sgx_trts/src/memchr.rs

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/// A safe interface to `memchr`.
///
/// Returns the index corresponding to the first occurrence of `needle` in
/// `haystack`, or `None` if one is not found.
///
// #[inline]
// pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {
//     ::sys::memchr::memchr(needle, haystack)
// }

/// A safe interface to `memrchr`.
///
/// Returns the index corresponding to the last occurrence of `needle` in
/// `haystack`, or `None` if one is not found.
///
// #[inline]
// pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {
//     ::sys::memchr::memrchr(needle, haystack)
// }

use libc;

pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> {

    let p = unsafe {
        libc::memchr(
            haystack.as_ptr(),
            needle,
            haystack.len())
    };
    if p.is_null() {
        None
    } else {
        Some(p as usize - (haystack.as_ptr() as usize))
    }
}

pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> {

    fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {

        // GNU's memrchr() will - unlike memchr() - error if haystack is empty.
        if haystack.is_empty() {return None}
        let p = unsafe {
            libc::memrchr(
                haystack.as_ptr(),
                needle,
                haystack.len())
        };
        if p.is_null() {
            None
        } else {
            Some(p as usize - (haystack.as_ptr() as usize))
        }
    }

    memrchr_specific(needle, haystack)
}