Rollup merge of rust-lang#39615 - phungleson:corefloat, r=alexcrichton

Improve format float

* Move float into mod float like in test
* Add more tests for f64 f32, lower exp, upper exp, which can come if handy in the future if we want refactor further
* Use `assert_eq` for clearer error messages

src/libcore/fmt/float.rs

@@ -0,0 +1,94 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use fmt::{Formatter, Result, LowerExp, UpperExp, Display, Debug};
+use num::flt2dec;
+
+// Common code of floating point Debug and Display.
+fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T, negative_zero: bool) -> Result
+ where T: flt2dec::DecodableFloat
+{
+ let force_sign = fmt.sign_plus();
+ let sign = match (force_sign, negative_zero) {
+ (false, false) => flt2dec::Sign::Minus,
+ (false, true) => flt2dec::Sign::MinusRaw,
+ (true, false) => flt2dec::Sign::MinusPlus,
+ (true, true) => flt2dec::Sign::MinusPlusRaw,
+ };
+
+ let mut buf = [0; 1024]; // enough for f32 and f64
+ let mut parts = [flt2dec::Part::Zero(0); 16];
+ let formatted = if let Some(precision) = fmt.precision {
+ flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact, *num, sign,
+ precision, false, &mut buf, &mut parts)
+ } else {
+ flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num, sign,
+ 0, false, &mut buf, &mut parts)
+ };
+ fmt.pad_formatted_parts(&formatted)
+}
+
+// Common code of floating point LowerExp and UpperExp.
+fn float_to_exponential_common<T>(fmt: &mut Formatter, num: &T, upper: bool) -> Result
+ where T: flt2dec::DecodableFloat
+{
+ let force_sign = fmt.sign_plus();
+ let sign = match force_sign {
+ false => flt2dec::Sign::Minus,
+ true => flt2dec::Sign::MinusPlus,
+ };
+
+ let mut buf = [0; 1024]; // enough for f32 and f64
+ let mut parts = [flt2dec::Part::Zero(0); 16];
+ let formatted = if let Some(precision) = fmt.precision {
+ // 1 integral digit + `precision` fractional digits = `precision + 1` total digits
+ flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact, *num, sign,
+ precision + 1, upper, &mut buf, &mut parts)
+ } else {
+ flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num, sign,
+ (0, 0), upper, &mut buf, &mut parts)
+ };
+ fmt.pad_formatted_parts(&formatted)
+}
+
+macro_rules! floating {
+ ($ty:ident) => (
+ #[stable(feature = "rust1", since = "1.0.0")]
+ impl Debug for $ty {
+ fn fmt(&self, fmt: &mut Formatter) -> Result {
+ float_to_decimal_common(fmt, self, true)
+ }
+ }
+
+ #[stable(feature = "rust1", since = "1.0.0")]
+ impl Display for $ty {
+ fn fmt(&self, fmt: &mut Formatter) -> Result {
+ float_to_decimal_common(fmt, self, false)
+ }
+ }
+
+ #[stable(feature = "rust1", since = "1.0.0")]
+ impl LowerExp for $ty {
+ fn fmt(&self, fmt: &mut Formatter) -> Result {
+ float_to_exponential_common(fmt, self, false)
+ }
+ }
+
+ #[stable(feature = "rust1", since = "1.0.0")]
+ impl UpperExp for $ty {
+ fn fmt(&self, fmt: &mut Formatter) -> Result {
+ float_to_exponential_common(fmt, self, true)
+ }
+ }
+ )
+}
+
+floating! { f32 }
+floating! { f64 }

src/libcore/fmt/mod.rs

@@ -21,6 +21,10 @@ use result;
 use slice;
 use str;
 
+mod float;
+mod num;
+mod builders;
+
 #[unstable(feature = "fmt_flags_align", issue = "27726")]
 /// Possible alignments returned by `Formatter::align`
 #[derive(Debug)]
@@ -38,9 +42,6 @@ pub enum Alignment {
 #[stable(feature = "debug_builders", since = "1.2.0")]
 pub use self::builders::{DebugStruct, DebugTuple, DebugSet, DebugList, DebugMap};
 
-mod num;
-mod builders;
-
 #[unstable(feature = "fmt_internals", reason = "internal to format_args!",
  issue = "0")]
 #[doc(hidden)]
@@ -1511,86 +1512,6 @@ impl<'a, T: ?Sized> Pointer for &'a mut T {
  }
 }
 
-// Common code of floating point Debug and Display.
-fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T, negative_zero: bool) -> Result
- where T: flt2dec::DecodableFloat
-{
- let force_sign = fmt.sign_plus();
- let sign = match (force_sign, negative_zero) {
- (false, false) => flt2dec::Sign::Minus,
- (false, true) => flt2dec::Sign::MinusRaw,
- (true, false) => flt2dec::Sign::MinusPlus,
- (true, true) => flt2dec::Sign::MinusPlusRaw,
- };
-
- let mut buf = [0; 1024]; // enough for f32 and f64
- let mut parts = [flt2dec::Part::Zero(0); 16];
- let formatted = if let Some(precision) = fmt.precision {
- flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact, *num, sign,
- precision, false, &mut buf, &mut parts)
- } else {
- flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num, sign,
- 0, false, &mut buf, &mut parts)
- };
- fmt.pad_formatted_parts(&formatted)
-}
-
-// Common code of floating point LowerExp and UpperExp.
-fn float_to_exponential_common<T>(fmt: &mut Formatter, num: &T, upper: bool) -> Result
- where T: flt2dec::DecodableFloat
-{
- let force_sign = fmt.sign_plus();
- let sign = match force_sign {
- false => flt2dec::Sign::Minus,
- true => flt2dec::Sign::MinusPlus,
- };
-
- let mut buf = [0; 1024]; // enough for f32 and f64
- let mut parts = [flt2dec::Part::Zero(0); 16];
- let formatted = if let Some(precision) = fmt.precision {
- // 1 integral digit + `precision` fractional digits = `precision + 1` total digits
- flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact, *num, sign,
- precision + 1, upper, &mut buf, &mut parts)
- } else {
- flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num, sign,
- (0, 0), upper, &mut buf, &mut parts)
- };
- fmt.pad_formatted_parts(&formatted)
-}
-
-macro_rules! floating { ($ty:ident) => {
-
- #[stable(feature = "rust1", since = "1.0.0")]
- impl Debug for $ty {
- fn fmt(&self, fmt: &mut Formatter) -> Result {
- float_to_decimal_common(fmt, self, true)
- }
- }
-
- #[stable(feature = "rust1", since = "1.0.0")]
- impl Display for $ty {
- fn fmt(&self, fmt: &mut Formatter) -> Result {
- float_to_decimal_common(fmt, self, false)
- }
- }
-
- #[stable(feature = "rust1", since = "1.0.0")]
- impl LowerExp for $ty {
- fn fmt(&self, fmt: &mut Formatter) -> Result {
- float_to_exponential_common(fmt, self, false)
- }
- }
-
- #[stable(feature = "rust1", since = "1.0.0")]
- impl UpperExp for $ty {
- fn fmt(&self, fmt: &mut Formatter) -> Result {
- float_to_exponential_common(fmt, self, true)
- }
- }
-} }
-floating! { f32 }
-floating! { f64 }
-
 // Implementation of Display/Debug for various core types
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/libcoretest/fmt/float.rs

@@ -9,11 +9,29 @@
 // except according to those terms.
 
 #[test]
-fn test_format_float() {
- assert!("1" == format!("{:.0}", 1.0f64));
- assert!("9" == format!("{:.0}", 9.4f64));
- assert!("10" == format!("{:.0}", 9.9f64));
- assert!("9.8" == format!("{:.1}", 9.849f64));
- assert!("9.9" == format!("{:.1}", 9.851f64));
- assert!("1" == format!("{:.0}", 0.5f64));
+fn test_format_f64() {
+ assert_eq!("1", format!("{:.0}", 1.0f64));
+ assert_eq!("9", format!("{:.0}", 9.4f64));
+ 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!("1.23456789e6", format!("{:e}", 1234567.89f64));
+ assert_eq!("1.23456789e3", format!("{:e}", 1234.56789f64));
+ assert_eq!("1.23456789E6", format!("{:E}", 1234567.89f64));
+ assert_eq!("1.23456789E3", format!("{:E}", 1234.56789f64));
+}
+
+#[test]
+fn test_format_f32() {
+ assert_eq!("1", format!("{:.0}", 1.0f32));
+ assert_eq!("9", format!("{:.0}", 9.4f32));
+ 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!("1.2345679e6", format!("{:e}", 1234567.89f32));
+ assert_eq!("1.2345679e3", format!("{:e}", 1234.56789f32));
+ assert_eq!("1.2345679E6", format!("{:E}", 1234567.89f32));
+ assert_eq!("1.2345679E3", format!("{:E}", 1234.56789f32));
 }