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Diffstat (limited to 'vendor/bit_field/src/lib.rs')
| -rw-r--r-- | vendor/bit_field/src/lib.rs | 374 |
1 files changed, 0 insertions, 374 deletions
diff --git a/vendor/bit_field/src/lib.rs b/vendor/bit_field/src/lib.rs deleted file mode 100644 index 21e682b..0000000 --- a/vendor/bit_field/src/lib.rs +++ /dev/null @@ -1,374 +0,0 @@ -//! Provides the abstraction of a bit field, which allows for bit-level update and retrieval -//! operations. - -#![no_std] - -#[cfg(test)] -mod tests; - -use core::ops::{Bound, Range, RangeBounds}; - -/// A generic trait which provides methods for extracting and setting specific bits or ranges of -/// bits. -pub trait BitField { - /// The number of bits in this bit field. - /// - /// ```rust - /// use bit_field::BitField; - /// - /// assert_eq!(u32::BIT_LENGTH, 32); - /// assert_eq!(u64::BIT_LENGTH, 64); - /// ``` - const BIT_LENGTH: usize; - - /// Obtains the bit at the index `bit`; note that index 0 is the least significant bit, while - /// index `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitField; - /// - /// let value: u32 = 0b110101; - /// - /// assert_eq!(value.get_bit(1), false); - /// assert_eq!(value.get_bit(2), true); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the bit index is out of bounds of the bit field. - fn get_bit(&self, bit: usize) -> bool; - - /// Obtains the range of bits specified by `range`; note that index 0 is the least significant - /// bit, while index `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitField; - /// - /// let value: u32 = 0b110101; - /// - /// assert_eq!(value.get_bits(0..3), 0b101); - /// assert_eq!(value.get_bits(2..6), 0b1101); - /// assert_eq!(value.get_bits(..), 0b110101); - /// assert_eq!(value.get_bits(3..=3), value.get_bit(3) as u32); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the start or end indexes of the range are out of bounds of the - /// bit field. - fn get_bits<T: RangeBounds<usize>>(&self, range: T) -> Self; - - /// Sets the bit at the index `bit` to the value `value` (where true means a value of '1' and - /// false means a value of '0'); note that index 0 is the least significant bit, while index - /// `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitField; - /// - /// let mut value = 0u32; - /// - /// value.set_bit(1, true); - /// assert_eq!(value, 2u32); - /// - /// value.set_bit(3, true); - /// assert_eq!(value, 10u32); - /// - /// value.set_bit(1, false); - /// assert_eq!(value, 8u32); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the bit index is out of the bounds of the bit field. - fn set_bit(&mut self, bit: usize, value: bool) -> &mut Self; - - /// Sets the range of bits defined by the range `range` to the lower bits of `value`; to be - /// specific, if the range is N bits long, the N lower bits of `value` will be used; if any of - /// the other bits in `value` are set to 1, this function will panic. - /// - /// ```rust - /// use bit_field::BitField; - /// - /// let mut value = 0u32; - /// - /// value.set_bits(0..2, 0b11); - /// assert_eq!(value, 0b11); - /// - /// value.set_bits(2..=3, 0b11); - /// assert_eq!(value, 0b1111); - /// - /// value.set_bits(..4, 0b1010); - /// assert_eq!(value, 0b1010); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the range is out of bounds of the bit field, or if there are `1`s - /// not in the lower N bits of `value`. - fn set_bits<T: RangeBounds<usize>>(&mut self, range: T, value: Self) -> &mut Self; -} - -pub trait BitArray<T: BitField> { - /// Returns the length, eg number of bits, in this bit array. - /// - /// ```rust - /// use bit_field::BitArray; - /// - /// assert_eq!([0u8, 4u8, 8u8].bit_length(), 24); - /// assert_eq!([0u32, 5u32].bit_length(), 64); - /// ``` - fn bit_length(&self) -> usize; - - /// Obtains the bit at the index `bit`; note that index 0 is the least significant bit, while - /// index `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitArray; - /// - /// let value: [u32; 1] = [0b110101]; - /// - /// assert_eq!(value.get_bit(1), false); - /// assert_eq!(value.get_bit(2), true); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the bit index is out of bounds of the bit array. - fn get_bit(&self, bit: usize) -> bool; - - /// Obtains the range of bits specified by `range`; note that index 0 is the least significant - /// bit, while index `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitArray; - /// - /// let value: [u32; 2] = [0b110101, 0b11]; - /// - /// assert_eq!(value.get_bits(0..3), 0b101); - /// assert_eq!(value.get_bits(..6), 0b110101); - /// assert_eq!(value.get_bits(31..33), 0b10); - /// assert_eq!(value.get_bits(5..=32), 0b1_0000_0000_0000_0000_0000_0000_001); - /// assert_eq!(value.get_bits(34..), 0); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the start or end indexes of the range are out of bounds of the - /// bit array, or if the range can't be contained by the bit field T. - fn get_bits<U: RangeBounds<usize>>(&self, range: U) -> T; - - /// Sets the bit at the index `bit` to the value `value` (where true means a value of '1' and - /// false means a value of '0'); note that index 0 is the least significant bit, while index - /// `length() - 1` is the most significant bit. - /// - /// ```rust - /// use bit_field::BitArray; - /// - /// let mut value = [0u32]; - /// - /// value.set_bit(1, true); - /// assert_eq!(value, [2u32]); - /// - /// value.set_bit(3, true); - /// assert_eq!(value, [10u32]); - /// - /// value.set_bit(1, false); - /// assert_eq!(value, [8u32]); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the bit index is out of the bounds of the bit array. - fn set_bit(&mut self, bit: usize, value: bool); - - /// Sets the range of bits defined by the range `range` to the lower bits of `value`; to be - /// specific, if the range is N bits long, the N lower bits of `value` will be used; if any of - /// the other bits in `value` are set to 1, this function will panic. - /// - /// ```rust - /// use bit_field::BitArray; - /// - /// let mut value = [0u32, 0u32]; - /// - /// value.set_bits(0..2, 0b11); - /// assert_eq!(value, [0b11, 0u32]); - /// - /// value.set_bits(31..35, 0b1010); - /// assert_eq!(value, [0x0003, 0b101]); - /// ``` - /// - /// ## Panics - /// - /// This method will panic if the range is out of bounds of the bit array, - /// if the range can't be contained by the bit field T, or if there are `1`s - /// not in the lower N bits of `value`. - fn set_bits<U: RangeBounds<usize>>(&mut self, range: U, value: T); -} - -/// An internal macro used for implementing BitField on the standard integral types. -macro_rules! bitfield_numeric_impl { - ($($t:ty)*) => ($( - impl BitField for $t { - const BIT_LENGTH: usize = ::core::mem::size_of::<Self>() as usize * 8; - - #[track_caller] - #[inline] - fn get_bit(&self, bit: usize) -> bool { - assert!(bit < Self::BIT_LENGTH); - - (*self & (1 << bit)) != 0 - } - - #[track_caller] - #[inline] - fn get_bits<T: RangeBounds<usize>>(&self, range: T) -> Self { - let range = to_regular_range(&range, Self::BIT_LENGTH); - - assert!(range.start < Self::BIT_LENGTH); - assert!(range.end <= Self::BIT_LENGTH); - assert!(range.start < range.end); - - // shift away high bits - let bits = *self << (Self::BIT_LENGTH - range.end) >> (Self::BIT_LENGTH - range.end); - - // shift away low bits - bits >> range.start - } - - #[track_caller] - #[inline] - fn set_bit(&mut self, bit: usize, value: bool) -> &mut Self { - assert!(bit < Self::BIT_LENGTH); - - if value { - *self |= 1 << bit; - } else { - *self &= !(1 << bit); - } - - self - } - - #[track_caller] - #[inline] - fn set_bits<T: RangeBounds<usize>>(&mut self, range: T, value: Self) -> &mut Self { - let range = to_regular_range(&range, Self::BIT_LENGTH); - - assert!(range.start < Self::BIT_LENGTH); - assert!(range.end <= Self::BIT_LENGTH); - assert!(range.start < range.end); - assert!(value << (Self::BIT_LENGTH - (range.end - range.start)) >> - (Self::BIT_LENGTH - (range.end - range.start)) == value, - "value does not fit into bit range"); - - let bitmask: Self = !(!0 << (Self::BIT_LENGTH - range.end) >> - (Self::BIT_LENGTH - range.end) >> - range.start << range.start); - - // set bits - *self = (*self & bitmask) | (value << range.start); - - self - } - } - )*) -} - -bitfield_numeric_impl! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize } - -impl<T: BitField> BitArray<T> for [T] { - #[inline] - fn bit_length(&self) -> usize { - self.len() * T::BIT_LENGTH - } - - #[track_caller] - #[inline] - fn get_bit(&self, bit: usize) -> bool { - let slice_index = bit / T::BIT_LENGTH; - let bit_index = bit % T::BIT_LENGTH; - self[slice_index].get_bit(bit_index) - } - - #[track_caller] - #[inline] - fn get_bits<U: RangeBounds<usize>>(&self, range: U) -> T { - let range = to_regular_range(&range, self.bit_length()); - - assert!(range.len() <= T::BIT_LENGTH); - - let slice_start = range.start / T::BIT_LENGTH; - let slice_end = range.end / T::BIT_LENGTH; - let bit_start = range.start % T::BIT_LENGTH; - let bit_end = range.end % T::BIT_LENGTH; - let len = range.len(); - - assert!(slice_end - slice_start <= 1); - - if slice_start == slice_end { - self[slice_start].get_bits(bit_start..bit_end) - } else if bit_end == 0 { - self[slice_start].get_bits(bit_start..T::BIT_LENGTH) - } else { - let mut ret = self[slice_start].get_bits(bit_start..T::BIT_LENGTH); - ret.set_bits( - (T::BIT_LENGTH - bit_start)..len, - self[slice_end].get_bits(0..bit_end), - ); - ret - } - } - - #[track_caller] - #[inline] - fn set_bit(&mut self, bit: usize, value: bool) { - let slice_index = bit / T::BIT_LENGTH; - let bit_index = bit % T::BIT_LENGTH; - self[slice_index].set_bit(bit_index, value); - } - - #[track_caller] - #[inline] - fn set_bits<U: RangeBounds<usize>>(&mut self, range: U, value: T) { - let range = to_regular_range(&range, self.bit_length()); - - assert!(range.len() <= T::BIT_LENGTH); - - let slice_start = range.start / T::BIT_LENGTH; - let slice_end = range.end / T::BIT_LENGTH; - let bit_start = range.start % T::BIT_LENGTH; - let bit_end = range.end % T::BIT_LENGTH; - - assert!(slice_end - slice_start <= 1); - - if slice_start == slice_end { - self[slice_start].set_bits(bit_start..bit_end, value); - } else if bit_end == 0 { - self[slice_start].set_bits(bit_start..T::BIT_LENGTH, value); - } else { - self[slice_start].set_bits( - bit_start..T::BIT_LENGTH, - value.get_bits(0..T::BIT_LENGTH - bit_start), - ); - self[slice_end].set_bits( - 0..bit_end, - value.get_bits(T::BIT_LENGTH - bit_start..T::BIT_LENGTH), - ); - } - } -} - -fn to_regular_range<T: RangeBounds<usize>>(generic_rage: &T, bit_length: usize) -> Range<usize> { - let start = match generic_rage.start_bound() { - Bound::Excluded(&value) => value + 1, - Bound::Included(&value) => value, - Bound::Unbounded => 0, - }; - let end = match generic_rage.end_bound() { - Bound::Excluded(&value) => value, - Bound::Included(&value) => value + 1, - Bound::Unbounded => bit_length, - }; - - start..end -} |