From e5a4114262731a720d17179a20469f05372ce2a5 Mon Sep 17 00:00:00 2001
From: Philipp Oppermann <dev@phil-opp.com>
Date: Wed, 9 Dec 2015 00:12:55 +0100
Subject: [PATCH] Add unsafe next_table methods

---
 src/memory/paging/table.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/memory/paging/table.rs b/src/memory/paging/table.rs
index 41d92742..4ede5f9e 100644
--- a/src/memory/paging/table.rs
+++ b/src/memory/paging/table.rs
@@ -14,6 +14,26 @@ impl Table {
             entry.set_unused();
         }
     }
+
+    fn next_table_address(&self, index: usize) -> Option<usize> {
+        let entry_flags = self[index].flags();
+        if entry_flags.contains(PRESENT) && !entry_flags.contains(HUGE_PAGE) {
+            let table_address = self as *const _ as usize;
+            Some((table_address << 9) | (index << 12))
+        } else {
+            None
+        }
+    }
+
+    pub unsafe fn next_table(&self, index: usize) -> Option<&Table> {
+        self.next_table_address(index)
+            .map(|t| unsafe { &*(t as *const _) })
+    }
+
+    pub unsafe fn next_table_mut(&mut self, index: usize) -> Option<&mut Table> {
+        self.next_table_address(index)
+            .map(|t| unsafe { &mut *(t as *mut _) })
+    }
 }
 
 impl Index<usize> for Table {