[jira] [Commented] (HBASE-10771) Primitive type put/get APIs in ByteRange

["Matt Corgan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-10771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13965067#comment-13965067 ] 

Matt Corgan commented on HBASE-10771:
-------------------------------------

taking a look at patch_2 after a mention in HBASE-10861

{code}Pair<Long, Integer> getVLong(int index) throws IOException{code}this returns a fairly heavyweight object.  maybe it should just return a primitive long and we could have a public static method "int numVLongBytes(long n)" that quickly computes the number of bytes.  here is a different VLong format i wrote a while back.  i don't know what the numBytes formula for this particular VLong would be, but you can see how efficiently it could possibly be calculated.  probably much cheaper than creating 3 objects
{code}
	public static int numBytes(long in){// do a check for illegal arguments if not protected
		if(in == 0){ return 1; }// doesn't work with the formula below
		return (70 - Long.numberOfLeadingZeros(in)) / 7;// 70 comes from 64+(7-1)
	}

	public static byte[] getBytes(long value){
		int numBytes = numBytes(value);
		byte[] bytes = new byte[numBytes];
		long remainder = value;
		for(int i = 0; i < numBytes - 1; ++i){
			bytes[i] = (byte)((remainder & LONG_7_RIGHT_BITS_SET) | LONG_8TH_BIT_SET);// set the left bit
			remainder >>= 7;
		}
		bytes[numBytes - 1] = (byte)(remainder & LONG_7_RIGHT_BITS_SET);// do not set the left bit
		return bytes;
	}
{code}
also not sure the checked IOException is necessary since all of these methods could encounter similar corruption errors, plus the actual IO has presumably already been done earlier.

{code}
+  @Override
+  public long getLong(int index) {
+    return Bytes.toLong(bytes, index);
+  }
{code}
does the hbase Bytes util have the exact same format that ByteBuffers use?  native java format can be seen in java.nio.Bits.java




> Primitive type put/get APIs in ByteRange 
> -----------------------------------------
>
>                 Key: HBASE-10771
>                 URL: https://issues.apache.org/jira/browse/HBASE-10771
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>             Fix For: 0.99.0
>
>         Attachments: HBASE-10771.patch, HBASE-10771_V2.patch
>
>
> While doing HBASE-10713 I came across the need to write int/long (and read also) from a ByteRange.  CellBlocks are backed by ByteRange. So we can add such APIs.
> Also as per HBASE-10750  we return a ByteRange from MSLAB and also discussion under HBASE-10191 suggest we can have BR backed HFileBlocks etc.  



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