[fix] Possible overflow when allocating contiguous physical memory in bitmap-allocator (#10)

When `align_log2 >= 64` , the values of `1 << align_log2` and `base` will always be equal to 0, causing the while loop not to terminate and the program to panic.

Author: LiuJun5817

src/lib.rs

@@ -313,7 +313,7 @@ fn find_contiguous(
     size: usize,
     align_log2: usize,
 ) -> Option<usize> {
-    if capacity < (1 << align_log2) || ba.is_empty() {
+    if align_log2 >= 64 || capacity < (1 << align_log2) || ba.is_empty() {
         return None;
     }
 
@@ -356,7 +356,7 @@ fn check_contiguous(
     size: usize,
     align_log2: usize,
 ) -> bool {
-    if capacity < (1 << align_log2) || ba.is_empty() {
+    if align_log2 >= 64 || capacity < (1 << align_log2) || ba.is_empty() {
         return false;
     }