      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
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221

    // 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.
    //
    // ignore-lexer-test FIXME #15679

    //! Hex binary-to-text encoding

    pub use self::FromHexError::*;

    use std::fmt;
    use std::error;

    /// A trait for converting a value to hexadecimal encoding
    pub trait ToHex {
        /// Converts the value of `self` to a hex value, returning the owned
        /// string.
        fn to_hex(&self) -> String;
    }

    static CHARS: &'static[u8] = b"0123456789abcdef";

    impl ToHex for [u8] {
        /// Turn a vector of `u8` bytes into a hexadecimal string.
        ///
        /// # Example
        ///
        /// ```rust
        /// extern crate rustc_serialize;
        /// use rustc_serialize::hex::ToHex;
        ///
        /// fn main () {
        ///     let str = [52,32].to_hex();
        ///     println!("{}", str);
        /// }
        /// ```
        fn to_hex(&self) -> String {
            let mut v = Vec::with_capacity(self.len() * 2);
            for &byte in self.iter() {
                v.push(CHARS[(byte >> 4) as usize]);
                v.push(CHARS[(byte & 0xf) as usize]);
            }

            unsafe {
                String::from_utf8_unchecked(v)
            }
        }
    }

    impl<'a, T: ?Sized + ToHex> ToHex for &'a T {
        fn to_hex(&self) -> String {
            (**self).to_hex()
        }
    }

    /// A trait for converting hexadecimal encoded values
    pub trait FromHex {
        /// Converts the value of `self`, interpreted as hexadecimal encoded data,
        /// into an owned vector of bytes, returning the vector.
        fn from_hex(&self) -> Result<Vec<u8>, FromHexError>;
    }

    /// Errors that can occur when decoding a hex encoded string
    #[derive(Clone, Copy)]
    pub enum FromHexError {
        /// The input contained a character not part of the hex format
        InvalidHexCharacter(char, usize),
        /// The input had an invalid length
        InvalidHexLength,
    }

    impl fmt::Debug for FromHexError {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            match *self {
                InvalidHexCharacter(ch, idx) =>
                    write!(f, "Invalid character '{}' at position {}", ch, idx),
                InvalidHexLength => write!(f, "Invalid input length"),
            }
        }
    }

    impl error::Error for FromHexError {
        fn description(&self) -> &str {
            match *self {
                InvalidHexCharacter(_, _) => "invalid character",
                InvalidHexLength => "invalid length",
            }
        }
    }

    impl fmt::Display for FromHexError {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            fmt::Debug::fmt(&self, f)
        }
    }

    impl FromHex for str {
        /// Convert any hexadecimal encoded string (literal, `@`, `&`, or `~`)
        /// to the byte values it encodes.
        ///
        /// You can use the `String::from_utf8` function to turn a
        /// `Vec<u8>` into a string with characters corresponding to those values.
        ///
        /// # Example
        ///
        /// This converts a string literal to hexadecimal and back.
        ///
        /// ```rust
        /// extern crate rustc_serialize;
        /// use rustc_serialize::hex::{FromHex, ToHex};
        ///
        /// fn main () {
        ///     let hello_str = "Hello, World".as_bytes().to_hex();
        ///     println!("{}", hello_str);
        ///     let bytes = hello_str.from_hex().unwrap();
        ///     println!("{:?}", bytes);
        ///     let result_str = String::from_utf8(bytes).unwrap();
        ///     println!("{}", result_str);
        /// }
        /// ```
        fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
            // This may be an overestimate if there is any whitespace
            let mut b = Vec::with_capacity(self.len() / 2);
            let mut modulus = 0;
            let mut buf = 0;

            for (idx, byte) in self.bytes().enumerate() {
                buf <<= 4;

                match byte {
                    b'A'...b'F' => buf |= byte - b'A' + 10,
                    b'a'...b'f' => buf |= byte - b'a' + 10,
                    b'0'...b'9' => buf |= byte - b'0',
                    b' '|b'\r'|b'\n'|b'\t' => {
                        buf >>= 4;
                        continue
                    }
                    _ => {
                        let ch = self[idx..].chars().next().unwrap();
                        return Err(InvalidHexCharacter(ch, idx))
                    }
                }

                modulus += 1;
                if modulus == 2 {
                    modulus = 0;
                    b.push(buf);
                }
            }

            match modulus {
                0 => Ok(b.into_iter().collect()),
                _ => Err(InvalidHexLength),
            }
        }
    }

    impl<'a, T: ?Sized + FromHex> FromHex for &'a T {
        fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
            (**self).from_hex()
        }
    }

    #[cfg(test)]
    mod tests {
        use hex::{FromHex, ToHex};

        #[test]
        pub fn test_to_hex() {
            assert_eq!("foobar".as_bytes().to_hex(), "666f6f626172");
        }

        #[test]
        pub fn test_from_hex_okay() {
            assert_eq!("666f6f626172".from_hex().unwrap(),
                       b"foobar");
            assert_eq!("666F6F626172".from_hex().unwrap(),
                       b"foobar");
        }

        #[test]
        pub fn test_from_hex_odd_len() {
            assert!("666".from_hex().is_err());
            assert!("66 6".from_hex().is_err());
        }

        #[test]
        pub fn test_from_hex_invalid_char() {
            assert!("66y6".from_hex().is_err());
        }

        #[test]
        pub fn test_from_hex_ignores_whitespace() {
            assert_eq!("666f 6f6\r\n26172 ".from_hex().unwrap(),
                       b"foobar");
        }

        #[test]
        pub fn test_to_hex_all_bytes() {
            for i in 0..256 {
                assert_eq!([i as u8].to_hex(), format!("{:02x}", i));
            }
        }

        #[test]
        pub fn test_from_hex_all_bytes() {
            for i in 0..256 {
                let ii: &[u8] = &[i as u8];
                assert_eq!(format!("{:02x}", i).from_hex().unwrap(),
                           ii);
                assert_eq!(format!("{:02X}", i).from_hex().unwrap(),
                           ii);
            }
        }
    }

# 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`)