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use search::twoway::TwoWay;
/// Each test is a (needle, haystack, expected_fwd, expected_rev) tuple.
type SearchTest = (&'static str, &'static str, Option<usize>, Option<usize>);
const SEARCH_TESTS: &'static [SearchTest] = &[
("", "", Some(0), Some(0)),
("", "a", Some(0), Some(1)),
("", "ab", Some(0), Some(2)),
("", "abc", Some(0), Some(3)),
("a", "", None, None),
("a", "a", Some(0), Some(0)),
("a", "aa", Some(0), Some(1)),
("a", "ba", Some(1), Some(1)),
("a", "bba", Some(2), Some(2)),
("a", "bbba", Some(3), Some(3)),
("a", "bbbab", Some(3), Some(3)),
("a", "bbbabb", Some(3), Some(3)),
("a", "bbbabbb", Some(3), Some(3)),
("a", "bbbbbb", None, None),
("ab", "", None, None),
("ab", "a", None, None),
("ab", "b", None, None),
("ab", "ab", Some(0), Some(0)),
("ab", "aab", Some(1), Some(1)),
("ab", "aaab", Some(2), Some(2)),
("ab", "abaab", Some(0), Some(3)),
("ab", "baaab", Some(3), Some(3)),
("ab", "acb", None, None),
("ab", "abba", Some(0), Some(0)),
("abc", "ab", None, None),
("abc", "abc", Some(0), Some(0)),
("abc", "abcz", Some(0), Some(0)),
("abc", "abczz", Some(0), Some(0)),
("abc", "zabc", Some(1), Some(1)),
("abc", "zzabc", Some(2), Some(2)),
("abc", "azbc", None, None),
("abc", "abzc", None, None),
("abczdef", "abczdefzzzzzzzzzzzzzzzzzzzz", Some(0), Some(0)),
("abczdef", "zzzzzzzzzzzzzzzzzzzzabczdef", Some(20), Some(20)),
// Failures caught by quickcheck.
("\u{0}\u{15}", "\u{0}\u{15}\u{15}\u{0}", Some(0), Some(0)),
("\u{0}\u{1e}", "\u{1e}\u{0}", None, None),
];
#[test]
fn unit_twoway_fwd() {
run_search_tests_fwd("TwoWay", |n, h| TwoWay::forward(n).find(h));
}
#[test]
fn unit_twoway_rev() {
run_search_tests_rev("TwoWay", |n, h| TwoWay::reverse(n).rfind(h));
}
/// Run the substring search tests. `name` should be the type of searcher used,
/// for diagnostics. `search` should be a closure that accepts a needle and a
/// haystack and returns the starting position of the first occurrence of
/// needle in the haystack, or `None` if one doesn't exist.
fn run_search_tests_fwd(
name: &str,
mut search: impl FnMut(&[u8], &[u8]) -> Option<usize>,
) {
for &(needle, haystack, expected_fwd, _) in SEARCH_TESTS {
let (n, h) = (needle.as_bytes(), haystack.as_bytes());
assert_eq!(
expected_fwd,
search(n, h),
"{}: needle: {:?}, haystack: {:?}, expected: {:?}",
name,
n,
h,
expected_fwd
);
}
}
/// Run the substring search tests. `name` should be the type of searcher used,
/// for diagnostics. `search` should be a closure that accepts a needle and a
/// haystack and returns the starting position of the last occurrence of
/// needle in the haystack, or `None` if one doesn't exist.
fn run_search_tests_rev(
name: &str,
mut search: impl FnMut(&[u8], &[u8]) -> Option<usize>,
) {
for &(needle, haystack, _, expected_rev) in SEARCH_TESTS {
let (n, h) = (needle.as_bytes(), haystack.as_bytes());
assert_eq!(
expected_rev,
search(n, h),
"{}: needle: {:?}, haystack: {:?}, expected: {:?}",
name,
n,
h,
expected_rev
);
}
}
quickcheck! {
fn qc_twoway_fwd_prefix_is_substring(bs: Vec<u8>) -> bool {
prop_prefix_is_substring(false, &bs, |n, h| TwoWay::forward(n).find(h))
}
fn qc_twoway_fwd_suffix_is_substring(bs: Vec<u8>) -> bool {
prop_suffix_is_substring(false, &bs, |n, h| TwoWay::forward(n).find(h))
}
fn qc_twoway_rev_prefix_is_substring(bs: Vec<u8>) -> bool {
prop_prefix_is_substring(true, &bs, |n, h| TwoWay::reverse(n).rfind(h))
}
fn qc_twoway_rev_suffix_is_substring(bs: Vec<u8>) -> bool {
prop_suffix_is_substring(true, &bs, |n, h| TwoWay::reverse(n).rfind(h))
}
fn qc_twoway_fwd_matches_naive(
needle: Vec<u8>,
haystack: Vec<u8>
) -> bool {
prop_matches_naive(
false,
&needle,
&haystack,
|n, h| TwoWay::forward(n).find(h),
)
}
fn qc_twoway_rev_matches_naive(
needle: Vec<u8>,
haystack: Vec<u8>
) -> bool {
prop_matches_naive(
true,
&needle,
&haystack,
|n, h| TwoWay::reverse(n).rfind(h),
)
}
}
/// Check that every prefix of the given byte string is a substring.
fn prop_prefix_is_substring(
reverse: bool,
bs: &[u8],
mut search: impl FnMut(&[u8], &[u8]) -> Option<usize>,
) -> bool {
if bs.is_empty() {
return true;
}
for i in 0..(bs.len() - 1) {
let prefix = &bs[..i];
if reverse {
assert_eq!(naive_rfind(prefix, bs), search(prefix, bs));
} else {
assert_eq!(naive_find(prefix, bs), search(prefix, bs));
}
}
true
}
/// Check that every suffix of the given byte string is a substring.
fn prop_suffix_is_substring(
reverse: bool,
bs: &[u8],
mut search: impl FnMut(&[u8], &[u8]) -> Option<usize>,
) -> bool {
if bs.is_empty() {
return true;
}
for i in 0..(bs.len() - 1) {
let suffix = &bs[i..];
if reverse {
assert_eq!(naive_rfind(suffix, bs), search(suffix, bs));
} else {
assert_eq!(naive_find(suffix, bs), search(suffix, bs));
}
}
true
}
/// Check that naive substring search matches the result of the given search
/// algorithm.
fn prop_matches_naive(
reverse: bool,
needle: &[u8],
haystack: &[u8],
mut search: impl FnMut(&[u8], &[u8]) -> Option<usize>,
) -> bool {
if reverse {
naive_rfind(needle, haystack) == search(needle, haystack)
} else {
naive_find(needle, haystack) == search(needle, haystack)
}
}
/// Naively search forwards for the given needle in the given haystack.
fn naive_find(needle: &[u8], haystack: &[u8]) -> Option<usize> {
if needle.is_empty() {
return Some(0);
} else if haystack.len() < needle.len() {
return None;
}
for i in 0..(haystack.len() - needle.len() + 1) {
if needle == &haystack[i..i + needle.len()] {
return Some(i);
}
}
None
}
/// Naively search in reverse for the given needle in the given haystack.
fn naive_rfind(needle: &[u8], haystack: &[u8]) -> Option<usize> {
if needle.is_empty() {
return Some(haystack.len());
} else if haystack.len() < needle.len() {
return None;
}
for i in (0..(haystack.len() - needle.len() + 1)).rev() {
if needle == &haystack[i..i + needle.len()] {
return Some(i);
}
}
None
}
|
