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cOMS/utils/BitUtils.h
Dennis Eichhorn eb9a135ca7
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fixing bugs and adding some test scripts
2025-04-27 20:10:58 +00:00

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/**
* Jingga
*
* @copyright Jingga
* @license OMS License 2.0
* @version 1.0.0
* @link https://jingga.app
*/
#ifndef COMS_UTILS_BIT_H
#define COMS_UTILS_BIT_H
//#include <intrin.h>
#include "../stdlib/Types.h"
#include "../architecture/Intrinsics.h"
// @todo Replace many of these functions with intrinsic functions
// This file can remain but the callers should get adjusted
// Obviously we would have to check at runtime if ABM is supported
// Left to right (big endian)
// "bits" refers to the bits of the data type (e.g. 8, 16, 32, 64)
#define IS_BIT_SET_L2R(num, pos, bits) ((bool) ((num) & (1 << ((bits - 1) - (pos)))))
#define BIT_SET_L2R(num, pos, bits) ((num) | (1U << ((bits - 1) - (pos))))
#define BIT_UNSET_L2R(num, pos, bits) ((num) & ~(1U << ((bits - 1) - (pos))))
#define BIT_FLIP_L2R(num, pos, bits) ((num) ^ (1U << ((bits - 1) - (pos))))
#define BIT_SET_TO_L2R(num, pos, x, bits) (((num) & ~((uint32_t)(1) << ((bits) - 1 - (pos)))) | (((uint32_t)(x) & 1U) << ((bits) - 1 - (pos))))
#define BITS_GET_8_L2R(num, pos, to_read) (((num) >> (8 - (pos) - (to_read))) & ((1U << (to_read)) - 1))
#define BITS_GET_16_L2R(num, pos, to_read) (((num) >> (16 - (pos) - (to_read))) & ((1U << (to_read)) - 1))
#define BITS_GET_32_L2R(num, pos, to_read) (((num) >> (32 - (pos) - (to_read))) & ((1U << (to_read)) - 1))
#define BITS_GET_64_L2R(num, pos, to_read) (((num) >> (64 - (pos) - (to_read))) & ((1ULL << (to_read)) - 1))
// Merges an array of bytes as an int value (16bit, 32bit, 64bit)
// Depending on the endianness of the system you could simply cast the array
#define BYTES_MERGE_2_L2R(arr) (((arr)[0] << 8) | (arr)[1])
#define BYTES_MERGE_4_L2R(arr) (((arr)[0] << 24) | ((arr)[1] << 16) | ((arr)[2] << 8) | (arr)[3])
#define BYTES_MERGE_8_L2R(arr) (((uint64_t)(arr)[0] << 56) | ((uint64_t)(arr)[1] << 48) | ((uint64_t)(arr)[2] << 40) | ((uint64_t)(arr)[3] << 32) | ((uint64_t)(arr)[4] << 24) | ((uint64_t)(arr)[5] << 16) | ((uint64_t)(arr)[6] << 8) | ((uint64_t)(arr)[7]))
// Right to left (little endian)
#define IS_BIT_SET_R2L(num, pos) ((bool) ((num) & (1 << (pos))))
#define IS_BIT_SET_64_R2L(num, pos) ((bool) ((num) & (1ULL << (pos))))
#define BIT_SET_R2L(num, pos) ((num) | ((uint32) 1 << (pos)))
#define BIT_UNSET_R2L(num, pos) ((num) & ~((uint32) 1 << (pos)))
#define BIT_FLIP_R2L(num, pos) ((num) ^ ((uint32) 1 << (pos)))
#define BIT_SET_TO_R2L(num, pos, x) (((num) & ~((uint32_t)(1) << (pos))) | ((uint32_t)(x) << (pos)))
// @performance Try to use this version over the L2R version for performance reasons
#define BITS_GET_8_R2L(num, pos, to_read) (((num) >> (pos)) & ((1U << (to_read)) - 1))
#define BITS_GET_16_R2L(num, pos, to_read) (((num) >> (pos)) & ((1U << (to_read)) - 1))
#define BITS_GET_32_R2L(num, pos, to_read) (((num) >> (pos)) & ((1U << (to_read)) - 1))
#define BITS_GET_64_R2L(num, pos, to_read) (((num) >> (pos)) & ((1ULL << (to_read)) - 1))
// Merges an array of bytes as an int value (16bit, 32bit, 64bit)
// Depending on the endianness of the system you could simply cast the array
#define BYTES_MERGE_2_R2L(arr) (((arr)[1] << 8) | (arr)[0])
#define BYTES_MERGE_4_R2L(arr) (((arr)[3] << 24) | ((arr)[2] << 16) | ((arr)[1] << 8) | (arr)[0])
#define BYTES_MERGE_8_R2L(arr) (((uint64_t)(arr)[7] << 56) | ((uint64_t)(arr)[6] << 48) | ((uint64_t)(arr)[5] << 40) | ((uint64_t)(arr)[4] << 32) | ((uint64_t)(arr)[3] << 24) | ((uint64_t)(arr)[2] << 16) | ((uint64_t)(arr)[1] << 8) | ((uint64_t)(arr)[0]))
struct BitWalk {
byte* pos;
uint32 bit_pos;
};
inline
void bits_walk(BitWalk* stream, uint32 bits_to_walk) noexcept
{
stream->bit_pos += bits_to_walk;
stream->pos += stream->bit_pos / 8;
stream->bit_pos %= 8;
}
inline
void bits_flush(BitWalk* stream) noexcept
{
if (stream->bit_pos > 0) {
stream->bit_pos = 0;
++stream->pos;
}
}
// inline
// uint8 bits_consume_8(BitWalk* stream, uint32 bits_to_consume)
// {
// uint8 result;
// uint32 remaining = 8 - stream->bit_pos;
// uint32 range_1 = bits_to_consume >= remaining
// ? remaining
// : bits_to_consume;
// result = (*stream->pos >> (remaining - range_1)) & ((1 << range_1) - 1);
// stream->bit_pos += range_1;
// if (bits_to_consume < remaining) {
// return result;
// }
// ++stream->pos;
// stream->bit_pos = 0;
// bits_to_consume -= range_1;
// /*
// uint32 full_bytes = bits_to_consume / 8;
// if (full_bytes > 0) {
// for (int i = 0; i < full_bytes; ++i) {
// result = (result << 8) | *stream->pos;
// ++stream->pos;
// }
// }
// */
// if (bits_to_consume == 0) {
// return result;
// }
// stream->bit_pos += bits_to_consume;
// return (result << bits_to_consume) | ((*stream->pos >> (8 - bits_to_consume)) & ((1 << bits_to_consume) - 1));
// }
// inline
// uint16 bits_consume_16(BitWalk* stream, uint32 bits_to_consume)
// {
// uint16 result;
// uint32 remaining = 8 - stream->bit_pos;
// uint32 range_1 = bits_to_consume >= remaining
// ? remaining
// : bits_to_consume;
// result = (*stream->pos >> (remaining - range_1)) & ((1 << range_1) - 1);
// stream->bit_pos += range_1;
// if (bits_to_consume < remaining) {
// return result;
// }
// ++stream->pos;
// stream->bit_pos = 0;
// bits_to_consume -= range_1;
// uint32 full_bytes = bits_to_consume / 8;
// if (full_bytes > 0) {
// for (int i = 0; i < full_bytes; ++i) {
// result = (result << 8) | *stream->pos;
// ++stream->pos;
// }
// }
// uint32 range_2 = bits_to_consume - full_bytes * 8;
// if (range_2 == 0) {
// return result;
// }
// stream->bit_pos += range_2;
// return (result << range_2) | ((*stream->pos >> (8 - range_2)) & ((1 << range_2) - 1));
// }
// inline
// uint32 bits_consume_32(BitWalk* stream, uint32 bits_to_consume)
// {
// uint32 result;
// uint32 remaining = 8 - stream->bit_pos;
// uint32 range_1 = bits_to_consume >= remaining
// ? remaining
// : bits_to_consume;
// result = (*stream->pos >> (remaining - range_1)) & ((1 << range_1) - 1);
// stream->bit_pos += range_1;
// if (bits_to_consume < remaining) {
// return result;
// }
// ++stream->pos;
// stream->bit_pos = 0;
// bits_to_consume -= range_1;
// uint32 full_bytes = bits_to_consume / 8;
// if (full_bytes > 0) {
// for (int i = 0; i < full_bytes; ++i) {
// result = (result << 8) | *stream->pos;
// ++stream->pos;
// }
// }
// uint32 range_2 = bits_to_consume - full_bytes * 8;
// if (range_2 == 0) {
// return result;
// }
// stream->bit_pos += range_2;
// return (result << range_2) | ((*stream->pos >> (8 - range_2)) & ((1 << range_2) - 1));
// }
// inline
// uint64 bits_consume_64(BitWalk* stream, uint32 bits_to_consume)
// {
// uint64 result;
// uint32 remaining = 8 - stream->bit_pos;
// uint32 range_1 = bits_to_consume >= remaining
// ? remaining
// : bits_to_consume;
// result = (*stream->pos >> (remaining - range_1)) & ((1 << range_1) - 1);
// stream->bit_pos += range_1;
// if (bits_to_consume < remaining) {
// return result;
// }
// ++stream->pos;
// stream->bit_pos = 0;
// bits_to_consume -= range_1;
// uint32 full_bytes = bits_to_consume / 8;
// if (full_bytes > 0) {
// for (int i = 0; i < full_bytes; ++i) {
// result = (result << 8) | *stream->pos;
// ++stream->pos;
// }
// }
// uint32 range_2 = bits_to_consume - full_bytes * 8;
// if (range_2 == 0) {
// return result;
// }
// stream->bit_pos += range_2;
// return (result << range_2) | ((*stream->pos >> (8 - range_2)) & ((1 << range_2) - 1));
// }
// uint8 bits_peek_8(BitWalk* stream, uint32 bits_to_consume) {
// byte* pos = stream->pos;
// byte bit_pos = stream->bit_pos;
// uint8 bits = bits_consume_8(stream, bits_to_consume);
// stream->pos = pos;
// stream->bit_pos = bit_pos;
// return bits;
// }
// uint16 bits_peek_16(BitWalk* stream, uint32 bits_to_consume) {
// byte* pos = stream->pos;
// byte bit_pos = stream->bit_pos;
// uint16 bits = bits_consume_16(stream, bits_to_consume);
// stream->pos = pos;
// stream->bit_pos = bit_pos;
// return bits;
// }
// uint32 bits_peek_32(BitWalk* stream, uint32 bits_to_consume) {
// byte* pos = stream->pos;
// byte bit_pos = stream->bit_pos;
// uint32 bits = bits_consume_32(stream, bits_to_consume);
// stream->pos = pos;
// stream->bit_pos = bit_pos;
// return bits;
// }
// uint64 bits_peek_64(BitWalk* stream, uint32 bits_to_consume) {
// byte* pos = stream->pos;
// byte bit_pos = stream->bit_pos;
// uint64 bits = bits_consume_64(stream, bits_to_consume);
// stream->pos = pos;
// stream->bit_pos = bit_pos;
// return bits;
// }
static
inline int32 find_first_set_bit(int32 value) noexcept {
if (value == 0) {
return 0;
}
#if __GNUC__ || __clang__
return __builtin_ffs(value);
#elif _MSC_VER
unsigned long index;
if (_BitScanForward(&index, value)) {
return (int32) index + 1;
} else {
return 0;
}
#else
int32 index = 1;
while (value) {
if (value & 1) {
return index;
}
value >>= 1;
index++;
}
return 0;
#endif
}
inline
uint32 bits_reverse(uint32 data, uint32 count) noexcept
{
uint32 reversed = 0;
for (uint32 i = 0; i <= (count / 2); ++i) {
uint32 inv = count - i - 1;
reversed |= ((data >> i) & 0x1) << inv;
reversed |= ((data >> inv) & 0x1) << i;
}
return reversed;
}
static const byte BIT_COUNT_LOOKUP_TABLE[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
};
inline
byte bits_count(uint64 data, bool use_abm = false) noexcept {
if (use_abm) {
return (byte) intrin_bits_count_64(data);
} else {
return BIT_COUNT_LOOKUP_TABLE[data & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 8) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 16) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 24) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 32) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 40) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 48) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 56) & 0xFF];
}
}
inline
byte bits_count(uint32 data, bool use_abm = false) noexcept {
if (use_abm) {
return intrin_bits_count_32(data);
} else {
return BIT_COUNT_LOOKUP_TABLE[data & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 8) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 16) & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 24) & 0xFF];
}
}
inline
byte bits_count(uint16 data) noexcept {
return BIT_COUNT_LOOKUP_TABLE[data & 0xFF]
+ BIT_COUNT_LOOKUP_TABLE[(data >> 8) & 0xFF];
}
inline
byte bits_count(uint8 data) noexcept {
return BIT_COUNT_LOOKUP_TABLE[data];
}
#endif
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