ToProtoVisitor.hpp

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/*
 * Copyright (C) 2017-2018  Christian Berger
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#ifndef CLUON_TOPROTOVISITOR_HPP
#define CLUON_TOPROTOVISITOR_HPP

#include "cluon/ProtoConstants.hpp"
#include "cluon/cluon.hpp"

#include <cstdint>
#include <sstream>
#include <string>

namespace cluon {
class LIBCLUON_API ToProtoVisitor {
   private:
    ToProtoVisitor(const ToProtoVisitor &) = delete;
    ToProtoVisitor(ToProtoVisitor &&)      = delete;
    ToProtoVisitor &operator=(const ToProtoVisitor &) = delete;
    ToProtoVisitor &operator=(ToProtoVisitor &&) = delete;

   public:
    ToProtoVisitor()  = default;
    ~ToProtoVisitor() = default;

    std::string encodedData() const noexcept;

   public:
    // The following methods are provided to allow an instance of this class to
    // be used as visitor for an instance with the method signature void accept<T>(T&);

    void preVisit(int32_t id, const std::string &shortName, const std::string &longName) noexcept;
    void postVisit() noexcept;

    void visit(uint32_t id, std::string &&typeName, std::string &&name, bool &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, char &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, int8_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, uint8_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, int16_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, uint16_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, int32_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, uint32_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, int64_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, uint64_t &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, float &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, double &v) noexcept;
    void visit(uint32_t id, std::string &&typeName, std::string &&name, std::string &v) noexcept;

    template <typename T>
    void visit(uint32_t &id, std::string &&typeName, std::string &&name, T &value) noexcept {
        (void)typeName;
        (void)name;

        toVarInt(m_buffer, std::move(encodeKey(id, static_cast<uint8_t>(ProtoConstants::LENGTH_DELIMITED))));
        cluon::ToProtoVisitor nestedProtoEncoder;
        value.accept(nestedProtoEncoder);
        encode(m_buffer, std::move(nestedProtoEncoder.encodedData()));
    }

   private:
    std::size_t encode(std::ostream &o, bool &v) noexcept;
    std::size_t encode(std::ostream &o, int8_t &v) noexcept;
    std::size_t encode(std::ostream &o, uint8_t &v) noexcept;
    std::size_t encode(std::ostream &o, int16_t &v) noexcept;
    std::size_t encode(std::ostream &o, uint16_t &v) noexcept;
    std::size_t encode(std::ostream &o, int32_t &v) noexcept;
    std::size_t encode(std::ostream &o, uint32_t &v) noexcept;
    std::size_t encode(std::ostream &o, int64_t &v) noexcept;
    std::size_t encode(std::ostream &o, uint64_t &v) noexcept;
    std::size_t encode(std::ostream &o, float &v) noexcept;
    std::size_t encode(std::ostream &o, double &v) noexcept;
    std::size_t encode(std::ostream &o, const std::string &v) noexcept;

   private:
    uint8_t toZigZag8(int8_t v) noexcept;
    uint16_t toZigZag16(int16_t v) noexcept;
    uint32_t toZigZag32(int32_t v) noexcept;
    uint64_t toZigZag64(int64_t v) noexcept;

    std::size_t toVarInt(std::ostream &out, uint64_t v) noexcept;

    template <typename T>
    std::size_t toKeyValue(uint32_t fieldIdentifier, T &v) noexcept {
        std::size_t size{0};
        uint64_t key = encodeKey(fieldIdentifier, static_cast<uint8_t>(ProtoConstants::VARINT));
        size += toVarInt(m_buffer, key);
        size += encode(m_buffer, v);
        return size;
    }

    uint64_t encodeKey(uint32_t fieldIdentifier, uint8_t protoType) noexcept;

   private:
    std::stringstream m_buffer{""};
};
} // namespace cluon

#endif