This commit is contained in:
David Tolnay
2020-05-30 11:38:10 -07:00
parent 4962ce3cf9
commit ce933f892e
2 changed files with 66 additions and 3 deletions
+1 -1
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@@ -19,7 +19,7 @@ C, [https://github.com/ulfjack/ryu][upstream].
uses nothing from the Rust standard library so is usable from no_std crates.*
[paper]: https://dl.acm.org/citation.cfm?id=3192369
[upstream]: https://github.com/ulfjack/ryu/tree/58c1344fe5354ca7046dee869b2c9656a4d86a8a
[upstream]: https://github.com/ulfjack/ryu/tree/25ccda88fdc49d5534fb82a87a9cafe9d2ce6d11
```toml
[dependencies]
+65 -2
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@@ -18,8 +18,8 @@
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.
// Returns the number of decimal digits in v, which must not be negative, and
// must not contain more than 9 digits.
// Returns the number of decimal digits in v, which must not contain more than 9
// digits.
#[cfg_attr(feature = "no-panic", inline)]
pub fn decimal_length9(v: u32) -> u32 {
// Function precondition: v is not a 10-digit number.
@@ -75,3 +75,66 @@ pub fn log10_pow5(e: i32) -> u32 {
debug_assert!(e <= 2620);
(e as u32 * 732923) >> 20
}
#[cfg(test)]
mod tests {
use super::*;
fn ceil_log2_pow5(e: i32) -> i32 {
pow5bits(e)
}
#[test]
fn test_decimal_length9() {
assert_eq!(1, decimal_length9(0));
assert_eq!(1, decimal_length9(1));
assert_eq!(1, decimal_length9(9));
assert_eq!(2, decimal_length9(10));
assert_eq!(2, decimal_length9(99));
assert_eq!(3, decimal_length9(100));
assert_eq!(3, decimal_length9(999));
assert_eq!(9, decimal_length9(999999999));
}
#[test]
fn test_ceil_log2_pow5() {
assert_eq!(1, ceil_log2_pow5(0));
assert_eq!(3, ceil_log2_pow5(1));
assert_eq!(5, ceil_log2_pow5(2));
assert_eq!(7, ceil_log2_pow5(3));
assert_eq!(10, ceil_log2_pow5(4));
assert_eq!(8192, ceil_log2_pow5(3528));
}
#[test]
fn test_log10_pow2() {
assert_eq!(0, log10_pow2(0));
assert_eq!(0, log10_pow2(1));
assert_eq!(0, log10_pow2(2));
assert_eq!(0, log10_pow2(3));
assert_eq!(1, log10_pow2(4));
assert_eq!(496, log10_pow2(1650));
}
#[test]
fn test_log10_pow5() {
assert_eq!(0, log10_pow5(0));
assert_eq!(0, log10_pow5(1));
assert_eq!(1, log10_pow5(2));
assert_eq!(2, log10_pow5(3));
assert_eq!(2, log10_pow5(4));
assert_eq!(1831, log10_pow5(2620));
}
#[test]
fn test_float_to_bits() {
assert_eq!(0, 0.0_f32.to_bits());
assert_eq!(0x40490fda, 3.1415926_f32.to_bits());
}
#[test]
fn test_double_to_bits() {
assert_eq!(0, 0.0_f64.to_bits());
assert_eq!(0x400921FB54442D18, 3.1415926535897932384626433_f64.to_bits());
}
}