| // This module defines safe wrappers around memchr (POSIX) and memrchr (GNU |
| // extension). |
| |
| #![allow(dead_code)] |
| |
| extern crate libc; |
| |
| use self::libc::{c_int, c_void, size_t}; |
| |
| pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> { |
| let p = unsafe { |
| libc::memchr( |
| haystack.as_ptr() as *const c_void, |
| needle as c_int, |
| haystack.len() as size_t, |
| ) |
| }; |
| if p.is_null() { |
| None |
| } else { |
| Some(p as usize - (haystack.as_ptr() as usize)) |
| } |
| } |
| |
| // memrchr is a GNU extension. We know it's available on Linux, so start there. |
| #[cfg(target_os = "linux")] |
| pub fn memrchr(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() as *const c_void, |
| needle as c_int, |
| haystack.len() as size_t, |
| ) |
| }; |
| if p.is_null() { |
| None |
| } else { |
| Some(p as usize - (haystack.as_ptr() as usize)) |
| } |
| } |