turbonss/deps/cmph/cxxmph/mph_bits.h
2023-08-21 13:50:16 +03:00

74 lines
1.9 KiB
C++

#ifndef __CXXMPH_MPH_BITS_H__
#define __CXXMPH_MPH_BITS_H__
#include <stdint.h> // for uint32_t and friends
#include <array>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <limits>
#include <vector>
#include <utility>
namespace cxxmph {
class dynamic_2bitset {
public:
dynamic_2bitset();
~dynamic_2bitset();
dynamic_2bitset(uint32_t size, bool fill = false);
const uint8_t operator[](uint32_t i) const { return get(i); }
const uint8_t get(uint32_t i) const {
assert(i < size());
assert((i >> 2) < data_.size());
return (data_[(i >> 2)] >> (((i & 3) << 1)) & 3);
}
void set(uint32_t i, uint8_t v) {
assert((i >> 2) < data_.size());
data_[(i >> 2)] |= ones() ^ dynamic_2bitset::vmask[i & 3];
data_[(i >> 2)] &= ((v << ((i & 3) << 1)) | dynamic_2bitset::vmask[i & 3]);
assert(v <= 3);
assert(get(i) == v);
}
void resize(uint32_t size) {
size_ = size;
data_.resize(size >> 2, fill_*ones());
}
void swap(dynamic_2bitset& other) {
std::swap(other.size_, size_);
std::swap(other.fill_, fill_);
other.data_.swap(data_);
}
void clear() { data_.clear(); size_ = 0; }
uint32_t size() const { return size_; }
static const uint8_t vmask[];
const std::vector<uint8_t>& data() const { return data_; }
private:
uint32_t size_;
bool fill_;
std::vector<uint8_t> data_;
const uint8_t ones() { return std::numeric_limits<uint8_t>::max(); }
};
static uint32_t nextpoweroftwo(uint32_t k) {
if (k == 0) return 1;
k--;
for (uint32_t i=1; i<sizeof(uint32_t)*CHAR_BIT; i<<=1) k = k | k >> i;
return k+1;
}
// Interesting bit tricks that might end up here:
// http://graphics.stanford.edu/~seander/bithacks.html#ZeroInWord
// Fast a % (k*2^t)
// http://www.azillionmonkeys.com/qed/adiv.html
// rank and select:
// http://vigna.dsi.unimi.it/ftp/papers/Broadword.pdf
} // namespace cxxmph
#endif