      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

    // Copyright 2013-2014 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.

    //! Operations on ASCII strings and characters.
    //!
    //! Most string operations in Rust act on UTF-8 strings. However, at times it
    //! makes more sense to only consider the ASCII character set for a specific
    //! operation.
    //!
    //! The [`escape_default`] function provides an iterator over the bytes of an
    //! escaped version of the character given.
    //!
    //! [`escape_default`]: fn.escape_default.html

    #![stable(feature = "core_ascii", since = "1.26.0")]

    use fmt;
    use ops::Range;
    use iter::FusedIterator;

    /// An iterator over the escaped version of a byte.
    ///
    /// This `struct` is created by the [`escape_default`] function. See its
    /// documentation for more.
    ///
    /// [`escape_default`]: fn.escape_default.html
    #[stable(feature = "rust1", since = "1.0.0")]
    pub struct EscapeDefault {
        range: Range<usize>,
        data: [u8; 4],
    }

    /// Returns an iterator that produces an escaped version of a `u8`.
    ///
    /// The default is chosen with a bias toward producing literals that are
    /// legal in a variety of languages, including C++11 and similar C-family
    /// languages. The exact rules are:
    ///
    /// * Tab is escaped as `\t`.
    /// * Carriage return is escaped as `\r`.
    /// * Line feed is escaped as `\n`.
    /// * Single quote is escaped as `\'`.
    /// * Double quote is escaped as `\"`.
    /// * Backslash is escaped as `\\`.
    /// * Any character in the 'printable ASCII' range `0x20` .. `0x7e`
    ///   inclusive is not escaped.
    /// * Any other chars are given hex escapes of the form '\xNN'.
    /// * Unicode escapes are never generated by this function.
    ///
    /// # Examples
    ///
    /// ```
    /// use std::ascii;
    ///
    /// let escaped = ascii::escape_default(b'0').next().unwrap();
    /// assert_eq!(b'0', escaped);
    ///
    /// let mut escaped = ascii::escape_default(b'\t');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b't', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'\r');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'r', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'\n');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'n', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'\'');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'\'', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'"');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'"', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'\\');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'\\', escaped.next().unwrap());
    ///
    /// let mut escaped = ascii::escape_default(b'\x9d');
    ///
    /// assert_eq!(b'\\', escaped.next().unwrap());
    /// assert_eq!(b'x', escaped.next().unwrap());
    /// assert_eq!(b'9', escaped.next().unwrap());
    /// assert_eq!(b'd', escaped.next().unwrap());
    /// ```
    #[stable(feature = "rust1", since = "1.0.0")]
    pub fn escape_default(c: u8) -> EscapeDefault {
        let (data, len) = match c {
            b'\t' => ([b'\\', b't', 0, 0], 2),
            b'\r' => ([b'\\', b'r', 0, 0], 2),
            b'\n' => ([b'\\', b'n', 0, 0], 2),
            b'\\' => ([b'\\', b'\\', 0, 0], 2),
            b'\'' => ([b'\\', b'\'', 0, 0], 2),
            b'"' => ([b'\\', b'"', 0, 0], 2),
            b'\x20' ..= b'\x7e' => ([c, 0, 0, 0], 1),
            _ => ([b'\\', b'x', hexify(c >> 4), hexify(c & 0xf)], 4),
        };

        return EscapeDefault { range: 0..len, data };

        fn hexify(b: u8) -> u8 {
            match b {
                0 ..= 9 => b'0' + b,
                _ => b'a' + b - 10,
            }
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Iterator for EscapeDefault {
        type Item = u8;
        fn next(&mut self) -> Option<u8> { self.range.next().map(|i| self.data[i]) }
        fn size_hint(&self) -> (usize, Option<usize>) { self.range.size_hint() }
    }
    #[stable(feature = "rust1", since = "1.0.0")]
    impl DoubleEndedIterator for EscapeDefault {
        fn next_back(&mut self) -> Option<u8> {
            self.range.next_back().map(|i| self.data[i])
        }
    }
    #[stable(feature = "rust1", since = "1.0.0")]
    impl ExactSizeIterator for EscapeDefault {}
    #[stable(feature = "fused", since = "1.26.0")]
    impl FusedIterator for EscapeDefault {}

    #[stable(feature = "std_debug", since = "1.16.0")]
    impl fmt::Debug for EscapeDefault {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            f.pad("EscapeDefault { .. }")
        }
    }

# 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`)