sgx_trts/src/libc.rs

// Copyright (c) 2017 Baidu, Inc. All Rights Reserved.
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//! This mod provides the interface connecting Rust's memory management system
//! to the Intel's SGX SDK's malloc system.
//!
//! It is a c-style interface and self-explained. Currently we don't have much
//! time for documenting it.
use sgx_types::*;

#[link(name = "sgx_tstdc")]
extern {
    
    //pub fn memchr(s: * const c_void, c: c_int, n: size_t) -> *mut c_void;
    //pub fn memrchr(cx: *const c_void, c: c_int, n: size_t) -> *mut c_void;
    pub fn strlen(s: * const c_char) -> size_t;
    pub fn calloc(nobj: size_t, size: size_t) -> * mut c_void;
    pub fn malloc(size: size_t) -> * mut c_void;
    pub fn realloc(p: * mut c_void, size: size_t) -> * mut c_void;
    pub fn free(p: * mut c_void);
    pub fn posix_memalign(memptr: * mut * mut c_void, align: size_t, size: size_t) -> c_int;
}

pub unsafe fn memchr(s: * const u8, c: u8, n: usize) -> * const u8 {

    let mut ret = 0 as * const u8;
    let mut p = s;

    for _ in 0..n {
        if *p == c {
            ret = p;
            break;
        }
        p = p.offset(1);
    }
    ret
}

pub unsafe fn memrchr(s: * const u8, c: u8, n: usize) -> * const u8 {
 
    if n == 0 {return 0 as * const u8}
    
    let mut ret = 0 as * const u8;
    let mut p: * const u8 = (s as usize + (n - 1)) as * const u8;
    for _ in 0..n {
        if *p == c {
            ret = p;
            break;
        }
         p = p.offset(-1);
    }
    ret
}