Avoid some allocs

Author: josh-newman

src/validators/config.rs

@@ -28,14 +28,31 @@ impl ValBytesMode {
     pub fn deserialize_string<'py>(self, s: &str) -> Result<EitherBytes<'_, 'py>, ErrorType> {
         match self.ser {
             BytesMode::Utf8 => Ok(EitherBytes::Cow(Cow::Borrowed(s.as_bytes()))),
-            BytesMode::Base64 => match base64::engine::general_purpose::URL_SAFE.decode(to_base64_urlsafe(s)) {
-                Ok(bytes) => Ok(EitherBytes::from(bytes)),
-                Err(err) => Err(ErrorType::BytesInvalidEncoding {
-                    encoding: "base64".to_string(),
-                    encoding_error: err.to_string(),
-                    context: None,
-                }),
-            },
+            BytesMode::Base64 => {
+                fn decode(input: &str) -> Result<Vec<u8>, ErrorType> {
+                    base64::engine::general_purpose::URL_SAFE.decode(input).map_err(|err| {
+                        ErrorType::BytesInvalidEncoding {
+                            encoding: "base64".to_string(),
+                            encoding_error: err.to_string(),
+                            context: None,
+                        }
+                    })
+                }
+                let result = if s.contains(|c| c == '+' || c == '/') {
+                    let replaced: String = s
+                        .chars()
+                        .map(|c| match c {
+                            '+' => '-',
+                            '/' => '_',
+                            _ => c,
+                        })
+                        .collect();
+                    decode(&replaced)
+                } else {
+                    decode(s)
+                };
+                result.map(EitherBytes::from)
+            }
             BytesMode::Hex => match hex::decode(s) {
                 Ok(vec) => Ok(EitherBytes::from(vec)),
                 Err(err) => Err(ErrorType::BytesInvalidEncoding {
@@ -47,11 +64,3 @@ impl ValBytesMode {
         }
     }
 }
-
-fn to_base64_urlsafe(s: &str) -> String {
-    if s.contains(|c| c == '+' || c == '/') {
-        s.replace('+', "-").replace('/', "_")
-    } else {
-        s.to_string()
-    }
-}