Struct brainfuck::tape::VecTape
[−]
[src]
pub struct VecTape { // some fields omitted }
A tape with dynamically allocated cells.
This tape is implemented with a Vec<u8>
so it only uses memory it
needs. The cells are of type u8
, and the tape's length is forced to
be no greater than TAPE_LENGTH
so this tape is nice.
Methods from Deref<Target=u8>
fn count_ones(self) -> u32
Returns the number of ones in the binary representation of self
.
Examples
Basic usage:
let n = 0b01001100u8; assert_eq!(n.count_ones(), 3);
fn count_zeros(self) -> u32
Returns the number of zeros in the binary representation of self
.
Examples
Basic usage:
let n = 0b01001100u8; assert_eq!(n.count_zeros(), 5);
fn leading_zeros(self) -> u32
Returns the number of leading zeros in the binary representation
of self
.
Examples
Basic usage:
let n = 0b0101000u16; assert_eq!(n.leading_zeros(), 10);
fn trailing_zeros(self) -> u32
Returns the number of trailing zeros in the binary representation
of self
.
Examples
Basic usage:
let n = 0b0101000u16; assert_eq!(n.trailing_zeros(), 3);
fn rotate_left(self, n: u32) -> u8
Shifts the bits to the left by a specified amount, n
,
wrapping the truncated bits to the end of the resulting integer.
Examples
Basic usage:
let n = 0x0123456789ABCDEFu64; let m = 0x3456789ABCDEF012u64; assert_eq!(n.rotate_left(12), m);
fn rotate_right(self, n: u32) -> u8
Shifts the bits to the right by a specified amount, n
,
wrapping the truncated bits to the beginning of the resulting
integer.
Examples
Basic usage:
let n = 0x0123456789ABCDEFu64; let m = 0xDEF0123456789ABCu64; assert_eq!(n.rotate_right(12), m);
fn swap_bytes(self) -> u8
Reverses the byte order of the integer.
Examples
Basic usage:
let n = 0x0123456789ABCDEFu64; let m = 0xEFCDAB8967452301u64; assert_eq!(n.swap_bytes(), m);
fn to_be(self) -> u8
Converts self
to big endian from the target's endianness.
On big endian this is a no-op. On little endian the bytes are swapped.
Examples
Basic usage:
let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(n.to_be(), n) } else { assert_eq!(n.to_be(), n.swap_bytes()) }
fn to_le(self) -> u8
Converts self
to little endian from the target's endianness.
On little endian this is a no-op. On big endian the bytes are swapped.
Examples
Basic usage:
let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(n.to_le(), n) } else { assert_eq!(n.to_le(), n.swap_bytes()) }
fn checked_add(self, other: u8) -> Option<u8>
Checked integer addition. Computes self + other
, returning None
if overflow occurred.
Examples
Basic usage:
assert_eq!(5u16.checked_add(65530), Some(65535)); assert_eq!(6u16.checked_add(65530), None);
fn checked_sub(self, other: u8) -> Option<u8>
Checked integer subtraction. Computes self - other
, returning
None
if underflow occurred.
Examples
Basic usage:
assert_eq!((-127i8).checked_sub(1), Some(-128)); assert_eq!((-128i8).checked_sub(1), None);
fn checked_mul(self, other: u8) -> Option<u8>
Checked integer multiplication. Computes self * other
, returning
None
if underflow or overflow occurred.
Examples
Basic usage:
assert_eq!(5u8.checked_mul(51), Some(255)); assert_eq!(5u8.checked_mul(52), None);
fn checked_div(self, other: u8) -> Option<u8>
Checked integer division. Computes self / other
, returning None
if other == 0
or the operation results in underflow or overflow.
Examples
Basic usage:
assert_eq!((-127i8).checked_div(-1), Some(127)); assert_eq!((-128i8).checked_div(-1), None); assert_eq!((1i8).checked_div(0), None);
fn saturating_add(self, other: u8) -> u8
Saturating integer addition. Computes self + other
, saturating at
the numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_add(1), 101); assert_eq!(100i8.saturating_add(127), 127);
fn saturating_sub(self, other: u8) -> u8
Saturating integer subtraction. Computes self - other
, saturating
at the numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_sub(127), -27); assert_eq!((-100i8).saturating_sub(127), -128);
fn wrapping_add(self, rhs: u8) -> u8
Wrapping (modular) addition. Computes self + other
,
wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(100i8.wrapping_add(27), 127); assert_eq!(100i8.wrapping_add(127), -29);
fn wrapping_sub(self, rhs: u8) -> u8
Wrapping (modular) subtraction. Computes self - other
,
wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(0i8.wrapping_sub(127), -127); assert_eq!((-2i8).wrapping_sub(127), 127);
fn wrapping_mul(self, rhs: u8) -> u8
Wrapping (modular) multiplication. Computes self * other
, wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(10i8.wrapping_mul(12), 120); assert_eq!(11i8.wrapping_mul(12), -124);
fn wrapping_div(self, rhs: u8) -> u8
Wrapping (modular) division. Computes self / other
,
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
divides MIN / -1
on a signed type (where MIN
is the
negative minimal value for the type); this is equivalent
to -MIN
, a positive value that is too large to represent
in the type. In such a case, this function returns MIN
itself.
Examples
Basic usage:
assert_eq!(100u8.wrapping_div(10), 10); assert_eq!((-128i8).wrapping_div(-1), -128);
fn wrapping_rem(self, rhs: u8) -> u8
Wrapping (modular) remainder. Computes self % other
,
wrapping around at the boundary of the type.
Such wrap-around never actually occurs mathematically;
implementation artifacts make x % y
invalid for MIN / -1
on a signed type (where MIN
is the negative
minimal value). In such a case, this function returns 0
.
Examples
Basic usage:
assert_eq!(100i8.wrapping_rem(10), 0); assert_eq!((-128i8).wrapping_rem(-1), 0);
fn wrapping_neg(self) -> u8
Wrapping (modular) negation. Computes -self
,
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
negates MIN
on a signed type (where MIN
is the
negative minimal value for the type); this is a positive
value that is too large to represent in the type. In such
a case, this function returns MIN
itself.
Examples
Basic usage:
assert_eq!(100i8.wrapping_neg(), -100); assert_eq!((-128i8).wrapping_neg(), -128);
fn wrapping_shl(self, rhs: u32) -> u8
Panic-free bitwise shift-left; yields self << mask(rhs)
,
where mask
removes any high-order bits of rhs
that
would cause the shift to exceed the bitwidth of the type.
Examples
Basic usage:
assert_eq!(1u8.wrapping_shl(7), 128); assert_eq!(1u8.wrapping_shl(8), 1);
fn wrapping_shr(self, rhs: u32) -> u8
Panic-free bitwise shift-right; yields self >> mask(rhs)
,
where mask
removes any high-order bits of rhs
that
would cause the shift to exceed the bitwidth of the type.
Examples
Basic usage:
assert_eq!(128u8.wrapping_shr(7), 1); assert_eq!(128u8.wrapping_shr(8), 128);
fn pow(self, exp: u32) -> u8
Raises self to the power of exp
, using exponentiation by squaring.
Examples
Basic usage:
assert_eq!(2i32.pow(4), 16);
fn is_power_of_two(self) -> bool
Returns true
if and only if self == 2^k
for some k
.
Examples
Basic usage:
assert!(16u8.is_power_of_two()); assert!(!10u8.is_power_of_two());
fn next_power_of_two(self) -> u8
Returns the smallest power of two greater than or equal to self
.
Unspecified behavior on overflow.
Examples
Basic usage:
assert_eq!(2u8.next_power_of_two(), 2); assert_eq!(3u8.next_power_of_two(), 4);
fn checked_next_power_of_two(self) -> Option<u8>
Returns the smallest power of two greater than or equal to n
. If
the next power of two is greater than the type's maximum value,
None
is returned, otherwise the power of two is wrapped in Some
.
Examples
Basic usage:
assert_eq!(2u8.checked_next_power_of_two(), Some(2)); assert_eq!(3u8.checked_next_power_of_two(), Some(4)); assert_eq!(200u8.checked_next_power_of_two(), None);