From 262c7decfe2dafe88cf21c792c523b381064bced Mon Sep 17 00:00:00 2001
From: Kristofers Solo <dev@kristofers.xyz>
Date: Thu, 6 Nov 2025 11:03:29 +0200
Subject: [PATCH] fix(des): 64 bit block creation

---
 des/src/block/block64.rs | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/des/src/block/block64.rs b/des/src/block/block64.rs
index 23482c6..0744cad 100644
--- a/des/src/block/block64.rs
+++ b/des/src/block/block64.rs
@@ -74,11 +74,6 @@ fn parse_string_to_u64(s: &str) -> Result<u64, BlockError> {
         return parse_radix(bin_str, 2);
     }
 
-    // 8-character ASCII string conversion to u64
-    if trimmed.len() > 8 {
-        return Err(BlockError::InvalidByteStringLength(trimmed.len()));
-    }
-
     ascii_string_to_u64(trimmed)
 }
 
@@ -92,6 +87,10 @@ fn parse_radix(s: &str, radix: u32) -> Result<u64, BlockError> {
 }
 
 fn ascii_string_to_u64(s: &str) -> Result<u64, BlockError> {
+    if s.len() > 8 {
+        return Err(BlockError::InvalidByteStringLength(s.len()));
+    }
+
     if !s.is_ascii() {
         return Err(BlockError::conversion_error(
             "u64",
@@ -99,10 +98,9 @@ fn ascii_string_to_u64(s: &str) -> Result<u64, BlockError> {
         ));
     }
 
-    let mut bytes = [0; 8];
-    for (idx, byte) in s.bytes().enumerate() {
-        bytes[idx] = byte;
-    }
+    let mut bytes = [0u8; 8];
+    let offset = 8 - s.len();
+    bytes[offset..].copy_from_slice(s.as_bytes());
 
     Ok(u64::from_be_bytes(bytes))
 }