Function find

rust/stringzilla.rs:1337–1355

Locates the first matching substring within `haystack` that equals `needle`. This function is similar to the `memmem()` function in LibC, but, unlike `strstr()`, it requires the length of both haystack and needle to be known beforehand. # Arguments `haystack`: The byte slice to search. `needle`: The byte slice to find within the haystack. # Returns An `Option ` representing the starting

(haystack: H, needle: N)

/// An `Option<usize>` representing the starting index of the first occurrence of `needle`
/// within `haystack` if found, otherwise `None`.
pub fn find<H, N>(haystack: H, needle: N) -> Option<usize>
where
    H: AsRef<[u8]>,
    N: AsRef<[u8]>,
{
    let haystack_ref = haystack.as_ref();
    let needle_ref = needle.as_ref();
    let haystack_pointer = haystack_ref.as_ptr() as _;
    let haystack_length = haystack_ref.len();
    let needle_pointer = needle_ref.as_ptr() as _;
    let needle_length = needle_ref.len();
    let result = unsafe { sz_find(haystack_pointer, haystack_length, needle_pointer, needle_length) };

    if result.is_null() {
        None
    } else {
        Some(unsafe { result.offset_from(haystack_pointer) }.try_into().unwrap())
    }
}

/// Locates the last matching substring within `haystack` that equals `needle`.
/// This function is useful for finding the most recent or last occurrence of a pattern