it(stream_), v);
    }
    void begin_array(size_t s)
    {
      serialize_varint(s);
    }
    void begin_array() { }
    void delimit_array() { }
    void end_array() { }
 
    void begin_string(const char *delimiter="\"") { }
    void end_string(const char *delimiter="\"") { }
 
    void write_variant_tag(variant_tag_type t) {
      serialize_int(t);
    }
};
 
POP_WARNINGS