bstr/byteset/
mod.rs

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1use memchr::{memchr, memchr2, memchr3, memrchr, memrchr2, memrchr3};
2
3mod scalar;
4
5#[inline]
6fn build_table(byteset: &[u8]) -> [u8; 256] {
7    let mut table = [0u8; 256];
8    for &b in byteset {
9        table[b as usize] = 1;
10    }
11    table
12}
13
14#[inline]
15pub(crate) fn find(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
16    match byteset.len() {
17        0 => return None,
18        1 => memchr(byteset[0], haystack),
19        2 => memchr2(byteset[0], byteset[1], haystack),
20        3 => memchr3(byteset[0], byteset[1], byteset[2], haystack),
21        _ => {
22            let table = build_table(byteset);
23            scalar::forward_search_bytes(haystack, |b| table[b as usize] != 0)
24        }
25    }
26}
27
28#[inline]
29pub(crate) fn rfind(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
30    match byteset.len() {
31        0 => return None,
32        1 => memrchr(byteset[0], haystack),
33        2 => memrchr2(byteset[0], byteset[1], haystack),
34        3 => memrchr3(byteset[0], byteset[1], byteset[2], haystack),
35        _ => {
36            let table = build_table(byteset);
37            scalar::reverse_search_bytes(haystack, |b| table[b as usize] != 0)
38        }
39    }
40}
41
42#[inline]
43pub(crate) fn find_not(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
44    if haystack.is_empty() {
45        return None;
46    }
47    match byteset.len() {
48        0 => return Some(0),
49        1 => scalar::inv_memchr(byteset[0], haystack),
50        2 => scalar::forward_search_bytes(haystack, |b| {
51            b != byteset[0] && b != byteset[1]
52        }),
53        3 => scalar::forward_search_bytes(haystack, |b| {
54            b != byteset[0] && b != byteset[1] && b != byteset[2]
55        }),
56        _ => {
57            let table = build_table(byteset);
58            scalar::forward_search_bytes(haystack, |b| table[b as usize] == 0)
59        }
60    }
61}
62#[inline]
63pub(crate) fn rfind_not(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
64    if haystack.is_empty() {
65        return None;
66    }
67    match byteset.len() {
68        0 => return Some(haystack.len() - 1),
69        1 => scalar::inv_memrchr(byteset[0], haystack),
70        2 => scalar::reverse_search_bytes(haystack, |b| {
71            b != byteset[0] && b != byteset[1]
72        }),
73        3 => scalar::reverse_search_bytes(haystack, |b| {
74            b != byteset[0] && b != byteset[1] && b != byteset[2]
75        }),
76        _ => {
77            let table = build_table(byteset);
78            scalar::reverse_search_bytes(haystack, |b| table[b as usize] == 0)
79        }
80    }
81}
82
83#[cfg(all(test, feature = "std", not(miri)))]
84mod tests {
85    quickcheck::quickcheck! {
86        fn qc_byteset_forward_matches_naive(
87            haystack: Vec<u8>,
88            needles: Vec<u8>
89        ) -> bool {
90            super::find(&haystack, &needles)
91                == haystack.iter().position(|b| needles.contains(b))
92        }
93        fn qc_byteset_backwards_matches_naive(
94            haystack: Vec<u8>,
95            needles: Vec<u8>
96        ) -> bool {
97            super::rfind(&haystack, &needles)
98                == haystack.iter().rposition(|b| needles.contains(b))
99        }
100        fn qc_byteset_forward_not_matches_naive(
101            haystack: Vec<u8>,
102            needles: Vec<u8>
103        ) -> bool {
104            super::find_not(&haystack, &needles)
105                == haystack.iter().position(|b| !needles.contains(b))
106        }
107        fn qc_byteset_backwards_not_matches_naive(
108            haystack: Vec<u8>,
109            needles: Vec<u8>
110        ) -> bool {
111            super::rfind_not(&haystack, &needles)
112                == haystack.iter().rposition(|b| !needles.contains(b))
113        }
114    }
115}
bstr/byteset/mod.rs

bstr/byteset/
mod.rs
