Serializer.h

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// Copyright © 2008-2024 Pioneer Developers. See AUTHORS.txt for details
// Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
#ifndef _SERIALIZE_H
#define _SERIALIZE_H
 
#include "Aabb.h"
#include "ByteRange.h"
#include "Color.h"
#include "Quaternion.h"
#include "vector3.h"
#include <cstring>
#include <stdexcept>
#include <string>
 
#if (__GNUC__ && (__BYTE_ORDER_ == __ORDER_BIG_ENDIAN__)) || (__clang__ && __BIG_ENDIAN__)
#error Serializer.h is incompatible with big-endian architectures!
#endif
 
// Note: this serializer implementation is for use on little-endian runtimes
// only. It depends on floating point types having the same IEEE-754 semantics
// on both ends, and allows you to write unsafe code if care is not taken.
// It is intended only for the efficient (de)serialization of model binary data;
// where possible, prefer serializing state information via JSON instead.
namespace Serializer {
    static_assert((sizeof(Uint32) == 4 && alignof(Uint32) <= 4), "Int32 is sized differently on this platform and will not serialize properly.");
    static_assert((sizeof(Uint64) == 8 && alignof(Uint64) <= 8), "Int64 is sized differently on this platform and will not serialize properly.");
    static_assert((sizeof(Color) == 4 && alignof(Color) <= 1), "Color is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(vector2f) == 8 && alignof(vector2f) <= 4), "Vector2f is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(vector2d) == 16 && alignof(vector2d) <= 8), "Vector2d is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(vector3f) == 12 && alignof(vector3f) <= 4), "Vector3f is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(vector3d) == 24 && alignof(vector3d) <= 8), "Vector3d is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(Quaternionf) == 16 && alignof(Quaternionf) <= 4), "Quaternionf is padded differently on this platform and will not serialize properly.");
    static_assert((sizeof(Aabb) == 56 && alignof(Aabb) <= 8), "Aabb is padded differently on this platform and will not serialize properly.");
 
    class Writer {
    public:
        Writer() {}
        const std::string &GetData() { return m_str; }
 
        template <typename T>
        void writeObject(const T &obj)
        {
            m_str.append(reinterpret_cast<const char *>(&obj), sizeof(T));
        }
 
        void writeObject(const std::string &obj)
        {
            writeObject<Uint32>(obj.size());
            m_str.append(obj.c_str(), obj.size());
        }
 
        void writeObject(const char *s)
        {
            if (!s) { // don't fail on invalid string, just write a zero-length blob.
                *this << 0U;
                return;
            }
 
            Uint32 len = strlen(s);
            *this << len;
            m_str.append(s, len);
        }
 
        void writeObject(const vector2f &vec) { *this << vec.x << vec.y; }
        void writeObject(const vector2d &vec) { *this << vec.x << vec.y; }
        void writeObject(const vector3f &vec) { *this << vec.x << vec.y << vec.z; }
        void writeObject(const vector3d &vec) { *this << vec.x << vec.y << vec.z; }
        void writeObject(const Color &col) { *this << col.r << col.g << col.b << col.a; }
        void writeObject(const Quaternionf &quat) { *this << quat.w << quat.x << quat.y << quat.z; }
        void writeObject(const Quaterniond &quat) { *this << quat.w << quat.x << quat.y << quat.z; }
        void writeObject(const Aabb &aabb) { *this << aabb.min << aabb.max << aabb.radius; }
 
        template <typename T>
        Writer &operator<<(const T &obj)
        {
            writeObject(obj);
            return *this;
        }
 
        void Blob(ByteRange range)
        {
            assert(range.Size() < SDL_MAX_UINT32);
            Int32(range.Size());
            if (range.Size()) {
                m_str.append(range.begin, range.Size());
            }
        }
        void Byte(Uint8 x) { *this << x; }
        void Bool(bool x) { *this << x; }
        void Int16(Uint16 x) { *this << x; }
        void Int32(Uint32 x) { *this << x; }
        void Int64(Uint64 x) { *this << x; }
        void Float(float f) { *this << f; }
        void Double(double f) { *this << f; }
        void String(const char *s) { *this << s; }
        void String(const std::string &s) { *this << s; }
 
        void Vector2f(vector2f vec) { *this << vec; }
        void Vector2d(vector2d vec) { *this << vec; }
        void Vector3f(vector3f vec) { *this << vec; }
        void Vector3d(vector3d vec) { *this << vec; }
        void WrQuaternionf(const Quaternionf &q) { *this << q; }
        void Color4UB(const Color &c) { *this << c; }
        void WrSection(const std::string &section_label, const std::string &section_data) { *this << section_label << section_data; }
 
    private:
        std::string m_str;
    };
 
    class Reader {
        template <typename T>
        T obj()
        {
            T _ob;
            readObject(_ob);
            return _ob;
        }
 
    public:
        Reader() :
            m_at(nullptr),
            m_streamVersion(-1)
        {
        }
 
        explicit Reader(const ByteRange &data) :
            m_data(data),
            m_at(data.begin)
        {
        }
 
        bool AtEnd() { return m_at != m_data.end; }
 
        bool Check(std::size_t needed_size)
        {
            return m_data.end >= m_at + needed_size;
        }
 
        void Seek(int pos)
        {
            assert(pos >= 0 && std::size_t(pos) < m_data.Size());
            m_at = m_data.begin + pos;
        }
 
        std::size_t Pos() { return std::size_t(m_at - m_data.begin); }
 
        template <typename T>
        void readObject(T &out)
        {
#ifdef DEBUG
            if (!Check(sizeof(T)))
                throw std::out_of_range("Serializer::Reader encountered truncated stream.");
#endif
 
            std::memcpy(&out, m_at, sizeof(T)); // use memcpy to handle unaligned reads
            m_at += sizeof(T);
        }
 
        void readObject(std::string &out)
        {
            ByteRange range = Blob();
            out = std::string(range.begin, range.Size());
            if (!out.empty() && *(out.end() - 1) == '\0') // HACK, old SGM files have trailing '\0' de-serialised sometimes
                out.pop_back();
        }
 
        void readObject(vector2f &vec) { *this >> vec.x >> vec.y; }
        void readObject(vector2d &vec) { *this >> vec.x >> vec.y; }
        void readObject(vector3f &vec) { *this >> vec.x >> vec.y >> vec.z; }
        void readObject(vector3d &vec) { *this >> vec.x >> vec.y >> vec.z; }
        void readObject(Color &col) { *this >> col.r >> col.g >> col.b >> col.a; }
        void readObject(Quaternionf &quat) { *this >> quat.w >> quat.x >> quat.y >> quat.z; }
        void readObject(Quaterniond &quat) { *this >> quat.w >> quat.x >> quat.y >> quat.z; }
        void readObject(Aabb &aabb) { *this >> aabb.min >> aabb.max >> aabb.radius; }
 
        template <typename T>
        Reader &operator>>(T &out)
        {
            readObject(out);
            return *this;
        }
 
        ByteRange Blob()
        {
            auto len = Int32();
            if (len == 0) return ByteRange();
            if (len > (m_data.end - m_at))
                throw std::out_of_range("Serializer::Reader encountered truncated stream.");
 
            auto range = ByteRange(m_at, m_at + len);
            m_at += len;
            return range;
        }
 
        // Prefer using Reader::operator>> instead; these functions involve creating an unnessesary temporary variable.
        bool Bool() { return obj<bool>(); }
        Uint8 Byte() { return obj<Uint8>(); }
        Uint16 Int16() { return obj<Uint16>(); }
        Uint32 Int32() { return obj<Uint32>(); }
        Uint64 Int64() { return obj<Uint64>(); }
        float Float() { return obj<float>(); }
        double Double() { return obj<double>(); }
 
        std::string String() { return obj<std::string>(); }
 
        Color Color4UB() { return obj<Color>(); }
        vector2f Vector2f() { return obj<vector2f>(); }
        vector2d Vector2d() { return obj<vector2d>(); }
        vector3f Vector3f() { return obj<vector3f>(); }
        vector3d Vector3d() { return obj<vector3d>(); }
 
        Quaternionf RdQuaternionf() { return obj<Quaternionf>(); }
 
        Reader RdSection(const std::string &section_label_expected);
 
        int StreamVersion() const { return m_streamVersion; }
        void SetStreamVersion(int x) { m_streamVersion = x; }
 
    private:
        ByteRange m_data;
        const char *m_at;
        int m_streamVersion;
    };
 
} // namespace Serializer
 
#endif /* _SERIALIZE_H */