Serialize numeric to tape (#4069) (#4073)

arrow-json/src/reader/mod.rs

@@ -634,6 +634,7 @@ fn make_decoder(
 
 #[cfg(test)]
 mod tests {
+    use serde_json::json;
     use std::fs::File;
     use std::io::{BufReader, Cursor, Seek};
     use std::sync::Arc;
@@ -1976,4 +1977,26 @@ mod tests {
             "Json error: whilst decoding field 'a': whilst decoding field 'child': expected primitive got [123, 3465346]"
         );
     }
+
+    #[test]
+    fn test_serialize_timestamp() {
+        let json = vec![
+            json!({"timestamp": 1681319393}),
+            json!({"timestamp": "1970-01-01T00:00:00+02:00"}),
+        ];
+        let schema = Schema::new(vec![Field::new(
+            "timestamp",
+            DataType::Timestamp(TimeUnit::Second, None),
+            true,
+        )]);
+        let mut decoder = ReaderBuilder::new(Arc::new(schema))
+            .build_decoder()
+            .unwrap();
+        decoder.serialize(&json).unwrap();
+        let batch = decoder.flush().unwrap().unwrap();
+        assert_eq!(batch.num_rows(), 2);
+        assert_eq!(batch.num_columns(), 1);
+        let values = batch.column(0).as_primitive::<TimestampSecondType>();
+        assert_eq!(values.values(), &[1681319393, -7200]);
+    }
 }

arrow-json/src/reader/serializer.rs

@@ -68,6 +68,13 @@ impl<'a> TapeSerializer<'a> {
             offsets,
         }
     }
+
+    fn serialize_number(&mut self, v: &[u8]) {
+        self.bytes.extend_from_slice(v);
+        let idx = self.offsets.len() - 1;
+        self.elements.push(TapeElement::Number(idx as _));
+        self.offsets.push(self.bytes.len());
+    }
 }
 
 /// The tape stores all values as strings, and so must serialize numeric types
@@ -81,7 +88,8 @@ macro_rules! serialize_numeric {
     ($s:ident, $t:ty, $v:ident) => {{
         let mut buffer = [0_u8; <$t>::FORMATTED_SIZE];
         let s = lexical_core::write($v, &mut buffer);
-        $s.serialize_bytes(s)
+        $s.serialize_number(s);
+        Ok(())
     }};
 }