Trait gstreamer::prelude::MulDiv [] [src]

pub trait MulDiv<RHS = Self> {
    type Output;
    fn mul_div_floor(self, num: RHS, denom: RHS) -> Option<Self::Output>;
fn mul_div_round(self, num: RHS, denom: RHS) -> Option<Self::Output>;
fn mul_div_ceil(self, num: RHS, denom: RHS) -> Option<Self::Output>; }

Trait for calculating val * num / denom with different rounding modes and overflow protection.

Implementations of this trait have to ensure that even if the result of the multiplication does not fit into the type, as long as it would fit after the division the correct result has to be returned instead of None. None only should be returned if the overall result does not fit into the type.

This specifically means that e.g. the u64 implementation must, depending on the arguments, be able to do 128 bit integer multiplication.

Associated Types

Required Methods

Calculates floor(val * num / denom), i.e. the next integer to the result of the division with the smaller absolute value.

Example

extern crate muldiv;
use muldiv::MulDiv;

// Returns x==Some(6)
let x = 3i8.mul_div_floor(4, 2);

// Returns x==Some(3)
let x = 5i8.mul_div_floor(2, 3);

// Returns x==Some(-3)
let x = (-5i8).mul_div_floor(2, 3);

// Returns x==Some(4)
let x = 3i8.mul_div_floor(3, 2);

// Returns x==Some(-4)
let x = (-3i8).mul_div_floor(3, 2);

// Returns x==None
let x = 127i8.mul_div_floor(4, 3);

Calculates round(val * num / denom), i.e. the closest integer to the result of the division. If both surrounding integers are the same distance, the one with the bigger absolute value is returned.

Example

extern crate muldiv;
use muldiv::MulDiv;

// Returns x==Some(6)
let x = 3i8.mul_div_round(4, 2);

// Returns x==Some(3)
let x = 5i8.mul_div_round(2, 3);

// Returns x==Some(-3)
let x = (-5i8).mul_div_round(2, 3);

// Returns x==Some(5)
let x = 3i8.mul_div_round(3, 2);

// Returns x==Some(-5)
let x = (-3i8).mul_div_round(3, 2);

// Returns x==None
let x = 127i8.mul_div_floor(4, 3);

Calculates ceil(val * num / denom), i.e. the next integer to the result of the division with the bigger absolute value.

Example

extern crate muldiv;
use muldiv::MulDiv;

// Returns x==Some(6)
let x = 3i8.mul_div_ceil(4, 2);

// Returns x==Some(4)
let x = 5i8.mul_div_ceil(2, 3);

// Returns x==Some(-4)
let x = (-5i8).mul_div_ceil(2, 3);

// Returns x==Some(5)
let x = 3i8.mul_div_ceil(3, 2);

// Returns x==Some(-5)
let x = (-3i8).mul_div_ceil(3, 2);

// Returns x==None
let x = (127i8).mul_div_ceil(4, 3);

Implementations on Foreign Types

impl MulDiv<i8> for i8
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impl MulDiv<i32> for i32
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impl MulDiv<i16> for i16
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impl MulDiv<i64> for i64
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impl MulDiv<u32> for u32
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impl MulDiv<u64> for u64
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impl MulDiv<u16> for u16
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impl MulDiv<u8> for u8
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Implementors