Buffer.h

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/**
* @file Buffer.h.
* @brief The Buffer Class Definitions.
* @author Spices & Muduo.
*/
 
#pragma once
#include "Core/Core.h"
#include "InetAddress.h"
 
namespace Spices {
 
namespace Net {
 
    /**
    * @brief Wrapper of readwrite buffer.
    */
    class Buffer
    {
    public:
 
        static constexpr size_t header = 8;
        static constexpr size_t initialSize = 1024;
 
    public:
 
        /**
        * @brief Constructor Function.
        * @param[in] bytes Buffer read area Bytes.
        */
        Buffer(size_t bytes = initialSize)
            : m_Buffer(header + initialSize)
            , m_ReaderIndex(header)
            , m_WriterIndex(header)
        {}
 
        /**
        * @brief Destructor Function.
        */
        virtual ~Buffer() = default;
 
        /**
        * @brief Get readable area bytes.
        * @return Returns readable area bytes.
        */
        size_t ReadableBytes() const
        {
            return m_WriterIndex - m_ReaderIndex;
        }
 
        /**
        * @brief Get writeable area bytes.
        * @return Returns writeable area bytes.
        */
        size_t WriteableBytes() const
        {
            return m_Buffer.size() - m_WriterIndex;
        }
 
        /**
        * @brief Get header area bytes.
        * @return Returns header area bytes.
        */
        size_t HeaderBytes() const
        {
            return m_ReaderIndex;
        }
 
        /**
        * @brief Get read area start pointer.
        * @return Returns read area start pointer.
        */
        const char* Peek() const
        {
            return Begin() + m_ReaderIndex;
        }
 
        /**
        * @brief Retrieve some buffer data from data area.
        * @param[in] len Retrieve length.
        */
        void Retrieve(size_t len);
 
        /**
        * @brief Retrieve all buffer data.
        */
        void RetrieveAll()
        {
            m_ReaderIndex = m_WriterIndex = header;
        }
 
        /**
        * @brief Get readable area data as string.
        * @return Returns readable area data
        */
        std::string RetrieveAllAsString()
        {
            return RetrieveAsString(ReadableBytes());
        }
 
        /**
        * @brief Get retrieve area data as string.
        * @param[in] len Retrieve length.
        * @return Returns retrieve area data
        */
        std::string RetrieveAsString(size_t len);
 
        /**
        * @brief Ensure enough bytes to write.
        * @param[in] len bytes.
        */
        void EnsureWriteableBytes(size_t len);
 
        /**
        * @brief Append Message to this buffer.
        * @param[in] msg Message.
        */
        void Append(const std::string& msg);
 
        /**
        * @brief Append another buffer data.
        * @param[in] data Buffer start pointer.
        * @param[in] len Buffer bytes.
        */
        void Append(const char* data, size_t len);
 
        /**
        * @brief Get writeable area pointer.
        * @return Returns writeable area pointer.
        */
        char* BeginWrite()
        {
            return Begin() + m_WriterIndex;
        }
 
        /**
        * @brief Get writeable area pointer.
        * @return Returns writeable area pointer.
        */
        const char* BeginWrite() const
        {
            return Begin() + m_WriterIndex;
        }
 
        /**
        * @brief Read from Socket.
        * @param[in] fd SOCKET.
        * @param[in,out] saveErrno Error value.
        * @return Returns read bytes.
        * @note read api can only be used in linux, on windows use recv instead,
        */
        size_t ReadFd(SOCKET fd, int* saveErrno);
 
        /**
        * @brief Write to Socket.
        * @param[in] fd SOCKET.
        * @param[in,out] saveErrno Error value.
        * @return Returns write bytes.
        * @note write api can only be used in linux, on windows use send instead,
        */
        size_t WriteFd(SOCKET fd, int* saveErrno) const;
 
    private:
 
        /**
        * @brief Get Buffer start pointer.
        * @return Returns Buffer start pointer.
        */
        char* Begin()
        {
            return m_Buffer.data();
        }
 
        /**
        * @brief Get Buffer start pointer.
        * @return Returns Buffer start pointer.
        */
        const char* Begin() const
        {
            return m_Buffer.data();
        }
 
        /**
        * @brief Expend buffer size.
        * @param[in] len buffer size.
        */
        void expend(size_t len);
 
    private:
 
        /**
        * @brief Buffer data.
        */
        std::vector<char> m_Buffer;
 
        /**
        * @brief Reader pointer.
        */
        size_t m_ReaderIndex;
 
        /**
        * @brief Writer pointer.
        */
        size_t m_WriterIndex;
    };
 
}
 
}