openmw/components/nif/nifstream.hpp

/// Functions used to read raw binary data from .nif files

#ifndef OPENMW_COMPONENTS_NIF_NIFSTREAM_HPP
#define OPENMW_COMPONENTS_NIF_NIFSTREAM_HPP

#include <array>
#include <cassert>
#include <cerrno>
#include <format>
#include <istream>
#include <stdexcept>
#include <stdint.h>
#include <string>
#include <system_error>
#include <type_traits>
#include <vector>

#include <components/files/istreamptr.hpp>
#include <components/misc/endianness.hpp>
#include <components/misc/float16.hpp>

#include <osg/BoundingSphere>
#include <osg/Quat>
#include <osg/Vec3f>
#include <osg/Vec4f>

#include "niftypes.hpp"

namespace ToUTF8
{
    class StatelessUtf8Encoder;
}

namespace Nif
{

    class Reader;

    template <std::size_t numInstances, typename T>
    inline void readBufferOfType(Files::IStreamPtr& pIStream, T* dest)
    {
        static_assert(
            std::is_arithmetic_v<T> || std::is_same_v<T, Misc::float16_t>, "Buffer element type is not arithmetic");
        static_assert(!std::is_same_v<T, bool>, "Buffer element type is boolean");
        pIStream->read((char*)dest, numInstances * sizeof(T));
        if (pIStream->fail())
            throw std::runtime_error(std::format("Failed to read typed ({}) dynamic buffer of {} instances: {}",
                typeid(T).name(), numInstances, std::generic_category().message(errno)));
        if constexpr (Misc::IS_BIG_ENDIAN)
            for (std::size_t i = 0; i < numInstances; i++)
                Misc::swapEndiannessInplace(dest[i]);
    }

    template <std::size_t numInstances, typename T>
    inline void readBufferOfType(Files::IStreamPtr& pIStream, T (&dest)[numInstances])
    {
        readBufferOfType<numInstances>(pIStream, static_cast<T*>(dest));
    }

    template <typename T>
    inline void readDynamicBufferOfType(Files::IStreamPtr& pIStream, T* dest, std::size_t numInstances)
    {
        static_assert(
            std::is_arithmetic_v<T> || std::is_same_v<T, Misc::float16_t>, "Buffer element type is not arithmetic");
        static_assert(!std::is_same_v<T, bool>, "Buffer element type is boolean");
        pIStream->read((char*)dest, numInstances * sizeof(T));
        if (pIStream->fail())
            throw std::runtime_error(std::format("Failed to read typed ({}) dynamic buffer of {} instances: {}",
                typeid(T).name(), numInstances, std::generic_category().message(errno)));
        if constexpr (Misc::IS_BIG_ENDIAN)
            for (std::size_t i = 0; i < numInstances; i++)
                Misc::swapEndiannessInplace(dest[i]);
    }

    class NIFStream
    {
        const Reader& mReader;
        Files::IStreamPtr mStream;
        const ToUTF8::StatelessUtf8Encoder* mEncoder;
        std::string mBuffer;

    public:
        explicit NIFStream(
            const Reader& reader, Files::IStreamPtr&& stream, const ToUTF8::StatelessUtf8Encoder* encoder)
            : mReader(reader)
            , mStream(std::move(stream))
            , mEncoder(encoder)
        {
        }

        const Reader& getFile() const { return mReader; }

        unsigned int getVersion() const;
        unsigned int getUserVersion() const;
        unsigned int getBethVersion() const;

        /// Convert human-readable version numbers into a number that can be compared.
        static constexpr uint32_t generateVersion(uint8_t major, uint8_t minor, uint8_t patch, uint8_t rev)
        {
            return (major << 24) + (minor << 16) + (patch << 8) + rev;
        }

        void skip(size_t size) { mStream->ignore(size); }

        /// Read into a single instance of type
        template <class T>
        void read(T& data)
        {
            readBufferOfType<1>(mStream, &data);
        }

        /// Read multiple instances of type into an array
        template <class T, size_t size>
        void readArray(std::array<T, size>& arr)
        {
            readBufferOfType<size>(mStream, arr.data());
        }

        /// Read instances of type into a dynamic buffer
        template <class T>
        void read(T* dest, size_t size)
        {
            readDynamicBufferOfType<T>(mStream, dest, size);
        }

        /// Read multiple instances of type into a vector
        template <class T>
        void readVector(std::vector<T>& vec, size_t size)
        {
            if (size == 0)
                return;
            vec.resize(size);
            read(vec.data(), size);
        }

        /// Extract an instance of type
        template <class T>
        T get()
        {
            T data;
            read(data);
            return data;
        }

        /// Read a string of the given length
        std::string getSizedString(size_t length);

        /// Read a string of the length specified in the file
        std::string getSizedString() { return getSizedString(get<uint32_t>()); }

        /// Read a list of strings without using the string table, e.g. the string table itself
        void getSizedStrings(std::vector<std::string>& vec, size_t size);

        /// Read a Bethesda header string that uses a byte for length
        std::string getExportString() { return getSizedString(get<uint8_t>()); }

        /// Read the version string which doesn't start with a number and ends with "\n"
        std::string getVersionString();

        /// Read a sequence of null-terminated strings
        std::string getStringPalette();
    };

    template <>
    void NIFStream::read<osg::Vec2f>(osg::Vec2f& vec);
    template <>
    void NIFStream::read<osg::Vec3f>(osg::Vec3f& vec);
    template <>
    void NIFStream::read<osg::Vec4f>(osg::Vec4f& vec);
    template <>
    void NIFStream::read<Matrix3>(Matrix3& mat);
    template <>
    void NIFStream::read<osg::Quat>(osg::Quat& quat);
    template <>
    void NIFStream::read<osg::BoundingSpheref>(osg::BoundingSpheref& sphere);
    template <>
    void NIFStream::read<NiTransform>(NiTransform& transform);
    template <>
    void NIFStream::read<NiQuatTransform>(NiQuatTransform& transform);
    template <>
    void NIFStream::read<bool>(bool& data);
    template <>
    void NIFStream::read<std::string>(std::string& str);

    template <>
    void NIFStream::read<osg::Vec2f>(osg::Vec2f* dest, size_t size);
    template <>
    void NIFStream::read<osg::Vec3f>(osg::Vec3f* dest, size_t size);
    template <>
    void NIFStream::read<osg::Vec4f>(osg::Vec4f* dest, size_t size);
    template <>
    void NIFStream::read<Matrix3>(Matrix3* dest, size_t size);
    template <>
    void NIFStream::read<osg::Quat>(osg::Quat* dest, size_t size);
    template <>
    void NIFStream::read<osg::BoundingSpheref>(osg::BoundingSpheref* dest, size_t size);
    template <>
    void NIFStream::read<NiTransform>(NiTransform* dest, size_t size);
    template <>
    void NIFStream::read<NiQuatTransform>(NiQuatTransform* dest, size_t size);
    template <>
    void NIFStream::read<bool>(bool* dest, size_t size);
    template <>
    void NIFStream::read<std::string>(std::string* dest, size_t size);

}

#endif