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random: Do it in 64-bits

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Turns out we can do it without switching to 128-bit wide numbers.

Co-authored-by: Xiretza <xiretza@xiretza.xyz>
This commit is contained in:
Fabian Boehm
2023-02-19 20:02:55 +01:00
parent 4fd1458d85
commit f01a5d2a1b
1 changed files with 4 additions and 23 deletions
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27
fish-rust/src/builtins/random.rs
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@@ -148,7 +148,7 @@ fn parse<T: PrimInt>(
// Possibilities can be abs(i64::MIN) + i64::MAX,
// so we do this as i128
let possibilities = (end as i128 - start as i128) / (step as i128);
let possibilities = end.abs_diff(start) / step;
if possibilities == 0 {
streams.err.append(wgettext_fmt!(
@@ -160,29 +160,10 @@ fn parse<T: PrimInt>(
let rand = engine.gen_range(0..=possibilities);
let result = start as i128 + rand as i128 * step as i128;
let result = start.checked_add_unsigned(rand * step).unwrap();
// We do our math as i128,
// and then we check if it fits in 64 bit - signed or unsigned!
match i64::try_from(result) {
Ok(x) => {
streams.out.append(sprintf!("%d\n"L, x));
return STATUS_CMD_OK;
},
Err(_) => {
match u64::try_from(result) {
Ok(x) => {
streams.out.append(sprintf!("%d\n"L, x));
return STATUS_CMD_OK;
},
Err(_) => {
streams.err.append(wgettext_fmt!(
"%ls: range contains only one possible value\n",
cmd,
));
return STATUS_INVALID_ARGS;
},
}
},
}
streams.out.append(sprintf!("%d\n"L, result));
return STATUS_CMD_OK;
}