Unsafe.{get,put}-X-Unaligned; Efficient array comparison intrinsics

[Paul Sandoz]

On Feb 24, 2015, at 3:59 PM, Andrew Haley <aph at redhat.com> wrote:
> 
>>>> If we expose the endianness query via a new method in unsafe we
>>>> should reuse that in java.nio.Bits and get rid of the associated
>>>> static code block.
>>> 
>>> Sure, I already did that.
>>> 
>> 
>> Locally i guess? (just in case i missed something in the current webrev).
> 
> Ah.  I used the query but I forgot to get rid of the static code
> block:
> 
> http://cr.openjdk.java.net/~aph/unaligned.jdk.1/src/java.base/share/classes/java/nio/Bits.java.cdiff.html
> 

We are talking about different queries :-) (although the doPrivileged can now go).

I was referring to:

 570     private static final ByteOrder byteOrder;
 571 
...

 577 
 578     static {
 579         long a = unsafe.allocateMemory(8);
 580         try {
 581             unsafe.putLong(a, 0x0102030405060708L);
 582             byte b = unsafe.getByte(a);
 583             switch (b) {
 584             case 0x01: byteOrder = ByteOrder.BIG_ENDIAN;     break;
 585             case 0x08: byteOrder = ByteOrder.LITTLE_ENDIAN;  break;
 586             default:
 587                 assert false;
 588                 byteOrder = null;
 589             }
 590         } finally {
 591             unsafe.freeMemory(a);
 592         }
 593     }

Which i think could be replaced with:

  private static final ByteOrder byteOrder = unsafe.getByteOrder() ? ByteOrder.BIG_ENDIAN : ByteOrder.LITTLE_ENDIAN;

Paul.