[−][src]Trait bv::BlockType

pub trait BlockType: Copy + PartialEq + Ord + BitAnd<Output = Self> + BitOr<Output = Self> + BitXor<Output = Self> + Not<Output = Self> + Shl<usize, Output = Self> + Shr<usize, Output = Self> + Sub<Output = Self> {
    fn wrapping_shl(self, shift: u32) -> Self;

    fn wrapping_sub(self, other: Self) -> Self;

    fn leading_zeros(self) -> usize;

    fn to_usize(self) -> Option<usize>;

    fn zero() -> Self;

    fn one() -> Self;

    fn nbits() -> usize { ... }

    fn div_nbits(index: u64) -> usize { ... }

    fn checked_div_nbits(index: u64) -> Option<usize> { ... }

    fn ceil_div_nbits(index: u64) -> usize { ... }

    fn checked_ceil_div_nbits(index: u64) -> Option<usize> { ... }

    fn mod_nbits(index: u64) -> usize { ... }

    fn mul_nbits(index: usize) -> u64 { ... }

    fn block_bits(len: u64, position: usize) -> usize { ... }

    fn lg_nbits() -> usize { ... }

    fn lg_nbits_mask<Result: BlockType>() -> Result { ... }

    fn low_mask(element_bits: usize) -> Self { ... }

    fn nth_mask(bit_index: usize) -> Self { ... }

    fn get_bit(self, bit_index: usize) -> bool { ... }

    fn with_bit(self, bit_index: usize, bit_value: bool) -> Self { ... }

    fn get_bits(self, start: usize, len: usize) -> Self { ... }

    fn with_bits(self, start: usize, len: usize, value: Self) -> Self { ... }

    fn ceil_lg(self) -> usize { ... }

    fn floor_lg(self) -> usize { ... }
}

Interface to primitive bit storage.

Types implementing this trait can be used as the blocks of a bit-vector.

Required methods

fn wrapping_shl(self, shift: u32) -> Self

A shift-left operation that does not overflow.

fn wrapping_sub(self, other: Self) -> Self

A subtraction operation that does not overflow.

fn leading_zeros(self) -> usize

Returns the number of leading zero bits in the given number.

fn to_usize(self) -> Option<usize>

Converts the number to a usize, if it fits.

fn zero() -> Self

Returns 0.

fn one() -> Self

Returns 1.

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Provided methods

fn nbits() -> usize

The number of bits in a block.

fn div_nbits(index: u64) -> usize

Returns index / Self::nbits(), computed by shifting.

This is intended for converting a bit address into a block address, which is why it takes u64 and returns usize. There is no check that the result actually fits in a usize, so this should only be used when index is already known to be small enough.

fn checked_div_nbits(index: u64) -> Option<usize>

Returns index / Self::nbits(), computed by shifting.

This is intended for converting a bit address into a block address, which is why it takes u64 and returns usize. It can only fail (returning None) if usize is 32 bits.

fn ceil_div_nbits(index: u64) -> usize

Returns index / Self::nbits() rounded up, computed by shifting.

This is intended for converting a bit size into a block size, which is why it takes u64 and returns usize.

fn checked_ceil_div_nbits(index: u64) -> Option<usize>

Returns index / Self::nbits() rounded up, computed by shifting.

This is intended for converting a bit size into a block size, which is why it takes u64 and returns usize. There is no check that the result actually fits in a usize, so this should only be used when index is already known to be small enough.

fn mod_nbits(index: u64) -> usize

Returns index % Self::nbits(), computed by masking.

This is intended for converting a bit address into a bit offset within a block, which is why it takes u64 and returns usize.

fn mul_nbits(index: usize) -> u64

Returns index * Self::nbits(), computed by shifting.

This is intended for converting a block address into a bit address, which is why it takes a usize and returns a u64.

fn block_bits(len: u64, position: usize) -> usize

The number of bits in the block at position, given a total bit length of len.

This will be Self::nbits() for all but the last block, for which it may be less.

Precondition

position * Self::nbits() <= len, or the block doesn't exist and the result is undefined.

fn lg_nbits() -> usize

Log-base-2 of the number of bits in a block.

fn lg_nbits_mask<Result: BlockType>() -> Result

Mask with the lowest-order lg_nbits() set.

fn low_mask(element_bits: usize) -> Self

The bit mask consisting of Self::nbits() - element_bits zeroes followed by element_bits ones.

The default implementation has a branch, but should be overrided with a branchless algorithm if possible.

Precondition

element_bits <= Self::nbits()

fn nth_mask(bit_index: usize) -> Self

The bit mask with the bit_indexth bit set.

Bits are indexed in little-endian style based at 0.

Precondition

bit_index < Self::nbits()

fn get_bit(self, bit_index: usize) -> bool

Extracts the value of the bit_indexth bit.

Panics

Panics if bit_index is out of bounds.

fn with_bit(self, bit_index: usize, bit_value: bool) -> Self

Functionally updates the value of the bit_indexth bit to bit_value.

Panics

Panics if bit_index is out of bounds.

fn get_bits(self, start: usize, len: usize) -> Self

Extracts len bits starting at bit offset start.

Panics

Panics of the bit span is out of bounds.

fn with_bits(self, start: usize, len: usize, value: Self) -> Self

Functionally updates len bits to value starting at offset start.

Panics

Panics of the bit span is out of bounds.

fn ceil_lg(self) -> usize

Returns the smallest number n such that 2.pow(n) >= self.

fn floor_lg(self) -> usize

Returns the largest number n such that 2.pow(n) <= self.

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Implementations on Foreign Types

impl BlockType for u8[src]

impl BlockType for u16[src]

impl BlockType for u32[src]

impl BlockType for u64[src]

impl BlockType for u128[src]

impl BlockType for usize[src]

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Implementors

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