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#pragma once
#include "schema.hpp"
#include <forstio/buffer.hpp>
#include <forstio/error.hpp>
#include <cstdint>
#include <cstring>
namespace saw {
/**
* Helper class to encode/decode any primitive type into/from litte endian.
* The shift class does this by shifting bytes. This type of procedure is
* platform independent. So it does not matter if the memory layout is
* little endian or big endian
*/
template<typename T> class shift_stream_value {
static_assert(always_false<T>, "Shift Stream Value only supports Primitives");
};
template <typename T, size_t N> class shift_stream_value<schema::Primitive<T,N>> {
public:
inline static error_or<void> decode(typename native_data_type<schema::Primitive<T,N>>::type &val, buffer &buff) {
if (buff.read_composite_length() < N) {
return make_error<err::buffer_exhausted>();
}
typename native_data_type<schema::Primitive<schema::UnsignedInteger,N>>::type raw = 0;
for (size_t i = 0; i < N; ++i) {
raw |= (static_cast<typename native_data_type<schema::Primitive<T,N>>::type>(buff.read(i)) << (i * 8));
}
memcpy(&val, &raw, N);
buff.read_advance(N);
return void_t{};
}
inline static error_or<void> encode(const typename native_data_type<schema::Primitive<T,N>>::type &val, buffer &buff) {
error err = buff.write_require_length(N);
if (err.failed()) {
return err;
}
typename native_data_type<schema::Primitive<schema::UnsignedInteger,N>>::type raw{};
memcpy(&raw, &val, N);
for (size_t i = 0; i < N; ++i) {
buff.write(i) = raw >> (i * 8);
}
buff.write_advance(N);
return void_t{};
}
inline static size_t size() { return N; }
};
template <typename T> using stream_value = shift_stream_value<T>;
} // namespace saw
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