#pragma once

#include <stdint.h>
#include "succinct_config.hpp"

#if SUCCINCT_USE_INTRINSICS
#include <xmmintrin.h>

#if defined(__GNUC__) || defined(__clang__)
#    define __INTRIN_INLINE inline __attribute__((__always_inline__))
#elif defined(_MSC_VER)
#    define __INTRIN_INLINE inline __forceinline
#else
#    define __INTRIN_INLINE inline
#endif

#endif

#if SUCCINCT_USE_POPCNT
#    if !SUCCINCT_USE_INTRINSICS
#        error "Intrinsics support needed for popcnt"
#    endif
#include <smmintrin.h>
#endif



namespace succinct { namespace intrinsics {


#if SUCCINCT_USE_INTRINSICS

    __INTRIN_INLINE uint64_t byteswap64(uint64_t value)
    {
#if defined(__GNUC__) || defined(__clang__)
        return __builtin_bswap64(value);
#elif defined(_MSC_VER)
        return _byteswap_uint64(value);
#else
#     error Unsupported platform
#endif
    }

    __INTRIN_INLINE bool bsf64(unsigned long* const index, const uint64_t mask)
    {
#if defined(__GNUC__) || defined(__clang__)
        if (mask) {
            *index = (unsigned long)__builtin_ctzll(mask);
            return true;
        } else {
            return false;
        }
#elif defined(_MSC_VER)
        return _BitScanForward64(index, mask) != 0;
#else
#     error Unsupported platform
#endif
    }

    __INTRIN_INLINE bool bsr64(unsigned long* const index, const uint64_t mask)
    {
#if defined(__GNUC__) || defined(__clang__)
        if (mask) {
            *index = (unsigned long)(63 - __builtin_clzll(mask));
            return true;
        } else {
            return false;
        }
#elif defined(_MSC_VER)
        return _BitScanReverse64(index, mask) != 0;
#else
#     error Unsupported platform
#endif
    }

    template <typename T>
    __INTRIN_INLINE void prefetch(T const* ptr)
    {
        _mm_prefetch((const char*)ptr, _MM_HINT_T0);
    }

#else /* SUCCINCT_USE_INTRINSICS */

    template <typename T>
    inline void prefetch(T const* /* ptr */)
    {
        /* do nothing */
    }

#endif /* SUCCINCT_USE_INTRINSICS */

#if SUCCINCT_USE_POPCNT

    __INTRIN_INLINE uint64_t popcount(uint64_t x)
    {
        return uint64_t(_mm_popcnt_u64(x));
    }

#endif /* SUCCINCT_USE_POPCNT */

}}