Stream.hpp

#pragma once
#include <cstddef>
#include <span>
#include <fstream>
 
namespace RavEngine {
 
    enum class IStreamStatus {
        Success,
        EndOfStream,
        Unknown
    };
 
    struct IStreamResult {
        size_t bytesRead;
        IStreamStatus status;
    };
 
    struct IStream {
 
        virtual IStreamResult read(std::span<std::byte> outData) = 0;
        virtual void reset() = 0;
 
        template<typename T>
        IStreamResult readT(T* data) {
            return read({ reinterpret_cast<std::byte*>(data),sizeof(T) });
        }
 
        virtual void advance(size_t) = 0;
 
        virtual size_t size() = 0;
        virtual size_t current_pos() = 0;
    };
 
    
    class MemoryStream : public IStream {
        std::span<std::byte> data;
        size_t offset = 0;
    public:
        MemoryStream(const decltype(data)& data) : data(data) {};
 
        IStreamResult read(std::span<std::byte> outData) final;
 
        void reset() final;
        void advance(size_t) final;
 
        size_t size() final;
        size_t current_pos() final;
    };
 
    class FileStream : public IStream{
        std::ifstream input;
        std::streampos begin;
    public:
        FileStream(decltype(input) && input);
 
        IStreamResult read(std::span<std::byte> outData) final;
 
        void reset() final;
        void advance(size_t) final;
 
        size_t size() final;
        size_t current_pos() final;
    };
}