From c9f55a4c5d3c9a340efc759921d27f2cad3a3916 Mon Sep 17 00:00:00 2001
From: Marek <mail@marek.onl>
Date: Tue, 4 Apr 2023 18:38:28 +0200
Subject: [PATCH] Use `u64` instead of `usize` for `byte_count`

---
 zcash_proofs/src/hashreader.rs | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/zcash_proofs/src/hashreader.rs b/zcash_proofs/src/hashreader.rs
index 47fbc648e..553cdd965 100644
--- a/zcash_proofs/src/hashreader.rs
+++ b/zcash_proofs/src/hashreader.rs
@@ -11,7 +11,7 @@ use blake2b_simd::State;
 pub struct HashReader<R: Read> {
     reader: R,
     hasher: State,
-    byte_count: usize,
+    byte_count: u64,
 }
 
 impl<R: Read> HashReader<R> {
@@ -37,7 +37,7 @@ impl<R: Read> HashReader<R> {
     }
 
     /// Return the number of bytes read so far.
-    pub fn byte_count(&self) -> usize {
+    pub fn byte_count(&self) -> u64 {
         self.byte_count
     }
 }
@@ -48,7 +48,13 @@ impl<R: Read> Read for HashReader<R> {
 
         if bytes > 0 {
             self.hasher.update(&buf[0..bytes]);
-            self.byte_count += bytes;
+            let byte_count = u64::try_from(bytes).map_err(|_| {
+                io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "Could not fit the number of read bytes into u64.",
+                )
+            })?;
+            self.byte_count += byte_count;
         }
 
         Ok(bytes)