websocket_message.hpp

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#ifndef CPP_WEB_SERVER_WEBSOCKET_MESSAGE_HPP
#define CPP_WEB_SERVER_WEBSOCKET_MESSAGE_HPP

#include <boost/asio.hpp>
#include <boost/logic/tribool.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/tuple/tuple.hpp>

#if defined(_MSC_VER)
#    define PACKED_STRUCT(name) \
        __pragma(pack(push, 1)) struct name __pragma(pack(pop))
#elif defined(__GNUC__)
#    define PACKED_STRUCT(name) struct __attribute__((packed)) name
#else
#    warning I don't know how to create a packed struct with your compiler
#    define PACKED_STRUCT(name) struct name
#endif

namespace async_web_server_cpp
{

class WebsocketMessage;

class WebsocketFrame
{
public:
    PACKED_STRUCT(Header)
    {
        enum opcode
        {
            opcode_continuation = 0,
            opcode_text = 1,
            opcode_binary = 2,
            opcode_close = 8,
            opcode_ping = 9,
            opcode_pong = 10,
        } opcode : 4;
        bool rsv3 : 1;
        bool rsv2 : 1;
        bool rsv1 : 1;
        bool fin : 1;

        unsigned char len : 7;
        bool mask : 1;
    };
    static_assert(sizeof(Header) == 2,
                  "the Header struct is not properly packed");
    union
    {
        Header header;
        char header_bytes[2];
    };
    uint64_t length;
    unsigned char mask[4];
    std::string content;

    bool fromMessage(const WebsocketMessage& message);
    bool serialize(std::vector<unsigned char>& buffer);
};

class WebsocketFrameParser
{
public:
    WebsocketFrameParser();
    void reset();
    boost::tribool consume(WebsocketFrame& frame, char input);
    template<typename InputIterator>
    boost::tuple<boost::tribool, InputIterator>
    parse(WebsocketFrame& frame, InputIterator begin, InputIterator end)
    {
        while (begin != end)
        {
            boost::tribool result = consume(frame, *begin++);
            if (result || !result)
                return boost::make_tuple(result, begin);
        }
        boost::tribool result = boost::indeterminate;
        return boost::make_tuple(result, begin);
    }

private:
    enum state
    {
        header_byte1,
        header_byte2,
        length_8bytes_left,
        length_7bytes_left,
        length_6bytes_left,
        length_5bytes_left,
        length_4bytes_left,
        length_3bytes_left,
        length_2bytes_left,
        length_1bytes_left,
        mask_byte1,
        mask_byte2,
        mask_byte3,
        mask_byte4,
        body
    } state_;
};

class WebsocketMessage
{
public:
    WebsocketMessage();
    enum type
    {
        type_unknown,
        type_text,
        type_binary,
        type_close,
        type_ping,
        type_pong,
    } type;
    std::string content;
};

class WebsocketFrameBuffer
{
public:
    boost::tribool consume(WebsocketMessage& message, WebsocketFrame& frame);
};

}  // namespace async_web_server_cpp

#undef PACKED_STRUCT

#endif