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//! Miscellaneous bit operations for any [`Integer`]. //! //! See the [`BitOps`] trait for examples. //! //! [`Integer`]: ../num_integer/trait.Integer.html //! [`BitOps`]: ./trait.BitOps.html extern crate num_integer; use num_integer::Integer; use std::ops::{BitAnd, Shl, Shr}; /// Miscellaneous bit operations for any [`Integer`]. /// /// # Examples /// /// ``` /// use bitops::BitOps; /// /// let x = 0b1010_1011_0000_1100; // 0xab0c /// let flag = 0b1000; /// /// assert!(flag.is_flag()); /// assert!(flag.is_bit_set(3)); /// /// assert!(x.is_flag_set(flag)); /// assert_eq!(x.bits_as_int(8, 4), 0xb); /// ``` /// /// [`Integer`]: ../num_integer/trait.Integer.html pub trait BitOps: Copy + Integer + BitAnd<Output = Self> + Shl<Output = Self> + Shr<Output = Self> + From<u8> { /// Returns whether this number only has one bit set. /// /// # Examples /// /// ``` /// use bitops::BitOps; /// /// assert!(0b1000.is_flag()); /// assert!(!0b1001.is_flag()); /// ``` #[inline] fn is_flag(&self) -> bool { *self > Self::zero() && (*self & (*self - Self::one())) == Self::zero() } /// Returns whether the given bit number is set. /// /// # Panics /// /// Panics if `bit` is greater than the number of bits in this Integer. /// /// # Examples /// /// ``` /// use bitops::BitOps; /// /// assert!(0b1000.is_bit_set(3)); /// ``` #[inline] fn is_bit_set(&self, bit: u8) -> bool { self.is_flag_set(Self::one() << Self::from(bit)) } /// Returns whether the given flag is set. /// /// # Examples /// /// ``` /// use bitops::BitOps; /// /// assert!(0b11010.is_flag_set(0b11000)); /// ``` #[inline] fn is_flag_set(&self, flag: Self) -> bool { *self & flag > Self::zero() } /// Returns a number with bit 0 starting at the given bit and up to `count` left most bits. /// This is basically a right shift by `bit` and masked with `(1 << count) - 1`. /// /// # Panics /// /// Panics if `bit` is greater than the number of bits in this Integer. /// /// # Examples /// /// ``` /// use bitops::BitOps; /// /// assert_eq!(0xab000.bits_as_int(12, 8), 0xab); /// ``` #[inline] fn bits_as_int(&self, bit: u8, count: u8) -> Self { (*self >> Self::from(bit)) & ((Self::one() << Self::from(count)) - Self::one()) } } /// Implements the [`BitOps`] trait for all types that meet the requirements. impl<N> BitOps for N where N: Copy + Integer + BitAnd<Output = Self> + Shl<Output = Self> + Shr<Output = Self> + From<u8>, { } mod tests { #[allow(unused_imports)] use super::BitOps; #[test] fn flag_zero() { assert!(!0.is_flag()); } #[test] fn flag_set_blank() { assert!(!0x0000.is_flag_set(0)); } #[test] fn bits_at_zero() { assert_eq!(0xabcd.bits_as_int(0, 8), 0xcd); } #[test] #[should_panic] fn bits_overflow() { 0u16.bits_as_int(16, 0); } }