Module size::ops

Implementations of basic arithmetic operations on/between Size values.

Only operations that make sense are implemented, e.g. while it is OK to add two Size objects, it does not make sense to multiply them. Meanwhile, 17 MiB / 2 is perfectly rational and returns a size of 3.5 MiB, but 12 KB + 14 isn’t (as the addition of a scalar value to a sized type is undefined) – on the other hand, 12 KB + 14 B is both supported and perfectly fine.

Some examples of supported mathematical operations:

use size::Size;

// Perform scalar multiplication/division on a `Size`
let s1 = Size::from_mib(13) / 2;
assert_eq!(s1, Size::from_mib(6.5_f32));

// Perform addition or subtraction of two `Size` instances,
// regardless of their underlying types
let s2 = Size::from_kib(4) + Size::from_mb(8);
assert_eq!(s2.bytes(), 8_004_096);

// Express the negative difference between two sizes
let s3 = Size::from_mib(12) - Size::from_mib(14.2_f64);
assert_eq!(s3, Size::from_kib(-2252.8));

Some other things you cannot do are multiply/divide two sizes (did you mean to multiply one size by a scalar value instead?), add/subtract scalar values from sizes (you can call size.bytes() then do all the scalar math you like, however), or perform mathematical operations that exceed the bounds of the intermediate type (f64 by default or i64 if no_std mode is used).

A current limitation of this crate that may be revisited at a later date is that mathematical operations (or textual representation, for that matter) of that result in a size that exceeds the bounds of an i64 are not supported (i.e. they will not be promoted to a floating-point-backed Size instance) and will panic in debug mode or silently fail with undefined results in release mode.