From 848744403a67965f792d9f0eacb7700d8e325c2f Mon Sep 17 00:00:00 2001 From: Andrew Tribick Date: Tue, 11 Oct 2022 23:09:23 +0200 Subject: [PATCH 1/2] Fix inconsistent rounding of 0.5 when formatted to 0 decimal places --- library/core/src/num/flt2dec/strategy/dragon.rs | 2 +- library/core/tests/fmt/float.rs | 4 ++-- library/core/tests/num/flt2dec/mod.rs | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/library/core/src/num/flt2dec/strategy/dragon.rs b/library/core/src/num/flt2dec/strategy/dragon.rs index 8ced5971ec2..71b14d0ae3f 100644 --- a/library/core/src/num/flt2dec/strategy/dragon.rs +++ b/library/core/src/num/flt2dec/strategy/dragon.rs @@ -366,7 +366,7 @@ pub fn format_exact<'a>( if order == Ordering::Greater || (order == Ordering::Equal // SAFETY: `buf[len-1]` is initialized. - && (len == 0 || unsafe { buf[len - 1].assume_init() } & 1 == 1)) + && len > 0 && unsafe { buf[len - 1].assume_init() } & 1 == 1) { // if rounding up changes the length, the exponent should also change. // but we've been requested a fixed number of digits, so do not alter the buffer... diff --git a/library/core/tests/fmt/float.rs b/library/core/tests/fmt/float.rs index 47a7400f76e..bc0bef6d776 100644 --- a/library/core/tests/fmt/float.rs +++ b/library/core/tests/fmt/float.rs @@ -5,7 +5,7 @@ fn test_format_f64() { assert_eq!("10", format!("{:.0}", 9.9f64)); assert_eq!("9.8", format!("{:.1}", 9.849f64)); assert_eq!("9.9", format!("{:.1}", 9.851f64)); - assert_eq!("1", format!("{:.0}", 0.5f64)); + assert_eq!("0", format!("{:.0}", 0.5f64)); assert_eq!("1.23456789e6", format!("{:e}", 1234567.89f64)); assert_eq!("1.23456789e3", format!("{:e}", 1234.56789f64)); assert_eq!("1.23456789E6", format!("{:E}", 1234567.89f64)); @@ -31,7 +31,7 @@ fn test_format_f32() { assert_eq!("10", format!("{:.0}", 9.9f32)); assert_eq!("9.8", format!("{:.1}", 9.849f32)); assert_eq!("9.9", format!("{:.1}", 9.851f32)); - assert_eq!("1", format!("{:.0}", 0.5f32)); + assert_eq!("0", format!("{:.0}", 0.5f32)); assert_eq!("1.2345679e6", format!("{:e}", 1234567.89f32)); assert_eq!("1.2345679e3", format!("{:e}", 1234.56789f32)); assert_eq!("1.2345679E6", format!("{:E}", 1234567.89f32)); diff --git a/library/core/tests/num/flt2dec/mod.rs b/library/core/tests/num/flt2dec/mod.rs index 798473bbde3..30843cc3dd7 100644 --- a/library/core/tests/num/flt2dec/mod.rs +++ b/library/core/tests/num/flt2dec/mod.rs @@ -138,7 +138,7 @@ fn check_exact(mut f: F, v: T, vstr: &str, expected: &[u8], expectedk: i16 // check exact rounding for zero- and negative-width cases let start; - if expected[0] >= b'5' { + if expected[0] > b'5' { try_fixed!(f(&decoded) => &mut buf, expectedk, b"1", expectedk + 1; "zero-width rounding-up mismatch for v={v}: \ actual {actual:?}, expected {expected:?}", @@ -1007,7 +1007,7 @@ fn to_string(f: &mut F, v: T, sign: Sign, frac_digits: usize) -> String assert_eq!(to_string(f, 999.5, Minus, 3), "999.500"); assert_eq!(to_string(f, 999.5, Minus, 30), "999.500000000000000000000000000000"); - assert_eq!(to_string(f, 0.5, Minus, 0), "1"); + assert_eq!(to_string(f, 0.5, Minus, 0), "0"); assert_eq!(to_string(f, 0.5, Minus, 1), "0.5"); assert_eq!(to_string(f, 0.5, Minus, 2), "0.50"); assert_eq!(to_string(f, 0.5, Minus, 3), "0.500"); From aa9837ba29d88d0748e2599e46403f333a629836 Mon Sep 17 00:00:00 2001 From: Andrew Tribick Date: Thu, 20 Oct 2022 22:09:24 +0200 Subject: [PATCH 2/2] Add tests for rounding of ties during float formatting --- library/core/tests/fmt/float.rs | 120 ++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) diff --git a/library/core/tests/fmt/float.rs b/library/core/tests/fmt/float.rs index bc0bef6d776..003782f34dc 100644 --- a/library/core/tests/fmt/float.rs +++ b/library/core/tests/fmt/float.rs @@ -24,6 +24,66 @@ fn test_format_f64() { assert_eq!("1234.6", format!("{:.1?}", 1234.56789f64)); } +#[test] +fn test_format_f64_rounds_ties_to_even() { + assert_eq!("0", format!("{:.0}", 0.5f64)); + assert_eq!("2", format!("{:.0}", 1.5f64)); + assert_eq!("2", format!("{:.0}", 2.5f64)); + assert_eq!("4", format!("{:.0}", 3.5f64)); + assert_eq!("4", format!("{:.0}", 4.5f64)); + assert_eq!("6", format!("{:.0}", 5.5f64)); + assert_eq!("128", format!("{:.0}", 127.5f64)); + assert_eq!("128", format!("{:.0}", 128.5f64)); + assert_eq!("0.2", format!("{:.1}", 0.25f64)); + assert_eq!("0.8", format!("{:.1}", 0.75f64)); + assert_eq!("0.12", format!("{:.2}", 0.125f64)); + assert_eq!("0.88", format!("{:.2}", 0.875f64)); + assert_eq!("0.062", format!("{:.3}", 0.062f64)); + assert_eq!("-0", format!("{:.0}", -0.5f64)); + assert_eq!("-2", format!("{:.0}", -1.5f64)); + assert_eq!("-2", format!("{:.0}", -2.5f64)); + assert_eq!("-4", format!("{:.0}", -3.5f64)); + assert_eq!("-4", format!("{:.0}", -4.5f64)); + assert_eq!("-6", format!("{:.0}", -5.5f64)); + assert_eq!("-128", format!("{:.0}", -127.5f64)); + assert_eq!("-128", format!("{:.0}", -128.5f64)); + assert_eq!("-0.2", format!("{:.1}", -0.25f64)); + assert_eq!("-0.8", format!("{:.1}", -0.75f64)); + assert_eq!("-0.12", format!("{:.2}", -0.125f64)); + assert_eq!("-0.88", format!("{:.2}", -0.875f64)); + assert_eq!("-0.062", format!("{:.3}", -0.062f64)); + + assert_eq!("2e0", format!("{:.0e}", 1.5f64)); + assert_eq!("2e0", format!("{:.0e}", 2.5f64)); + assert_eq!("4e0", format!("{:.0e}", 3.5f64)); + assert_eq!("4e0", format!("{:.0e}", 4.5f64)); + assert_eq!("6e0", format!("{:.0e}", 5.5f64)); + assert_eq!("1.28e2", format!("{:.2e}", 127.5f64)); + assert_eq!("1.28e2", format!("{:.2e}", 128.5f64)); + assert_eq!("-2e0", format!("{:.0e}", -1.5f64)); + assert_eq!("-2e0", format!("{:.0e}", -2.5f64)); + assert_eq!("-4e0", format!("{:.0e}", -3.5f64)); + assert_eq!("-4e0", format!("{:.0e}", -4.5f64)); + assert_eq!("-6e0", format!("{:.0e}", -5.5f64)); + assert_eq!("-1.28e2", format!("{:.2e}", -127.5f64)); + assert_eq!("-1.28e2", format!("{:.2e}", -128.5f64)); + + assert_eq!("2E0", format!("{:.0E}", 1.5f64)); + assert_eq!("2E0", format!("{:.0E}", 2.5f64)); + assert_eq!("4E0", format!("{:.0E}", 3.5f64)); + assert_eq!("4E0", format!("{:.0E}", 4.5f64)); + assert_eq!("6E0", format!("{:.0E}", 5.5f64)); + assert_eq!("1.28E2", format!("{:.2E}", 127.5f64)); + assert_eq!("1.28E2", format!("{:.2E}", 128.5f64)); + assert_eq!("-2E0", format!("{:.0E}", -1.5f64)); + assert_eq!("-2E0", format!("{:.0E}", -2.5f64)); + assert_eq!("-4E0", format!("{:.0E}", -3.5f64)); + assert_eq!("-4E0", format!("{:.0E}", -4.5f64)); + assert_eq!("-6E0", format!("{:.0E}", -5.5f64)); + assert_eq!("-1.28E2", format!("{:.2E}", -127.5f64)); + assert_eq!("-1.28E2", format!("{:.2E}", -128.5f64)); +} + #[test] fn test_format_f32() { assert_eq!("1", format!("{:.0}", 1.0f32)); @@ -50,6 +110,66 @@ fn test_format_f32() { assert_eq!("1234.6", format!("{:.1?}", 1234.56789f32)); } +#[test] +fn test_format_f32_rounds_ties_to_even() { + assert_eq!("0", format!("{:.0}", 0.5f32)); + assert_eq!("2", format!("{:.0}", 1.5f32)); + assert_eq!("2", format!("{:.0}", 2.5f32)); + assert_eq!("4", format!("{:.0}", 3.5f32)); + assert_eq!("4", format!("{:.0}", 4.5f32)); + assert_eq!("6", format!("{:.0}", 5.5f32)); + assert_eq!("128", format!("{:.0}", 127.5f32)); + assert_eq!("128", format!("{:.0}", 128.5f32)); + assert_eq!("0.2", format!("{:.1}", 0.25f32)); + assert_eq!("0.8", format!("{:.1}", 0.75f32)); + assert_eq!("0.12", format!("{:.2}", 0.125f32)); + assert_eq!("0.88", format!("{:.2}", 0.875f32)); + assert_eq!("0.062", format!("{:.3}", 0.062f32)); + assert_eq!("-0", format!("{:.0}", -0.5f32)); + assert_eq!("-2", format!("{:.0}", -1.5f32)); + assert_eq!("-2", format!("{:.0}", -2.5f32)); + assert_eq!("-4", format!("{:.0}", -3.5f32)); + assert_eq!("-4", format!("{:.0}", -4.5f32)); + assert_eq!("-6", format!("{:.0}", -5.5f32)); + assert_eq!("-128", format!("{:.0}", -127.5f32)); + assert_eq!("-128", format!("{:.0}", -128.5f32)); + assert_eq!("-0.2", format!("{:.1}", -0.25f32)); + assert_eq!("-0.8", format!("{:.1}", -0.75f32)); + assert_eq!("-0.12", format!("{:.2}", -0.125f32)); + assert_eq!("-0.88", format!("{:.2}", -0.875f32)); + assert_eq!("-0.062", format!("{:.3}", -0.062f32)); + + assert_eq!("2e0", format!("{:.0e}", 1.5f32)); + assert_eq!("2e0", format!("{:.0e}", 2.5f32)); + assert_eq!("4e0", format!("{:.0e}", 3.5f32)); + assert_eq!("4e0", format!("{:.0e}", 4.5f32)); + assert_eq!("6e0", format!("{:.0e}", 5.5f32)); + assert_eq!("1.28e2", format!("{:.2e}", 127.5f32)); + assert_eq!("1.28e2", format!("{:.2e}", 128.5f32)); + assert_eq!("-2e0", format!("{:.0e}", -1.5f32)); + assert_eq!("-2e0", format!("{:.0e}", -2.5f32)); + assert_eq!("-4e0", format!("{:.0e}", -3.5f32)); + assert_eq!("-4e0", format!("{:.0e}", -4.5f32)); + assert_eq!("-6e0", format!("{:.0e}", -5.5f32)); + assert_eq!("-1.28e2", format!("{:.2e}", -127.5f32)); + assert_eq!("-1.28e2", format!("{:.2e}", -128.5f32)); + + assert_eq!("2E0", format!("{:.0E}", 1.5f32)); + assert_eq!("2E0", format!("{:.0E}", 2.5f32)); + assert_eq!("4E0", format!("{:.0E}", 3.5f32)); + assert_eq!("4E0", format!("{:.0E}", 4.5f32)); + assert_eq!("6E0", format!("{:.0E}", 5.5f32)); + assert_eq!("1.28E2", format!("{:.2E}", 127.5f32)); + assert_eq!("1.28E2", format!("{:.2E}", 128.5f32)); + assert_eq!("-2E0", format!("{:.0E}", -1.5f32)); + assert_eq!("-2E0", format!("{:.0E}", -2.5f32)); + assert_eq!("-4E0", format!("{:.0E}", -3.5f32)); + assert_eq!("-4E0", format!("{:.0E}", -4.5f32)); + assert_eq!("-6E0", format!("{:.0E}", -5.5f32)); + assert_eq!("-1.28E2", format!("{:.2E}", -127.5f32)); + assert_eq!("-1.28E2", format!("{:.2E}", -128.5f32)); +} + fn is_exponential(s: &str) -> bool { s.contains("e") || s.contains("E") }