[iotdb] 01/01: Improve Plain Encode

[ja...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

jackietien pushed a commit to branch PlainEncodeImprove
in repository https://gitbox.apache.org/repos/asf/iotdb.git

commit 707c4dff009228ef7d1e04f7cbb62112fd5d31a5
Author: JackieTien97 <ja...@gmail.com>
AuthorDate: Fri May 27 14:12:20 2022 +0800

    Improve Plain Encode
---
 .../tsfile/encoding/encoder/PlainEncoder.java      | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/tsfile/src/main/java/org/apache/iotdb/tsfile/encoding/encoder/PlainEncoder.java b/tsfile/src/main/java/org/apache/iotdb/tsfile/encoding/encoder/PlainEncoder.java
index 1a2271836b..694dad8baf 100644
--- a/tsfile/src/main/java/org/apache/iotdb/tsfile/encoding/encoder/PlainEncoder.java
+++ b/tsfile/src/main/java/org/apache/iotdb/tsfile/encoding/encoder/PlainEncoder.java
@@ -36,8 +36,9 @@ import java.math.BigDecimal;
 public class PlainEncoder extends Encoder {
 
   private static final Logger logger = LoggerFactory.getLogger(PlainEncoder.class);
-  private TSDataType dataType;
-  private int maxStringLength;
+  private final TSDataType dataType;
+  private final int maxStringLength;
+  private final byte[] writeBufferForLong = new byte[8];
 
   public PlainEncoder(TSDataType dataType, int maxStringLength) {
     super(TSEncoding.PLAIN);
@@ -67,9 +68,20 @@ public class PlainEncoder extends Encoder {
 
   @Override
   public void encode(long value, ByteArrayOutputStream out) {
-    for (int i = 7; i >= 0; i--) {
-      out.write((byte) (((value) >> (i * 8)) & 0xFF));
-    }
+    final int first = (int) (value);
+    final int second = (int) ((value >>> 32));
+    // Implementation taken from Apache Avro (org.apache.avro.io.BinaryData)
+    // the compiler seems to execute this order the best, likely due to
+    // register allocation -- the lifetime of constants is minimized.
+    writeBufferForLong[0] = (byte) (first);
+    writeBufferForLong[4] = (byte) (second);
+    writeBufferForLong[5] = (byte) (second >>> 8);
+    writeBufferForLong[1] = (byte) (first >>> 8);
+    writeBufferForLong[2] = (byte) (first >>> 16);
+    writeBufferForLong[6] = (byte) (second >>> 16);
+    writeBufferForLong[7] = (byte) (second >>> 24);
+    writeBufferForLong[3] = (byte) (first >>> 24);
+    out.write(writeBufferForLong, 0, 8);
   }
 
   @Override