PointPubSubTypes.cpp

浏览该文件的文档.

// Copyright 2016 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
/*!
 * @file PointPubSubTypes.cpp
 * This header file contains the implementation of the serialization functions.
 *
 * This file was generated by the tool fastcdrgen.
 */
 
#include <fastcdr/FastBuffer.h>
#include <fastcdr/Cdr.h>
 
#include "PointPubSubTypes.h"
 
using SerializedPayload_t = eprosima::fastrtps::rtps::SerializedPayload_t;
using InstanceHandle_t = eprosima::fastrtps::rtps::InstanceHandle_t;
// 命名空间geometry_msgs，用于组织相关的消息类型相关代码
namespace geometry_msgs {
    // 嵌套的msg命名空间，进一步细分消息相关的类型和操作
    namespace msg {
        // PointPubSubType类的定义，用于处理Point类型消息的发布/订阅相关操作（如序列化、反序列化等）
        PointPubSubType::PointPubSubType()
        {
            // 设置类型名称，这里明确指定了与geometry_msgs::msg::dds_::Point_相关的名称
            setName("geometry_msgs::msg::dds_::Point_");
            // 获取Point类型的最大CDR序列化大小，CDR是一种数据序列化格式
            auto type_size = Point::getMaxCdrSerializedSize();
            // 根据可能的子消息对齐要求，对类型大小进行对齐处理（按4字节对齐）
            type_size += eprosima::fastcdr::Cdr::alignment(type_size, 4); /* possible submessage alignment */
             // 计算最终的类型大小，加上4字节用于封装
            m_typeSize = static_cast<uint32_t>(type_size) + 4; /*encapsulation*/
            // 判断Point类型是否定义了获取键（Key）的操作
            m_isGetKeyDefined = Point::isKeyDefined();
            // 根据Point类型获取键的最大CDR序列化大小来确定键缓冲区的长度，取较大值
            size_t keyLength = Point::getKeyMaxCdrSerializedSize() > 16 ?
                    Point::getKeyMaxCdrSerializedSize() : 16;
             // 分配键缓冲区内存空间
            m_keyBuffer = reinterpret_cast<unsigned char*>(malloc(keyLength));
            // 将键缓冲区初始化为全0
            memset(m_keyBuffer, 0, keyLength);
        }
// PointPubSubType类的析构函数，用于释放之前分配的键缓冲区内存
        PointPubSubType::~PointPubSubType()
        {
            if (m_keyBuffer != nullptr)
            {
                free(m_keyBuffer);
            }
        }
// 序列化函数，将Point类型的数据对象序列化为可以传输的格式（存入SerializedPayload_t中）
        bool PointPubSubType::serialize(
                void* data,
                SerializedPayload_t* payload)
        {
             // 将传入的void*类型数据转换为Point*类型指针，方便后续操作
            Point* p_type = static_cast<Point*>(data);
 
            // Object that manages the raw buffer.
            eprosima::fastcdr::FastBuffer fastbuffer(reinterpret_cast<char*>(payload->data), payload->max_size);
            // Object that serializes the data.
            eprosima::fastcdr::Cdr ser(fastbuffer, eprosima::fastcdr::Cdr::DEFAULT_ENDIAN, eprosima::fastcdr::Cdr::DDS_CDR);
            payload->encapsulation = ser.endianness() == eprosima::fastcdr::Cdr::BIG_ENDIANNESS ? CDR_BE : CDR_LE;
            // Serialize encapsulation
            ser.serialize_encapsulation();
 
            try
            {
                // Serialize the object.
                p_type->serialize(ser);
            }
            catch (eprosima::fastcdr::exception::NotEnoughMemoryException& /*exception*/)
            {
                // 如果出现内存不足异常，返回false表示序列化失败
                return false;
            }
 
            // Get the serialized length
            payload->length = static_cast<uint32_t>(ser.getSerializedDataLength());
            return true;
        }
// 反序列化函数，将接收到的SerializedPayload_t格式的数据转换为Point类型的数据对象
        bool PointPubSubType::deserialize(
                SerializedPayload_t* payload,
                void* data)
        {
            try
            {
                //Convert DATA to pointer of your type
                Point* p_type = static_cast<Point*>(data);
 
                // Object that manages the raw buffer.
                eprosima::fastcdr::FastBuffer fastbuffer(reinterpret_cast<char*>(payload->data), payload->length);
 
                // Object that deserializes the data.
                eprosima::fastcdr::Cdr deser(fastbuffer, eprosima::fastcdr::Cdr::DEFAULT_ENDIAN, eprosima::fastcdr::Cdr::DDS_CDR);
 
                // Deserialize encapsulation.
                deser.read_encapsulation();
                payload->encapsulation = deser.endianness() == eprosima::fastcdr::Cdr::BIG_ENDIANNESS ? CDR_BE : CDR_LE;
 
                // Deserialize the object.
                p_type->deserialize(deser);
            }
            catch (eprosima::fastcdr::exception::NotEnoughMemoryException& /*exception*/)
            {
                // 如果出现内存不足异常，返回false表示反序列化失败
                return false;
            }
 
            return true;
        }
// 返回一个函数对象，该函数对象用于获取给定Point数据对象序列化后的大小
        std::function<uint32_t()> PointPubSubType::getSerializedSizeProvider(
                void* data)
        {
            return [data]() -> uint32_t
                   {
                    // 计算并返回序列化后的大小，包括Point类型自身序列化大小和封装的4字节
                       return static_cast<uint32_t>(type::getCdrSerializedSize(*static_cast<Point*>(data))) +
                              4u /*encapsulation*/;
                   };
        }
 // 创建一个新的Point类型数据对象，返回其void*指针，用于后续的赋值等操作
        void* PointPubSubType::createData()
        {
            return reinterpret_cast<void*>(new Point());
        }
// 删除之前创建的Point类型数据对象，释放内存
        void PointPubSubType::deleteData(
                void* data)
        {
            delete(reinterpret_cast<Point*>(data));
        }
 // 获取给定Point数据对象的键（Key）信息，用于标识该对象，存入InstanceHandle_t中
        bool PointPubSubType::getKey(
                void* data,
                InstanceHandle_t* handle,
                bool force_md5)
        {
            if (!m_isGetKeyDefined)
            {
                // 如果Point类型没有定义获取键的操作，直接返回false
                return false;
            }
 
            Point* p_type = static_cast<Point*>(data);
 
            // Object that manages the raw buffer.
            eprosima::fastcdr::FastBuffer fastbuffer(reinterpret_cast<char*>(m_keyBuffer),
                    Point::getKeyMaxCdrSerializedSize());
 
            // Object that serializes the data.
            eprosima::fastcdr::Cdr ser(fastbuffer, eprosima::fastcdr::Cdr::BIG_ENDIANNESS);
            p_type->serializeKey(ser);
            if (force_md5 || Point::getKeyMaxCdrSerializedSize() > 16)
            {
                // 如果需要使用MD5计算或者键的最大序列化大小超过16字节，则进行MD5相关操作
                m_md5.init();
                m_md5.update(m_keyBuffer, static_cast<unsigned int>(ser.getSerializedDataLength()));
                m_md5.finalize();
                for (uint8_t i = 0; i < 16; ++i)
                {
                    handle->value[i] = m_md5.digest[i];
                }
            }
            else
            {
                // 否则直接将键缓冲区中的内容复制到InstanceHandle_t的value数组中
                for (uint8_t i = 0; i < 16; ++i)
                {
                    handle->value[i] = m_keyBuffer[i];
                }
            }
            return true;
        }
    } //End of namespace msg
} //End of namespace geometry_msgs