From cd0163da154367f5437ae1423bc97c450d74adf7 Mon Sep 17 00:00:00 2001
From: Chuyan Zhang <me@zcy.moe>
Date: Sat, 18 Nov 2023 02:15:11 -0800
Subject: I hate cache!

---
 src/cached_inode.rs | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'src/cached_inode.rs')

diff --git a/src/cached_inode.rs b/src/cached_inode.rs
index 814c1aa..a4e8202 100644
--- a/src/cached_inode.rs
+++ b/src/cached_inode.rs
@@ -1,3 +1,4 @@
+use crate::disk::data_block::{Block, DataBlock};
 use crate::disk::inode::Inode;
 
 pub struct CachedInode {
@@ -5,3 +6,28 @@ pub struct CachedInode {
     pub index: usize,
     pub dirty: bool,
 }
+
+#[derive(Clone)]
+pub struct CachedBlock<T: Block> {
+    pub block: T,
+    pub index: usize,
+    pub dirty: bool,
+}
+
+impl<T: Block> CachedBlock<T> {
+    fn cast<U: Block>(&self) -> CachedBlock<U> {
+        unsafe { std::mem::transmute_copy(&self) }
+    }
+}
+
+pub fn convert_mut<U: Block, T: Block>(input_block: &mut CachedBlock<U>) -> &mut CachedBlock<T> {
+    let ptr = input_block as *const CachedBlock<U> as *mut u8;
+    let block = ptr.cast::<CachedBlock<T>>();
+    unsafe { &mut *block }
+}
+
+pub fn convert<U: Block, T: Block>(input_block: &CachedBlock<U>) -> &CachedBlock<T> {
+    let ptr = input_block as *const CachedBlock<U> as *mut u8;
+    let block = ptr.cast::<CachedBlock<T>>();
+    unsafe { &*block }
+}
-- 
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