basenc: decode --base58 input in one piece

src/uu/base32/src/base_common.rs

@@ -752,6 +752,8 @@ pub mod fast_decode {
                 ));
             }
 
+            // Encodings without partial decode (base58) are one big number, so
+            // they are decoded in one go after the loop, never in chunks.
             if supports_partial_decode {
                 flush_ready_chunks(
                     &mut buffer,
@@ -761,14 +763,6 @@ pub mod fast_decode {
                     &mut decoded_buffer,
                     output,
                 )?;
-            } else if buffer.len() == decode_in_chunks_of_size {
-                decode_in_chunks_to_buffer(
-                    supports_fast_decode_and_encode,
-                    &buffer,
-                    &mut decoded_buffer,
-                )?;
-                write_to_output(&mut decoded_buffer, output)?;
-                buffer.clear();
             }
         }
 

tests/by-util/test_basenc.rs

@@ -184,6 +184,26 @@ fn test_base58_large_file_no_chunking() {
     // spell-checker:enable
 }
 
+#[test]
+fn test_base58_decode_large_input_round_trip() {
+    // Decoding must not cut the input into 1024-digit chunks either.
+    // spell-checker:disable
+    let input = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. ".repeat(50);
+    // spell-checker:enable
+    let encoded = new_ucmd!()
+        .arg("--base58")
+        .pipe_in(input.clone())
+        .succeeds()
+        .stdout_move_str();
+    assert!(encoded.len() > 1024);
+
+    new_ucmd!()
+        .args(&["--base58", "-d"])
+        .pipe_in(encoded)
+        .succeeds()
+        .stdout_is(input);
+}
+
 #[test]
 fn test_choose_last_encoding_base64() {
     new_ucmd!()