[MAPREDUCE-6714] Refactor UncompressedSplitLineReader.fillBuffer()

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.8.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Hadoop Flags: Reviewed
• Assignee: Daniel Templeton
• Reporter: Daniel Templeton
• Created: 10/Jun/16 00:57
• Updated: 30/Aug/16 01:13
• Resolved: 10/Jun/16 10:18

Description

MAPREDUCE-6635 made this change:

-      maxBytesToRead = Math.min(maxBytesToRead,
-                                (int)(splitLength - totalBytesRead));
+      long leftBytesForSplit = splitLength - totalBytesRead;
+      // check if leftBytesForSplit exceed Integer.MAX_VALUE
+      if (leftBytesForSplit <= Integer.MAX_VALUE) {
+        maxBytesToRead = Math.min(maxBytesToRead, (int)leftBytesForSplit);
+      }

The result is one more comparison than necessary and code that's a little convoluted. The code can be simplified as:

      long leftBytesForSplit = splitLength - totalBytesRead;

      if (leftBytesForSplit < maxBytesToRead) {
        maxBytesToRead = (int)leftBytesForSplit;
      }

The comparison will auto promote maxBytesToRead, making it safe.