From 94a562b37f6c737af3f6daab864216f1acdba222 Mon Sep 17 00:00:00 2001
From: grjte <grjte@protonmail.com>
Date: Thu, 7 Nov 2024 18:09:35 +0000
Subject: [PATCH] fix: add missing error messages to decode

---
 src/decoder.nr | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/decoder.nr b/src/decoder.nr
index cac31c7..dfc3792 100644
--- a/src/decoder.nr
+++ b/src/decoder.nr
@@ -581,10 +581,22 @@ impl Base64DecodeBE {
             );
             // enforce Base64 padding is valid
             if num_padding_chars == 2 {
-                assert(input[InputElements - 1] == BASE64_PADDING_CHAR);
-                assert(input[InputElements - 2] == BASE64_PADDING_CHAR);
+                let offset = InputElements - 1;
+                assert(
+                    input[offset] == BASE64_PADDING_CHAR,
+                    f"DecodeError: expected padding at offset {offset}.",
+                );
+                let offset = InputElements - 2;
+                assert(
+                    input[offset] == BASE64_PADDING_CHAR,
+                    f"DecodeError: expected padding at offset {offset}.",
+                );
             } else if num_padding_chars == 1 {
-                assert(input[InputElements - 1] == BASE64_PADDING_CHAR);
+                let offset = InputElements - 1;
+                assert(
+                    input[InputElements - 1] == BASE64_PADDING_CHAR,
+                    f"DecodeError: expected padding at offset {offset}.",
+                );
             }
         } else {
             let expected = encoded_length - num_padding_chars;