On Wed, 5 Feb 2025 23:41:19 GMT, Chen Liang <li...@openjdk.org> wrote:
> `MethodHandles.byteArrayViewVarHandle` exposes checked multi-byte access to
> byte arrays via VarHandle. This larger access speeds up many operations, yet
> it cannot be used in early bootstrap, and as a result, people tend to use
> `Unsafe` which can threaten memory safety of the Java Platform.
>
> To promote the safe use of multi-byte access, I propose to move the checked
> implementations from VarHandle to ByteArray to allow earlier use and reduce
> maintenance costs. In addition, ByteArrayLittleEndian is consolidated, and
> now the access methods are distinguished by BO (byte order) / BE (big endian)
> / LE (little endian) suffixes to indicate their access features.
test/jdk/jdk/internal/util/ByteArray/Types.java line 27:
> 25: * @test
> 26: * @bug 8349503
> 27: * @library /test/lib
Suggestion:
* @library /test/lib
* @key randomness
test/jdk/jdk/internal/util/ByteArray/Types.java line 64:
> 62: new ReadCase<>("u2", ByteArray::getUnsignedShortBO,
> ByteArray::getUnsignedShortBE, ByteArray::getUnsignedShortLE, 2, u2 -> ((u2
> >> Byte.SIZE) & 0xFF) | ((u2 << Byte.SIZE) & 0xFF00),
> Comparator.naturalOrder()),
> 63: new ReadCase<>("int", ByteArray::getIntBO,
> ByteArray::getIntBE, ByteArray::getIntLE, Integer.BYTES,
> Integer::reverseBytes, Comparator.naturalOrder()),
> 64: new ReadCase<>("float", ByteArray::getFloatBO,
> ByteArray::getFloatBE, ByteArray::getFloatLE, Float.BYTES, null,
> Comparator.comparing(Float::floatToRawIntBits)),
Would it be possible to have a local `reverseBytes` for `float` and `double` as
well?
test/jdk/jdk/internal/util/ByteArray/Types.java line 124:
> 122: new WriteCase<>("int", ByteArray::setIntBO,
> ByteArray::setIntBE, ByteArray::setIntLE, Integer.BYTES, List.of(42)),
> 123: new WriteCase<>("float", ByteArray::setFloatBO,
> ByteArray::setFloatBE, ByteArray::setFloatLE, Float.BYTES, List.of(Float.NaN,
> Float.intBitsToFloat(0x7FF23847))),
> 124: new WriteCase<>("float raw", ByteArray::setFloatRawBO,
> ByteArray::setFloatRawBE, ByteArray::setFloatRawLE, Float.BYTES,
> List.of(1.0F)),
Raw seems to be exercised only on unproblematic cases, not on NaNs.
Similarly for "double raw".
test/jdk/jdk/internal/util/ByteArray/Types.java line 152:
> 150: assertThrows(IndexOutOfBoundsException.class, () ->
> leWriter.set(arr, arrayLen - size + 1, value));
> 151:
> 152: int index = 0;
This is always 0.
test/jdk/jdk/internal/util/ByteArray/Types.java line 173:
> 171: var arrBe1 = arr.clone();
> 172: beWriter.set(arrBe1, index, v1);
> 173: assertArrayEquals(arrBe, arrBe1);
What about the little-endian case?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/23478#discussion_r1944742266
PR Review Comment: https://git.openjdk.org/jdk/pull/23478#discussion_r1944786100
PR Review Comment: https://git.openjdk.org/jdk/pull/23478#discussion_r1944783068
PR Review Comment: https://git.openjdk.org/jdk/pull/23478#discussion_r1944769063
PR Review Comment: https://git.openjdk.org/jdk/pull/23478#discussion_r1944772926
