From 8e831839feee2b16a51575026179ef1a60f239ad Mon Sep 17 00:00:00 2001
From: Brooks <brooks@anza.xyz>
Date: Fri, 11 Oct 2024 11:39:13 -0400
Subject: [PATCH] Displays LtHash's Checksum as base58 (#3142)

---
 Cargo.lock                  |  1 +
 lattice-hash/Cargo.toml     |  1 +
 lattice-hash/src/lt_hash.rs | 20 +++++++++++++++++---
 programs/sbf/Cargo.lock     |  1 +
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4b7d175c4e06ef..78438b2e9ea6a3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6874,6 +6874,7 @@ version = "2.1.0"
 dependencies = [
  "base64 0.22.1",
  "blake3",
+ "bs58",
  "bytemuck",
  "criterion",
  "rand 0.8.5",
diff --git a/lattice-hash/Cargo.toml b/lattice-hash/Cargo.toml
index 44d257091f642f..3fce6f0180fa01 100644
--- a/lattice-hash/Cargo.toml
+++ b/lattice-hash/Cargo.toml
@@ -10,6 +10,7 @@ edition = { workspace = true }
 [dependencies]
 base64 = { workspace = true }
 blake3 = { workspace = true }
+bs58 = { workspace = true }
 bytemuck = { workspace = true, features = ["must_cast"] }
 
 [dev-dependencies]
diff --git a/lattice-hash/src/lt_hash.rs b/lattice-hash/src/lt_hash.rs
index 100c9a10a6d53a..9cdfe555eb24ec 100644
--- a/lattice-hash/src/lt_hash.rs
+++ b/lattice-hash/src/lt_hash.rs
@@ -1,6 +1,6 @@
 use {
     base64::{display::Base64Display, prelude::BASE64_STANDARD},
-    std::fmt,
+    std::{fmt, str},
 };
 
 /// A 16-bit, 1024 element lattice-based incremental hash based on blake3
@@ -77,8 +77,14 @@ impl Checksum {
 
 impl fmt::Display for Checksum {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let base64 = Base64Display::new(&self.0, &BASE64_STANDARD);
-        write!(f, "{base64}")
+        /// Maximum string length of a base58 encoded Checksum.
+        const MAX_BASE58_LEN: usize = 44;
+        let mut buf = [0u8; MAX_BASE58_LEN];
+        // SAFETY: The only error is if the buffer is too small
+        let len = bs58::encode(&self.0).onto(buf.as_mut_slice()).unwrap();
+        // SAFETY: The base58 alphabet is utf8
+        let str = str::from_utf8(&buf[..len]).unwrap();
+        write!(f, "{str}")
     }
 }
 
@@ -377,4 +383,12 @@ mod tests {
             assert_eq!(actual_checksum, expected_checksum);
         }
     }
+
+    #[test]
+    fn test_checksum_display() {
+        let lt_hash = LtHash::identity();
+        let checksum = lt_hash.checksum();
+        let str = checksum.to_string();
+        assert_eq!(str.as_str(), "DoL6fvKuTpTQCyUh83NxQw2ewKzWYtq9gsTKp1eQiGC2");
+    }
 }
diff --git a/programs/sbf/Cargo.lock b/programs/sbf/Cargo.lock
index 617dce0e924299..6900b5ac87e17d 100644
--- a/programs/sbf/Cargo.lock
+++ b/programs/sbf/Cargo.lock
@@ -5427,6 +5427,7 @@ version = "2.1.0"
 dependencies = [
  "base64 0.22.1",
  "blake3",
+ "bs58",
  "bytemuck",
 ]