fix: add a dedicated function to get to the base of the buffer #141

Author: cdellacqua

src/ringbuffer_trait.rs

@@ -498,7 +498,7 @@ macro_rules! impl_ringbuffer {
 /// Implement various functions on implementors of [`RingBuffer`].
 /// This is to avoid duplicate code.
 macro_rules! impl_ringbuffer_ext {
-    ($get_unchecked: ident, $get_unchecked_mut: ident, $readptr: ident, $writeptr: ident, $mask: expr) => {
+    ($get_base_ptr: ident, $get_base_mut_ptr: ident, $get_unchecked: ident, $get_unchecked_mut: ident, $readptr: ident, $writeptr: ident, $mask: expr) => {
         #[inline]
         fn get_signed(&self, index: isize) -> Option<&T> {
             use core::ops::Not;
@@ -597,7 +597,7 @@ macro_rules! impl_ringbuffer_ext {
                 return;
             }
 
-            let base: *const T = $get_unchecked(rb, 0);
+            let base: *const T = $get_base_ptr(rb);
             let size = Self::ptr_buffer_size(rb);
             let offset_readptr = (*rb).$readptr + offset;
 
@@ -640,7 +640,7 @@ macro_rules! impl_ringbuffer_ext {
                 return;
             }
 
-            let base: *mut T = $get_unchecked_mut(rb, 0);
+            let base: *mut T = $get_base_mut_ptr(rb);
             let size = Self::ptr_buffer_size(rb);
             let offset_readptr = (*rb).$readptr + offset;
 

src/with_alloc/alloc_ringbuffer.rs

@@ -274,6 +274,8 @@ unsafe impl<T> RingBuffer<T> for AllocRingBuffer<T> {
     }
 
     impl_ringbuffer_ext!(
+        get_base_ptr,
+        get_base_mut_ptr,
         get_unchecked,
         get_unchecked_mut,
         readptr,
@@ -332,6 +334,16 @@ impl<T> AllocRingBuffer<T> {
     }
 }
 
+/// Get a const pointer to the buffer
+unsafe fn get_base_ptr<T>(rb: *const AllocRingBuffer<T>) -> *const T {
+    (*rb).buf.cast()
+}
+
+/// Get a mut pointer to the buffer
+unsafe fn get_base_mut_ptr<T>(rb: *mut AllocRingBuffer<T>) -> *mut T {
+    (*rb).buf
+}
+
 /// Get a reference from the buffer without checking it is initialized.
 ///
 /// Caller must be sure the index is in bounds, or this will panic.

src/with_const_generics.rs

@@ -189,6 +189,16 @@ impl<T, const CAP: usize> ConstGenericRingBuffer<T, CAP> {
     }
 }
 
+/// Get a const pointer to the buffer
+unsafe fn get_base_ptr<T, const N: usize>(rb: *const ConstGenericRingBuffer<T, N>) -> *const T {
+    (*rb).buf.as_ptr().cast()
+}
+
+/// Get a mut pointer to the buffer
+unsafe fn get_base_mut_ptr<T, const N: usize>(rb: *mut ConstGenericRingBuffer<T, N>) -> *mut T {
+    (*rb).buf.as_mut_ptr().cast()
+}
+
 /// Get a reference from the buffer without checking it is initialized
 /// Caller MUST be sure this index is initialized, or undefined behavior will happen
 unsafe fn get_unchecked<'a, T, const N: usize>(
@@ -305,6 +315,8 @@ unsafe impl<T, const CAP: usize> RingBuffer<T> for ConstGenericRingBuffer<T, CAP
     }
 
     impl_ringbuffer_ext!(
+        get_base_ptr,
+        get_base_mut_ptr,
         get_unchecked,
         get_unchecked_mut,
         readptr,