Network: Added Packet class for serialization

src/network/CMakeLists.txt

@@ -1,11 +1,13 @@
 set(SRCS
             network.cpp
+            packet.cpp
             room.cpp
             room_member.cpp
             )
 
 set(HEADERS
             network.h
+            packet.h
             room.h
             room_member.h
             )

src/network/packet.cpp

@@ -0,0 +1,229 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#ifdef _WIN32
+#include <winsock2.h>
+#else
+#include <arpa/inet.h>
+#endif
+#include <cstring>
+#include <string>
+#include "network/packet.h"
+
+namespace Network {
+
+Packet::Packet() : read_pos(0), is_valid(true) {}
+
+Packet::~Packet() {}
+
+void Packet::Append(const void* in_data, std::size_t size_in_bytes) {
+    if (in_data && (size_in_bytes > 0)) {
+        std::size_t start = data.size();
+        data.resize(start + size_in_bytes);
+        std::memcpy(&data[start], in_data, size_in_bytes);
+    }
+}
+
+void Packet::Read(void* out_data, std::size_t size_in_bytes) {
+    if (out_data && CheckSize(size_in_bytes)) {
+        std::memcpy(out_data, &data[read_pos], size_in_bytes);
+        read_pos += size_in_bytes;
+    }
+}
+
+void Packet::Clear() {
+    data.clear();
+    read_pos = 0;
+    is_valid = true;
+}
+
+const void* Packet::GetData() const {
+    return !data.empty() ? &data[0] : NULL;
+}
+
+void Packet::IgnoreBytes(u32 length) {
+    read_pos += length;
+}
+
+std::size_t Packet::GetDataSize() const {
+    return data.size();
+}
+
+bool Packet::EndOfPacket() const {
+    return read_pos >= data.size();
+}
+
+Packet::operator BoolType() const {
+    return is_valid ? &Packet::CheckSize : NULL;
+}
+
+Packet& Packet::operator>>(bool& out_data) {
+    u8 value;
+    if (*this >> value) {
+        out_data = (value != 0);
+    }
+    return *this;
+}
+
+Packet& Packet::operator>>(s8& out_data) {
+    Read(&out_data, sizeof(out_data));
+    return *this;
+}
+
+Packet& Packet::operator>>(u8& out_data) {
+    Read(&out_data, sizeof(out_data));
+    return *this;
+}
+
+Packet& Packet::operator>>(s16& out_data) {
+    s16 value;
+    Read(&value, sizeof(value));
+    out_data = ntohs(value);
+    return *this;
+}
+
+Packet& Packet::operator>>(u16& out_data) {
+    u16 value;
+    Read(&value, sizeof(value));
+    out_data = ntohs(value);
+    return *this;
+}
+
+Packet& Packet::operator>>(s32& out_data) {
+    s32 value;
+    Read(&value, sizeof(value));
+    out_data = ntohl(value);
+    return *this;
+}
+
+Packet& Packet::operator>>(u32& out_data) {
+    u32 value;
+    Read(&value, sizeof(value));
+    out_data = ntohl(value);
+    return *this;
+}
+
+Packet& Packet::operator>>(float& out_data) {
+    Read(&out_data, sizeof(out_data));
+    return *this;
+}
+
+Packet& Packet::operator>>(double& out_data) {
+    Read(&out_data, sizeof(out_data));
+    return *this;
+}
+
+Packet& Packet::operator>>(char* out_data) {
+    // First extract string length
+    u32 length = 0;
+    *this >> length;
+
+    if ((length > 0) && CheckSize(length)) {
+        // Then extract characters
+        std::memcpy(out_data, &data[read_pos], length);
+        out_data[length] = '\0';
+
+        // Update reading position
+        read_pos += length;
+    }
+
+    return *this;
+}
+
+Packet& Packet::operator>>(std::string& out_data) {
+    // First extract string length
+    u32 length = 0;
+    *this >> length;
+
+    out_data.clear();
+    if ((length > 0) && CheckSize(length)) {
+        // Then extract characters
+        out_data.assign(&data[read_pos], length);
+
+        // Update reading position
+        read_pos += length;
+    }
+
+    return *this;
+}
+
+Packet& Packet::operator<<(bool in_data) {
+    *this << static_cast<u8>(in_data);
+    return *this;
+}
+
+Packet& Packet::operator<<(s8 in_data) {
+    Append(&in_data, sizeof(in_data));
+    return *this;
+}
+
+Packet& Packet::operator<<(u8 in_data) {
+    Append(&in_data, sizeof(in_data));
+    return *this;
+}
+
+Packet& Packet::operator<<(s16 in_data) {
+    s16 toWrite = htons(in_data);
+    Append(&toWrite, sizeof(toWrite));
+    return *this;
+}
+
+Packet& Packet::operator<<(u16 in_data) {
+    u16 toWrite = htons(in_data);
+    Append(&toWrite, sizeof(toWrite));
+    return *this;
+}
+
+Packet& Packet::operator<<(s32 in_data) {
+    s32 toWrite = htonl(in_data);
+    Append(&toWrite, sizeof(toWrite));
+    return *this;
+}
+
+Packet& Packet::operator<<(u32 in_data) {
+    u32 toWrite = htonl(in_data);
+    Append(&toWrite, sizeof(toWrite));
+    return *this;
+}
+
+Packet& Packet::operator<<(float in_data) {
+    Append(&in_data, sizeof(in_data));
+    return *this;
+}
+
+Packet& Packet::operator<<(double in_data) {
+    Append(&in_data, sizeof(in_data));
+    return *this;
+}
+
+Packet& Packet::operator<<(const char* in_data) {
+    // First insert string length
+    u32 length = std::strlen(in_data);
+    *this << length;
+
+    // Then insert characters
+    Append(in_data, length * sizeof(char));
+
+    return *this;
+}
+
+Packet& Packet::operator<<(const std::string& in_data) {
+    // First insert string length
+    u32 length = static_cast<u32>(in_data.size());
+    *this << length;
+
+    // Then insert characters
+    if (length > 0)
+        Append(in_data.c_str(), length * sizeof(std::string::value_type));
+
+    return *this;
+}
+
+bool Packet::CheckSize(std::size_t size) {
+    is_valid = is_valid && (read_pos + size <= data.size());
+
+    return is_valid;
+}
+
+} // namespace Network

src/network/packet.h

@@ -0,0 +1,192 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <vector>
+#include "common/common_types.h"
+
+namespace Network {
+
+/// A class for serialize data for network transfer. It also handles endianess
+class Packet {
+    /// A bool-like type that cannot be converted to integer or pointer types
+    typedef bool (Packet::*BoolType)(std::size_t);
+
+public:
+    Packet();
+    ~Packet();
+
+    /**
+     * Append data to the end of the packet
+     * @param data        Pointer to the sequence of bytes to append
+     * @param size_in_bytes Number of bytes to append
+     */
+    void Append(const void* data, std::size_t size_in_bytes);
+
+    /**
+     * Reads data from the current read position of the packet
+     * @param out_data        Pointer where the data should get written to
+     * @param size_in_bytes Number of bytes to read
+     */
+    void Read(void* out_data, std::size_t size_in_bytes);
+
+    /**
+     * Clear the packet
+     * After calling Clear, the packet is empty.
+     */
+    void Clear();
+
+    /**
+     * Ignores bytes while reading
+     * @param length THe number of bytes to ignore
+     */
+    void IgnoreBytes(u32 length);
+
+    /**
+     * Get a pointer to the data contained in the packet
+     * @return Pointer to the data
+     */
+    const void* GetData() const;
+
+    /**
+     * This function returns the number of bytes pointed to by
+     * what getData returns.
+     * @return Data size, in bytes
+     */
+    std::size_t GetDataSize() const;
+
+    /**
+     * This function is useful to know if there is some data
+     * left to be read, without actually reading it.
+     * @return True if all data was read, false otherwise
+     */
+    bool EndOfPacket() const;
+    /**
+     * Test the validity of the packet, for reading
+     * This operator allows to test the packet as a boolean
+     * variable, to check if a reading operation was successful.
+     *
+     * A packet will be in an invalid state if it has no more
+     * data to read.
+     *
+     * This behaviour is the same as standard C++ streams.
+     *
+     * Usage example:
+     * @code
+     * float x;
+     * packet >> x;
+     * if (packet)
+     * {
+     *    // ok, x was extracted successfully
+     * }
+     *
+     * // -- or --
+     *
+     * float x;
+     * if (packet >> x)
+     * {
+     *    // ok, x was extracted successfully
+     * }
+     * @endcode
+     *
+     * Don't focus on the return type, it's equivalent to bool but
+     * it disallows unwanted implicit conversions to integer or
+     * pointer types.
+     *
+     * @return True if last data extraction from packet was successful
+     */
+    operator BoolType() const;
+
+    /// Overloads of operator >> to read data from the packet
+    Packet& operator>>(bool& out_data);
+    Packet& operator>>(s8& out_data);
+    Packet& operator>>(u8& out_data);
+    Packet& operator>>(s16& out_data);
+    Packet& operator>>(u16& out_data);
+    Packet& operator>>(s32& out_data);
+    Packet& operator>>(u32& out_data);
+    Packet& operator>>(float& out_data);
+    Packet& operator>>(double& out_data);
+    Packet& operator>>(char* out_data);
+    Packet& operator>>(std::string& out_data);
+    template <typename T>
+    Packet& operator>>(std::vector<T>& out_data);
+    template <typename T, std::size_t S>
+    Packet& operator>>(std::array<T, S>& out_data);
+
+    /// Overloads of operator << to write data into the packet
+    Packet& operator<<(bool in_data);
+    Packet& operator<<(s8 in_data);
+    Packet& operator<<(u8 in_data);
+    Packet& operator<<(s16 in_data);
+    Packet& operator<<(u16 in_data);
+    Packet& operator<<(s32 in_data);
+    Packet& operator<<(u32 in_data);
+    Packet& operator<<(float in_data);
+    Packet& operator<<(double in_data);
+    Packet& operator<<(const char* in_data);
+    Packet& operator<<(const std::string& in_data);
+    template <typename T>
+    Packet& operator<<(const std::vector<T>& in_data);
+    template <typename T, std::size_t S>
+    Packet& operator<<(const std::array<T, S>& data);
+
+private:
+    /// Disallow comparisons between packets
+    bool operator==(const Packet& right) const;
+    bool operator!=(const Packet& right) const;
+
+    /**
+     * Check if the packet can extract a given number of bytes
+     * This function updates accordingly the state of the packet.
+     * @param size Size to check
+     * @return True if size bytes can be read from the packet
+     */
+    bool CheckSize(std::size_t size);
+
+    // Member data
+    std::vector<char> data; ///< Data stored in the packet
+    std::size_t read_pos;   ///< Current reading position in the packet
+    bool is_valid;          ///< Reading state of the packet
+};
+
+template <typename T>
+Packet& Packet::operator>>(std::vector<T>& out_data) {
+    for (u32 i = 0; i < out_data.size(); ++i) {
+        T character = 0;
+        *this >> character;
+        out_data[i] = character;
+    }
+    return *this;
+}
+
+template <typename T, std::size_t S>
+Packet& Packet::operator>>(std::array<T, S>& out_data) {
+    for (u32 i = 0; i < out_data.size(); ++i) {
+        T character = 0;
+        *this >> character;
+        out_data[i] = character;
+    }
+    return *this;
+}
+
+template <typename T>
+Packet& Packet::operator<<(const std::vector<T>& in_data) {
+    for (u32 i = 0; i < in_data.size(); ++i) {
+        *this << in_data[i];
+    }
+    return *this;
+}
+
+template <typename T, std::size_t S>
+Packet& Packet::operator<<(const std::array<T, S>& in_data) {
+    for (u32 i = 0; i < in_data.size(); ++i) {
+        *this << in_data[i];
+    }
+    return *this;
+}
+
+} // namespace Network