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extern crate std;
use self::std::io::Error as IoError;
use stack::{Stack, GuardedStack};
mod sys;
#[derive(Debug)]
pub struct OsStack {
ptr: *mut u8,
len: usize,
}
unsafe impl Send for OsStack {}
impl OsStack {
pub fn new(size: usize) -> Result<OsStack, IoError> {
let page_size = sys::page_size();
let len = if size == 0 { page_size } else { size };
let len = (len + page_size - 1) & !(page_size - 1);
let len = len + page_size;
let ptr = try!(unsafe { sys::map_stack(len) });
let stack = OsStack {
ptr: ptr,
len: len,
};
try!(unsafe { sys::protect_stack(stack.ptr) });
Ok(stack)
}
}
unsafe impl Stack for OsStack {
#[inline(always)]
fn base(&self) -> *mut u8 {
unsafe {
self.ptr.offset(self.len as isize)
}
}
#[inline(always)]
fn limit(&self) -> *mut u8 {
unsafe {
self.ptr.offset(sys::page_size() as isize)
}
}
}
unsafe impl GuardedStack for OsStack {}
impl Drop for OsStack {
fn drop(&mut self) {
unsafe { sys::unmap_stack(self.ptr, self.len) }.expect("cannot unmap stack")
}
}