base58: it wasn't working properly with long input

Author: sylvestre

src/uucore/src/lib/features/encoding.rs

@@ -266,36 +266,50 @@ impl SupportsFastDecodeAndEncode for Base58Wrapper {
             return Ok(());
         }
 
-        // Convert bytes to big integer
-        let mut num: Vec<u32> = Vec::new();
+        // Convert bytes to big integer (Vec<u32> in little-endian format)
+        let mut num = Vec::with_capacity(input_trimmed.len().div_ceil(4) + 1);
         for &byte in input_trimmed {
-            let mut carry = byte as u32;
+            let mut carry = byte as u64;
             for n in &mut num {
-                let tmp = (*n as u64) * 256 + carry as u64;
+                let tmp = (*n as u64) * 256 + carry;
                 *n = tmp as u32;
-                carry = (tmp >> 32) as u32;
+                carry = tmp >> 32;
             }
             if carry > 0 {
-                num.push(carry);
+                num.push(carry as u32);
             }
         }
 
         // Convert to base58
-        let mut result = Vec::new();
+        let mut result = Vec::with_capacity((input_trimmed.len() * 138 / 100) + 1);
         let alphabet = self.alphabet();
 
-        while !num.is_empty() && num.iter().any(|&n| n != 0) {
+        // Optimized check: stop when all elements are zero
+        while !num.is_empty() {
+            // Check if we're done (all zeros)
+            let mut all_zero = true;
             let mut carry = 0u64;
+
             for n in num.iter_mut().rev() {
                 let tmp = carry * (1u64 << 32) + *n as u64;
                 *n = (tmp / 58) as u32;
                 carry = tmp % 58;
+                if *n != 0 {
+                    all_zero = false;
+                }
             }
+
             result.push(alphabet[carry as usize]);
 
-            // Remove leading zeros
-            while num.last() == Some(&0) && num.len() > 1 {
-                num.pop();
+            if all_zero {
+                break;
+            }
+
+            // Trim trailing zeros less frequently
+            if num.len() > 1 && result.len() % 8 == 0 {
+                while num.last() == Some(&0) && num.len() > 1 {
+                    num.pop();
+                }
             }
         }
 
@@ -305,15 +319,18 @@ impl SupportsFastDecodeAndEncode for Base58Wrapper {
         }
 
         // Add result (reversed because we built it backwards)
-        for byte in result.into_iter().rev() {
+        for &byte in result.iter().rev() {
             output.push_back(byte);
         }
 
         Ok(())
     }
 
     fn unpadded_multiple(&self) -> usize {
-        1 // Base58 doesn't use padding
+        // Base58 must encode the entire input as one big integer, not in chunks
+        // Use a very large value to effectively disable chunking, but avoid overflow
+        // when multiplied by ENCODE_IN_CHUNKS_OF_SIZE_MULTIPLE (1024) in base_common
+        usize::MAX / 2048
     }
 
     fn valid_decoding_multiple(&self) -> usize {

tests/by-util/test_basenc.rs

@@ -211,6 +211,31 @@ fn test_base58_decode() {
         .stdout_only("Hello, World!");
 }
 
+#[test]
+fn test_base58_large_file_no_chunking() {
+    // Regression test: base58 must process entire input as one big integer,
+    // not in 1024-byte chunks. This test ensures files >1024 bytes work correctly.
+    let (at, mut ucmd) = at_and_ucmd!();
+    let filename = "large_file.txt";
+
+    // spell-checker:disable
+    let input = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. ".repeat(50);
+    // spell-checker:enable
+    at.write(filename, &input);
+
+    let result = ucmd.arg("--base58").arg(filename).succeeds();
+    let encoded = result.stdout_str();
+
+    // Verify the output ends with the expected suffix (matches GNU basenc output)
+    // spell-checker:disable
+    assert!(
+        encoded
+            .trim_end()
+            .ends_with("ZNRRacEnhrY83ZEYkpwWVZNFK5DFRasr\nw693NsNGtiQ9fYAj")
+    );
+    // spell-checker:enable
+}
+
 #[test]
 fn test_choose_last_encoding_base64() {
     new_ucmd!()