perf: use alloc instead of realloc

1 files changed, 33 insertions, 22 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 31e8810..175eef9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,5 @@
 #![deny(clippy::all, clippy::pedantic)]
-use std::alloc::{alloc, dealloc, handle_alloc_error, realloc, Layout};
+use std::alloc::{alloc, dealloc, handle_alloc_error, Layout};
 use std::any::{Any, TypeId};
 use std::cmp::max;
 use std::mem::MaybeUninit;
@@ -320,30 +320,32 @@ impl MultiVec
         let Some(new_ptr) = NonNull::new(if layout.size() == 0 {
             std::ptr::dangling_mut()
         } else {
-            unsafe { realloc(self.ptr.as_ptr().cast::<u8>(), *layout, new_layout.size()) }
+            unsafe { alloc(new_layout) }
         }) else {
             handle_alloc_error(new_layout);
         };
 
-        for (field_index, field) in fields.as_ref().iter().enumerate().rev() {
-            let old_field_arr_byte_offset = self.field_arr_byte_offsets[field_index];
-            let new_field_arr_byte_offset = new_field_arr_byte_offsets[field_index];
+        for field_index in 0..self.field_cnt() {
+            let field_slice = self.get_field_slice(field_index);
 
-            let old_field_arr_ptr =
-                unsafe { new_ptr.byte_add(old_field_arr_byte_offset) };
-
-            let new_field_arr_ptr =
-                unsafe { new_ptr.byte_add(new_field_arr_byte_offset) };
+            let new_byte_offset = new_field_arr_byte_offsets[field_index];
 
             unsafe {
-                std::ptr::copy(
-                    old_field_arr_ptr.as_ptr(),
-                    new_field_arr_ptr.as_ptr(),
-                    field.size() * self.capacity,
+                std::ptr::copy_nonoverlapping(
+                    field_slice.bytes.as_ptr(),
+                    new_ptr
+                        .byte_add(new_byte_offset)
+                        .cast::<MaybeUninit<u8>>()
+                        .as_ptr(),
+                    field_slice.bytes.len(),
                 );
             }
         }
 
+        unsafe {
+            self.dealloc();
+        }
+
         self.ptr = new_ptr.cast::<MaybeUninit<u8>>();
         self.layout = Some(new_layout);
         self.capacity = new_capacity;
@@ -419,6 +421,21 @@ impl MultiVec
             }
         }
     }
+
+    unsafe fn dealloc(&mut self)
+    {
+        let Some(layout) = self.layout else {
+            return;
+        };
+
+        if layout.size() == 0 {
+            return;
+        }
+
+        unsafe {
+            std::alloc::dealloc(self.ptr.as_ptr().cast::<u8>(), layout);
+        }
+    }
 }
 
 //impl<ItemT> FromIterator<ItemT> for MultiVec<ItemT>
@@ -474,14 +491,8 @@ impl Drop for MultiVec
             }
         }
 
-        if let Some(layout) = self.layout {
-            if layout.size() == 0 {
-                return;
-            }
-
-            unsafe {
-                std::alloc::dealloc(self.ptr.as_ptr().cast::<u8>(), layout);
-            }
+        unsafe {
+            self.dealloc();
         }
     }
 }