init ok

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "malloc-array"
 description = "libc heap array allocator"
-version = "1.1.1"
+version = "1.2.1"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2018"
 license = "GPL-3.0-or-later"

README.md

@@ -26,6 +26,39 @@ drop(array); // This is now safe.
 
  [replace_and_forget]: https://docs.rs/malloc-array/1.0.0/malloc_array/struct.HeapArray.html#method.replace_and_forget
  
+#### Alternatively initialising with iterator
+The library also provides the `InitIter` type, which is a mutable iterator for `HeapArray<T>` that allows you to safely initialise porentially uninitialised elements.
+
+``` rust
+let mut array = heap![String; 10];
+for mut init in array.initialise()
+{
+	init.set(format!("string!"));
+	// Also see docs for `init::Init` type.
+}
+drop(array); // This is now safe.
+```
+##### Filling the iterator
+The iterator also provides methods to fill itself of uninitialised values.
+
+###### Fill with `Clone`
+``` rust
+array.initialise().fill("value".to_owned());
+```
+###### Fill with lambda
+``` rust
+array.initialise().fill_with(|| "value".to_owned());
+```
+###### Fill with `Default`
+``` rust
+array.initialise().fill_default();
+```
+###### Uninitialise the memory
+Since it is unknown if the type `T` supports zero-initialisation, zeroing the memory is counted as making it uninitialised.
+``` rust
+array.initialise().uninit(); //Sets all the rest of the iterator bytes to 0.
+```
+
 ### Creating initialised arrays.
 These are created with `malloc()` and set with `replace_and_forget` (or, for the special case of `u8` sized types, `memset`).
 ``` rust
@@ -44,7 +77,7 @@ These are created with either `malloc(0)`, or if the `zst_noalloc` feature is en
 heap![];
 ```
 `zst_noalloc` is enabled by default and causes instances with `len_bytes() == 0` to have `NULL` internal pointers instead of dangling ones returned by `malloc(0)`.
-This behaviour my not be desireable and if it is not, disable the default featues.
+This behaviour may not be desireable and if it is not, disable the default featues.
 
 ### Dropping on free
 Arrays created this way are dropped in a way that ensures each element is also dropped. For anything implementing the `Copy` trait, this is redundant.

src/init.rs

@@ -3,12 +3,14 @@ use std::{
     marker::PhantomData,
 };
 
+/// Iterator for initialising potentially uninitialised `HeapArray<T>`.
 pub struct InitIter<'a, T>
 {
     from: &'a mut HeapArray<T>,
     current_idex: usize,
 }
 
+/// A safe wrapper to initialise potentially uninitialised data.
 pub struct Init<'a, T>
 {
     ptr: *mut T,
@@ -25,6 +27,17 @@ impl<'a, T> InitIter<'a, T>
 	    current_idex,
 	}
     }
+
+    /// Consumes the instance, zeroing all remaining bytes in the iterator.
+    pub fn uninit(self)
+    {
+	let len = self.from.len_bytes() - (self.current_idex * HeapArray::<T>::element_size());
+	if len > 0 {
+	    unsafe {
+		ptr::memset(self.from.as_mut_ptr().offset(self.current_idex as isize) as *mut u8, 0, len);
+	    }
+	}
+    }
 }
 
 impl<'a, T> Iterator for InitIter<'a, T>
@@ -48,16 +61,71 @@ impl<'a, T> Iterator for InitIter<'a, T>
     }
 }
 
+pub trait InitIterExt<T>
+{
+
+    /// Fill the rest of the iterator with a `clone()`d value.
+    fn fill(self, value: T) where T: Clone;
+
+    /// Fill the rest of the iterator with output from a function.
+    fn fill_with<F>(self, func: F) where F: FnMut() -> T;
+
+    /// Fill the rest of the iterator with `default()`
+    fn fill_default(self) where T: Default;
+}
+
+impl<'a, T,I> InitIterExt<T> for I
+where I: Iterator<Item=Init<'a, T>>,
+      T: 'a
+{
+    fn fill(self, value: T)
+    where T:Clone
+    {
+	for mut x in self
+	{
+	    if !x.is_init() {
+		x.put(value.clone());
+	    }
+	}
+    }
+    fn fill_with<F>(self, mut func: F)
+    where F: FnMut() -> T
+    {
+	for mut x in self
+	{
+	    if !x.is_init() {
+		x.put(func());
+	    }
+	}
+    }
+    fn fill_default(self)
+    where T:Default
+    {
+	for mut x in self
+	{
+	    if !x.is_init() {
+		x.put(Default::default());
+	    }
+	}
+    }
+}
+
 impl<'a, T> Init<'a, T>
 {
+
+    /// Has the value been set with `put()` or `assume_init()` yet?
     pub fn is_init(&self) -> bool
     {
 	self.init_ok
     }
+
+    /// Assume the value has been initialised.
     pub unsafe fn assume_init(&mut self)
     {
 	self.init_ok = true;
     }
+
+    /// Initialise or reset the value and then return a mutable reference to it.
     pub fn put(&mut self, value: T) -> &mut T
     {
 	if self.init_ok {
@@ -72,6 +140,8 @@ impl<'a, T> Init<'a, T>
 	    &mut (*self.ptr)
 	}
     }
+
+    /// Get a reference to the value if it has been initialised.
     pub fn get(&self) -> Option<&T>
     {
 	unsafe {
@@ -82,6 +152,8 @@ impl<'a, T> Init<'a, T>
 	    }
 	}
     }
+
+    /// Get a mutable reference to the value if it has been initialised.
     pub fn get_mut(&mut self) -> Option<&mut T>
     {
 	unsafe {

src/iter.rs

@@ -7,11 +7,15 @@ use std::{
     marker::{
 	Send,Sync,
     },
+    ops::{
+	Drop,
+    },
 };
 use ptr::{
     VoidPointer,
 };
 
+/// An iterator that consumes `HeapArray<T>` instance and ensures all memory is appropriately freed when consumed or dropped.
 pub struct IntoIter<T>
 {
     start: *mut T,
@@ -20,7 +24,7 @@ pub struct IntoIter<T>
 }
 
 unsafe impl<T: Send> Send for IntoIter<T>{}
-unsafe impl<T: Sync> Sync for IntoIter<T>{}
+unsafe impl<T: Sync> Sync for IntoIter<T>{} //this is probably fine right?
 
 impl<T> IntoIter<T>
 {
@@ -39,6 +43,31 @@ impl<T> IntoIter<T>
 	    self.start = ptr::null();
 	}
     }
+    fn drain_if_needed(&mut self)
+    {
+	if self.start != ptr::null() {
+
+	    unsafe {
+		if self.current_offset<self.sz {
+		    for i in self.current_offset..self.sz
+		    {
+			drop(ptr::take(self.start.offset(i as isize)));
+		    }
+		}
+
+		alloc::free(self.start as VoidPointer);
+	    }
+	    self.start = ptr::null();
+	}
+    }
+}
+
+impl<T> Drop for IntoIter<T>
+{
+    fn drop(&mut self)
+    {
+	self.drain_if_needed();
+    }
 }
 
 impl<T> Iterator for IntoIter<T>

src/lib.rs

@@ -75,6 +75,10 @@ mod tests {
 	{
 	    assert_eq!(&x[..6], "string");	    
 	}
+
+	let non = heap!["strings".to_owned(), "strings!!!".to_owned()];
+	let iter = non.into_iter();
+	drop(iter);
     }
     
     #[test]
@@ -117,11 +121,36 @@ mod tests {
 	{
 	    string.put("Hiya".to_owned());
 	}
-
+	assert_eq!(array.len(), 32);
 	for x in array.into_iter()
 	{
 	    assert_eq!(x, "Hiya");
 	}
+
+	let mut array = heap![String; 10];
+	array.initialise().fill("wowe".to_owned());
+	for x in array.into_iter()
+	{
+	    assert_eq!(x, "wowe");
+	}
+
+	
+
+	let mut array = heap![String; 10];
+	array.initialise().fill_with(|| "wow".to_owned());
+	for x in array.into_iter()
+	{
+	    assert_eq!(x, "wow");
+	}
+
+	
+
+	let mut array = heap![String; 10];
+	array.initialise().fill_default();
+	for x in array.into_iter()
+	{
+	    assert_eq!(x, "");
+	}
     }
 }
 
@@ -129,6 +158,7 @@ mod ptr;
 mod alloc;
 mod reinterpret;
 pub mod init;
+pub use init::InitIterExt;
 
 use std::{
     ops::{
@@ -270,7 +300,7 @@ impl<T> HeapArray<T>
 	std::mem::size_of::<T>() == 1
     }
 
-    
+    /// Create an iterator for safely setting potentially uninitialised values within the instance.
     pub fn initialise<'a>(&'a mut self) -> init::InitIter<'a, T>
     {
 	init::InitIter::new(self, 0)
@@ -441,7 +471,7 @@ impl<T> HeapArray<T>
 	self.free();
     }
 
-    /// Coerce of clone memory from a boxed slice.
+    /// Coerce or clone memory from a boxed slice.
     pub fn from_boxed_slice(bx: Box<[T]>) -> Self
     {
 	#[cfg(feature="assume_libc")]