1 | #pragma once |
2 | |
3 | #include <stdint.h> |
4 | #include <cstddef> |
5 | #include <type_traits> |
6 | using std::size_t; |
7 | |
8 | #include "bitops.h" |
9 | |
10 | #if defined(_MSC_VER) |
11 | #include <intrin.h> |
12 | #endif |
13 | |
14 | |
15 | static inline uint32_t PopCountImpl(uint8_t n) { |
16 | extern uint8_t const* PopCountLUT8; |
17 | return PopCountLUT8[n]; |
18 | } |
19 | |
20 | static inline uint32_t PopCountImpl(uint16_t n) { |
21 | #if defined(_MSC_VER) |
22 | return __popcnt16(n); |
23 | #else |
24 | extern uint8_t const* PopCountLUT16; |
25 | return PopCountLUT16[n]; |
26 | #endif |
27 | } |
28 | |
29 | static inline uint32_t PopCountImpl(uint32_t n) { |
30 | #if defined(_MSC_VER) |
31 | return __popcnt(n); |
32 | #elif defined(__GNUC__) // it is true for Clang also |
33 | return __builtin_popcount(n); |
34 | #else |
35 | return PopCountImpl((uint16_t)LO_16(n)) + PopCountImpl((uint16_t)HI_16(n)); |
36 | #endif |
37 | } |
38 | |
39 | static inline uint32_t PopCountImpl(uint64_t n) { |
40 | #if defined(_MSC_VER) && !defined(_i386_) |
41 | return __popcnt64(n); |
42 | #elif defined(__GNUC__) // it is true for Clang also |
43 | return __builtin_popcountll(n); |
44 | #else |
45 | return PopCountImpl((uint32_t)LO_32(n)) + PopCountImpl((uint32_t)HI_32(n)); |
46 | #endif |
47 | } |
48 | |
49 | template <class T> |
50 | static inline uint32_t PopCount(T n) { |
51 | using TCvt = std::make_unsigned_t<std::decay_t<T>>; |
52 | |
53 | return PopCountImpl(static_cast<TCvt>(n)); |
54 | } |
55 | |