/*

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 */

#pragma once

// basic int types and size_t

#include <cstdint>

#include <cstdio>

#ifdef _WIN32

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

 * Windows specific macros

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

#ifdef FAISS_MAIN_LIB

#define FAISS_API __declspec(dllexport)

#else // _FAISS_MAIN_LIB

#define FAISS_API __declspec(dllimport)

#endif // FAISS_MAIN_LIB

#define strtok_r strtok_s

#ifdef _MSC_VER

#define __PRETTY_FUNCTION__ __FUNCSIG__

#endif // _MSC_VER

#define posix_memalign(p, a, s) \

    (((*(p)) = _aligned_malloc((s), (a))), *(p) ? 0 : errno)

#define posix_memalign_free _aligned_free

// aligned should be in front of the declaration

#define ALIGNED(x) __declspec(align(x))

// redefine the GCC intrinsics with Windows equivalents

#ifdef _MSC_VER

#include <intrin.h>

#include <limits.h>

#ifndef __clang__

inline int __builtin_ctzll(uint64_t x) {

    unsigned long ret;

    _BitScanForward64(&ret, x);

    return (int)ret;

}

#endif

// cudatoolkit provides __builtin_ctz for NVCC >= 11.0

#if !defined(__CUDACC__) || __CUDACC_VER_MAJOR__ < 11

inline int __builtin_ctz(unsigned long x) {

    unsigned long ret;

    _BitScanForward(&ret, x);

    return (int)ret;

}

#endif

#ifndef __clang__

inline int __builtin_clzll(uint64_t x) {

#if defined(_M_X64) || defined(__x86_64__)

    return (int)__lzcnt64(x);

#elif defined(_M_ARM64)

    unsigned long index;

    int count = sizeof(uint64_t) * CHAR_BIT;

    if (_BitScanReverse64(&index, x)) {

        count = count - 1 - index;

    }

    return count;

#endif

}

#endif

#define __builtin_popcount __popcnt

#define __builtin_popcountl __popcnt64

#define __builtin_popcountll __popcnt64

#ifndef __clang__

#define __m128i_u __m128i

#define __m256i_u __m256i

#endif

// MSVC does not define __SSEx__, and _M_IX86_FP is only defined on 32-bit

// processors cf.

// https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros

#ifdef __AVX__

#define __SSE__ 1

#define __SSE2__ 1

#define __SSE3__ 1

#define __SSE4_1__ 1

#define __SSE4_2__ 1

#endif

// MSVC sets FMA and F16C automatically when using AVX2

// Ref. FMA (under /arch:AVX2):

// https://docs.microsoft.com/en-us/cpp/build/reference/arch-x64 Ref. F16C (2nd

// paragraph): https://walbourn.github.io/directxmath-avx2/

#ifdef __AVX2__

#define __FMA__ 1

#define __F16C__ 1

#endif

#endif // _MSC_VER

#define FAISS_ALWAYS_INLINE __forceinline

#else

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

 * Linux and OSX

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

#define FAISS_API

#define posix_memalign_free free

// aligned should be *in front* of the declaration, for compatibility with

// windows

#ifdef SWIG

#define ALIGNED(x)

#else

#define ALIGNED(x) __attribute__((aligned(x)))

#endif

#define FAISS_ALWAYS_INLINE __attribute__((always_inline)) inline

#endif

#if defined(__GNUC__) || defined(__clang__)

#define FAISS_DEPRECATED(msg) __attribute__((deprecated(msg)))

#else

#define FAISS_DEPRECATED(msg)

#endif // GCC or Clang

// Localized enablement of imprecise floating point operations

// You need to use all 3 macros to cover all compilers.

#if defined(_MSC_VER)

#define FAISS_PRAGMA_IMPRECISE_LOOP

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN \

    __pragma(float_control(precise, off, push))

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END __pragma(float_control(pop))

#elif defined(__clang__)

#if defined(__PPC__)

#define FAISS_PRAGMA_IMPRECISE_LOOP \

    _Pragma("clang loop vectorize_width(4) interleave_count(8)")

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN \

    _Pragma("float_control(precise, off, push)")

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END _Pragma("float_control(pop)")

#else

#define FAISS_PRAGMA_IMPRECISE_LOOP \

    _Pragma("clang loop vectorize(enable) interleave(enable)")

// clang-format off

// the following ifdef is needed, because old versions of clang (prior to 14)

// do not generate FMAs on x86 unless this pragma is used. On the other hand,

// ARM does not support the following pragma flag.

// TODO: find out how to enable FMAs on clang 10 and earlier.

#if defined(__x86_64__) && (defined(__clang_major__) && (__clang_major__ > 10))

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN \

    _Pragma("float_control(precise, off, push)")

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END _Pragma("float_control(pop)")

#else

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END

#endif

#endif

#elif defined(__GNUC__)

// Unfortunately, GCC does not provide a pragma for detecting it.

// So, we have to stick to GNUC, which is defined by MANY compilers.

// This is why clang/icc needs to be checked first.

// todo: add __INTEL_COMPILER check for the classic ICC

// todo: add __INTEL_LLVM_COMPILER for ICX

#define FAISS_PRAGMA_IMPRECISE_LOOP

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN \

    _Pragma("GCC push_options") \

    _Pragma("GCC optimize (\"unroll-loops,associative-math,no-signed-zeros\")")

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END \

    _Pragma("GCC pop_options")

#else

#define FAISS_PRAGMA_IMPRECISE_LOOP

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_BEGIN

#define FAISS_PRAGMA_IMPRECISE_FUNCTION_END

#endif

// clang-format on

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

 * BIGENDIAN specific macros

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

#if !defined(_MSC_VER) && \

        (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))

#define FAISS_BIG_ENDIAN

#endif

#define Swap2Bytes(val) ((((val) >> 8) & 0x00FF) | (((val) << 8) & 0xFF00))

#define Swap4Bytes(val)                                           \

    ((((val) >> 24) & 0x000000FF) | (((val) >> 8) & 0x0000FF00) | \

     (((val) << 8) & 0x00FF0000) | (((val) << 24) & 0xFF000000))