/*
 * Author: Sven Gothel <sgothel@jausoft.com>
 * Copyright (c) 2020 Gothel Software e.K.
 * Copyright (c) 2020 ZAFENA AB
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef JAU_BYTE_UTIL_HPP_
#define JAU_BYTE_UTIL_HPP_

#include <cstring>
#include <string>
#include <memory>
#include <cstdint>
#include <vector>
#include <type_traits>

#include <jau/cpp_lang_util.hpp>
#include <jau/cpp_pragma.hpp>
#include <jau/packed_attribute.hpp>

#include <jau/int_types.hpp>

namespace jau {

    /** @defgroup ByteUtils Byte Utilities
     * Byte utility functions and types for endian- and bit conversions,
     * inclusive alignment handling and general get & put functionality.
     *
     * This category is also supporting \ref Integer.
     *
     * All \ref endian API entries are of `constexpr` and hence evaluated at compile time.<br>
     * Therefore, if-branches and expressions are also of `constexpr` and optimized 'away' at compile time.<br>
     * This includes the `cpu_to_<endian>(..)` and `<endian>_to_cpu(..)` etc utility functions.
     *
     * See \ref endian enum class regarding endian `constexpr` compile time determination.
     *
     * Aligned memory transfer from and to potentially unaligned memory
     * is performed via put_uint16(), get_uint16() with all its explicit stdint types,
     * as well as the generic template functions put_value() and get_value().
     * The implementation uses \ref packed_t to resolve a potential memory alignment issue *free of costs*,
     * see \ref packed_t_alignment_cast.
     *
     * @{
     */

    #if defined __has_builtin
        #if __has_builtin(__builtin_bswap16)
            #define __has_builtin_bswap16 1
        #endif
    #elif defined(__GNUC__) && __GNUC_PREREQ (4, 8)
        #define __has_builtin_bswap16 1
    #endif
    #if defined __has_builtin
        #if __has_builtin(__builtin_bswap32)
            #define __has_builtin_bswap32 1
        #endif
    #elif defined(__GNUC__) && __GNUC_PREREQ (4, 8)
        #define __has_builtin_bswap32 1
    #endif
    #if defined __has_builtin
        #if __has_builtin(__builtin_bswap64)
            #define __has_builtin_bswap64 1
        #endif
    #elif defined(__GNUC__) && __GNUC_PREREQ (4, 8)
        #define __has_builtin_bswap64 1
    #endif

    // Remember: constexpr specifier used in a function or static data member (since C++17) declaration implies inline.

    constexpr uint16_t bswap(uint16_t const source) noexcept {
        #if defined __has_builtin_bswap16
            return __builtin_bswap16(source);
        #else
            return (uint16_t) ( ( ( (source) >> 8 ) & 0xff ) |
                                ( ( (source) & 0xff) << 8 ) );
        #endif
    }

    constexpr uint32_t bswap(uint32_t const source) noexcept {
        #if defined __has_builtin_bswap32
            return __builtin_bswap32(source);
        #else
            return ( ( source & 0xff000000U ) >> 24 ) |
                   ( ( source & 0x00ff0000U ) >>  8 ) |
                   ( ( source & 0x0000ff00U ) <<  8 ) |
                   ( ( source & 0x000000ffU ) << 24 );
        #endif
    }

    constexpr uint64_t bswap(uint64_t const & source) noexcept {
        #if defined __has_builtin_bswap64
            return __builtin_bswap64(source);
        #else
            return ( ( source & 0xff00000000000000ULL ) >> 56 ) |
                   ( ( source & 0x00ff000000000000ULL ) >> 40 ) |
                   ( ( source & 0x0000ff0000000000ULL ) >> 24 ) |
                   ( ( source & 0x000000ff00000000ULL ) >>  8 ) |
                   ( ( source & 0x00000000ff000000ULL ) <<  8 ) |
                   ( ( source & 0x0000000000ff0000ULL ) << 24 ) |
                   ( ( source & 0x000000000000ff00ULL ) << 40 ) |
                   ( ( source & 0x00000000000000ffULL ) << 56 );
        #endif
    }

    constexpr void bswap(uint8_t * sink, uint8_t const * source, nsize_t len) {
        source += len - 1;
        for (; len > 0; len--) {
            *sink++ = *source--;
        }
    }

    constexpr uint128_t bswap(uint128_t const & source) noexcept {
        uint128_t dest;
        bswap(dest.data, source.data, 16);
        return dest;
    }

    constexpr uint192_t bswap(uint192_t const & source) noexcept {
        uint192_t dest;
        bswap(dest.data, source.data, 24);
        return dest;
    }

    constexpr uint256_t bswap(uint256_t const & source) noexcept {
        uint256_t dest;
        bswap(dest.data, source.data, 32);
        return dest;
    }

    /**
    // *************************************************
    // *************************************************
    // *************************************************
     */

    PRAGMA_DISABLE_WARNING_PUSH
    PRAGMA_DISABLE_WARNING_MULTICHAR

    namespace impl {
        constexpr uint32_t get_host_order() noexcept {
            if constexpr ( jau::is_builtin_bit_cast_available() ) {
                constexpr uint8_t b[4] { 0x44, 0x43, 0x42, 0x41 }; // h->l: 41 42 43 44 = 'ABCD' hex ASCII code
                return jau::bit_cast<uint32_t, uint8_t[4]>( b );
            } else {
                // The pragma to stop multichar warning == error `-Werror=multichar` doesn't seem to work with GCC <= 10.2
                // Hence we have to disable this specific warning via: `-Wno-multichar`
                // until all our compiler support `__builtin_bit_cast(T, a)`
                return 'ABCD'; // h->l: 41 42 43 44 = 'ABCD' hex ASCII code
            }
        }
    }

    /**
     * Endian identifier, indicating endianess of all scalar types.
     *
     * Inspired by C++20 std::endian
     *
     * Corner case platforms currently not supported,
     * i.e. unified endianess and mixed endianess.
     *
     * All endian API entries are of `constexpr` and hence evaluated at compile time.<br>
     * Therefore, if-branches and expressions are also of `constexpr` and optimized 'away' at compile time.<br>
     * This includes the `cpu_to_<endian>(..)` and `<endian>_to_cpu(..)` etc utility functions.
     *
     * On i386 platforms the host byte order is Least Significant Byte first (LSB) or Little-Endian,
     * whereas the network byte order, as used on the Internet, is Most Significant Byte first (MSB) or Big-Endian.
     * See #include <arpa/inet.h>
     *
     * Bluetooth is LSB or Little-Endian!
     */
    enum class endian : uint32_t
    {
        /** Identifier for little endian. */
        little      = 0x41424344U, // h->l: 41 42 43 44 = 'ABCD' hex ASCII code

        /** Identifier for big endian. */
        big         = 0x44434241U, // h->l: 44 43 42 41 = 'DCBA' hex ASCII code

        /** Identifier for DEC PDP-11, aka `ENDIAN_LITTLE_WORD`. */
        pdp         = 0x43444142U, // h->l: 43 44 41 42 = 'CDAB' hex ASCII code

        /** Identifier for Honeywell 316, aka `ENDIAN_BIG_WORD`. */
        honeywell   = 0x42414443U, // h->l: 42 41 44 43 = 'BADC' hex ASCII code

        /** Undetermined endian */
        undefined   = 0x00000000U,

        /** Identifier for native platform type, one of the above. */
        native      = impl::get_host_order()
    };

    PRAGMA_DISABLE_WARNING_POP

    /**
     * Return std::string representation of the given \ref endian.
     * @param v the \ref endian value
     * @return the std::string representation
     */
    std::string to_string(const endian& v) noexcept;

    /**
     * Evaluates `true` if the given \ref endian is defined,
     * i.e. `little`, `big`, `pdp` or `honeywell`.
     */
    constexpr bool isDefinedEndian(const endian &v) noexcept {
        switch(v) {
            case endian::little:
                [[fallthrough]];
            case endian::big:
                [[fallthrough]];
            case endian::pdp:
                [[fallthrough]];
            case endian::honeywell:
                return true;
            default:
                return false;
        }
    }

    /**
     * Evaluates `true` if platform is running in little \ref endian mode,
     * i.e. `jau::endian::little == jau::endian::native`.
     */
    constexpr bool isLittleEndian() noexcept {
        return endian::little == endian::native;
    }

    /**
     * Evaluates `true` if platform is running in big \ref endian mode,
     * i.e. `jau::endian::big == jau::endian::native`.
     */
    constexpr bool isBigEndian() noexcept {
        return endian::big == endian::native;
    }

    /**
     * Evaluates `true` if platform is running in little or big \ref endian mode,
     * i.e. `jau::endian::little == jau::endian::native || jau::endian::big == jau::endian::native`.
     */
    constexpr bool isLittleOrBigEndian() noexcept {
        return jau::endian::little == jau::endian::native || jau::endian::big == jau::endian::native;
    }

    /**
     * A little-endian type trait for convenience ..
     * <p>
     * Since all \ref endian definitions are of `constexpr`, code can simply use expressions of these
     * for compile-time evaluation and optimization. A template `SFINAE` is not required.
     * </p>
     * @tparam Dummy_type just to make template `SFINAE` happy
     */
    template <typename Dummy_type> struct has_endian_little : std::integral_constant<bool, endian::little == endian::native> {};

    /**
     * Value access of little-endian type trait for convenience ..
     * <p>
     * Since all \ref endian definitions are of `constexpr`, code can simply use expressions of these
     * for compile-time evaluation and optimization. A template `SFINAE` is not required.
     * </p>
     * @tparam Dummy_type just to make template `SFINAE` happy
     */
    template <typename Dummy_type> constexpr bool has_endian_little_v = has_endian_little<Dummy_type>::value;

    /**
     * A big-endian type trait for convenience ..
     * <p>
     * Since all \ref endian definitions are of `constexpr`, code can simply use expressions of these
     * for compile-time evaluation and optimization. A template `SFINAE` is not required.
     * </p>
     * @tparam Dummy_type just to make template `SFINAE` happy
     */
    template <typename Dummy_type> struct has_endian_big : std::integral_constant<bool, endian::big == endian::native> {};

    /**
     * Value access of big-endian type trait for convenience ..
     * <p>
     * Since all \ref endian definitions are of `constexpr`, code can simply use expressions of these
     * for compile-time evaluation and optimization. A template `SFINAE` is not required.
     * </p>
     * @tparam Dummy_type just to make template `SFINAE` happy
     */
    template <typename Dummy_type> constexpr bool has_endian_big_v = has_endian_big<Dummy_type>::value;

    /**
    // *************************************************
    // *************************************************
    // *************************************************
     */

    constexpr uint16_t be_to_cpu(uint16_t const n) noexcept {
        static_assert(isLittleOrBigEndian()); // one static_assert is sufficient for whole compilation unit
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint16_t cpu_to_be(uint16_t const h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint16_t le_to_cpu(uint16_t const l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint16_t cpu_to_le(uint16_t const h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }

    constexpr uint32_t be_to_cpu(uint32_t const n) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint32_t cpu_to_be(uint32_t const h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint32_t le_to_cpu(uint32_t const l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint32_t cpu_to_le(uint32_t const h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }

    constexpr uint64_t be_to_cpu(uint64_t const & n) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint64_t cpu_to_be(uint64_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint64_t le_to_cpu(uint64_t const & l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint64_t cpu_to_le(uint64_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return 0; // unreachable -> static_assert(..) above
        }
    }

    constexpr uint128_t be_to_cpu(uint128_t const & n) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint128_t cpu_to_be(uint128_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint128_t le_to_cpu(uint128_t const & l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint128_t cpu_to_le(uint128_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }

    constexpr uint192_t be_to_cpu(uint192_t const & n) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint192_t cpu_to_be(uint192_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint192_t le_to_cpu(uint192_t const & l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint192_t cpu_to_le(uint192_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }

    constexpr uint256_t be_to_cpu(uint256_t const & n) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(n);
        } else if constexpr ( isBigEndian() ) {
            return n;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint256_t cpu_to_be(uint256_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return bswap(h);
        } else if constexpr ( isBigEndian() ) {
            return h;
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint256_t le_to_cpu(uint256_t const & l) noexcept {
        if constexpr ( isLittleEndian() ) {
            return l;
        } else if constexpr ( isBigEndian() ) {
            return bswap(l);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }
    }
    constexpr uint256_t cpu_to_le(uint256_t const & h) noexcept {
        if constexpr ( isLittleEndian() ) {
            return h;
        } else if constexpr ( isBigEndian() ) {
            return bswap(h);
        } else {
            return {}; // unreachable -> static_assert(..) above
        }

    }

    /**
    // *************************************************
    // *************************************************
    // *************************************************
     */

    constexpr void put_uint8(uint8_t * buffer, nsize_t const byte_offset, const uint8_t v) noexcept
    {
        *pointer_cast<uint8_t *>( buffer + byte_offset ) = v;
    }
    constexpr uint8_t get_uint8(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return *pointer_cast<uint8_t const *>( buffer + byte_offset );
    }
    constexpr int8_t get_int8(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return *pointer_cast<int8_t const *>( buffer + byte_offset );
    }

    /**
     * Return packed_t::store after converting it to from either endian::little ot endian::big depending on given `littleEndian`
     * to endian::native.
     * @tparam T
     * @param source
     * @param littleEndian
     */
    template<typename T>
    constexpr T get_packed_value(const packed_t<T>* source, const bool littleEndian) noexcept { return littleEndian ? le_to_cpu(source->store) : be_to_cpu(source->store); }

    /**
     * Put the given uint16_t value into the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint16(uint8_t * buffer, nsize_t const byte_offset, const uint16_t v) noexcept
    {
        pointer_cast<packed_t<uint16_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * Put the given uint16_t value into the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * The value is converted from endian::native to either endian::little ot endian::big depending on given `littleEndian`
     * before it is stored in memory.
     *
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint16(uint8_t * buffer, nsize_t const byte_offset, const uint16_t v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint16_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * Returns a uint16_t value from the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint16_t get_uint16(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint16_t>*>( buffer + byte_offset )->store;
    }
    /**
     * Returns a uint16_t value from the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * The value is converted from either endian::little ot endian::big depending on given `littleEndian`
     * to endian::native before it is returned to the caller.
     *
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint16_t get_uint16(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint16_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint32(uint8_t * buffer, nsize_t const byte_offset, const uint32_t v) noexcept
    {
        pointer_cast<packed_t<uint32_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint32(uint8_t * buffer, nsize_t const byte_offset, const uint32_t v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint32_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint32_t get_uint32(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint32_t>*>( buffer + byte_offset )->store;
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint32_t get_uint32(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint32_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint64(uint8_t * buffer, nsize_t const byte_offset, const uint64_t & v) noexcept
    {
        pointer_cast<packed_t<uint64_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint64(uint8_t * buffer, nsize_t const byte_offset, const uint64_t & v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint64_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint64_t get_uint64(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint64_t>*>( buffer + byte_offset )->store;
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint64_t get_uint64(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint64_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint128(uint8_t * buffer, nsize_t const byte_offset, const uint128_t & v) noexcept
    {
        pointer_cast<packed_t<uint128_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint128(uint8_t * buffer, nsize_t const byte_offset, const uint128_t & v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint128_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint128_t get_uint128(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint128_t>*>( buffer + byte_offset )->store;
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint128_t get_uint128(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint128_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint192(uint8_t * buffer, nsize_t const byte_offset, const uint192_t & v) noexcept
    {
        pointer_cast<packed_t<uint192_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint192(uint8_t * buffer, nsize_t const byte_offset, const uint192_t & v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint192_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint192_t get_uint192(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint192_t>*>( buffer + byte_offset )->store;
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint192_t get_uint192(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint192_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint256(uint8_t * buffer, nsize_t const byte_offset, const uint256_t & v) noexcept
    {
        pointer_cast<packed_t<uint256_t>*>( buffer + byte_offset )->store = v;
    }
    /**
     * See put_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr void put_uint256(uint8_t * buffer, nsize_t const byte_offset, const uint256_t & v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<uint256_t>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint256_t get_uint256(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<uint256_t>*>( buffer + byte_offset )->store;
    }
    /**
     * See get_uint16() for reference.
     * @see \ref packed_t_alignment_cast
     */
    constexpr uint256_t get_uint256(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<uint256_t>*>( buffer + byte_offset ), littleEndian);
    }

    /**
    // *************************************************
    // *************************************************
    // *************************************************
     */

    /**
     * Put the given T value into the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * @tparam T
     * @param buffer
     * @param byte_offset
     * @param v
     * @see \ref packed_t_alignment_cast
     */
    template<typename T>
    constexpr
    typename std::enable_if_t<
        std::is_standard_layout_v<T>,
        void>
    put_value(uint8_t * buffer, nsize_t const byte_offset, const T& v) noexcept
    {
        // reinterpret_cast<packed_t<T>*>( buffer + byte_offset )->store = v;
        pointer_cast<packed_t<T>*>( buffer + byte_offset )->store = v;
    }

    /**
     * Put the given T value into the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * The value is converted from endian::native to either endian::little ot endian::big depending on given `littleEndian`
     * before it is stored in memory.
     *
     * @tparam T
     * @param buffer
     * @param byte_offset
     * @param v
     * @param littleEndian
     * @see \ref packed_t_alignment_cast
     */
    template<typename T>
    constexpr
    typename std::enable_if_t<
        std::is_standard_layout_v<T>,
        void>
    put_value(uint8_t * buffer, nsize_t const byte_offset, const T& v, const bool littleEndian) noexcept
    {
        pointer_cast<packed_t<T>*>( buffer + byte_offset )->store = littleEndian ? cpu_to_le(v) : cpu_to_be(v);
    }

    /**
     * Returns a T value from the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * @tparam T
     * @param buffer
     * @param byte_offset
     * @return
     * @see \ref packed_t_alignment_cast
     */
    template<typename T>
    constexpr
    typename std::enable_if_t<
        std::is_standard_layout_v<T>,
        T>
    get_value(uint8_t const * buffer, nsize_t const byte_offset) noexcept
    {
        return pointer_cast<const packed_t<T>*>( buffer + byte_offset )->store;
    }

    /**
     * Returns a T value from the given byte address
     * using \ref packed_t to resolve a potential memory alignment issue *free of costs*.
     *
     * The value is converted from either endian::little ot endian::big depending on given `littleEndian`
     * to endian::native before it is returned to the caller.
     *
     * @tparam T
     * @param buffer
     * @param byte_offset
     * @param littleEndian
     * @return
     * @see \ref packed_t_alignment_cast
     */
    template<typename T>
    constexpr
    typename std::enable_if_t<
        std::is_standard_layout_v<T>,
        T>
    get_value(uint8_t const * buffer, nsize_t const byte_offset, const bool littleEndian) noexcept
    {
        return get_packed_value(pointer_cast<const packed_t<T>*>( buffer + byte_offset ), littleEndian);
    }

    /**@}*/

} // namespace jau

/** \example test_basictypeconv.cpp
 * This C++ unit test validates the jau::bswap and get/set value implementation
 */

#endif /* JAU_BYTE_UTIL_HPP_ */