This repo provides an alternative to C++'s std::bitset with all the features of C++20's <bit> header.
As with std::bitset, bitarray supports arbitrary length arrays of bits. It also supports dynamic bit lengths bitvector (on std::vector). It supports mmap'd bitsets bitspan (via std::span).
It aims to be simpler, faster, and more featureful.
Faster, because:
- most operations are in-place, to eliminate large copies
- the word size can be larger to reduce the number of iterations. potentially doing half as many iterations, std::bitset uses long
- or the word size can be smaller to reduce wasted space (relevant for many small bitsets)
The added features are (or will be):
- Easy casts between
bitarray,bitvector,bitspan - Easy constructors from
std::array,std::vector,std::span,std::initializer_list - Directly access all the underlying words
- bitset only allows you to get the lowest unsigned long long's worth of bits
- or output to a string of '1's and '0's...
- Easily change the underlying word type for whatever performance/storage needs (8/16/32/64/128 bit types are all supported and tested)
- Supports all C++20 bitwise operations
- popcount, rotl, rotr, count_{l,r}_{zero,one}
- deposit/extract and interleave/deinterleave, supported by pdep/pext
- C++20
- Target CPU with support for the BMI2 instruction set (for pdep/pext support, which gather/scatter and interleave/deinterleave rely on)
For testing and installing:
- Meson
sudo apt install meson
Include bitarray.hh and use bitarray::bitarray<N> instead of std::bitset<N>, or bitarray::bitvector(N), or bitarray::bitspan(span)
test.sh