2020-06-16 21:19:26 +00:00
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use crate::{LvError, LvResult};
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use core::mem;
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use core::ops::{Deref, DerefMut};
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use core::ptr;
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use core::ptr::NonNull;
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/// Places `T` into LVGL memory.
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2020-06-17 06:38:35 +00:00
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pub struct Box<T>(NonNull<T>);
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2020-06-16 21:19:26 +00:00
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2020-06-17 06:38:35 +00:00
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impl<T> Box<T> {
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2020-06-16 21:19:26 +00:00
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pub fn new(inner: T) -> LvResult<Box<T>> {
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let layout = mem::size_of::<T>();
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let inner = unsafe {
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let ptr = lvgl_sys::lv_mem_alloc(layout as lvgl_sys::size_t) as *mut T;
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match NonNull::new(ptr) {
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Some(v) => {
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2020-06-17 06:38:35 +00:00
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// Move `T` to LVGL managed memory
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2020-06-16 21:19:26 +00:00
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ptr::write(ptr, inner);
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Ok(v)
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}
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None => Err(LvError::LvOOMemory),
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}
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};
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Ok(Box(inner?))
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}
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pub fn into_raw(b: Box<T>) -> *mut T {
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let b = mem::ManuallyDrop::new(b);
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b.0.as_ptr()
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}
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}
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2020-06-17 06:38:35 +00:00
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impl<T> Drop for Box<T> {
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2020-06-16 21:19:26 +00:00
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fn drop(&mut self) {
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unsafe {
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lvgl_sys::lv_mem_free(self.0.as_ptr() as *const cty::c_void);
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}
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}
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}
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2020-06-17 06:38:35 +00:00
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impl<T> Deref for Box<T> {
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2020-06-16 21:19:26 +00:00
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type Target = T;
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fn deref(&self) -> &T {
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unsafe { self.0.as_ref() }
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}
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}
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2020-06-17 06:38:35 +00:00
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impl<T> DerefMut for Box<T> {
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2020-06-16 21:19:26 +00:00
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fn deref_mut(&mut self) -> &mut T {
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unsafe { self.0.as_mut() }
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}
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}
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2020-06-17 06:38:35 +00:00
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impl<T> AsMut<T> for Box<T> {
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2020-06-16 21:19:26 +00:00
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fn as_mut(&mut self) -> &mut T {
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unsafe { self.0.as_mut() }
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn place_value_in_lv_mem() {
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unsafe {
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lvgl_sys::_lv_mem_init();
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};
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let v = Box::new(5).unwrap();
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drop(v);
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let v = Box::new(10).unwrap();
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drop(v);
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}
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#[test]
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fn place_complex_value_in_lv_mem() {
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unsafe {
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lvgl_sys::_lv_mem_init();
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};
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struct Point {
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x: u64,
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y: u64,
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disp: i32,
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}
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let p = Point {
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x: 32,
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y: 240,
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disp: -100,
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};
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let b = Box::new(p).unwrap();
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assert_eq!(b.x, 32);
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assert_eq!(b.y, 240);
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assert_eq!(b.disp, -100);
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}
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}
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