diff --git a/Include/auROXTL/auBitsUtils.hpp b/Include/auROXTL/auBitsUtils.hpp index 06eac47..a53bd87 100644 --- a/Include/auROXTL/auBitsUtils.hpp +++ b/Include/auROXTL/auBitsUtils.hpp @@ -7,6 +7,53 @@ ***/ #pragma once +// options: _AU_FORCE_NO_FLIP8_MAP, _AU_DO_NOT_USE_BITFLIP_U16, _AU_DO_NOT_USE_BITFLIP_U32 +namespace __audetail +{ + inline const constexpr AuUInt8 kFlipBitsU4Lookup[16] { + 0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe, + 0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf + }; + +#if !defined(_AU_FORCE_NO_FLIP8_MAP) +#define _AU_HAS_FLIP8 + inline const constexpr AuUInt8 kFlipBitsU8Lookup[256] { + 0, 128, 64, 192, 32, 160, 96, 224, + 16, 144, 80, 208, 48, 176, 112, 240, + 8, 136, 72, 200, 40, 168, 104, 232, + 24, 152, 88, 216, 56, 184, 120, 248, + 4, 132, 68, 196, 36, 164, 100, 228, + 20, 148, 84, 212, 52, 180, 116, 244, + 12, 140, 76, 204, 44, 172, 108, 236, + 28, 156, 92, 220, 60, 188, 124, 252, + 2, 130, 66, 194, 34, 162, 98, 226, + 18, 146, 82, 210, 50, 178, 114, 242, + 10, 138, 74, 202, 42, 170, 106, 234, + 26, 154, 90, 218, 58, 186, 122, 250, + 6, 134, 70, 198, 38, 166, 102, 230, + 22, 150, 86, 214, 54, 182, 118, 246, + 14, 142, 78, 206, 46, 174, 110, 238, + 30, 158, 94, 222, 62, 190, 126, 254, + 1, 129, 65, 193, 33, 161, 97, 225, + 17, 145, 81, 209, 49, 177, 113, 241, + 9, 137, 73, 201, 41, 169, 105, 233, + 25, 153, 89, 217, 57, 185, 121, 249, + 5, 133, 69, 197, 37, 165, 101, 229, + 21, 149, 85, 213, 53, 181, 117, 245, + 13, 141, 77, 205, 45, 173, 109, 237, + 29, 157, 93, 221, 61, 189, 125, 253, + 3, 131, 67, 195, 35, 163, 99, 227, + 19, 147, 83, 211, 51, 179, 115, 243, + 11, 139, 75, 203, 43, 171, 107, 235, + 27, 155, 91, 219, 59, 187, 123, 251, + 7, 135, 71, 199, 39, 167, 103, 231, + 23, 151, 87, 215, 55, 183, 119, 247, + 15, 143, 79, 207, 47, 175, 111, 239, + 31, 159, 95, 223, 63, 191, 127, 255 + }; +#endif +} + template static auline bool AuTestBit(T value, AuUInt8 idx) { @@ -325,4 +372,82 @@ static AuUInt8 AuPopCnt(T in) } return {}; +} + +template +constexpr T AuBitReverse(T uBits); + +template <> +constexpr AuUInt8 AuBitReverse(AuUInt8 uBits) +{ + return (__audetail::kFlipBitsU8Lookup[uBits & 0b1111] << 4) | + (__audetail::kFlipBitsU8Lookup[uBits >> 4] ); + +} + +template <> +constexpr AuUInt16 AuBitReverse(AuUInt16 uBits) +{ +#if !defined(_AU_DO_NOT_USE_BITFLIP_U16) + uBits = ((uBits >> 1) & 0x5555u) | ((uBits & 0x5555u) << 1); + uBits = ((uBits >> 2) & 0x3333u) | ((uBits & 0x3333u) << 2); + uBits = ((uBits >> 4) & 0x0f0fu) | ((uBits & 0x0f0fu) << 4); + uBits = ((uBits >> 8) & 0x00ffu) | ((uBits & 0x00ffu) << 8); + return uBits; +#endif + +#if !defined(_AU_HAS_FLIP8) + return AuUInt16(AuBitReverse(AuUInt8((uBits >> 8u) & 0xFFu))) | + AuUInt16(AuUInt16(AuBitReverse(AuUInt8(uBits & 0xFFu))) << 8u); +#else + return 0 | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 8) & 0xFF]) << 0u | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 0) & 0xFF]) << 8u; +#endif +} + +template <> +constexpr AuUInt32 AuBitReverse(AuUInt32 uBits) +{ +#if !defined(_AU_DO_NOT_USE_BITFLIP_U32) + uBits = ((uBits >> 1) & 0x55555555u) | ((uBits & 0x55555555u) << 1); + uBits = ((uBits >> 2) & 0x33333333u) | ((uBits & 0x33333333u) << 2); + uBits = ((uBits >> 4) & 0x0f0f0f0fu) | ((uBits & 0x0f0f0f0fu) << 4); + uBits = ((uBits >> 8) & 0x00ff00ffu) | ((uBits & 0x00ff00ffu) << 8); + uBits = ((uBits >> 16) & 0xffffu) | ((uBits & 0xffffu) << 16); + return uBits; +#endif + +#if !defined(_AU_HAS_FLIP8) + return 0 | + AuUInt32(AuBitReverse((uBits >> 24) & 0xFF)) << 0ul | + AuUInt32(AuBitReverse((uBits >> 16) & 0xFF)) << 8ul | + AuUInt32(AuBitReverse((uBits >> 8) & 0xFF)) << 16ul | + AuUInt32(AuBitReverse((uBits >> 0) & 0xFF)) << 24ul; +#else + return 0 | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 24) & 0xFF]) << 0ul | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 16) & 0xFF]) << 8ul | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 8) & 0xFF]) << 16ul | + AuUInt32(__audetail::kFlipBitsU8Lookup[(uBits >> 0) & 0xFF]) << 24ul; +#endif +} + +template <> +constexpr AuUInt64 AuBitReverse(AuUInt64 uBits) +{ + return AuUInt64(AuBitReverse(AuUInt32((uBits >> 32ull) & 0xFFFFFFFFul))) | + AuUInt64(AuUInt64(AuBitReverse(AuUInt32(uBits & 0xFFFFFFFFul))) << 32UL); +} + +template +constexpr T AuBitsReverse(T uBits) +{ + return AuBitReverse(uBits); +} + +template +constexpr T AuReverseBits(T uBits) +{ + return AuBitReverse(uBits); } \ No newline at end of file