Byte Conversions

Description

The library provides functions for converting safe integer types to and from big-endian byte order. These operate on the non-bounded unsigned types (u8, u16, u32, u64, u128) and their verified counterparts.

On big-endian platforms these are no-ops. On little-endian platforms they delegate to byteswap.

#include <boost/safe_numbers/byte_conversions.hpp>

to_be

Converts a value from the native byte order to big-endian byte order.

Runtime Overload

template <non_bounded_integral_library_type T>
    requires (!is_verified_type_v<T>)
constexpr auto to_be(const T value) noexcept -> T;

Parameters

value — The value to convert.

Return Value

If std::endian::native == std::endian::big, returns value unchanged. Otherwise, returns byteswap(value).

Complexity

O(1).

Example

using namespace boost::safe_numbers;

auto be_val = to_be(u32{0x01020304});
// On little-endian: be_val == u32{0x04030201}
// On big-endian:    be_val == u32{0x01020304}

Verified Overload

template <non_bounded_integral_library_type T>
consteval auto to_be(const verified_type_basis<T> value) noexcept -> verified_type_basis<T>;

Compile-time only overload for verified types.

Since to_be is consteval for verified types, the result is guaranteed to be a compile-time constant.

Example

using namespace boost::safe_numbers;

constexpr auto be_val = to_be(verified_u32{u32{0x01020304}});

from_be

Converts a value from big-endian byte order to the native byte order.

This is the inverse of to_be. Since byte swapping is its own inverse, from_be delegates directly to to_be.

Runtime Overload

template <non_bounded_integral_library_type T>
    requires (!is_verified_type_v<T>)
constexpr auto from_be(const T value) noexcept -> T;

Parameters

value — The big-endian value to convert to native byte order.

Return Value

The value in native byte order. Equivalent to to_be(value).

Complexity

O(1).

Example

using namespace boost::safe_numbers;

auto native_val = from_be(to_be(u64{0x0123456789ABCDEF}));
// native_val == u64{0x0123456789ABCDEF}  (round-trip)

Verified Overload

template <non_bounded_integral_library_type T>
consteval auto from_be(const verified_type_basis<T> value) noexcept -> verified_type_basis<T>;

Compile-time only overload for verified types.

Since from_be is consteval for verified types, the result is guaranteed to be a compile-time constant.

Example

using namespace boost::safe_numbers;

constexpr auto val = verified_u32{u32{0xDEADBEEF}};
constexpr auto round_tripped = from_be(to_be(val));
static_assert(round_tripped == val);

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