160 lines
3.3 KiB
C++
160 lines
3.3 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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#include "td/utils/logging.h"
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#if TD_MSVC
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#include <intrin.h>
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#endif
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namespace td {
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inline int32 count_leading_zeroes32(uint32 x);
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inline int32 count_leading_zeroes64(uint64 x);
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inline int32 count_trailing_zeroes32(uint32 x);
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inline int32 count_trailing_zeroes64(uint64 x);
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inline uint32 bswap32(uint32 x);
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inline uint64 bswap64(uint64 x);
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inline int32 count_bits32(uint32 x);
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inline int32 count_bits64(uint64 x);
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#if TD_MSVC
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inline int32 count_leading_zeroes32(uint32 x) {
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unsigned long res = 0;
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if (_BitScanReverse(&res, x)) {
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return 31 - res;
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}
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return 32;
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}
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inline int32 count_leading_zeroes64(uint64 x) {
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#if defined(_M_X64)
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unsigned long res = 0;
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if (_BitScanReverse64(&res, x)) {
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return 63 - res;
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}
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return 64;
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#else
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if ((x >> 32) == 0) {
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return count_leading_zeroes32(static_cast<uint32>(x)) + 32;
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} else {
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return count_leading_zeroes32(static_cast<uint32>(x >> 32));
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}
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#endif
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}
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inline int32 count_trailing_zeroes32(uint32 x) {
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unsigned long res = 0;
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if (_BitScanForward(&res, x)) {
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return res;
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}
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return 32;
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}
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inline int32 count_trailing_zeroes64(uint64 x) {
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#if defined(_M_X64)
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unsigned long res = 0;
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if (_BitScanForward64(&res, x)) {
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return res;
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}
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return 64;
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#else
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if (static_cast<uint32>(x) == 0) {
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return count_trailing_zeroes32(static_cast<uint32>(x >> 32)) + 32;
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} else {
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return count_trailing_zeroes32(static_cast<uint32>(x));
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}
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#endif
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}
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inline uint32 bswap32(uint32 x) {
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return _byteswap_ulong(x);
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}
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inline uint64 bswap64(uint64 x) {
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return _byteswap_uint64(x);
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}
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inline int32 count_bits32(uint32 x) {
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return __popcnt(x);
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}
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inline int32 count_bits64(uint64 x) {
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#if defined(_M_X64)
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return __popcnt64(x);
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#else
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return count_bits32(static_cast<uint32>(x >> 32)) + count_bits32(static_cast<uint32>(x));
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#endif
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}
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#else
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inline int32 count_leading_zeroes32(uint32 x) {
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if (x == 0) {
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return 32;
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}
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return __builtin_clz(x);
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}
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inline int32 count_leading_zeroes64(uint64 x) {
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if (x == 0) {
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return 64;
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}
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return __builtin_clzll(x);
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}
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inline int32 count_trailing_zeroes32(uint32 x) {
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if (x == 0) {
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return 32;
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}
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return __builtin_ctz(x);
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}
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inline int32 count_trailing_zeroes64(uint64 x) {
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if (x == 0) {
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return 64;
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}
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return __builtin_ctzll(x);
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}
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inline uint32 bswap32(uint32 x) {
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return __builtin_bswap32(x);
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}
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inline uint64 bswap64(uint64 x) {
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return __builtin_bswap64(x);
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}
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inline int32 count_bits32(uint32 x) {
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return __builtin_popcount(x);
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}
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inline int32 count_bits64(uint64 x) {
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return __builtin_popcountll(x);
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}
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#endif
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//TODO: optimize
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inline int32 count_leading_zeroes_non_zero32(uint32 x) {
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DCHECK(x != 0);
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return count_leading_zeroes32(x);
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}
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inline int32 count_leading_zeroes_non_zero64(uint64 x) {
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DCHECK(x != 0);
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return count_leading_zeroes64(x);
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}
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inline int32 count_trailing_zeroes_non_zero32(uint32 x) {
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DCHECK(x != 0);
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return count_trailing_zeroes32(x);
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}
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inline int32 count_trailing_zeroes_non_zero64(uint64 x) {
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DCHECK(x != 0);
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return count_trailing_zeroes64(x);
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}
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} // namespace td
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