      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157

    // 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 mem;
    use num::flt2dec;

    // Don't inline this so callers don't use the stack space this function
    // requires unless they have to.
    #[inline(never)]
    fn float_to_decimal_common_exact<T>(fmt: &mut Formatter, num: &T,
                                        sign: flt2dec::Sign, precision: usize) -> Result
        where T: flt2dec::DecodableFloat
    {
        unsafe {
            let mut buf: [u8; 1024] = mem::uninitialized(); // enough for f32 and f64
            let mut parts: [flt2dec::Part; 4] = mem::uninitialized();
            let formatted = flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact,
                                                        *num, sign, precision,
                                                        false, &mut buf, &mut parts);
            fmt.pad_formatted_parts(&formatted)
        }
    }

    // Don't inline this so callers that call both this and the above won't wind
    // up using the combined stack space of both functions in some cases.
    #[inline(never)]
    fn float_to_decimal_common_shortest<T>(fmt: &mut Formatter, num: &T,
                                           sign: flt2dec::Sign, precision: usize) -> Result
        where T: flt2dec::DecodableFloat
    {
        unsafe {
            // enough for f32 and f64
            let mut buf: [u8; flt2dec::MAX_SIG_DIGITS] = mem::uninitialized();
            let mut parts: [flt2dec::Part; 4] = mem::uninitialized();
            let formatted = flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num,
                                                     sign, precision, false, &mut buf, &mut parts);
            fmt.pad_formatted_parts(&formatted)
        }
    }

    // Common code of floating point Debug and Display.
    fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T,
                                  negative_zero: bool, min_precision: usize) -> 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,
        };

        if let Some(precision) = fmt.precision {
            float_to_decimal_common_exact(fmt, num, sign, precision)
        } else {
            float_to_decimal_common_shortest(fmt, num, sign, min_precision)
        }
    }

    // Don't inline this so callers don't use the stack space this function
    // requires unless they have to.
    #[inline(never)]
    fn float_to_exponential_common_exact<T>(fmt: &mut Formatter, num: &T,
                                            sign: flt2dec::Sign, precision: usize,
                                            upper: bool) -> Result
        where T: flt2dec::DecodableFloat
    {
        unsafe {
            let mut buf: [u8; 1024] = mem::uninitialized(); // enough for f32 and f64
            let mut parts: [flt2dec::Part; 6] = mem::uninitialized();
            let formatted = flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact,
                                                      *num, sign, precision,
                                                      upper, &mut buf, &mut parts);
            fmt.pad_formatted_parts(&formatted)
        }
    }

    // Don't inline this so callers that call both this and the above won't wind
    // up using the combined stack space of both functions in some cases.
    #[inline(never)]
    fn float_to_exponential_common_shortest<T>(fmt: &mut Formatter,
                                               num: &T, sign: flt2dec::Sign,
                                               upper: bool) -> Result
        where T: flt2dec::DecodableFloat
    {
        unsafe {
            // enough for f32 and f64
            let mut buf: [u8; flt2dec::MAX_SIG_DIGITS] = mem::uninitialized();
            let mut parts: [flt2dec::Part; 6] = mem::uninitialized();
            let formatted = flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest,
                                                         *num, sign, (0, 0), upper,
                                                         &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,
        };

        if let Some(precision) = fmt.precision {
            // 1 integral digit + `precision` fractional digits = `precision + 1` total digits
            float_to_exponential_common_exact(fmt, num, sign, precision + 1, upper)
        } else {
            float_to_exponential_common_shortest(fmt, num, sign, upper)
        }
    }

    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, 1)
                }
            }

            #[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, 0)
                }
            }

            #[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 }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g. `str,u8` or `String,struct:Vec,test`)