charlesconnell commented on code in PR #7418:
URL: https://github.com/apache/hbase/pull/7418#discussion_r2466872773
##########
hbase-common/src/main/java/org/apache/hadoop/hbase/util/ByteBufferUtils.java:
##########
@@ -88,349 +81,150 @@ abstract int findCommonPrefix(ByteBuffer left, int
leftOffset, int leftLength, B
int rightOffset, int rightLength);
}
+ /**
+ * <a href=
+ *
"https://github.com/google/guava/blob/v21.0/guava/src/com/google/common/primitives/UnsignedBytes.java#L362";>Adapted
+ * from Guava</a>
+ */
static class ComparerHolder {
- static final String UNSAFE_COMPARER_NAME = ComparerHolder.class.getName()
+ "$UnsafeComparer";
-
static final Comparer BEST_COMPARER = getBestComparer();
static Comparer getBestComparer() {
- try {
- Class<? extends Comparer> theClass =
- Class.forName(UNSAFE_COMPARER_NAME).asSubclass(Comparer.class);
-
- return theClass.getConstructor().newInstance();
- } catch (Throwable t) { // ensure we really catch *everything*
- return PureJavaComparer.INSTANCE;
- }
+ return VarHandleComparer.INSTANCE;
}
- static final class PureJavaComparer extends Comparer {
- static final PureJavaComparer INSTANCE = new PureJavaComparer();
+ static final class VarHandleComparer extends Comparer {
- private PureJavaComparer() {
- }
+ static final VarHandleComparer INSTANCE = new VarHandleComparer();
+ private static final int STRIDE = Long.BYTES;
@Override
- public int compareTo(byte[] buf1, int o1, int l1, ByteBuffer buf2, int
o2, int l2) {
- int end1 = o1 + l1;
- int end2 = o2 + l2;
- for (int i = o1, j = o2; i < end1 && j < end2; i++, j++) {
- int a = buf1[i] & 0xFF;
- int b = buf2.get(j) & 0xFF;
- if (a != b) {
- return a - b;
+ int compareTo(byte[] buf1, int o1, int l1, ByteBuffer buf2, int o2, int
l2) {
+ final int minLength = Math.min(l1, l2);
+ int strideLimit = minLength & ~(STRIDE - 1);
+ int i;
+
+ for (i = 0; i < strideLimit; i += STRIDE) {
+ // big-endian fetches are faster than little-endian because the
bytes don't need to get
+ // reversed
+ long lw = (long)
BYTE_ARRAY_LONG_VIEW_BIG_ENDIAN_VAR_HANDLE.get(buf1, o1 + i);
+ long rw = (long)
BYTE_BUFFER_LONG_VIEW_BIG_ENDIAN_VAR_HANDLE.get(buf2, o2 + i);
+ if (lw != rw) {
+ return ((lw + Long.MIN_VALUE) < (rw + Long.MIN_VALUE)) ? -1 : 1;
}
}
- return l1 - l2;
- }
- @Override
- public int compareTo(ByteBuffer buf1, int o1, int l1, ByteBuffer buf2,
int o2, int l2) {
- int end1 = o1 + l1;
- int end2 = o2 + l2;
- for (int i = o1, j = o2; i < end1 && j < end2; i++, j++) {
- int a = buf1.get(i) & 0xFF;
- int b = buf2.get(j) & 0xFF;
- if (a != b) {
- return a - b;
+ // The epilogue to cover the last (minLength % stride) elements.
+ for (; i < minLength; i++) {
+ int il = buf1[o1 + i] & 0xFF;
+ int ir = buf2.get(o2 + i) & 0xFF;
+ if (il != ir) {
+ return il - ir;
}
}
return l1 - l2;
}
- }
-
- static final class UnsafeComparer extends Comparer {
-
- public UnsafeComparer() {
- }
-
- static {
- if (!UNSAFE_UNALIGNED) {
- throw new Error();
- }
- }
-
- @Override
- public int compareTo(byte[] buf1, int o1, int l1, ByteBuffer buf2, int
o2, int l2) {
- long offset2Adj;
- Object refObj2 = null;
- if (buf2.isDirect()) {
- offset2Adj = o2 + UnsafeAccess.directBufferAddress(buf2);
- } else {
- offset2Adj = o2 + buf2.arrayOffset() +
UnsafeAccess.BYTE_ARRAY_BASE_OFFSET;
- refObj2 = buf2.array();
- }
- return compareToUnsafe(buf1, o1 + UnsafeAccess.BYTE_ARRAY_BASE_OFFSET,
l1, refObj2,
- offset2Adj, l2);
- }
@Override
public int compareTo(ByteBuffer buf1, int o1, int l1, ByteBuffer buf2,
int o2, int l2) {
- long offset1Adj, offset2Adj;
- Object refObj1 = null, refObj2 = null;
- if (buf1.isDirect()) {
- offset1Adj = o1 + UnsafeAccess.directBufferAddress(buf1);
- } else {
- offset1Adj = o1 + buf1.arrayOffset() +
UnsafeAccess.BYTE_ARRAY_BASE_OFFSET;
- refObj1 = buf1.array();
- }
- if (buf2.isDirect()) {
- offset2Adj = o2 + UnsafeAccess.directBufferAddress(buf2);
- } else {
- offset2Adj = o2 + buf2.arrayOffset() +
UnsafeAccess.BYTE_ARRAY_BASE_OFFSET;
- refObj2 = buf2.array();
+ final int minLength = Math.min(l1, l2);
+ int strideLimit = minLength & ~(STRIDE - 1);
+ int i;
+
+ for (i = 0; i < strideLimit; i += STRIDE) {
+ // big-endian fetches are faster than little-endian because the
bytes don't need to get
+ // reversed
+ long lw = (long)
BYTE_BUFFER_LONG_VIEW_BIG_ENDIAN_VAR_HANDLE.get(buf1, o1 + i);
+ long rw = (long)
BYTE_BUFFER_LONG_VIEW_BIG_ENDIAN_VAR_HANDLE.get(buf2, o2 + i);
+ if (lw != rw) {
+ return ((lw + Long.MIN_VALUE) < (rw + Long.MIN_VALUE)) ? -1 : 1;
+ }
}
- return compareToUnsafe(refObj1, offset1Adj, l1, refObj2, offset2Adj,
l2);
- }
- }
- }
-
- static class ConverterHolder {
- static final String UNSAFE_CONVERTER_NAME =
- ConverterHolder.class.getName() + "$UnsafeConverter";
- static final Converter BEST_CONVERTER = getBestConverter();
-
- static Converter getBestConverter() {
- try {
- Class<? extends Converter> theClass =
- Class.forName(UNSAFE_CONVERTER_NAME).asSubclass(Converter.class);
-
- // yes, UnsafeComparer does implement Comparer<byte[]>
- return theClass.getConstructor().newInstance();
- } catch (Throwable t) { // ensure we really catch *everything*
- return PureJavaConverter.INSTANCE;
- }
- }
-
- static final class PureJavaConverter extends Converter {
- static final PureJavaConverter INSTANCE = new PureJavaConverter();
-
- private PureJavaConverter() {
- }
-
- @Override
- short toShort(ByteBuffer buffer, int offset) {
- return buffer.getShort(offset);
- }
-
- @Override
- int toInt(ByteBuffer buffer) {
- return buffer.getInt();
- }
-
- @Override
- int toInt(ByteBuffer buffer, int offset) {
- return buffer.getInt(offset);
- }
-
- @Override
- long toLong(ByteBuffer buffer, int offset) {
- return buffer.getLong(offset);
- }
-
- @Override
- void putInt(ByteBuffer buffer, int val) {
- buffer.putInt(val);
- }
-
- @Override
- int putInt(ByteBuffer buffer, int index, int val) {
- buffer.putInt(index, val);
- return index + Bytes.SIZEOF_INT;
- }
- @Override
- void putShort(ByteBuffer buffer, short val) {
- buffer.putShort(val);
- }
-
- @Override
- int putShort(ByteBuffer buffer, int index, short val) {
- buffer.putShort(index, val);
- return index + Bytes.SIZEOF_SHORT;
- }
-
- @Override
- void putLong(ByteBuffer buffer, long val) {
- buffer.putLong(val);
- }
-
- @Override
- int putLong(ByteBuffer buffer, int index, long val) {
- buffer.putLong(index, val);
- return index + Bytes.SIZEOF_LONG;
- }
- }
-
- static final class UnsafeConverter extends Converter {
-
- public UnsafeConverter() {
- }
-
- static {
- if (!UNSAFE_UNALIGNED) {
- throw new Error();
+ // The epilogue to cover the last (minLength % stride) elements.
+ for (; i < minLength; i++) {
+ int il = buf1.get(o1 + i) & 0xFF;
+ int ir = buf2.get(o2 + i) & 0xFF;
+ if (il != ir) {
+ return il - ir;
+ }
}
- }
-
- @Override
- short toShort(ByteBuffer buffer, int offset) {
- return UnsafeAccess.toShort(buffer, offset);
- }
-
- @Override
- int toInt(ByteBuffer buffer) {
- int i = UnsafeAccess.toInt(buffer, buffer.position());
- buffer.position(buffer.position() + Bytes.SIZEOF_INT);
- return i;
- }
-
- @Override
- int toInt(ByteBuffer buffer, int offset) {
- return UnsafeAccess.toInt(buffer, offset);
- }
-
- @Override
- long toLong(ByteBuffer buffer, int offset) {
- return UnsafeAccess.toLong(buffer, offset);
- }
-
- @Override
- void putInt(ByteBuffer buffer, int val) {
- int newPos = UnsafeAccess.putInt(buffer, buffer.position(), val);
- buffer.position(newPos);
- }
-
- @Override
- int putInt(ByteBuffer buffer, int index, int val) {
- return UnsafeAccess.putInt(buffer, index, val);
- }
-
- @Override
- void putShort(ByteBuffer buffer, short val) {
- int newPos = UnsafeAccess.putShort(buffer, buffer.position(), val);
- buffer.position(newPos);
- }
-
- @Override
- int putShort(ByteBuffer buffer, int index, short val) {
- return UnsafeAccess.putShort(buffer, index, val);
- }
-
- @Override
- void putLong(ByteBuffer buffer, long val) {
- int newPos = UnsafeAccess.putLong(buffer, buffer.position(), val);
- buffer.position(newPos);
- }
-
- @Override
- int putLong(ByteBuffer buffer, int index, long val) {
- return UnsafeAccess.putLong(buffer, index, val);
+ return l1 - l2;
}
}
}
static class CommonPrefixerHolder {
- static final String UNSAFE_COMMON_PREFIXER_NAME =
- CommonPrefixerHolder.class.getName() + "$UnsafeCommonPrefixer";
-
static final CommonPrefixer BEST_COMMON_PREFIXER = getBestCommonPrefixer();
static CommonPrefixer getBestCommonPrefixer() {
Review Comment:
I am keeping the CommonPrefixer interface, because when the Vector API
(hopefully) gets standardized, we can try to load a Vector-based CommonPrefixer
at runtime
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