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Posted to common-commits@hadoop.apache.org by ji...@apache.org on 2014/03/21 00:11:03 UTC
svn commit: r1579815 -
/hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java
Author: jing9
Date: Thu Mar 20 23:11:01 2014
New Revision: 1579815
URL: http://svn.apache.org/r1579815
Log:
HDFS-6038. Merge r1579814 from branch-2.
Modified:
hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java
Modified: hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java?rev=1579815&r1=1579814&r2=1579815&view=diff
==============================================================================
--- hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java (original)
+++ hadoop/common/branches/branch-2.4/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/DataOutputBuffer.java Thu Mar 20 23:11:01 2014
@@ -23,6 +23,8 @@ import java.io.*;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
+import com.google.common.base.Preconditions;
+
/** A reusable {@link DataOutput} implementation that writes to an in-memory
* buffer.
*
@@ -68,6 +70,18 @@ public class DataOutputBuffer extends Da
in.readFully(buf, count, len);
count = newcount;
}
+
+ /**
+ * Set the count for the current buf.
+ * @param newCount the new count to set
+ * @return the original count
+ */
+ private int setCount(int newCount) {
+ Preconditions.checkArgument(newCount >= 0 && newCount <= buf.length);
+ int oldCount = count;
+ count = newCount;
+ return oldCount;
+ }
}
private Buffer buffer;
@@ -110,4 +124,21 @@ public class DataOutputBuffer extends Da
public void writeTo(OutputStream out) throws IOException {
buffer.writeTo(out);
}
+
+ /**
+ * Overwrite an integer into the internal buffer. Note that this call can only
+ * be used to overwrite existing data in the buffer, i.e., buffer#count cannot
+ * be increased, and DataOutputStream#written cannot be increased.
+ */
+ public void writeInt(int v, int offset) throws IOException {
+ Preconditions.checkState(offset + 4 <= buffer.getLength());
+ byte[] b = new byte[4];
+ b[0] = (byte) ((v >>> 24) & 0xFF);
+ b[1] = (byte) ((v >>> 16) & 0xFF);
+ b[2] = (byte) ((v >>> 8) & 0xFF);
+ b[3] = (byte) ((v >>> 0) & 0xFF);
+ int oldCount = buffer.setCount(offset);
+ buffer.write(b);
+ buffer.setCount(oldCount);
+ }
}