src/openvic-dataloader/detail/BasicBufferHandler.hpp


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#pragma once

#include <optional>

#include <openvic-dataloader/ParseError.hpp>
#include <openvic-dataloader/detail/OptionalConstexpr.hpp>

#include <lexy/encoding.hpp>
#include <lexy/input/buffer.hpp>
#include <lexy/input/file.hpp>

#include "detail/Errors.hpp"

namespace ovdl::detail {
   template<typename Encoding = lexy::default_encoding, typename MemoryResource = void>
   class BasicBufferHandler {
   public:
      using encoding_type = Encoding;

      OVDL_OPTIONAL_CONSTEXPR bool is_valid() const {
         return _buffer.data() != nullptr;
      }

      OVDL_OPTIONAL_CONSTEXPR std::optional<ovdl::ParseError> load_buffer_size(const char* data, std::size_t size) {
         _buffer = lexy::buffer<Encoding, MemoryResource>(data, size);
         return std::nullopt;
      }

      OVDL_OPTIONAL_CONSTEXPR std::optional<ovdl::ParseError> load_buffer(const char* start, const char* end) {
         _buffer = lexy::buffer<Encoding, MemoryResource>(start, end);
         return std::nullopt;
      }

      std::optional<ovdl::ParseError> load_file(const char* path) {
         auto file = lexy::read_file<Encoding, lexy::encoding_endianness::bom, MemoryResource>(path);
         if (!file) {
            return ovdl::errors::make_no_file_error(path);
         }

         _buffer = file.buffer();
         return std::nullopt;
      }

      const auto& get_buffer() const {
         return _buffer;
      }

   protected:
      lexy::buffer<Encoding, MemoryResource> _buffer;
   };
}