Struct std::collections::BitVecUnstable
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[src]
pub struct BitVec {
// some fields omitted
}The bitvector type.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); // insert all primes less than 10 bv.set(2, true); bv.set(3, true); bv.set(5, true); bv.set(7, true); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count()); // flip all values in bitvector, producing non-primes less than 10 bv.negate(); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count()); // reset bitvector to empty bv.clear(); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count()); }use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); // insert all primes less than 10 bv.set(2, true); bv.set(3, true); bv.set(5, true); bv.set(7, true); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count()); // flip all values in bitvector, producing non-primes less than 10 bv.negate(); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count()); // reset bitvector to empty bv.clear(); println!("{:?}", bv); println!("total bits set to true: {}", bv.iter().filter(|x| *x).count());
Methods
impl BitVec
fn new() -> BitVec
Creates an empty BitVec.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::new(); }use std::collections::BitVec; let mut bv = BitVec::new();
fn from_elem(nbits: usize, bit: bool) -> BitVec
Creates a BitVec that holds nbits elements, setting each element
to bit.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.len(), 10); for x in bv.iter() { assert_eq!(x, false); } }use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.len(), 10); for x in bv.iter() { assert_eq!(x, false); }
fn with_capacity(nbits: usize) -> BitVec
Constructs a new, empty BitVec with the specified capacity.
The bitvector will be able to hold at least capacity bits without
reallocating. If capacity is 0, it will not allocate.
It is important to note that this function does not specify the length of the returned bitvector, but only the capacity.
fn from_bytes(bytes: &[u8]) -> BitVec
Transforms a byte-vector into a BitVec. Each byte becomes eight bits,
with the most significant bits of each byte coming first. Each
bit becomes true if equal to 1 or false if equal to 0.
Examples
fn main() { use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b10100000, 0b00010010]); assert!(bv.eq_vec(&[true, false, true, false, false, false, false, false, false, false, false, true, false, false, true, false])); }use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b10100000, 0b00010010]); assert!(bv.eq_vec(&[true, false, true, false, false, false, false, false, false, false, false, true, false, false, true, false]));
fn from_fn<F>(len: usize, f: F) -> BitVec where F: FnMut(usize), <F as FnMut(usize)>::Output == bool
Creates a BitVec of the specified length where the value at each index
is f(index).
Examples
fn main() { use std::collections::BitVec; let bv = BitVec::from_fn(5, |i| { i % 2 == 0 }); assert!(bv.eq_vec(&[true, false, true, false, true])); }use std::collections::BitVec; let bv = BitVec::from_fn(5, |i| { i % 2 == 0 }); assert!(bv.eq_vec(&[true, false, true, false, true]));
fn get(&self, i: usize) -> Option<bool>
Retrieves the value at index i, or None if the index is out of bounds.
Examples
fn main() { use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b01100000]); assert_eq!(bv.get(0), Some(false)); assert_eq!(bv.get(1), Some(true)); assert_eq!(bv.get(100), None); // Can also use array indexing assert_eq!(bv[1], true); }use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b01100000]); assert_eq!(bv.get(0), Some(false)); assert_eq!(bv.get(1), Some(true)); assert_eq!(bv.get(100), None); // Can also use array indexing assert_eq!(bv[1], true);
fn set(&mut self, i: usize, x: bool)
Sets the value of a bit at an index i.
Panics
Panics if i is out of bounds.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(5, false); bv.set(3, true); assert_eq!(bv[3], true); }use std::collections::BitVec; let mut bv = BitVec::from_elem(5, false); bv.set(3, true); assert_eq!(bv[3], true);
fn set_all(&mut self)
Sets all bits to 1.
Examples
fn main() { use std::collections::BitVec; let before = 0b01100000; let after = 0b11111111; let mut bv = BitVec::from_bytes(&[before]); bv.set_all(); assert_eq!(bv, BitVec::from_bytes(&[after])); }use std::collections::BitVec; let before = 0b01100000; let after = 0b11111111; let mut bv = BitVec::from_bytes(&[before]); bv.set_all(); assert_eq!(bv, BitVec::from_bytes(&[after]));
fn negate(&mut self)
Flips all bits.
Examples
fn main() { use std::collections::BitVec; let before = 0b01100000; let after = 0b10011111; let mut bv = BitVec::from_bytes(&[before]); bv.negate(); assert_eq!(bv, BitVec::from_bytes(&[after])); }use std::collections::BitVec; let before = 0b01100000; let after = 0b10011111; let mut bv = BitVec::from_bytes(&[before]); bv.negate(); assert_eq!(bv, BitVec::from_bytes(&[after]));
fn union(&mut self, other: &BitVec) -> bool
Calculates the union of two bitvectors. This acts like the bitwise or
function.
Sets self to the union of self and other. Both bitvectors must be
the same length. Returns true if self changed.
Panics
Panics if the bitvectors are of different lengths.
Examples
fn main() { use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let res = 0b01111110; let mut a = BitVec::from_bytes(&[a]); let b = BitVec::from_bytes(&[b]); assert!(a.union(&b)); assert_eq!(a, BitVec::from_bytes(&[res])); }use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let res = 0b01111110; let mut a = BitVec::from_bytes(&[a]); let b = BitVec::from_bytes(&[b]); assert!(a.union(&b)); assert_eq!(a, BitVec::from_bytes(&[res]));
fn intersect(&mut self, other: &BitVec) -> bool
Calculates the intersection of two bitvectors. This acts like the
bitwise and function.
Sets self to the intersection of self and other. Both bitvectors
must be the same length. Returns true if self changed.
Panics
Panics if the bitvectors are of different lengths.
Examples
fn main() { use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let res = 0b01000000; let mut a = BitVec::from_bytes(&[a]); let b = BitVec::from_bytes(&[b]); assert!(a.intersect(&b)); assert_eq!(a, BitVec::from_bytes(&[res])); }use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let res = 0b01000000; let mut a = BitVec::from_bytes(&[a]); let b = BitVec::from_bytes(&[b]); assert!(a.intersect(&b)); assert_eq!(a, BitVec::from_bytes(&[res]));
fn difference(&mut self, other: &BitVec) -> bool
Calculates the difference between two bitvectors.
Sets each element of self to the value of that element minus the
element of other at the same index. Both bitvectors must be the same
length. Returns true if self changed.
Panics
Panics if the bitvectors are of different length.
Examples
fn main() { use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let a_b = 0b00100100; // a - b let b_a = 0b00011010; // b - a let mut bva = BitVec::from_bytes(&[a]); let bvb = BitVec::from_bytes(&[b]); assert!(bva.difference(&bvb)); assert_eq!(bva, BitVec::from_bytes(&[a_b])); let bva = BitVec::from_bytes(&[a]); let mut bvb = BitVec::from_bytes(&[b]); assert!(bvb.difference(&bva)); assert_eq!(bvb, BitVec::from_bytes(&[b_a])); }use std::collections::BitVec; let a = 0b01100100; let b = 0b01011010; let a_b = 0b00100100; // a - b let b_a = 0b00011010; // b - a let mut bva = BitVec::from_bytes(&[a]); let bvb = BitVec::from_bytes(&[b]); assert!(bva.difference(&bvb)); assert_eq!(bva, BitVec::from_bytes(&[a_b])); let bva = BitVec::from_bytes(&[a]); let mut bvb = BitVec::from_bytes(&[b]); assert!(bvb.difference(&bva)); assert_eq!(bvb, BitVec::from_bytes(&[b_a]));
fn all(&self) -> bool
Returns true if all bits are 1.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(5, true); assert_eq!(bv.all(), true); bv.set(1, false); assert_eq!(bv.all(), false); }use std::collections::BitVec; let mut bv = BitVec::from_elem(5, true); assert_eq!(bv.all(), true); bv.set(1, false); assert_eq!(bv.all(), false);
fn iter(&self) -> Iter
Returns an iterator over the elements of the vector in order.
Examples
fn main() { use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b01110100, 0b10010010]); assert_eq!(bv.iter().filter(|x| *x).count(), 7); }use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b01110100, 0b10010010]); assert_eq!(bv.iter().filter(|x| *x).count(), 7);
fn none(&self) -> bool
Returns true if all bits are 0.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.none(), true); bv.set(3, true); assert_eq!(bv.none(), false); }use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.none(), true); bv.set(3, true); assert_eq!(bv.none(), false);
fn any(&self) -> bool
Returns true if any bit is 1.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.any(), false); bv.set(3, true); assert_eq!(bv.any(), true); }use std::collections::BitVec; let mut bv = BitVec::from_elem(10, false); assert_eq!(bv.any(), false); bv.set(3, true); assert_eq!(bv.any(), true);
fn to_bytes(&self) -> Vec<u8>
Organises the bits into bytes, such that the first bit in the
BitVec becomes the high-order bit of the first byte. If the
size of the BitVec is not a multiple of eight then trailing bits
will be filled-in with false.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(3, true); bv.set(1, false); assert_eq!(bv.to_bytes(), vec!(0b10100000)); let mut bv = BitVec::from_elem(9, false); bv.set(2, true); bv.set(8, true); assert_eq!(bv.to_bytes(), vec!(0b00100000, 0b10000000)); }use std::collections::BitVec; let mut bv = BitVec::from_elem(3, true); bv.set(1, false); assert_eq!(bv.to_bytes(), vec!(0b10100000)); let mut bv = BitVec::from_elem(9, false); bv.set(2, true); bv.set(8, true); assert_eq!(bv.to_bytes(), vec!(0b00100000, 0b10000000));
fn eq_vec(&self, v: &[bool]) -> bool
Compares a BitVec to a slice of bools.
Both the BitVec and slice must have the same length.
Panics
Panics if the BitVec and slice are of different length.
Examples
fn main() { use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b10100000]); assert!(bv.eq_vec(&[true, false, true, false, false, false, false, false])); }use std::collections::BitVec; let bv = BitVec::from_bytes(&[0b10100000]); assert!(bv.eq_vec(&[true, false, true, false, false, false, false, false]));
fn truncate(&mut self, len: usize)
Shortens a BitVec, dropping excess elements.
If len is greater than the vector's current length, this has no
effect.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001011]); bv.truncate(2); assert!(bv.eq_vec(&[false, true])); }use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001011]); bv.truncate(2); assert!(bv.eq_vec(&[false, true]));
fn reserve(&mut self, additional: usize)
Reserves capacity for at least additional more bits to be inserted in the given
BitVec. The collection may reserve more space to avoid frequent reallocations.
Panics
Panics if the new capacity overflows usize.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(3, false); bv.reserve(10); assert_eq!(bv.len(), 3); assert!(bv.capacity() >= 13); }use std::collections::BitVec; let mut bv = BitVec::from_elem(3, false); bv.reserve(10); assert_eq!(bv.len(), 3); assert!(bv.capacity() >= 13);
fn reserve_exact(&mut self, additional: usize)
Reserves the minimum capacity for exactly additional more bits to be inserted in the
given BitVec. Does nothing if the capacity is already sufficient.
Note that the allocator may give the collection more space than it requests. Therefore
capacity can not be relied upon to be precisely minimal. Prefer reserve if future
insertions are expected.
Panics
Panics if the new capacity overflows usize.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_elem(3, false); bv.reserve(10); assert_eq!(bv.len(), 3); assert!(bv.capacity() >= 13); }use std::collections::BitVec; let mut bv = BitVec::from_elem(3, false); bv.reserve(10); assert_eq!(bv.len(), 3); assert!(bv.capacity() >= 13);
fn capacity(&self) -> usize
Returns the capacity in bits for this bit vector. Inserting any element less than this amount will not trigger a resizing.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::new(); bv.reserve(10); assert!(bv.capacity() >= 10); }use std::collections::BitVec; let mut bv = BitVec::new(); bv.reserve(10); assert!(bv.capacity() >= 10);
fn grow(&mut self, n: usize, value: bool)
Grows the BitVec in-place, adding n copies of value to the BitVec.
Panics
Panics if the new len overflows a usize.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001011]); bv.grow(2, true); assert_eq!(bv.len(), 10); assert_eq!(bv.to_bytes(), vec!(0b01001011, 0b11000000)); }use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001011]); bv.grow(2, true); assert_eq!(bv.len(), 10); assert_eq!(bv.to_bytes(), vec!(0b01001011, 0b11000000));
fn pop(&mut self) -> Option<bool>
Removes the last bit from the BitVec, and returns it. Returns None if the BitVec is empty.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001001]); assert_eq!(bv.pop(), Some(true)); assert_eq!(bv.pop(), Some(false)); assert_eq!(bv.len(), 6); }use std::collections::BitVec; let mut bv = BitVec::from_bytes(&[0b01001001]); assert_eq!(bv.pop(), Some(true)); assert_eq!(bv.pop(), Some(false)); assert_eq!(bv.len(), 6);
fn push(&mut self, elem: bool)
Pushes a bool onto the end.
Examples
fn main() { use std::collections::BitVec; let mut bv = BitVec::new(); bv.push(true); bv.push(false); assert!(bv.eq_vec(&[true, false])); }use std::collections::BitVec; let mut bv = BitVec::new(); bv.push(true); bv.push(false); assert!(bv.eq_vec(&[true, false]));
fn len(&self) -> usize
Return the total number of bits in this vector
fn is_empty(&self) -> bool
Returns true if there are no bits in this vector
fn clear(&mut self)
Clears all bits in this vector.