From 3559291e555fffdbf2a890ca1db3cb790c2f6b9e Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Sun, 21 Aug 2022 18:38:47 -0700 Subject: Move queue structure to its own module --- src/util/fifo_queue.rs | 183 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 src/util/fifo_queue.rs (limited to 'src/util/fifo_queue.rs') diff --git a/src/util/fifo_queue.rs b/src/util/fifo_queue.rs new file mode 100644 index 0000000..7ec939b --- /dev/null +++ b/src/util/fifo_queue.rs @@ -0,0 +1,183 @@ +use crate::sync::NullLock; +use crate::sync::interface::Mutex; +use crate::vprintln; +use core::fmt; +use core::fmt::{Debug,Formatter}; + +/// # Initialize Queue +/// - Name: Symbol name +/// - Size: Number of elements +/// - Default: Default value +/// - Type: Data Type +#[macro_export] +macro_rules! init_queue { + ($name:tt,$size:tt,$default:tt,$type:ty) => { + init_queue!{@gen [$name,$size,$default,$type,concat!("# ", stringify!($type), " Queue Allocator")]} + }; + (@gen [$name:tt,$size:tt,$default:tt,$type:ty,$doc:expr]) => { + #[doc = $doc] + #[link_section = ".data.alloc"] + pub static $name: QueueAllocator<'static, $type, {$size+2}> = QueueAllocator::<$type, {$size+2}>{inner: NullLock::new([QueueItem::new($default); {$size+2}])}; + }; +} + +#[derive(Copy,Clone)] +/// # 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 QueueItem<'_,T> { + /// # Constructor + pub const fn new(data: T) -> Self { + Self { + data: data, + next: None, + } + } + /// # Get the inner data + /// + /// Returns a borrow of the underlying data. + pub fn inner(&mut self) -> &mut T { + &mut self.data + } + /// # Get pointer to inner data + pub fn ptr(&mut self) -> *mut u8 { + self.inner() as *mut T as *mut u8 + } +} + +/// # Sharing Thread Safety for QueueItem +unsafe impl Send for QueueItem<'_,T> {} + +impl Debug for QueueItem<'_,T> { + /// # Debug formatter for `QueueItem` + /// + /// Output the encapsulated data + fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { + #[cfg(feature="verbose")] + return write!(f, "{:?} {:x} {:?}", self.data, self as *const QueueItem<'_,T> as usize, self.next); + + #[cfg(not(feature="verbose"))] + return write!(f, "{:?}", self.data); + } +} + +/// # 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) { + vprintln!("QA: Initializing Queue Allocator!"); + self.inner.lock(|queue| { + vprintln!("QA: Clearing internal references..."); + for idx in 2..COUNT { + if idx != COUNT-1 { + queue[idx].next = Some(&mut queue[idx+1] as *mut QueueItem<'a, T>); + } else { + queue[idx].next = None; + } + } + vprintln!("QA: Initializing head and tail..."); + queue[0].next = Some(&mut queue[2] as *mut QueueItem<'a, T>); + queue[1].next = Some(&mut queue[COUNT-1] as *mut QueueItem<'a, T>); + }); + vprintln!("QA: Initialized Queue Allocator!"); + } + + /// # 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>> { + vprintln!("QA: Allocating chunk!"); + return self.inner.lock(|pool| { + if let Some(entry) = pool[0].next { + vprintln!("QA: Found chunk!"); + pool[0].next = unsafe { (*entry).next }; + unsafe { + (*entry).next = None; + } + match pool[0].next { + None => { + pool[1].next = None + } + _ => {} + } + vprintln!("QA: \x1b[92mAllocated {:x}\x1b[0m", unsafe{(*entry).ptr() as usize}); + return Some(unsafe{&mut *entry as &mut QueueItem<'a,T>}); + } else { + vprintln!("QA: No chunks available!"); + return None; + } + }); + } + + /// # 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>) { + vprintln!("QA: Deallocating chunk!"); + self.inner.lock(|pool| { + freed_item.next = None; + match pool[1].next { + None => { + pool[0].next = Some(freed_item as *mut QueueItem<'a,T>); + } + Some(entry) => { + unsafe { + (*entry).next = Some(freed_item as *mut QueueItem<'a,T>); + } + } + } + pool[1].next = Some(freed_item as *mut QueueItem<'a,T>); + vprintln!("QA: \x1b[91mDeallocated {:x}\x1b[0m", freed_item.ptr() as usize); + }); + } +} + +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<'_>) -> fmt::Result { + self.inner.lock(|queue| { + #[cfg(feature="verbose")] + return write!(f, "{:?}", queue); + + #[cfg(not(feature="verbose"))] + return write!(f, "{:?}", queue); + }) + } +} -- cgit v1.2.1