From 0d061dac9e31831e4fe426a0df777463043868d7 Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Fri, 19 Aug 2022 20:20:16 -0700 Subject: Generic Allocation Scheme --- src/alloc.rs | 160 ++++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 110 insertions(+), 50 deletions(-) (limited to 'src/alloc.rs') diff --git a/src/alloc.rs b/src/alloc.rs index fd22c67..9b77f13 100644 --- a/src/alloc.rs +++ b/src/alloc.rs @@ -1,93 +1,153 @@ +//! # Allocate + +/// # Initialize Queue +/// - Name: Symbol name +/// - Size: Number of elements +/// - Default: Default value +/// - Type: Data Type +macro_rules! init_queue { + ($name:tt,$size:tt,$default:tt,$type:ty) => { + #[link_section = ".data.alloc"] + pub static $name: QueueAllocator<'static, $type, {$size+2}> = QueueAllocator::<$type, {$size+2}>{inner: NullLock::new([QueueItem{data: $default, next: None}; {$size+2}])}; + } +} + use crate::sync::NullLock; use crate::sync::interface::Mutex; - -const CHAR_COUNT: usize = 20; -const CHAR_POOL_SIZE: usize = CHAR_COUNT + 2; +use core::fmt::{Debug,Formatter,Result}; #[derive(Copy,Clone)] -pub struct CharCell { - pub data: char, - next: Option<*mut CharCell>, +/// # Queue Item +/// +/// Encapsulates a data element and a pointer to +/// the next `Queue` item +pub struct QueueItem<'a, T: Sized> { + /// # Data + /// + /// The encapsulated data + data: T, + /// # Pointer to the next item + /// + /// Stores either `None` or points + /// to the next item. + next: Option<*mut QueueItem<'a, T>>, } - -impl CharCell { - pub const fn new() -> Self { - Self { - data: '\0', - next: None, - } +impl QueueItem<'_,T> { + /// # Get the inner data + /// + /// Returns a borrow of the underlying data. + pub fn inner(&mut self) -> &mut T { + &mut self.data } } +/// # Sharing Thread Safety for QueueItem +unsafe impl Send for QueueItem<'_,T> {} -use core::fmt::{Debug,Formatter,Result}; -impl Debug for CharCell { +impl Debug for QueueItem<'_,T> { + /// # Debug formatter for `QueueItem` + /// + /// Output the encapsulated data fn fmt(&self, f: &mut Formatter<'_>) -> Result { - write!(f, "{}", self.data) + write!(f, "{:?}", self.data) } } -unsafe impl Send for CharCell {} - -pub struct CharAllocator(NullLock<[CharCell; CHAR_POOL_SIZE]>); - -impl CharAllocator { - pub const fn new() -> Self { - Self(NullLock::new([CharCell::new(); CHAR_POOL_SIZE])) - } +/// # Queue Allocator +/// +/// Structure to store a pool of allocated data structures. +pub struct QueueAllocator<'a, T: Sized, const COUNT: usize> { + /// # Synchronized Pool of items + /// + /// Stores synchronization wrapper around the data pool + pub inner: NullLock<[QueueItem<'a, T>;COUNT]>, +} +/// # Sharing Thread Safety for QueueAllocator +unsafe impl Send for QueueAllocator<'_,T,COUNT> {} +impl<'a, T: Sized,const COUNT: usize> QueueAllocator<'a, T, COUNT> { + /// # Initialization of Fixed-Size Pool + /// + /// Establishes the header and footer of the queue + /// as the first and second elements respectively. + /// All of the internal elements point to the next + /// one and the final element points to `None` pub fn init(&self) { - self.0.lock(|char_pool| { - for idx in 2..CHAR_POOL_SIZE { - if idx != CHAR_POOL_SIZE - 1 { - char_pool[idx].next = Some(&mut char_pool[idx+1] as *mut CharCell); + self.inner.lock(|queue| { + for idx in 2..queue.len() { + if idx != queue.len()-1 { + queue[idx].next = Some(&mut queue[idx+1] as *mut QueueItem<'_, T>); } else { - char_pool[idx].next = None; + queue[idx].next = None; } } - char_pool[0].next = Some(&mut char_pool[2] as *mut CharCell); - char_pool[1].next = Some(&mut char_pool[CHAR_POOL_SIZE-1] as *mut CharCell); + queue[0].next = Some(&mut queue[2] as *mut QueueItem<'_, T>); + queue[1].next = Some(&mut queue[queue.len()-1] as *mut QueueItem<'_, T>); }); } - pub fn alloc(&self) -> Option<&mut CharCell> { - return self.0.lock(|char_pool| { - if let Some(char_cell) = char_pool[0].next { - char_pool[0].next = unsafe{(*char_cell).next}; + /// # Allocate Data + /// + /// If there is a data chunk available, + /// return it, otherwise return `None` + #[allow(dead_code)] + pub fn alloc(&self) -> Option<&mut QueueItem<'a,T>> { + return self.inner.lock(|pool| { + if let Some(entry) = pool[0].next { + pool[0].next = unsafe { (*entry).next }; unsafe { - (*char_cell).next = None; + (*entry).next = None; } - return Some(unsafe{&mut *char_cell as &mut CharCell}); + match pool[0].next { + None => { + pool[1].next = None + } + _ => {} + } + return Some(unsafe{&mut *entry as &mut QueueItem<'a,T>}); } else { return None; } }); } - pub fn free(&self, cell: &mut CharCell) { - self.0.lock(|char_pool| { - cell.next = None; - match char_pool[1].next { + /// # Free + /// + /// Add the item to the end of the queue. + /// If there were no items, set it as the head. + #[allow(dead_code)] + pub fn free(&self, freed_item: &mut QueueItem<'a,T>) { + self.inner.lock(|pool| { + freed_item.next = None; + match pool[1].next { None => { - char_pool[0].next = Some(cell as *mut CharCell); + pool[0].next = Some(freed_item as *mut QueueItem<'a,T>); } - Some(ocell) => { + Some(entry) => { unsafe { - (*ocell).next = Some(cell as *mut CharCell); + if (entry as u32) == (freed_item as *mut QueueItem<'a,T> as u32) { + (*entry).next = Some(freed_item as *mut QueueItem<'a,T>); + } } } } - char_pool[1].next = Some(cell as *mut CharCell); + pool[1].next = Some(freed_item as *mut QueueItem<'a,T>); }); } } -impl Debug for CharAllocator { +impl Debug for QueueAllocator<'_,T,COUNT> { + /// # Debug Formatted Output + /// + /// Output each data point in the array with + /// its debug formatter. fn fmt(&self, f: &mut Formatter<'_>) -> Result { - self.0.lock(|pool| { - write!(f, "{:?}", pool) + self.inner.lock(|queue| { + write!(f, "{:?}", queue) }) } } -#[link_section = ".data.alloc"] -pub static CHAR_ALLOCATOR: CharAllocator = CharAllocator::new(); +/// Number of U64s to hand out +const U64_POOL_SIZE: usize = 2; + +init_queue!(U64_QUEUE_ALLOCATOR, U64_POOL_SIZE, 0, u64); -- cgit v1.2.1