memchr.rs.html -- source
Description: Source to the Rust file `libstd/sys/unix/memchr.rs`.
Keywords: rust, rustlang, rust-lang

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    // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
    // file at the top-level directory of this distribution and at
    // http://rust-lang.org/COPYRIGHT.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.
    //
    // Original implementation taken from rust-memchr
    // Copyright 2015 Andrew Gallant, bluss and Nicolas Koch

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

        let p = unsafe {
            libc::memchr(
                haystack.as_ptr() as *const libc::c_void,
                needle as libc::c_int,
                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> {

        #[cfg(target_os = "linux")]
        fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
            use libc;

            // 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() as *const libc::c_void,
                    needle as libc::c_int,
                    haystack.len())
            };
            if p.is_null() {
                None
            } else {
                Some(p as usize - (haystack.as_ptr() as usize))
            }
        }

        #[cfg(not(target_os = "linux"))]
        fn memrchr_specific(needle: u8, haystack: &[u8]) -> Option<usize> {
            ::core::slice::memchr::memrchr(needle, haystack)
        }

        memrchr_specific(needle, haystack)
    }

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