diff --git a/crates/ide/src/hover/render.rs b/crates/ide/src/hover/render.rs index 46242b75dd0b..9af5ff840733 100644 --- a/crates/ide/src/hover/render.rs +++ b/crates/ide/src/hover/render.rs @@ -1082,7 +1082,19 @@ fn render_memory_layout( if config.niches { if let Some(niches) = layout.niches() { - format_to!(label, "niches = {niches}, "); + if niches > 128 { + if is_pwr2(niches) { + format_to!(label, "niches = 2{}, ", pwr2_to_exponent(niches)); + } else if is_pwr2plus1(niches) { + format_to!(label, "niches = 2{} + 1, ", pwr2_to_exponent(niches - 1)); + } else if is_pwr2minus1(niches) { + format_to!(label, "niches = 2{} - 1, ", pwr2_to_exponent(niches + 1)); + } else { + format_to!(label, "niches = really rather quite large, "); + } + } else { + format_to!(label, "niches = {niches}, "); + } } } label.pop(); // ' ' @@ -1210,3 +1222,85 @@ fn render_dyn_compatibility( } } } + +fn is_pwr2(val: u128) -> bool { + val.count_ones() == 1 +} + +fn is_pwr2minus1(val: u128) -> bool { + val == u128::MAX || (val + 1).count_ones() == 1 +} + +fn is_pwr2plus1(val: u128) -> bool { + val != 0 && (val - 1).count_ones() == 1 +} + +fn pwr2_to_exponent(num: u128) -> String { + const DIGITS: [char; 10] = ['⁰', '¹', '²', '³', '⁴', '⁵', '⁶', '⁷', '⁸', '⁹']; + (127 - num.leading_zeros()) + .to_string() + .chars() + .map(|c| c.to_digit(10).unwrap() as usize) + .map(|idx| DIGITS[idx]) + .collect::() +} + +#[cfg(test)] +mod tests { + use super::*; + + const TESTERS: [u128; 10] = [0, 1, 2, 3, 4, 255, 256, 257, u128::MAX - 1, u128::MAX]; + + #[test] + fn test_is_pwr2() { + const OUTCOMES: [bool; 10] = + [false, true, true, false, true, false, true, false, false, false]; + for (test, expected) in TESTERS.iter().zip(OUTCOMES) { + let actual = is_pwr2(*test); + assert_eq!(actual, expected, "is_pwr2({test}) gave {actual}, expected {expected}"); + } + } + + #[test] + fn test_is_pwr2minus1() { + const OUTCOMES: [bool; 10] = + [true, true, false, true, false, true, false, false, false, true]; + for (test, expected) in TESTERS.iter().zip(OUTCOMES) { + let actual = is_pwr2minus1(*test); + assert_eq!(actual, expected, "is_pwr2minu1({test}) gave {actual}, expected {expected}"); + } + } + + #[test] + fn test_is_pwr2plus1() { + const OUTCOMES: [bool; 10] = + [false, false, true, true, false, false, false, true, false, false]; + for (test, expected) in TESTERS.iter().zip(OUTCOMES) { + let actual = is_pwr2plus1(*test); + assert_eq!(actual, expected, "is_pwr2plus1({test}) gave {actual}, expected {expected}"); + } + } + + #[test] + fn test_pwr2_to_exponent() { + const TESTERS: [u128; 9] = [ + 1, + 2, + 4, + 8, + 16, + 9223372036854775808, + 18446744073709551616, + 36893488147419103232, + 170141183460469231731687303715884105728, + ]; + const OUTCOMES: [&str; 9] = ["⁰", "¹", "²", "³", "⁴", "⁶³", "⁶⁴", "⁶⁵", "¹²⁷"]; + for (test, expected) in TESTERS.iter().zip(OUTCOMES) { + let actual = pwr2_to_exponent(*test); + assert_eq!( + actual, expected, + "pwr2_to_exponent({test}) returned {actual}, expected {expected}", + ); + } + } +}