read directly into buffer (#13)

Author: Disservin

src/common/compressed_training_file_reader.rs

@@ -52,6 +52,14 @@ impl<T: Read + Seek> CompressedTrainingDataFileReader<T> {
         Ok(data)
     }
 
+    pub fn read_next_chunk_into(&mut self, buffer: &mut Vec<u8>) -> Result<()> {
+        let header = self.read_chunk_header()?;
+        buffer.resize(header.chunk_size as usize, 0);
+        self.file.read_exact(buffer)?;
+        self.read_bytes += header.chunk_size as u64;
+        Ok(())
+    }
+
     fn read_chunk_header(&mut self) -> Result<Header> {
         let mut buf = [0u8; HEADER_SIZE];
 

src/reader/compressed_reader.rs

@@ -97,10 +97,11 @@ impl<T: Read + Seek> CompressedTrainingDataEntryReader<T> {
             reader.is_end = true;
             return Err(CompressedReaderError::EndOfFile);
         } else {
-            reader.chunk = match reader.input_file.as_mut().unwrap().read_next_chunk() {
-                Ok(chunk) => chunk,
-                Err(e) => return Err(CompressedReaderError::BinpackError(e)),
-            };
+            reader
+                .input_file
+                .as_mut()
+                .unwrap()
+                .read_next_chunk_into(&mut reader.chunk)?;
         }
 
         Ok(reader)