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/// Memcpy
///
/// Copy N bytes of memory from one location to another.
#[no_mangle]
pub unsafe extern fn memcpy(dest: *mut u8, src: *const u8,
n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
i += 1;
}
dest
}
/// Memmove
///
/// Copy N bytes of memory from src to dest. The memory areas may overlap.
#[no_mangle]
pub unsafe extern fn memmove(dest: *mut u8, src: *const u8,
n: usize) -> *mut u8 {
if src < dest as *const u8 {
let mut i = n;
while i != 0 {
i -= 1;
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
}
} else {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = *((src as usize + i) as *const u8);
i += 1;
}
}
dest
}
/// Memset
///
/// Fill a block of memory with a specified value.
#[no_mangle]
pub unsafe extern fn memset(dest: *mut u8, c: i32, n: usize) -> *mut u8 {
let mut i = 0;
while i < n {
*((dest as usize + i) as *mut u8) = c as u8;
i += 1;
}
dest
}
/// Memcmp
///
/// Compare two blocks of memory.
#[no_mangle]
pub unsafe extern fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32 {
let mut i = 0;
while i < n {
let a = *((s1 as usize + i) as *const u8);
let b = *((s2 as usize + i) as *const u8);
if a != b {
return a as i32 - b as i32
}
i += 1;
}
0
}