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/**
* Bitwise operations implementation for `[u8]`
*/
pub trait Bitwise {
/// Bitwise operator `<<`
/// Shift bits to the left
/// # Parameters
/// - `data`: The data to be shifted
/// - `n`: The number of bits to shift
/// # Returns
/// - `true` if the leftmost `1` bits are overflowed
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// let mut data: [u8; 2] = [0b1111_1111, 0b0000_0000];
/// assert_eq!(data.bit_shl(4), true);
/// assert_eq!(data, [0b1111_0000, 0b0000_0000]);
/// ```
fn bit_shl(&mut self, n: usize) -> bool;
/// Bitwise operator `>>`
/// Shift bits to the right
/// # Parameters
/// - `data`: The data to be shifted
/// - `n`: The number of bits to shift
/// # Returns
/// - `true` if the rightmost `1` bits are overflowed
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// let mut data = [0b1111_1111, 0b0000_0000];
/// assert_eq!(data.bit_shr(4), false);
/// assert_eq!(data, [0b0000_1111, 0b1111_0000]);
/// ```
/// # Note
/// The right shift will fill the leftmost bits with 0
/// and the rightmost bits with the original value
fn bit_shr(&mut self, n: usize) -> bool;
/// Reverse the bits of the data
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0000_1111, 0b0000_0011].bit_reverse(), [0b1100_0000, 0b1111_0000]);
/// ```
fn bit_reverse(&mut self) -> &mut Self;
/// Bitwise operator `!`
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0000_1111, 0b0000_0011].bit_not(), [0b1111_0000, 0b1111_1100]);
/// ```
fn bit_not(&mut self) -> &mut Self;
/// Bitwise operator `&` for big-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_be_and(&[0b1111_1111]), [0b0000_0000, 0b0011_0011]);
/// ```
fn bit_be_and(&mut self, other: &Self) -> &mut Self;
/// Bitwise operator `|` for big-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_be_or(&[0b1111_1111]), [0b0011_0011, 0b1111_1111]);
/// ```
fn bit_be_or(&mut self, other: &Self) -> &mut Self;
/// Bitwise operator `^` for big-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_be_xor(&[0b1111_1111]), [0b0011_0011, 0b1100_1100]);
/// ```
fn bit_be_xor(&mut self, other: &Self) -> &mut Self;
/// Bitwise operator `&` for little-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_le_and(&[0b1111_1111]), [0b0011_0011, 0b0000_0000]);
/// ```
fn bit_le_and(&mut self, other: &Self) -> &mut Self;
/// Bitwise operator `|` for little-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_le_or(&[0b1111_1111]), [0b1111_1111, 0b0011_0011]);
/// ```
fn bit_le_or(&mut self, other: &Self) -> &mut Self;
/// Bitwise operator `^` for little-endian
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0011_0011, 0b0011_0011].bit_le_xor(&[0b1111_1111]), [0b1100_1100, 0b0011_0011]);
/// ```
fn bit_le_xor(&mut self, other: &Self) -> &mut Self;
/// Check if all bits are zero
fn bit_all_zero(&self) -> bool;
/// Check if all bits are one
fn bit_all_one(&self) -> bool;
/// Count the number of trailing zeros
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0001_0000, 0b1000_0011].bit_leading_zeros(), 3);
/// assert_eq!([0b0000_0000, 0b1000_0011].bit_leading_zeros(), 8);
/// assert_eq!([0b0000_0000, 0b0001_0011].bit_leading_zeros(), 11);
/// assert_eq!([0b0000_0000, 0b0000_0000].bit_leading_zeros(), 16);
/// ```
fn bit_leading_zeros(&self) -> usize;
/// Count the number of leading zeros
/// # Examples
/// ```
/// # use nbits::core::Bitwise;
/// assert_eq!([0b0000_1111, 0b0000_1000].bit_trailing_zeros(), 3);
/// assert_eq!([0b0000_1111, 0b0000_0000].bit_trailing_zeros(), 8);
/// assert_eq!([0b1111_1000, 0b0000_0000].bit_trailing_zeros(), 11);
/// assert_eq!([0b0000_0000, 0b0000_0000].bit_trailing_zeros(), 16);
/// ```
fn bit_trailing_zeros(&self) -> usize;
}
impl Bitwise for [u8] {
fn bit_shl(&mut self, n: usize) -> bool {
let len = self.len();
let data = self;
if n >= len * 8 {
data.fill(0);
return true;
}
let (n, m) = (n / 8, n % 8);
data.copy_within(n.., 0);
data[len - n..].fill(0);
if m != 0 {
let mut carry = 0;
data.iter_mut().take(len - n).rev().for_each(|v| {
(*v, carry) = ((*v << m) | carry, *v >> (8 - m));
});
return carry != 0;
}
false
}
fn bit_shr(&mut self, n: usize) -> bool {
let len = self.len();
let data = self;
if n >= len * 8 {
data.fill(0);
return true;
}
let (n, m) = (n / 8, n % 8);
data.copy_within(..len - n, n);
data[..n].fill(0);
if m != 0 {
let mut carry = 0;
data.iter_mut().skip(n).for_each(|v| {
(*v, carry) = ((*v >> m) | carry, *v << (8 - m));
});
return carry != 0;
}
false
}
#[inline]
fn bit_reverse(&mut self) -> &mut Self {
self.reverse();
self.iter_mut().for_each(|a| *a = a.reverse_bits());
self
}
#[inline]
fn bit_not(&mut self) -> &mut Self {
self.iter_mut().for_each(|a| *a = !*a);
self
}
#[inline]
fn bit_be_and(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.rev()
.zip(other.iter().rev().chain(std::iter::repeat(&0)))
.for_each(|(a, b)| *a &= *b);
self
}
#[inline]
fn bit_be_or(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.rev()
.zip(other.iter().rev())
.for_each(|(a, b)| *a |= *b);
self
}
#[inline]
fn bit_be_xor(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.rev()
.zip(other.iter().rev().chain(std::iter::repeat(&0)))
.for_each(|(a, b)| *a ^= *b);
self
}
#[inline]
fn bit_le_and(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.zip(other.iter().chain(std::iter::repeat(&0)))
.for_each(|(a, b)| *a &= *b);
self
}
#[inline]
fn bit_le_or(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.zip(other.iter().chain(std::iter::repeat(&0)))
.for_each(|(a, b)| *a |= *b);
self
}
#[inline]
fn bit_le_xor(&mut self, other: &Self) -> &mut Self {
self.iter_mut()
.zip(other.iter().chain(std::iter::repeat(&0)))
.for_each(|(a, b)| *a ^= *b);
self
}
#[inline]
fn bit_all_zero(&self) -> bool {
self.iter().all(|&b| b == 0)
}
#[inline]
fn bit_all_one(&self) -> bool {
self.iter().all(|&b| b == 0xff)
}
#[inline]
fn bit_leading_zeros(&self) -> usize {
match self.iter().position(|&b| b != 0) {
Some(n) => n * 8 + self[n].leading_zeros() as usize,
None => self.len() * 8,
}
}
#[inline]
fn bit_trailing_zeros(&self) -> usize {
match self.iter().rposition(|&b| b != 0) {
Some(n) => (self.len() - 1 - n) * 8 + self[n].trailing_zeros() as usize,
None => self.len() * 8,
}
}
}
#[cfg(test)]
mod test_offset {
use super::Bitwise;
#[test]
fn test_bit_shl() {
let mut data: [u8; 2] = [0b1111_1111, 0b0000_0000];
assert_eq!(data.bit_shl(4), true);
assert_eq!(data, [0b1111_0000, 0b0000_0000]);
}
#[test]
fn test_bit_shr() {
let mut data: [u8; 2] = [0b1111_1111, 0b0000_0000];
assert_eq!(data.bit_shr(4), false);
assert_eq!(data, [0b0000_1111, 0b1111_0000]);
assert_eq!([0b1].bit_shr(1), true);
}
#[test]
fn test_bit_reverse() {
let mut data: [u8; 2] = [0b1111_1100, 0b1100_0000];
data.bit_reverse();
assert_eq!(data, [0b0000_0011, 0b0011_1111])
}
}