From 1907dab5ee4e08bf11cbdec135a797b844cabf8f Mon Sep 17 00:00:00 2001
From: Ming-Hung Tsai <mtsai@redhat.com>
Date: Tue, 18 May 2021 17:11:21 +0800
Subject: [PATCH] [cache (rust)] Implement Pack and Default for restoration

---
 src/cache/hint.rs    | 17 +++++++++++++++++
 src/cache/mapping.rs | 18 ++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/cache/hint.rs b/src/cache/hint.rs
index b066645..7dcc709 100644
--- a/src/cache/hint.rs
+++ b/src/cache/hint.rs
@@ -1,3 +1,5 @@
+use anyhow::Result;
+use byteorder::WriteBytesExt;
 use nom::IResult;
 use std::convert::TryInto;
 
@@ -26,4 +28,19 @@ impl Unpack for Hint {
     }
 }
 
+impl Pack for Hint {
+    fn pack<W: WriteBytesExt>(&self, data: &mut W) -> Result<()> {
+        for v in &self.hint {
+            data.write_u8(*v)?;
+        }
+        Ok(())
+    }
+}
+
+impl Default for Hint {
+    fn default() -> Self {
+        Hint { hint: [0; 4] }
+    }
+}
+
 //------------------------------------------
diff --git a/src/cache/mapping.rs b/src/cache/mapping.rs
index ac5a036..eed1840 100644
--- a/src/cache/mapping.rs
+++ b/src/cache/mapping.rs
@@ -1,3 +1,5 @@
+use anyhow::Result;
+use byteorder::WriteBytesExt;
 use nom::number::complete::*;
 use nom::IResult;
 
@@ -51,4 +53,20 @@ impl Unpack for Mapping {
     }
 }
 
+impl Pack for Mapping {
+    fn pack<W: WriteBytesExt>(&self, data: &mut W) -> Result<()> {
+        let m: u64 = (self.oblock << 16) | self.flags as u64;
+        m.pack(data)
+    }
+}
+
+impl Default for Mapping {
+    fn default() -> Self {
+        Mapping {
+            oblock: 0,
+            flags: 0,
+        }
+    }
+}
+
 //------------------------------------------