From eae4ac41104efa7d04ac0b9874a40f0d4826033b Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Tue, 14 Sep 2021 20:45:47 +0100
Subject: [PATCH] `impl memuse::DynamicUsage for Amount`

Required to use `DynamicUsage` with `orchard::Bundle<_, Amount>`.
---
 zcash_primitives/CHANGELOG.md                        |  2 ++
 zcash_primitives/Cargo.toml                          |  1 +
 .../src/transaction/components/amount.rs             | 12 ++++++++++++
 3 files changed, 15 insertions(+)

diff --git a/zcash_primitives/CHANGELOG.md b/zcash_primitives/CHANGELOG.md
index 8a1306968..bc0d56e7d 100644
--- a/zcash_primitives/CHANGELOG.md
+++ b/zcash_primitives/CHANGELOG.md
@@ -51,6 +51,8 @@ and this library adheres to Rust's notion of
     data, as described above.
 - `zcash_primitives::serialize` has been factored out as a new `zcash_encoding`
   crate, which can be found in the `components` directory.
+- `zcash_primitives::transaction::components::Amount` now implements
+  `memuse::DynamicUsage`, to enable `orchard::Bundle<_, Amount>::dynamic_usage`.
 
 ### Changed
 - MSRV is now 1.51.0.
diff --git a/zcash_primitives/Cargo.toml b/zcash_primitives/Cargo.toml
index 00cfc6271..bafb6f900 100644
--- a/zcash_primitives/Cargo.toml
+++ b/zcash_primitives/Cargo.toml
@@ -33,6 +33,7 @@ incrementalmerkletree = "0.1"
 jubjub = "0.8"
 lazy_static = "1"
 log = "0.4"
+memuse = "0.2"
 nonempty = "0.7"
 orchard = "0.0"
 pasta_curves = "0.2"
diff --git a/zcash_primitives/src/transaction/components/amount.rs b/zcash_primitives/src/transaction/components/amount.rs
index 601d29132..4b20a1cb1 100644
--- a/zcash_primitives/src/transaction/components/amount.rs
+++ b/zcash_primitives/src/transaction/components/amount.rs
@@ -23,6 +23,18 @@ pub const DEFAULT_FEE: Amount = Amount(1000);
 #[derive(Clone, Copy, Debug, PartialEq, PartialOrd, Eq, Ord)]
 pub struct Amount(i64);
 
+impl memuse::DynamicUsage for Amount {
+    #[inline(always)]
+    fn dynamic_usage(&self) -> usize {
+        0
+    }
+
+    #[inline(always)]
+    fn dynamic_usage_bounds(&self) -> (usize, Option<usize>) {
+        (0, Some(0))
+    }
+}
+
 impl Amount {
     /// Returns a zero-valued Amount.
     pub const fn zero() -> Self {