      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

    use std::fmt;
    use std::mem;

    use super::{
        FAIL_STATE,
        StateIdx, AcAutomaton, Transitions, Match,
        usize_bytes, vec_bytes,
    };
    use super::autiter::Automaton;

    /// A complete Aho-Corasick automaton.
    ///
    /// This uses a single transition matrix that permits each input character
    /// to move to the next state with a single lookup in the matrix.
    ///
    /// This is as fast as it gets, but it is guaranteed to use a lot of memory.
    /// Namely, it will use at least `4 * 256 * #states`, where the number of
    /// states is capped at length of all patterns concatenated.
    #[derive(Clone)]
    pub struct FullAcAutomaton<P> {
        pats: Vec<P>,
        trans: Vec<StateIdx>,  // row-major, where states are rows
        out: Vec<Vec<usize>>, // indexed by StateIdx
        start_bytes: Vec<u8>,
    }

    impl<P: AsRef<[u8]>> FullAcAutomaton<P> {
        /// Build a new expanded Aho-Corasick automaton from an existing
        /// Aho-Corasick automaton.
        pub fn new<T: Transitions>(ac: AcAutomaton<P, T>) -> FullAcAutomaton<P> {
            let mut fac = FullAcAutomaton {
                pats: vec![],
                trans: vec![FAIL_STATE; 256 * ac.states.len()],
                out: vec![vec![]; ac.states.len()],
                start_bytes: vec![],
            };
            fac.build_matrix(&ac);
            fac.pats = ac.pats;
            fac.start_bytes = ac.start_bytes;
            fac
        }

        #[doc(hidden)]
        pub fn memory_usage(&self) -> usize {
            self.pats.iter()
                .map(|p| vec_bytes() + p.as_ref().len())
                .fold(0, |a, b| a + b)
            + (4 * self.trans.len())
            + self.out.iter()
                  .map(|v| vec_bytes() + (usize_bytes() * v.len()))
                  .fold(0, |a, b| a + b)
            + self.start_bytes.len()
        }

        #[doc(hidden)]
        pub fn heap_bytes(&self) -> usize {
            self.pats.iter()
                .map(|p| mem::size_of::<P>() + p.as_ref().len())
                .fold(0, |a, b| a + b)
            + (4 * self.trans.len())
            + self.out.iter()
                  .map(|v| vec_bytes() + (usize_bytes() * v.len()))
                  .fold(0, |a, b| a + b)
            + self.start_bytes.len()
        }

        fn set(&mut self, si: StateIdx, i: u8, goto: StateIdx) {
            let ns = self.num_states();
            self.trans[i as usize * ns + si as usize] = goto;
        }

        #[doc(hidden)]
        #[inline]
        pub fn num_states(&self) -> usize {
            self.out.len()
        }
    }

    impl<P: AsRef<[u8]>> Automaton<P> for FullAcAutomaton<P> {
        #[inline]
        fn next_state(&self, si: StateIdx, i: u8) -> StateIdx {
            self.trans[i as usize * self.num_states() + si as usize]
        }

        #[inline]
        fn get_match(&self, si: StateIdx, outi: usize, texti: usize) -> Match {
            let pati = self.out[si as usize][outi];
            let patlen = self.pats[pati].as_ref().len();
            let start = texti + 1 - patlen;
            Match {
                pati: pati,
                start: start,
                end: start + patlen,
            }
        }

        #[inline]
        fn has_match(&self, si: StateIdx, outi: usize) -> bool {
            outi < self.out[si as usize].len()
        }

        #[inline]
        fn start_bytes(&self) -> &[u8] {
            &self.start_bytes
        }

        #[inline]
        fn patterns(&self) -> &[P] {
            &self.pats
        }

        #[inline]
        fn pattern(&self, i: usize) -> &P {
            &self.pats[i]
        }
    }

    impl<P: AsRef<[u8]>> FullAcAutomaton<P> {
        fn build_matrix<T: Transitions>(&mut self, ac: &AcAutomaton<P, T>) {
            for (si, s) in ac.states.iter().enumerate().skip(1) {
                for b in (0..256).map(|b| b as u8) {
                    self.set(si as StateIdx, b, ac.next_state(si as StateIdx, b));
                }
                for &pati in &s.out {
                    self.out[si].push(pati);
                }
            }
        }
    }

    impl<P: AsRef<[u8]> + fmt::Debug> fmt::Debug for FullAcAutomaton<P> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "FullAcAutomaton({:?})", self.pats)
        }
    }

# Help

## Keyboard Shortcuts

?
  Show this help dialog
S
  Focus the search field
⇤
  Move up in search results
⇥
  Move down in search results
⏎
  Go to active search result

## 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`)