vyre 0.4.0

GPU compute intermediate representation with a standard operation library
Documentation 
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use super::prefix_table;
use crate::ops::string_matching::search_contract::{
    to_u32_offset, validate_search_inputs, MatchError, NOT_FOUND,
};

/// Return the first KMP match offset, or [`NOT_FOUND`] when absent.
///
/// # Errors
///
/// Returns `Fix: ...` when the haystack or needle exceeds the documented T47
/// size cap.
pub fn kmp_find(haystack: &[u8], needle: &[u8]) -> Result<u32, MatchError> {
    validate_search_inputs(haystack, needle)?;
    if needle.is_empty() {
        return Ok(0);
    }
    if needle.len() > haystack.len() {
        return Ok(NOT_FOUND);
    }
    let table = prefix_table(needle);
    let mut matched = 0usize;
    for (index, &byte) in haystack.iter().enumerate() {
        while matched > 0 && byte != needle[matched] {
            matched = table[matched - 1];
        }
        if byte == needle[matched] {
            matched += 1;
            if matched == needle.len() {
                return to_u32_offset(index + 1 - needle.len());
            }
        }
    }
    Ok(NOT_FOUND)
}