A dynamically-sized vector over GF(2) with bit elements compactly stored in a standard vector of primitive unsigned words whose type is given by the template parameter Word. More...

#include <BitVec.h>

Inheritance diagram for gf2::BitVec< Word >:

Public Types
using	word_type = Word
	The underlying unsigned word type used to store the bits.

Public Member Functions
BitStore Required Methods.
constexpr usize	size () const
	Returns the number of bit-elements in the bit-vector.
constexpr usize	words () const
	Returns the number of words in the bit-vector's underlying word store.
constexpr Word	word (usize i) const
	Returns word i from the bit-vector's underlying word store.
constexpr void	set_word (usize i, Word word)
	Sets word i in the bit-vector's underlying word store to value (masked if necessary).
constexpr const Word *	data () const
	Returns a const pointer to the underlying store of words .
constexpr Word *	data ()
	Returns a pointer to the underlying store of words.
constexpr u8	offset () const
	Returns the offset (in bits) of the first bit in the store within the first word.
Constructors
constexpr	BitVec (usize len=0)
	Constructs a bit-vector of length n with all the bit elements set to 0.
constexpr	BitVec (usize len, Word word)
	Constructs a bit-vector with len elements by repeatedly copying all the bits from word.
Size and Capacity
constexpr usize	capacity () const
	Returns the current capacity of the bit-vector.
constexpr BitVec &	shrink_to_fit ()
	Shrinks the bit-vector's capacity as much as possible.
constexpr BitVec &	clear ()
	Removes all elements from the bit-vector so `size()==0`.
constexpr BitVec &	resize (usize n)
	Resize the bit-vector so that its size() is n.
constexpr void	clean ()
	Sets any unused bits in the last occupied word to 0.
Appending BitsIter
constexpr BitVec &	push (bool b)
	Pushes a single bit b onto the bit-vector.
template<unsigned_word Src>
auto	append (Src src)
	Appends all the bits from any unsigned integral src value and returns a reference to this for chaining.
template<typename Src>
constexpr BitVec &	append (const BitStore< Src > &src)
	Appends all the bits from any BitStore src onto the end of the bit-vector and returns this for chaining.
template<usize N>
auto	append (const std::bitset< N > &src)
	Appends all the bits from a std::bitset onto the end of the bit-vector and returns this for chaining.
constexpr BitVec &	append_digit (char c, int base)
	Appends a single character c onto the end of bit-vector and returns this for chaining.
constexpr BitVec &	append_hex_digit (char c)
	Appends a single hex digit character c onto the end of bit-vector and returns this for chaining.
Removing BitsIter
constexpr std::optional< bool >	pop ()
	Removes the last bit from the bit-vector and returns it or std::nullopt if the bit-vector is empty.
constexpr void	split_off (usize at, BitVec< Word > &dst)
	Splits a bit-vector into two at the given index, returning the second part in dst.
constexpr BitVec< Word >	split_off (usize at)
	Splits a bit-vector into two at the given index, returning a new BitVec.
template<unsigned_word Dst = Word>
constexpr std::optional< Dst >	split_off_unsigned ()
	Split off a single arbitrary sized unsigned integer off the end of the bit-vector and returns it or std::nullopt if the bit-vector is empty.
Required methods:
The BitStore subclasses implement the following methods ...
constexpr void	set_word (usize i, word_type value)
	This method sets "word" at index i to the specified value.
Individual bit reads:
constexpr bool	get (usize i) const
	Returns true if the bit at the given index i is set, false otherwise.
constexpr bool	operator[] (usize index) const
	Returns the boolean value of the bit element at index.
constexpr bool	front () const
	Returns true if the first bit element is set, false otherwise.
constexpr bool	back () const
	Returns true if the last bit element is set, false otherwise.
Individual bit mutators:
auto	set (usize index, bool value=true)
	Sets the bit-element at the given index to the specified boolean value & returns this for chaining. The default value for value is true.
auto	flip (usize index)
	Flips the value of the bit-element at the given index and returns this for chaining/.
constexpr auto	swap (usize i0, usize i1)
	Swaps the bits in the bit-store at indices i0 and i1 and returns this for chaining.
Store queries:
constexpr bool	is_empty () const
	Returns true if the store is empty, false otherwise.
constexpr bool	any () const
	Returns true if at least one bit in the store is set, false otherwise.
constexpr bool	all () const
	Returns true if all bits in the store are set, false otherwise.
constexpr bool	none () const
	Returns true if no bits in the store are set, false otherwise.
Store mutators:
auto	set_all (bool value=true)
	Sets the bits in the store to the boolean value and returns a reference to this for chaining.
auto	flip_all ()
	Flips the value of the bits in the store and returns a reference to this for chaining.
Store fills:
auto	copy (Src src)
	Copies the bits from an unsigned integral src value and returns a reference to this for chaining.
auto	fill (std::invocable< usize > auto f)
	Fill the store by repeatedly calling f(i) and returns a reference to this for chaining.
auto	random_fill (double p=0.5, u64 seed=0)
	Fill the store with random bits and returns a reference to this for chaining.
Bit counts:
constexpr usize	count_ones () const
	Returns the number of set bits in the store.
constexpr usize	count_zeros () const
	Returns the number of unset bits in the store.
constexpr usize	leading_zeros () const
	Returns the number of leading zeros in the store.
constexpr usize	trailing_zeros () const
	Returns the number of trailing zeros in the store.
Set bit indices:
std::optional< usize >	first_set () const
	Returns the index of the first set bit in the bit-store or {} if no bits are set.
std::optional< usize >	last_set () const
	Returns the index of the last set bit in the bit-store or {} if no bits are set.
std::optional< usize >	next_set (usize index) const
	Returns the index of the next set bit after index in the store or {} if no more set bits exist.
std::optional< usize >	previous_set (usize index) const
	Returns the index of the previous set bit before index in the store or {} if there are none.
Unset bit indices:
std::optional< usize >	first_unset () const
	Returns the index of the first unset bit in the bit-store or {} if no bits are unset.
std::optional< usize >	last_unset () const
	Returns the index of the last unset bit in the bit-store or {} if no bits are unset.
std::optional< usize >	next_unset (usize index) const
	Returns the index of the next unset bit after index in the store or {} if no more unset bits exist.
std::optional< usize >	previous_unset (usize index) const
	Returns the index of the previous unset bit before index in the store or {} if no more unset bits exist.
Iterators:
constexpr auto	bits () const
	Returns a const iterator over the bool values of the bits in the const bit-store.
constexpr auto	set_bit_indices () const
	Returns an iterator over the indices of any set bits in the bit-store.
constexpr auto	unset_bit_indices () const
	Returns an iterator over the indices of any unset bits in the bit-store.
constexpr auto	store_words () const
	Returns a const iterator over all the words underlying the bit-store.
constexpr auto	to_words () const
	Returns a copy of the words underlying this bit-store.
Spans:
constexpr auto	span (usize begin, usize end) const
	Returns an immutable bit-span encompassing the bits in the half-open range [begin, end).
Sub-vectors:
constexpr auto	sub (usize begin, usize end) const
	Returns a clone of the elements in the half-open range [begin, end) as a new bit-vector.
constexpr void	split_at (usize at, BitVec< word_type > &left, BitVec< word_type > &right) const
	Views a bit-store as two parts containing the elements [0, at) and [at, size()) respectively.
Riffling:
constexpr void	riffle_into (BitVec< word_type > &dst) const
	Interleaves the bits of this bit-store with zeros storing the result into the bit-vector dst.
constexpr auto	riffled () const
	Returns a new bit-vector that is the result of riffling the bits in this bit-store with zeros.
Bit shifts:
constexpr void	operator<<= (usize shift)
	In-place left shift of the bit-store by shift bits.
constexpr void	operator>>= (usize shift)
	In-place right shift of the bit-store by shift bits.
constexpr auto	operator<< (usize shift) const
	Returns a new bit-vector that is lhs shifted left by shift bits.
constexpr auto	operator>> (usize shift) const
	Returns a new bit-vector that is lhs shifted right by shift bits.
Bit-wise operations:
void	operator^= (const BitStore< Rhs > &rhs)
	In-place XOR with another equal-sized bit-store.
void	operator&= (const BitStore< Rhs > &rhs)
	In-place AND with another equal-sized bit-store.
void	operator\|= (const BitStore< Rhs > &rhs)
	In-place OR with another equal-sized bit-store.
auto	operator~ () const
	Returns a new bit-vector that has the same bits as the current bit-store but with all the bits flipped.
auto	operator^ (const BitStore< Rhs > &rhs) const
	Returns a new bit-vector that is the XOR of the current bit-store and another equal-sized bit-store.
auto	operator& (const BitStore< Rhs > &rhs) const
	Returns a new bit-vector that is the AND of the current bit-store and another equal-sized bit-store.
auto	operator\| (const BitStore< Rhs > &rhs) const
	Returns a new bit-vector that is the OR of the current bit-store and another equal-sized bit-store.
Arithmetic operations:
void	operator+= (const BitStore< Rhs > &rhs)
	In-place addition of this bit-store with the an equal-sized rhs bit-store.
void	operator-= (const BitStore< Rhs > &rhs)
	In-place subtraction of this bit-store with the an equal-sized rhs bit-store.
auto	operator+ (const BitStore< Rhs > &rhs) const
	Returns a new bit-vector that is the + of this store with the passed (equal-sized) rhs bit-store.
auto	operator- (const BitStore< Rhs > &rhs) const
	Returns a new bit-vector that is the - of this store with the passed (equal-sized) rhs bit-store.
String representations:
std::string	to_string (std::string_view sep="", std::string_view pre="", std::string_view post="") const
	Returns a binary string representation of the store.
std::string	to_pretty_string () const
	Returns a "pretty" string representation of the store.
std::string	to_binary_string (std::string_view sep="", std::string_view pre="", std::string_view post="") const
	Returns a binary string representation of the store.
std::string	to_hex_string () const
	Returns the "hex" string representation of the bits in the bit-store.
std::string	describe () const
	Returns a multi-line string describing the bit-vector in some detail.

Static Public Member Functions
Factory Constructors
static constexpr BitVec	with_capacity (usize capacity)
	Factory method to construct an empty bit-vector with at least the specified capacity.
static constexpr BitVec	zeros (usize n)
	Factory method to generate a bit-vector of length n where the elements are all 0.
static constexpr BitVec	ones (usize n)
	Factory method to generate a bit-vector of length n where the elements are all 1.
static constexpr BitVec	constant (usize n, bool value)
	Factory method to generate a bit-vector of length n where the elements are set to value.
static constexpr BitVec	unit (usize n, usize i)
	Factory method to generate a "unit" bit-vector of length n where only element i is set.
static constexpr BitVec	alternating (usize n)
	Factory method to generate a bit-vector of length n looking like 101010....
template<typename Src>
static constexpr BitVec	from (const BitStore< Src > &src)
	Factory method to construct a bit-vector by copying all the bits from any BitStore instance.
template<usize N>
static constexpr BitVec	from (const std::bitset< N > &src)
	Factory method to construct a bit-vector from the bits of a std::bitset.
static constexpr BitVec	from (usize len, std::invocable< usize > auto f)
	Factory method to construct a bit-vector by repeatedly calling f(i) for i in [0, len).
Random Bit-Vector Constructors
static BitVec	random (usize len, double p=0.5, u64 seed=0)
	Factory method to generate a bit-vector of size len where the elements are picked at random.
static BitVec	seeded_random (usize len, u64 seed)
	Factory method to generate a bit-vector of size len where the elements are from independent fair coin flips generated from an RNG seeded with the given seed.
static BitVec	biased_random (usize len, double p)
	Factory method to generate a bit-vector of size len where the elements are from independent fair coin flips and where each bit is 1 with probability p.
Constructors from Strings
static std::optional< BitVec >	from_string (std::string_view sv)
	Factory method to construct a bit-vector from a string s, returning std::nullopt on failure.
static std::optional< BitVec >	from_binary_string (std::string_view sv, bool no_punctuation=false)
	Factory method to construct a bit-vector from a binary string, returning std::nullopt on failure.
static std::optional< BitVec >	from_hex_string (std::string_view sv, bool no_punctuation=false)
	Factory method to construct a bit-vector from a hex string, returning std::nullopt on failure.

Static Public Attributes
static constexpr u8	bits_per_word = BITS<Word>
	The number of bits per Word.

Detailed Description

template<unsigned_word Word = usize>
class gf2::BitVec< Word >

A dynamically-sized vector over GF(2) with bit elements compactly stored in a standard vector of primitive unsigned words whose type is given by the template parameter Word.

The BitVec class inherits from the base gf2::BitStore class. We implement a small number of required methods and then inherit the majority of our functionality from that base.

Note: Inheritance is done using the CRTP to avoid all runtime virtual method dispatch overhad..

Constructor & Destructor Documentation

◆ BitVec() [1/2]

template<unsigned_word Word = usize>

gf2::BitVec< Word >::BitVec ( usize len = 0 )

inlineexplicitconstexpr

Constructs a bit-vector of length n with all the bit elements set to 0.

The bit elements are compactly packed into a a standard vector of unsigned words. The template parameter Word sets the type of those words. It has a reasonable default type that works for most cases.

Note: The default constructor returns the empty bit-vector with no elements.

Example

BitVec v0;
assert_eq(v0.to_string(), "");
BitVec<u8> v1{10};
assert_eq(v1.to_string(), "0000000000");

◆ BitVec() [2/2]

template<unsigned_word Word = usize>

gf2::BitVec< Word >::BitVec	(	usize	len,
		Word	word )

inlineexplicitconstexpr

Constructs a bit-vector with len elements by repeatedly copying all the bits from word.

You specify the length len of the bit-vector which means the final copy of word may be truncated and padded with zeros (unused bit slots are always set to zero in this library).

Example

BitVec<u8> v{10, u8{0b0101'0101}};
assert_eq(v.size(), 10);
assert_eq(v.to_string(), "1010101010");

Member Function Documentation

◆ all()

bool gf2::BitStore< BitVec< usize > >::all ( ) const

inlineconstexprinherited

Returns true if all bits in the store are set, false otherwise.

Note: Empty stores have no set bits (logical connective for all is AND with identity true).

Example

BitVec v{3};
assert_eq(v.all(), false);
v.set(0);
v.set(1);
v.set(2);
assert_eq(v.all(), true);

◆ alternating()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::alternating ( usize n )

inlinestaticconstexpr

Factory method to generate a bit-vector of length n looking like 101010....

Example

assert_eq(BitVec<u8>::alternating(10).to_string(), "1010101010");

gf2::BitVec::alternating

static constexpr BitVec alternating(usize n)

Factory method to generate a bit-vector of length n looking like 101010....

Definition BitVec.h:255

◆ any()

bool gf2::BitStore< BitVec< usize > >::any ( ) const

inlineconstexprinherited

Returns true if at least one bit in the store is set, false otherwise.

Note: Empty stores have no set bits (logical connective for any is OR with identity false).

Example

BitVec v{10};
assert_eq(v.any(), false);
v.set(0);
assert_eq(v.any(), true);

◆ append() [1/3]

template<unsigned_word Word = usize>

template<typename Src>

BitVec & gf2::BitVec< Word >::append ( const BitStore< Src > & src )

inlineconstexpr

Appends all the bits from any BitStore src onto the end of the bit-vector and returns this for chaining.

Note: Generally, we do not support interactions between bit-stores that use different underlying unsigned word types. This method is an exception, and the src bit-store may use a different unsigned type from the one used here.

Example

auto v = BitVec<u8>::zeros(10);
auto w = BitVec<u16>::ones(10);
v.append(w);
assert_eq(v.size(), 20);
assert_eq(v.to_string(), "00000000001111111111");

◆ append() [2/3]

template<unsigned_word Word = usize>

template<usize N>

auto gf2::BitVec< Word >::append ( const std::bitset< N > & src )

inline

Appends all the bits from a std::bitset onto the end of the bit-vector and returns this for chaining.

Example

std::bitset<10> src{0b1010101010};
BitVec v;
v.append(src);
assert_eq(v.to_string(), "0101010101");

◆ append() [3/3]

template<unsigned_word Word = usize>

template<unsigned_word Src>

auto gf2::BitVec< Word >::append ( Src src )

inline

Appends all the bits from any unsigned integral src value and returns a reference to this for chaining.

Note: We allow any unsigned integral source, e.g. appending a single u16 into a BitVec<u8>.

Example

auto v = BitVec<u8>::ones(4);
u16 src = 0b1010101010101010;
v.append(src);
assert_eq(v.to_string(), "11110101010101010101");
auto w = BitVec<u32>::ones(4);
w.append(src);
assert_eq(w.to_string(), "11110101010101010101");

◆ append_digit()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::append_digit	(	char	c,
		int	base )

inlineconstexpr

Appends a single character c onto the end of bit-vector and returns this for chaining.

The character is interpreted as a base base number wherebase must be one of 2, 4, 8, 16.

Note: This method does nothing if the base or character is not recognized.

Example

BitVec v;
v.append_digit('A', 16);
assert_eq(v.to_string(), "1010");
v.append_digit('X', 16);
assert_eq(v.to_string(), "1010");
v.append_digit('1', 8);
assert_eq(v.to_string(), "1010001");
v.append_digit('1', 4);
assert_eq(v.to_string(), "101000101");
v.append_digit('1', 2);
assert_eq(v.to_string(), "1010001011");

◆ append_hex_digit()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::append_hex_digit ( char c )

inlineconstexpr

Appends a single hex digit character c onto the end of bit-vector and returns this for chaining.

Note: This method does nothing if the character is not a hex digit.

This is the same as append_digit(c, 16) but we push hex digits more often than other bases and want to skip some checks for efficiency.

Example

BitVec v;
v.append_hex_digit('F');
assert_eq(v.to_string(), "1111");
v.append_hex_digit('X');
assert_eq(v.to_string(), "1111");
v.append_hex_digit('1');
assert_eq(v.to_string(), "11110001");

◆ back()

bool gf2::BitStore< BitVec< usize > >::back ( ) const

inlineconstexprinherited

Returns true if the last bit element is set, false otherwise.

Note: In debug mode the method panics of the store is empty.

Example

auto v = BitVec<>::ones(10);
assert_eq(v.back(), true);
v.set_all(false);
assert_eq(v.back(), false);

◆ biased_random()

template<unsigned_word Word = usize>

BitVec gf2::BitVec< Word >::biased_random	(	usize	len,
		double	p )

inlinestatic

Factory method to generate a bit-vector of size len where the elements are from independent fair coin flips and where each bit is 1 with probability p.

Parameters

len	The length of the bit-vector to generate.
p	The probability of the elements being 1.

Example

auto u = BitVec<>::biased_random(10, 0.3);
auto v = BitVec<>::biased_random(10, 0.3);
assert_eq(u.size(), v.size());

◆ bits()

auto gf2::BitStore< BitVec< usize > >::bits ( ) const

inlineconstexprinherited

Returns a const iterator over the bool values of the bits in the const bit-store.

You can use this iterator to iterate over the bits in the store and get the values of each bit as a bool.

Note: For the most part, try to avoid iterating through individual bits. It is much more efficient to use methods that work on whole words of bits at a time.

Example

auto u = BitVec<u8>::ones(10);

for (auto&& bit : u.bits()) assert_eq(bit, true);

◆ capacity()

template<unsigned_word Word = usize>

usize gf2::BitVec< Word >::capacity ( ) const

inlineconstexpr

Returns the current capacity of the bit-vector.

This is the total number of bits that the bit-vector can hold without allocating more memory. The number includes the number of bits already in use.

Example

BitVec v0;
assert_eq(v0.capacity(), 0);
BitVec<u64> v1(10);
assert_eq(v1.capacity(), 64);

◆ clean()

template<unsigned_word Word = usize>

void gf2::BitVec< Word >::clean ( )

inlineconstexpr

Sets any unused bits in the last occupied word to 0.

This is used to enforce the guarantee that unused bits in the store are always set to 0.

◆ clear()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::clear ( )

inlineconstexpr

Removes all elements from the bit-vector so size()==0.

The capacity is not changed by this operation.

◆ constant()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::constant	(	usize	n,
		bool	value )

inlinestaticconstexpr

Factory method to generate a bit-vector of length n where the elements are set to value.

Example

auto v = BitVec<>::constant(10, true);
assert_eq(v.to_string(), "1111111111");
auto w = BitVec<>::constant(10, false);
assert_eq(w.to_string(), "0000000000");

◆ copy()

auto gf2::BitStore< BitVec< usize > >::copy ( Src src )

inlineinherited

Copies the bits from an unsigned integral src value and returns a reference to this for chaining.

Notes:

The size of the store must match the number of bits in the source type.
We allow any unsigned integral source, e.g. copying a single u64 into a BitVec<u8> of size 64.
The least-significant bit of the source becomes the bit at index 0 in the store.

Example

BitVec<u8> v{16};
u16 src = 0b1010101010101010;
v.copy(src);
assert_eq(v.to_string(), "0101010101010101");
BitVec<u32> w{16};
w.copy(src);
assert_eq(w.to_string(), "0101010101010101");

◆ count_ones()

usize gf2::BitStore< BitVec< usize > >::count_ones ( ) const

inlineconstexprinherited

Returns the number of set bits in the store.

Example

BitVec v{10};
assert_eq(v.count_ones(), 0);
v.set(0);
assert_eq(v.count_ones(), 1);

◆ count_zeros()

usize gf2::BitStore< BitVec< usize > >::count_zeros ( ) const

inlineconstexprinherited

Returns the number of unset bits in the store.

Example

BitVec v{10};
assert_eq(v.count_zeros(), 10);
v.set(0);
assert_eq(v.count_zeros(), 9);

◆ data() [1/2]

template<unsigned_word Word = usize>

Word * gf2::BitVec< Word >::data ( )

inlineconstexpr

Returns a pointer to the underlying store of words.

Note: The pointer is non-const but you should be careful about using it to modify the words in the store.

Example

auto v = BitVec<u8>::ones(10);
auto ptr = v.data();
assert_eq(*ptr, 0b1111'1111);

◆ data() [2/2]

template<unsigned_word Word = usize>

const Word * gf2::BitVec< Word >::data ( ) const

inlineconstexpr

Returns a const pointer to the underlying store of words .

Example

auto v = BitVec<u8>::ones(10);
auto ptr = v.data();
assert_eq(*ptr, 0b1111'1111);

◆ describe()

std::string gf2::BitStore< BitVec< usize > >::describe ( ) const

inlineinherited

Returns a multi-line string describing the bit-vector in some detail.

This method is useful for debugging but you should not rely on the output format which may change.

◆ fill()

auto gf2::BitStore< BitVec< usize > >::fill ( std::invocable< usize > auto f )

inlineinherited

Fill the store by repeatedly calling f(i) and returns a reference to this for chaining.

Example

BitVec v{10};
v.fill([](usize i) { return i % 2 == 0; });
assert_eq(v.size(), 10);
assert_eq(v.to_string(), "1010101010");

◆ first_set()

std::optional< usize > gf2::BitStore< BitVec< usize > >::first_set ( ) const

inlineinherited

Returns the index of the first set bit in the bit-store or {} if no bits are set.

Example

auto v = BitVec<u8>::zeros(37);
assert(v.first_set() == std::optional<usize>{});
v.set(2);
assert(v.first_set() == std::optional<usize>{2});
v.set(2, false);
assert(v.first_set() == std::optional<usize>{});
v.set(27);
assert(v.first_set() == std::optional<usize>{27});
BitVec empty;
assert(empty.first_set() == std::optional<usize>{});

◆ first_unset()

std::optional< usize > gf2::BitStore< BitVec< usize > >::first_unset ( ) const

inlineinherited

Returns the index of the first unset bit in the bit-store or {} if no bits are unset.

Example

auto v = BitVec<u8>::ones(37);
assert(v.first_unset() == std::optional<usize>{});
v.set(2, false);
assert(v.first_unset() == std::optional<usize>{2});
v.set(2);
assert(v.first_unset() == std::optional<usize>{});
v.set(27, false);
assert(v.first_unset() == std::optional<usize>{27});
BitVec empty;
assert(empty.first_unset() == std::optional<usize>{});

◆ flip()

auto gf2::BitStore< BitVec< usize > >::flip ( usize index )

inlineinherited

Flips the value of the bit-element at the given index and returns this for chaining/.

Note: In debug mode the index is bounds-checked.

Example

auto v = BitVec<u8>::ones(10);
v.flip(0);
assert_eq(v.to_string(), "0111111111");
v.flip(1);
assert_eq(v.to_string(), "0011111111");
v.flip(9);
assert_eq(v.to_string(), "0011111110");

◆ flip_all()

auto gf2::BitStore< BitVec< usize > >::flip_all ( )

inlineinherited

Flips the value of the bits in the store and returns a reference to this for chaining.

Example

auto v = BitVec<u8>::zeros(10);
v.flip_all();
assert_eq(v.to_string(), "1111111111");

◆ from() [1/3]

template<unsigned_word Word = usize>

template<typename Src>

constexpr BitVec gf2::BitVec< Word >::from ( const BitStore< Src > & src )

inlinestaticconstexpr

Factory method to construct a bit-vector by copying all the bits from any BitStore instance.

Note

Generally, we do not support interactions between bit-stores that use different underlying unsigned word types. This method is an exception – the src bit-store may use a different unsigned type from the one used here. It makes it possible to convert between bit-vector types which is occasionally useful.

Example

auto v = BitVec<u8>::from(BitVec<u8>::ones(10));
assert_eq(v.size(), 10);
assert_eq(v.to_string(), "1111111111");
auto w = BitVec<u8>::from(BitVec<u16>::ones(20));
assert_eq(w.size(), 20);
assert_eq(w.to_string(), "11111111111111111111");
auto x = BitVec<u8>::from(BitVec<u32>::zeros(10));
assert_eq(x.size(), 10);
assert_eq(x.to_string(), "0000000000");

◆ from() [2/3]

template<unsigned_word Word = usize>

template<usize N>

constexpr BitVec gf2::BitVec< Word >::from ( const std::bitset< N > & src )

inlinestaticconstexpr

Factory method to construct a bit-vector from the bits of a std::bitset.

Note: std::bitset prints its bit elements in bit-order ...b2b1b0., we print in vector-order b0b1b2...

Example

std::bitset<10> src{0b1010101010};
auto v = BitVec<>::from(src);
assert_eq(v.to_string(), "0101010101");

◆ from() [3/3]

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::from	(	usize	len,
		std::invocable< usize > auto	f )

inlinestaticconstexpr

Factory method to construct a bit-vector by repeatedly calling f(i) for i in [0, len).

Parameters

len	The length of the bit-vector to generate.
f	The function to call for each index i in [0, len).

Example

auto v = BitVec<u8>::from(10, [](usize i) { return i % 2 == 0; });
assert_eq(v.size(), 10);
assert_eq(v.to_string(), "1010101010");

◆ from_binary_string()

template<unsigned_word Word = usize>

std::optional< BitVec > gf2::BitVec< Word >::from_binary_string	(	std::string_view	sv,
		bool	no_punctuation = false )

inlinestatic

Factory method to construct a bit-vector from a binary string, returning std::nullopt on failure.

The string can contain whitespace, commas, single quotes, and underscores. If the second argument is true, then the string is assumed to have none of the above characters. There can always be a "0b" prefix.

Example

auto v = BitVec<u8>::from_binary_string("0b1010'1010'10");
assert_eq(v->to_string(), "1010101010");
auto u = BitVec<u8>::from_binary_string("");
assert_eq(u->to_string(), "");

◆ from_hex_string()

template<unsigned_word Word = usize>

std::optional< BitVec > gf2::BitVec< Word >::from_hex_string	(	std::string_view	sv,
		bool	no_punctuation = false )

inlinestatic

Factory method to construct a bit-vector from a hex string, returning std::nullopt on failure.

The hex string should consist of the characters 0-9, A-F, a-f, with an optional prefix "0x" or "0X". The string may also have a suffix of the form ".base" where base is one of 2, 4 or 8 which indicates that the last digit should be interpreted as a base base number. This allows for bit-vectors whose length is not a multiple of 4.

Example

auto v1 = gf2::BitVec<>::from_hex_string("0xAA").value();
assert_eq(v1.to_string(), "10101010");
auto v2 = gf2::BitVec<>::from_hex_string("0x1").value();
assert_eq(v2.to_string(), "0001");
auto v3 = gf2::BitVec<>::from_hex_string("0x1.8").value();
assert_eq(v3.to_string(), "001");
auto v4 = gf2::BitVec<>::from_hex_string("0x1.4").value();
assert_eq(v4.to_string(), "01");
auto v5 = gf2::BitVec<>::from_hex_string("0x1.2").value();
assert_eq(v5.to_string(), "1");

◆ from_string()

template<unsigned_word Word = usize>

std::optional< BitVec > gf2::BitVec< Word >::from_string ( std::string_view sv )

inlinestatic

Factory method to construct a bit-vector from a string s, returning std::nullopt on failure.

The string can contain whitespace, commas, single quotes, and underscores and optionally a "0b", "0x", or "0X" prefix. If there is no prefix, and the string only contains '0' and '1' characters, we assume the string is binary. To force getting it interpreted as a hex string, add a prefix of "0x" or "0X".

A hex string can have a suffix of ".2", ".4", or ".8" to indicate the base of the last digit/character. This allows for bit-vectors of any length as opposed to just a multiple of 4.

Example

auto v1 = BitVec<>::from_string("0b1010_1010_10").value();
assert_eq(v1.to_string(), "1010101010");
auto v2 = BitVec<>::from_string("AA").value();
assert_eq(v2.to_string(), "10101010");
auto v3 = BitVec<>::from_string("1010'1010").value();
assert_eq(v3.to_string(), "10101010");
auto v4 = BitVec<>::from_string("0x1.8").value();
assert_eq(v4.to_string(), "001");

◆ front()

bool gf2::BitStore< BitVec< usize > >::front ( ) const

inlineconstexprinherited

Returns true if the first bit element is set, false otherwise.

Note: In debug mode the method panics of the store is empty.

Example

auto v = BitVec<>::ones(10);
assert_eq(v.front(), true);
v.set_all(false);
assert_eq(v.front(), false);

◆ get()

bool gf2::BitStore< BitVec< usize > >::get ( usize i ) const

inlineconstexprinherited

Returns true if the bit at the given index i is set, false otherwise.

Note: In debug mode the index i is bounds-checked.

Example

BitVec v{10};
assert_eq(v.get(0), false);
v.set(0);
assert_eq(v.get(0), true);

◆ is_empty()

bool gf2::BitStore< BitVec< usize > >::is_empty ( ) const

inlineconstexprinherited

Returns true if the store is empty, false otherwise.

Example

BitVec v;
assert_eq(v.is_empty(), true);
BitVec u{10};
assert_eq(u.is_empty(), false);

◆ last_set()

std::optional< usize > gf2::BitStore< BitVec< usize > >::last_set ( ) const

inlineinherited

Returns the index of the last set bit in the bit-store or {} if no bits are set.

Example

auto v = BitVec<u8>::zeros(37);
assert(v.last_set() == std::optional<usize>{});
v.set(2);
assert(v.last_set() == std::optional<usize>{2});
v.set(27);
assert(v.last_set() == std::optional<usize>{27});
BitVec empty;
assert(empty.last_set() == std::optional<usize>{});

◆ last_unset()

std::optional< usize > gf2::BitStore< BitVec< usize > >::last_unset ( ) const

inlineinherited

Returns the index of the last unset bit in the bit-store or {} if no bits are unset.

Example

auto v = BitVec<u8>::ones(37);
assert(v.last_unset() == std::optional<usize>{});
v.set(2, false);
assert(v.last_unset() == std::optional<usize>{2});
v.set(2);
assert(v.last_unset() == std::optional<usize>{});
v.set(27, false);
assert(v.last_unset() == std::optional<usize>{27});
BitVec empty;
assert(empty.last_unset() == std::optional<usize>{});

◆ leading_zeros()

usize gf2::BitStore< BitVec< usize > >::leading_zeros ( ) const

inlineconstexprinherited

Returns the number of leading zeros in the store.

Example

BitVec v{37};
assert_eq(v.leading_zeros(), 37);
v.set(27);
assert_eq(v.leading_zeros(), 27);
auto w = BitVec<u8>::ones(10);
assert_eq(w.leading_zeros(), 0);

◆ next_set()

std::optional< usize > gf2::BitStore< BitVec< usize > >::next_set ( usize index ) const

inlineinherited

Returns the index of the next set bit after index in the store or {} if no more set bits exist.

Example

auto v = BitVec<u8>::zeros(37);
assert(v.next_set(0) == std::optional<usize>{});
v.set(2);
v.set(27);
assert(v.next_set(0) == std::optional<usize>{2});
assert(v.next_set(2) == std::optional<usize>{27});
assert(v.next_set(27) == std::optional<usize>{});

◆ next_unset()

std::optional< usize > gf2::BitStore< BitVec< usize > >::next_unset ( usize index ) const

inlineinherited

Returns the index of the next unset bit after index in the store or {} if no more unset bits exist.

Example

auto v = BitVec<u8>::ones(37);
assert(v.next_unset(0) == std::optional<usize>{});
v.set(2, false);
v.set(27, false);
assert(v.next_unset(0) == std::optional<usize>{2});
assert(v.next_unset(2) == std::optional<usize>{27});
assert(v.next_unset(27) == std::optional<usize>{});
BitVec empty;
assert(empty.next_unset(0) == std::optional<usize>{});

◆ none()

bool gf2::BitStore< BitVec< usize > >::none ( ) const

inlineconstexprinherited

Returns true if no bits in the store are set, false otherwise.

Note: Empty store have no set bits (logical connective for none is AND with identity true).

Example

BitVec v{10};
assert_eq(v.none(), true);
v.set(0);
assert_eq(v.none(), false);

◆ offset()

template<unsigned_word Word = usize>

u8 gf2::BitVec< Word >::offset ( ) const

inlineconstexpr

Returns the offset (in bits) of the first bit in the store within the first word.

This is always zero for BitVec.

◆ ones()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::ones ( usize n )

inlinestaticconstexpr

Factory method to generate a bit-vector of length n where the elements are all 1.

Example

assert_eq(BitVec<>::ones(10).to_string(), "1111111111");

◆ operator&()

auto gf2::BitStore< BitVec< usize > >::operator& ( const BitStore< Rhs > & rhs ) const

inlineinherited

Returns a new bit-vector that is the AND of the current bit-store and another equal-sized bit-store.

Note: In debug mode, this method panics if the lengths of the two bit-stores do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
auto v2 = ~v1;
auto v3 = v1 & v2;
assert_eq(v3.to_string(), "0000000000");

◆ operator&=()

void gf2::BitStore< BitVec< usize > >::operator&= ( const BitStore< Rhs > & rhs )

inlineinherited

In-place AND with another equal-sized bit-store.

Note: In debug mode, this method panics if the lengths of the two bit-stores do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
v1 &= ~v1;
assert_eq(v1.to_string(), "0000000000");

◆ operator+()

auto gf2::BitStore< BitVec< usize > >::operator+ ( const BitStore< Rhs > & rhs ) const

inlineinherited

Returns a new bit-vector that is the + of this store with the passed (equal-sized) rhs bit-store.

In GF(2) subtraction is the same as XOR.

Note: In debug mode, this methods panics if the lengths of lhs and rhs do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
auto v2 = ~v1;
auto v3 = v1 + v2;
assert_eq(v3.to_string(), "1111111111");

◆ operator+=()

void gf2::BitStore< BitVec< usize > >::operator+= ( const BitStore< Rhs > & rhs )

inlineinherited

In-place addition of this bit-store with the an equal-sized rhs bit-store.

In GF(2) addition is the same as XOR.

Note: In debug mode, this methods panics if the lengths of lhs and rhs do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
v1 += ~v1;
assert_eq(v1.to_string(), "1111111111");

◆ operator-()

auto gf2::BitStore< BitVec< usize > >::operator- ( const BitStore< Rhs > & rhs ) const

inlineinherited

Returns a new bit-vector that is the - of this store with the passed (equal-sized) rhs bit-store.

In GF(2) subtraction is the same as XOR.

Note: In debug mode, this methods panics if the lengths of lhs and rhs do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
auto v2 = ~v1;
auto v3 = v1 - v2;
assert_eq(v3.to_string(), "1111111111");

◆ operator-=()

void gf2::BitStore< BitVec< usize > >::operator-= ( const BitStore< Rhs > & rhs )

inlineinherited

In-place subtraction of this bit-store with the an equal-sized rhs bit-store.

In GF(2) subtraction is the same as XOR.

Note: In debug mode, this methods panics if the lengths of lhs and rhs do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
v1 -= ~v1;
assert_eq(v1.to_string(), "1111111111");

◆ operator<<()

auto gf2::BitStore< BitVec< usize > >::operator<< ( usize shift ) const

inlineconstexprinherited

Returns a new bit-vector that is lhs shifted left by shift bits.

Shifting is in vector-order so if v = [v0,v1,v2,v3] then v << 1 is [v1,v2,v3,0] with zeros added to the right. Left shifting in vector-order is the same as right shifting in bit-order.

Note: Only accessible bits are affected by the shift.

Example

auto v = BitVec<u8>::ones(20);
auto w = v << 8;
assert_eq(w.to_string(), "11111111111100000000");

◆ operator<<=()

void gf2::BitStore< BitVec< usize > >::operator<<= ( usize shift )

inlineconstexprinherited

In-place left shift of the bit-store by shift bits.

Shifting is in vector-order so if v = [v0,v1,v2,v3] then v <<= 1 is [v1,v2,v3,0] with zeros added to the right. Left shifting in vector-order is the same as right shifting in bit-order.

Note: Only accessible bits are affected by the shift.

Example

auto v = BitVec<u8>::ones(20);
v <<= 8;
assert_eq(v.to_string(), "11111111111100000000");

◆ operator>>()

auto gf2::BitStore< BitVec< usize > >::operator>> ( usize shift ) const

inlineconstexprinherited

Returns a new bit-vector that is lhs shifted right by shift bits.

Shifting is in vector-order so if v = [v0,v1,v2,v3] then v >>= 1 is [0,v0,v1,v2] with zeros added to the left. Right shifting in vector-order is the same as left shifting in bit-order.

Note: Only accessible bits are affected by the shift.

Example

auto v = BitVec<u8>::ones(20);
auto w = v >> 8;
assert_eq(w.to_string(), "00000000111111111111");

◆ operator>>=()

void gf2::BitStore< BitVec< usize > >::operator>>= ( usize shift )

inlineconstexprinherited

In-place right shift of the bit-store by shift bits.

Shifting is in vector-order so if v = [v0,v1,v2,v3] then v >>= 1 is [0,v0,v1,v2] with zeros added to the left. Right shifting in vector-order is the same as left shifting in bit-order.

Note: Only accessible bits are affected by the shift.

Example

auto v = BitVec<u8>::ones(20);
v >>= 8;
assert_eq(v.to_string(), "00000000111111111111");

◆ operator[]()

bool gf2::BitStore< BitVec< usize > >::operator[] ( usize index ) const

inlineconstexprinherited

Returns the boolean value of the bit element at index.

Note: In debug mode the index is bounds-checked.

Example

BitVec v{10};
assert(v[2] == false);
v[2] = true;
assert(v[2] == true);
assert(v.to_string() == "0010000000");

◆ operator^()

auto gf2::BitStore< BitVec< usize > >::operator^ ( const BitStore< Rhs > & rhs ) const

inlineinherited

Returns a new bit-vector that is the XOR of the current bit-store and another equal-sized bit-store.

Note: In debug mode, this method panics if the lengths of the two bit-stores do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
auto v2 = ~v1;
auto v3 = v1 ^ v2;
assert_eq(v3.to_string(), "1111111111");

◆ operator^=()

void gf2::BitStore< BitVec< usize > >::operator^= ( const BitStore< Rhs > & rhs )

inlineinherited

In-place XOR with another equal-sized bit-store.

Note: In debug mode, this method panics if the lengths of the two bit-stores do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
v1 ^= ~v1;
assert_eq(v1.to_string(), "1111111111");

◆ operator|()

auto gf2::BitStore< BitVec< usize > >::operator| ( const BitStore< Rhs > & rhs ) const

inlineinherited

Returns a new bit-vector that is the OR of the current bit-store and another equal-sized bit-store.

Note: In debug mode, this methods panics if the lengths of lhs and rhs do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
auto v2 = ~v1;
auto v3 = v1 | v2;
assert_eq(v3.to_string(), "1111111111");

◆ operator|=()

void gf2::BitStore< BitVec< usize > >::operator|= ( const BitStore< Rhs > & rhs )

inlineinherited

In-place OR with another equal-sized bit-store.

Note: In debug mode, this method panics if the lengths of the two bit-stores do not match.

Example

auto v1 = BitVec<u8>::alternating(10);
v1 |= ~v1;
assert_eq(v1.to_string(), "1111111111");

◆ operator~()

auto gf2::BitStore< BitVec< usize > >::operator~ ( ) const

inlineinherited

Returns a new bit-vector that has the same bits as the current bit-store but with all the bits flipped.

Example

auto v = BitVec<u8>::alternating(10);
assert_eq(v.to_string(), "1010101010");
auto w = ~v;
assert_eq(w.to_string(), "0101010101");

◆ pop()

template<unsigned_word Word = usize>

std::optional< bool > gf2::BitVec< Word >::pop ( )

inlineconstexpr

Removes the last bit from the bit-vector and returns it or std::nullopt if the bit-vector is empty.

Example

BitVec v;
v.push(1);
v.push(0);
assert(v.to_string() == "10");
auto b1 = v.pop();
assert_eq(*b1, false);
assert(v.to_string() == "1");
auto b2 = v.pop();
assert_eq(*b2, true);
assert(v.to_string() == "");
auto b3 = v.pop();
assert(b3 == std::nullopt);

◆ previous_set()

std::optional< usize > gf2::BitStore< BitVec< usize > >::previous_set ( usize index ) const

inlineinherited

Returns the index of the previous set bit before index in the store or {} if there are none.

Example

auto v = BitVec<u8>::zeros(37);
assert(v.previous_set(36) == std::optional<usize>{});
v.set(2);
v.set(27);
assert(v.previous_set(36) == std::optional<usize>{27});
assert(v.previous_set(27) == std::optional<usize>{2});
assert(v.previous_set(2)  == std::optional<usize>{});

◆ previous_unset()

std::optional< usize > gf2::BitStore< BitVec< usize > >::previous_unset ( usize index ) const

inlineinherited

Returns the index of the previous unset bit before index in the store or {} if no more unset bits exist.

Example

auto v = BitVec<u8>::ones(37);
assert(v.previous_unset(0) == std::optional<usize>{});
v.set(2, false);
v.set(27, false);
assert(v.previous_unset(36) == std::optional<usize>{27});
assert(v.previous_unset(27) == std::optional<usize>{2});
assert(v.previous_unset(2) == std::optional<usize>{});
BitVec empty;
assert(empty.previous_unset(0) == std::optional<usize>{});

◆ push()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::push ( bool b )

inlineconstexpr

Pushes a single bit b onto the bit-vector.

Returns a reference to the current object for chaining.

Example

BitVec v;
v.push(1);
assert(v.to_string() == "1");
v.push(0);
assert(v.to_string() == "10");

◆ random()

template<unsigned_word Word = usize>

BitVec gf2::BitVec< Word >::random	(	usize	len,
		double	p = 0.5,
		u64	seed = 0 )

inlinestatic

Factory method to generate a bit-vector of size len where the elements are picked at random.

The default call BitVec<>::random(len) produces a random bit-vector with each bit being 1 with probability 0.5 and where the RNG is seeded from entropy.

Parameters

len	The length of the bit-vector to generate.
p	The probability of the elements being 1 (defaults to a fair coin, i.e. 50-50).
seed	The seed to use for the random number generator (defaults to 0, which means use entropy).

Note: If p < 0 then the bit-vector is all zeros, if p > 1 then the bit-vector is all ones.

Example

u64 seed = 1234567890;
auto u = BitVec<>::random(10, 0.5, seed);
auto v = BitVec<>::random(10, 0.5, seed);
assert(u == v);

◆ random_fill()

auto gf2::BitStore< BitVec< usize > >::random_fill	(	double	p = 0.5,
		u64	seed = 0 )

inlineinherited

Fill the store with random bits and returns a reference to this for chaining.

The default call random_fill() sets each bit to 1 with probability 0.5 (fair coin).

Parameters

p	The probability of the elements being 1 (defaults to a fair coin, i.e. 50-50).
seed	The seed to use for the random number generator (defaults to 0, which means use entropy).

Note: If p < 0 then the fill is all zeros, if p > 1 then the fill is all ones.

Example

BitVec u{10}, v{10};
u64 seed = 1234567890;
u.random_fill(0.5, seed);
v.random_fill(0.5, seed);
assert(u == v);

◆ resize()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::resize ( usize n )

inlineconstexpr

Resize the bit-vector so that its size() is n.

If n is greater than the bit-vector's current size, then the new elements are set to 0.
If n is less than the bit-vector's current size, then the bit-vector is truncated.

Example

auto v = BitVec<u8>::ones(1000);
v.resize(10);
assert_eq(v.to_string(), "1111111111");
v.resize(15);
assert_eq(v.to_string(), "111111111100000");

◆ riffle_into()

void gf2::BitStore< BitVec< usize > >::riffle_into ( BitVec< word_type > & dst ) const

inlineconstexprinherited

Interleaves the bits of this bit-store with zeros storing the result into the bit-vector dst.

On return, dst will have the bits of this bit-store interleaved with zeros. For example, if this bit-store has the bits abcde then dst will have the bits a0b0c0d0e.

Note: There is no last zero bit in dst.

Example

auto v = BitVec<u8>::ones(10);
BitVec<u8> dst;
v.riffle_into(dst);
assert_eq(dst.to_string(), "1010101010101010101");

◆ riffled()

auto gf2::BitStore< BitVec< usize > >::riffled ( ) const

inlineconstexprinherited

Returns a new bit-vector that is the result of riffling the bits in this bit-store with zeros.

If bit-store has the bits abcde then the output bit-vector will have the bits a0b0c0d0e.

Note: There is no last zero bit in dst.

Example

auto v = BitVec<u8>::ones(10);
auto dst = v.riffled();
assert_eq(dst.to_string(), "1010101010101010101");

◆ seeded_random()

template<unsigned_word Word = usize>

BitVec gf2::BitVec< Word >::seeded_random	(	usize	len,
		u64	seed )

inlinestatic

Factory method to generate a bit-vector of size len where the elements are from independent fair coin flips generated from an RNG seeded with the given seed.

This allows one to have reproducible random bit-vectors, which is useful for testing and debugging.

Parameters

len	The length of the bit-vector to generate.
seed	The seed to use for the random number generator (if you set this to 0 then entropy is used).

Note: If p < 0 then the bit-vector is all zeros, if p > 1 then the bit-vector is all ones.

Example

u64 seed = 1234567890;
auto u = BitVec<>::seeded_random(10, seed);
auto v = BitVec<>::seeded_random(10, seed);
assert(u == v);

◆ set()

auto gf2::BitStore< BitVec< usize > >::set	(	usize	index,
		bool	value = true )

inlineinherited

Sets the bit-element at the given index to the specified boolean value & returns this for chaining. The default value for value is true.

Note: In debug mode the index is bounds-checked.

Example

BitVec v{10};
assert_eq(v.get(0), false);
v.set(0);
assert_eq(v.get(0), true);

◆ set_all()

auto gf2::BitStore< BitVec< usize > >::set_all ( bool value = true )

inlineinherited

Sets the bits in the store to the boolean value and returns a reference to this for chaining.

By default, all bits are set to true.

Example

auto v = BitVec<u8>::zeros(10);
v.set_all();
assert_eq(v.to_string(), "1111111111");

◆ set_bit_indices()

auto gf2::BitStore< BitVec< usize > >::set_bit_indices ( ) const

inlineconstexprinherited

Returns an iterator over the indices of any set bits in the bit-store.

You can use this iterator to iterate over the set bits in the store and get the index of each bit.

Example

auto v = BitVec<u8>::alternating(10);
assert_eq(v.to_string(), "1010101010");
auto indices = std::ranges::to<std::vector>(v.set_bit_indices());
assert_eq(indices, (std::vector<usize>{0, 2, 4, 6, 8}));

◆ set_word() [1/2]

void gf2::BitStore< BitVec< usize > >::set_word	(	usize	i,
		word_type	value )

inlineconstexprinherited

This method sets "word" at index i to the specified value.

For example, if the store has 18 bit elements, then setting the first word changes bit elements 0 through 7, the second word changes bit elements 8 through 15, and the third word changes bit elements 16 and 17.

This method is trivially implemented by the BitVec class. However, the bits in a BitSpan may not be aligned to word boundaries but that class synthesises words as if they were by combining adjacent words as needed.

Note: The method must ensure that inaccessible bits in the underlying store are not changed by this call.

◆ set_word() [2/2]

template<unsigned_word Word = usize>

void gf2::BitVec< Word >::set_word	(	usize	i,
		Word	word )

inlineconstexpr

Sets word i in the bit-vector's underlying word store to value (masked if necessary).

The final word in the store may not be fully occupied but we ensure that unused bits remain set to 0.

Note: In debug mode the index is bounds checked.

Example

auto v = BitVec<u8>::zeros(10);
assert_eq(v.to_string(), "0000000000");
v.set_word(1, 0b1111'1111);
assert_eq(v.to_string(), "0000000011");
assert_eq(v.count_ones(), 2);

◆ shrink_to_fit()

template<unsigned_word Word = usize>

BitVec & gf2::BitVec< Word >::shrink_to_fit ( )

inlineconstexpr

Shrinks the bit-vector's capacity as much as possible.

This method may do nothing.

Example

auto v = BitVec<u8>::ones(1000);
v.resize(15);
v.shrink_to_fit();
assert_eq(v.capacity(), 16);

◆ size()

template<unsigned_word Word = usize>

usize gf2::BitVec< Word >::size ( ) const

inlineconstexpr

Returns the number of bit-elements in the bit-vector.

Example

BitVec v0;
assert_eq(v0.size(), 0);
BitVec<u8> v1(10);
assert_eq(v1.size(), 10);

◆ span()

auto gf2::BitStore< BitVec< usize > >::span	(	usize	begin,
		usize	end ) const

inlineconstexprinherited

Returns an immutable bit-span encompassing the bits in the half-open range [begin, end).

Immutability here is deep – the interior pointer in the returned span is to const words.

Note: This method panics if the bit-store is empty or if the range is not valid.

Example

auto v = BitVec<>::alternating(10);
auto s = v.span(1,5);
assert_eq(s.to_string(), "0101");

◆ split_at()

void gf2::BitStore< BitVec< usize > >::split_at	(	usize	at,
		BitVec< word_type > &	left,
		BitVec< word_type > &	right ) const

inlineconstexprinherited

Views a bit-store as two parts containing the elements [0, at) and [at, size()) respectively.

Clones of the parts are stored in the passed bit-vectors left and right.

On return, left contains the bits from the start of the bit-vector up to but not including at and right contains the bits from at to the end of the bit-vector. This bit-vector itself is not modified.

This lets one reuse the left and right destinations without having to allocate new bit-vectors. This is useful when implementing iterative algorithms that need to split a bit-vector into two parts repeatedly.

Note: This method panics if the split point is beyond the end of the bit-vector.

Example

auto v = BitVec<>::alternating(10);
BitVec left, right;
v.split_at(5, left, right);
assert_eq(left.to_string(), "10101");
assert_eq(right.to_string(), "01010");
assert_eq(v.to_string(), "1010101010");

◆ split_off() [1/2]

template<unsigned_word Word = usize>

BitVec< Word > gf2::BitVec< Word >::split_off ( usize at )

inlineconstexpr

Splits a bit-vector into two at the given index, returning a new BitVec.

The returned bit-vector contains the bits from at to the end of the bit-vector. The bit-vector is resized to only contain the bits in the half-open range [0, at).

Note: This method panics if the split point is beyond the end of the bit-vector.

Example

auto v = BitVec<>::alternating(10);
auto w = v.split_off(5);
assert_eq(v.to_string(), "10101");
assert_eq(w.to_string(), "01010");

◆ split_off() [2/2]

template<unsigned_word Word = usize>

void gf2::BitVec< Word >::split_off	(	usize	at,
		BitVec< Word > &	dst )

inlineconstexpr

Splits a bit-vector into two at the given index, returning the second part in dst.

On return, dst contains the bits from at to the end of the bit-vector. The bit-vector is resized to only contain the bits in the half-open range [0, at).

Note: This method panics if the split point is beyond the end of the bit-vector.

Example

auto v = BitVec<>::alternating(10);
BitVec dst;
v.split_off(5, dst);
assert_eq(v.to_string(), "10101");
assert_eq(dst.to_string(), "01010");

◆ split_off_unsigned()

template<unsigned_word Word = usize>

template<unsigned_word Dst = Word>

std::optional< Dst > gf2::BitVec< Word >::split_off_unsigned ( )

inlineconstexpr

Split off a single arbitrary sized unsigned integer off the end of the bit-vector and returns it or std::nullopt if the bit-vector is empty.

Note: You can split off a primitive unsigned integer type of any size from the end of a non-empty bit-vector.

For example, if v is a BitVec<u8>with 22 elements, then you can split off a u16 value from the end of v by calling v.split_off_unsigned<u16>(). This leaves the bit-vector with 6 elements.

Examples

auto v = BitVec<u8>::ones(22);
auto x16 = v.split_off_unsigned<u16>();
assert_eq(*x16, 0b1111'1111'1111'1111);
assert_eq(v.size(), 6);
assert_eq(v.to_string(), "111111");
auto w = BitVec<u8>::alternating(24);
auto x8 = w.split_off_unsigned<u8>();
assert_eq(*x8, 0b0101'0101);
assert_eq(w.size(), 16);
assert_eq(w.to_string(), "1010101010101010");
w.append(*x8);
assert_eq(w.to_string(), "101010101010101010101010");

◆ store_words()

auto gf2::BitStore< BitVec< usize > >::store_words ( ) const

inlineconstexprinherited

Returns a const iterator over all the words underlying the bit-store.

You can use this iterator to iterate over the words in the store and read the Word value of each word. Note that you cannot use this iterator to modify the words in the store.

Note: The words here may be a synthetic construct. The expectation is that the bit 0 in the store is located at the bit-location 0 of word(0). That is always the case for bit-vectors but bit-slices typically synthesise "words" on the fly from adjacent pairs of bit-vector words. Nevertheless, almost all the methods in BitStore are implemented efficiently by operating on those words.

Example

auto v = BitVec<u8>::ones(10);
assert_eq(v.to_string(), "1111111111");
auto indices = std::ranges::to<std::vector>(v.store_words());
assert_eq(indices, (std::vector<u8>{0b1111'1111, 0b0000'0011}));

◆ sub()

auto gf2::BitStore< BitVec< usize > >::sub	(	usize	begin,
		usize	end ) const

inlineconstexprinherited

Returns a clone of the elements in the half-open range [begin, end) as a new bit-vector.

Note: This method panics if the bit-vector is empty or if the range is not valid.

Example

auto v = BitVec<>::alternating(10);
auto s = v.sub(1,5);
assert_eq(s.to_string(), "0101");
s.set_all();
assert_eq(s.to_string(), "1111");
assert_eq(v.to_string(), "1010101010");

◆ swap()

auto gf2::BitStore< BitVec< usize > >::swap	(	usize	i0,
		usize	i1 )

inlineconstexprinherited

Swaps the bits in the bit-store at indices i0 and i1 and returns this for chaining.

Note: In debug mode, panics if either of the indices is out of bounds.

Example

auto v = BitVec<>::zeros(10);
v.set(0);
assert_eq(v.to_string(), "1000000000");
v.swap(0, 1);
assert_eq(v.to_string(), "0100000000");
v.swap(0, 1);
assert_eq(v.to_string(), "1000000000");
v.swap(0, 9);
assert_eq(v.to_string(), "0000000001");
v.swap(0, 9);
assert_eq(v.to_string(), "1000000000");

◆ to_binary_string()

std::string gf2::BitStore< BitVec< usize > >::to_binary_string	(	std::string_view	sep = "",
		std::string_view	pre = "",
		std::string_view	post = "" ) const

inlineinherited

Returns a binary string representation of the store.

The string is formatted as a sequence of 0s and 1s with the least significant bit on the right.

Parameters

sep	The separator between bit elements which defaults to no separator.
pre	The prefix to add to the string which defaults to no prefix.
post	The postfix to add to the string which defaults to no postfix.

Example

BitVec v{10};
assert_eq(v.to_binary_string(), "0000000000");
v.set(0);
assert_eq(v.to_binary_string(), "1000000000");
assert_eq(v.to_binary_string(",", "[", "]"), "[1,0,0,0,0,0,0,0,0,0]");

◆ to_hex_string()

std::string gf2::BitStore< BitVec< usize > >::to_hex_string ( ) const

inlineinherited

Returns the "hex" string representation of the bits in the bit-store.

The output is a string of hex characters without any spaces, commas, or other formatting.

The string may have a two character suffix of the form ".base" where base is one of 2, 4 or 8.
All hex characters encode 4 bits: "0X0" -> 0b0000, "0X1" -> 0b0001, ..., "0XF" -> 0b1111.
The three possible ".base" suffixes allow for bit-vectors whose length is not a multiple of 4.
Empty bit-vectors are represented as the empty string.

0X1 is the hex representation of the bit-vector 0001 => length 4.
0X1.8 is the hex representation of the bit-vector 001 => length 3.
0X1.4 is the hex representation of the bit-vector 01 => length 2.
0X1.2 is the hex representation of the bit-vector 1 => length 1.

The output is in vector-order. If "h0" is the first hex digit in the output string, you can print it as four binary digits v_0v_1v_2v_3. For example, if h0 = "A" which is 1010 in binary, then v = 1010.

Example

BitVec v0;
assert_eq(v0.to_hex_string(), "");
auto v1 = BitVec<>::ones(4);
assert_eq(v1.to_hex_string(), "F");
auto v2 = BitVec<>::ones(5);
assert_eq(v2.to_hex_string(), "F1.2");
auto v3 = BitVec<>::alternating(8);
assert_eq(v3.to_binary_string(), "10101010");
assert_eq(v3.to_hex_string(), "AA");

◆ to_pretty_string()

std::string gf2::BitStore< BitVec< usize > >::to_pretty_string ( ) const

inlineinherited

Returns a "pretty" string representation of the store.

The output is a string of 0's and 1's with spaces between each bit, and the whole thing enclosed in square brackets.

Example

auto v = BitVec<>::alternating(10);
assert_eq(v.to_pretty_string(), "[1,0,1,0,1,0,1,0,1,0]");
BitVec empty;
assert_eq(empty.to_pretty_string(), "[]");

◆ to_string()

std::string gf2::BitStore< BitVec< usize > >::to_string	(	std::string_view	sep = "",
		std::string_view	pre = "",
		std::string_view	post = "" ) const

inlineinherited

Returns a binary string representation of the store.

The string is formatted as a sequence of 0s and 1s with the least significant bit on the right.

Parameters

sep	The separator between bit elements which defaults to no separator.
pre	The prefix to add to the string which defaults to no prefix.
post	The postfix to add to the string which defaults to no postfix.

Example

BitVec v{10};
assert_eq(v.to_string(), "0000000000");
v.set(0);
assert_eq(v.to_string(), "1000000000");
assert_eq(v.to_string(",", "[", "]"), "[1,0,0,0,0,0,0,0,0,0]");

◆ to_words()

auto gf2::BitStore< BitVec< usize > >::to_words ( ) const

inlineconstexprinherited

Returns a copy of the words underlying this bit-store.

Note: The last word in the vector may not be fully occupied but unused slots will be all zeros.

Example

auto v = BitVec<u8>::ones(10);
auto words = v.to_words();
assert_eq(words, (std::vector<u8>{0b1111'1111, 0b0000'0011}));

◆ trailing_zeros()

usize gf2::BitStore< BitVec< usize > >::trailing_zeros ( ) const

inlineconstexprinherited

Returns the number of trailing zeros in the store.

Example

auto v = BitVec<u8>::zeros(27);
assert_eq(v.trailing_zeros(), 27);
v.set(0);
assert_eq(v.trailing_zeros(), 26);

◆ unit()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::unit	(	usize	n,
		usize	i )

inlinestaticconstexpr

Factory method to generate a "unit" bit-vector of length n where only element i is set.

This method panics if the condition i < n is not met.

Example

assert_eq(BitVec<>::unit(10, 0).to_string(), "1000000000");

assert_eq(BitVec<>::unit(10, 9).to_string(), "0000000001");

gf2::BitVec::unit

static constexpr BitVec unit(usize n, usize i)

Factory method to generate a "unit" bit-vector of length n where only element i is set.

Definition BitVec.h:242

◆ unset_bit_indices()

auto gf2::BitStore< BitVec< usize > >::unset_bit_indices ( ) const

inlineconstexprinherited

Returns an iterator over the indices of any unset bits in the bit-store.

You can use this iterator to iterate over the unset bits in the store and get the index of each bit.

Example

auto v = BitVec<u8>::alternating(10);
assert_eq(v.to_string(), "1010101010");
auto indices = std::ranges::to<std::vector>(v.unset_bit_indices());
assert_eq(indices, (std::vector<usize>{1, 3, 5, 7, 9}));

◆ with_capacity()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::with_capacity ( usize capacity )

inlinestaticconstexpr

Factory method to construct an empty bit-vector with at least the specified capacity.

Example

auto v = BitVec<>::with_capacity(10);
assert_eq(v.size(), 0);
assert(v.capacity() >=10);

◆ word()

template<unsigned_word Word = usize>

Word gf2::BitVec< Word >::word ( usize i ) const

inlineconstexpr

Returns word i from the bit-vector's underlying word store.

The final word in the store may not be fully occupied but we guarantee that unused bits are set to 0.

Note: In debug mode the index is bounds checked.

Example

auto v = BitVec<u8>::ones(10);
assert_eq(v.to_string(), "1111111111");
assert_eq(v.words(), 2);
assert_eq(v.word(0), 0b1111'1111);
assert_eq(v.word(1), 0b0000'0011);

◆ words()

template<unsigned_word Word = usize>

usize gf2::BitVec< Word >::words ( ) const

inlineconstexpr

Returns the number of words in the bit-vector's underlying word store.

The bit-elements are packed into a standard vector with this number of words.

Example

BitVec v0;
assert_eq(v0.words(), 0);
BitVec<u8> v1(10);
assert_eq(v1.words(), 2);

◆ zeros()

template<unsigned_word Word = usize>

constexpr BitVec gf2::BitVec< Word >::zeros ( usize n )

inlinestaticconstexpr

Factory method to generate a bit-vector of length n where the elements are all 0.

Example

auto v = BitVec<>::zeros(10);

assert_eq(v.to_string(), "0000000000");

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ BitVec() [1/2]

Example

◆ BitVec() [2/2]

Example

Member Function Documentation

◆ all()

Example

◆ alternating()

Example

◆ any()

Example

◆ append() [1/3]

Example

◆ append() [2/3]

Example

◆ append() [3/3]

Example

◆ append_digit()

Example

◆ append_hex_digit()

Example

◆ back()

Example

◆ biased_random()

Example

◆ bits()

Example

◆ capacity()

Example

◆ clean()

◆ clear()

◆ constant()

Example

◆ copy()

Notes:

Example

◆ count_ones()

Example

◆ count_zeros()

Example

◆ data() [1/2]

Example

◆ data() [2/2]

Example

◆ describe()

◆ fill()

Example

◆ first_set()

Example

◆ first_unset()

Example

◆ flip()

Example

◆ flip_all()

Example

◆ from() [1/3]

Note

Example

◆ from() [2/3]

Example

◆ from() [3/3]

Example

◆ from_binary_string()

Example

◆ from_hex_string()

Example

◆ from_string()

Example

◆ front()

Example

◆ get()

Example

◆ is_empty()

Example