Does the integer type matter for Bitvec::store

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#1

The bitvec documentation provides this example of using a bitvec here:

use bitvec::prelude::*;

let mut bv = bitvec![u8, Msb0; 0; 40];
bv[0 .. 10].store::<u16>(0x3A8);
bv[10 .. 20].store::<u16>(0x2F9);
bv[20 .. 30].store::<u16>(0x154);
bv[30 .. 40].store::<u16>(0x06D);

My question is, does the generic integer parameter on store matter for speed?

For example, would

bv[0 .. 10].store::<u16>(0x3A8);

be the same speed as

bv[0 .. 10].store::<usize>(0x3A8);

or would the usize variant be slower?

Thanks!

#2

Basically, the integer type determines the integer type of the underlying vector of numbers representing the bits. You can think that if you have a bitvec of u16, then it will have a "slice" of u16's, while if you have a u64, you'll have a slice of u64's.
There may be marginal differences in speed, for cumulative lookups, such as count or find first 0.
I tend to just stick a usize and be done with it. If you profile and discover that it really matters, then you can go ahead and benchmark. Otherwise, just use usize.

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#3

Ahh ok, that makes sense. Thank you!