2017-02-07 03:58:34 -06:00
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use fmt::{Formatter, Result, LowerExp, UpperExp, Display, Debug};
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use num::flt2dec;
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2017-04-13 14:49:37 -05:00
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// Don't inline this so callers don't use the stack space this function
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// requires unless they have to.
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#[inline(never)]
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fn float_to_decimal_common_exact<T>(fmt: &mut Formatter, num: &T,
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sign: flt2dec::Sign, precision: usize) -> Result
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where T: flt2dec::DecodableFloat
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{
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let mut buf = [0; 1024]; // enough for f32 and f64
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2017-04-13 15:24:30 -05:00
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let mut parts = [flt2dec::Part::Zero(0); 5];
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2017-04-13 14:49:37 -05:00
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let formatted = flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact,
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*num, sign, precision,
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false, &mut buf, &mut parts);
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fmt.pad_formatted_parts(&formatted)
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}
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// Don't inline this so callers that call both this and the above won't wind
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// up using the combined stack space of both functions in some cases.
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#[inline(never)]
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fn float_to_decimal_common_shortest<T>(fmt: &mut Formatter,
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num: &T, sign: flt2dec::Sign) -> Result
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where T: flt2dec::DecodableFloat
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{
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let mut buf = [0; flt2dec::MAX_SIG_DIGITS]; // enough for f32 and f64
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2017-04-13 15:24:30 -05:00
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let mut parts = [flt2dec::Part::Zero(0); 5];
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2017-04-13 14:49:37 -05:00
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let formatted = flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest,
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*num, sign, 0, false, &mut buf, &mut parts);
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fmt.pad_formatted_parts(&formatted)
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}
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2017-02-07 03:58:34 -06:00
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// Common code of floating point Debug and Display.
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fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T, negative_zero: bool) -> Result
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where T: flt2dec::DecodableFloat
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{
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let force_sign = fmt.sign_plus();
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let sign = match (force_sign, negative_zero) {
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(false, false) => flt2dec::Sign::Minus,
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(false, true) => flt2dec::Sign::MinusRaw,
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(true, false) => flt2dec::Sign::MinusPlus,
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(true, true) => flt2dec::Sign::MinusPlusRaw,
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};
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2017-04-13 14:49:37 -05:00
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if let Some(precision) = fmt.precision {
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float_to_decimal_common_exact(fmt, num, sign, precision)
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} else {
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float_to_decimal_common_shortest(fmt, num, sign)
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}
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}
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// Don't inline this so callers don't use the stack space this function
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// requires unless they have to.
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#[inline(never)]
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fn float_to_exponential_common_exact<T>(fmt: &mut Formatter, num: &T,
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sign: flt2dec::Sign, precision: usize,
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upper: bool) -> Result
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where T: flt2dec::DecodableFloat
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{
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2017-02-07 03:58:34 -06:00
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let mut buf = [0; 1024]; // enough for f32 and f64
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2017-04-13 15:24:30 -05:00
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let mut parts = [flt2dec::Part::Zero(0); 7];
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2017-04-13 14:49:37 -05:00
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let formatted = flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact,
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*num, sign, precision,
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upper, &mut buf, &mut parts);
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fmt.pad_formatted_parts(&formatted)
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}
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// Don't inline this so callers that call both this and the above won't wind
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// up using the combined stack space of both functions in some cases.
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#[inline(never)]
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fn float_to_exponential_common_shortest<T>(fmt: &mut Formatter,
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num: &T, sign: flt2dec::Sign,
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upper: bool) -> Result
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where T: flt2dec::DecodableFloat
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{
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let mut buf = [0; flt2dec::MAX_SIG_DIGITS]; // enough for f32 and f64
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2017-04-13 15:24:30 -05:00
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let mut parts = [flt2dec::Part::Zero(0); 7];
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2017-04-13 14:49:37 -05:00
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let formatted = flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num,
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sign, (0, 0), upper, &mut buf, &mut parts);
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2017-02-07 03:58:34 -06:00
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fmt.pad_formatted_parts(&formatted)
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}
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// Common code of floating point LowerExp and UpperExp.
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fn float_to_exponential_common<T>(fmt: &mut Formatter, num: &T, upper: bool) -> Result
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where T: flt2dec::DecodableFloat
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{
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let force_sign = fmt.sign_plus();
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let sign = match force_sign {
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false => flt2dec::Sign::Minus,
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true => flt2dec::Sign::MinusPlus,
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};
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2017-04-13 14:49:37 -05:00
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if let Some(precision) = fmt.precision {
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2017-02-07 03:58:34 -06:00
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// 1 integral digit + `precision` fractional digits = `precision + 1` total digits
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2017-04-13 14:49:37 -05:00
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float_to_exponential_common_exact(fmt, num, sign, precision + 1, upper)
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2017-02-07 03:58:34 -06:00
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} else {
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2017-04-13 14:49:37 -05:00
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float_to_exponential_common_shortest(fmt, num, sign, upper)
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}
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2017-02-07 03:58:34 -06:00
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}
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macro_rules! floating {
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($ty:ident) => (
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#[stable(feature = "rust1", since = "1.0.0")]
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impl Debug for $ty {
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fn fmt(&self, fmt: &mut Formatter) -> Result {
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float_to_decimal_common(fmt, self, true)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl Display for $ty {
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fn fmt(&self, fmt: &mut Formatter) -> Result {
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float_to_decimal_common(fmt, self, false)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl LowerExp for $ty {
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fn fmt(&self, fmt: &mut Formatter) -> Result {
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float_to_exponential_common(fmt, self, false)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl UpperExp for $ty {
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fn fmt(&self, fmt: &mut Formatter) -> Result {
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float_to_exponential_common(fmt, self, true)
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}
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}
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)
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}
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floating! { f32 }
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floating! { f64 }
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