Github user xwu0226 commented on a diff in the pull request:
https://github.com/apache/spark/pull/14842#discussion_r77226814
--- Diff:
core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
---
@@ -69,49 +100,161 @@ public static long computePrefix(double value) {
* ordering they define is compatible with radix sort.
*/
public abstract static class RadixSortSupport extends PrefixComparator {
+
/** @return Whether the sort should be descending in binary sort
order. */
public abstract boolean sortDescending();
/** @return Whether the sort should take into account the sign bit. */
public abstract boolean sortSigned();
+
+ /** @return Whether the sort should put null first or last. */
+ public abstract NullOrder nullOrder();
}
//
// Standard prefix comparator implementations
//
+ // unsigned asc null first (default)
public static final class UnsignedPrefixComparator extends
RadixSortSupport {
@Override public boolean sortDescending() { return false; }
@Override public boolean sortSigned() { return false; }
- @Override
+ @Override public NullOrder nullOrder() { return NullOrder.FIRST; }
public int compare(long aPrefix, long bPrefix) {
+ if (aPrefix == 0L && bPrefix == 0L) {
+ return 0;
+ }
+ if (aPrefix == 0L) {
+ return -1;
+ } else if (bPrefix == 0L) {
+ return 1;
+ }
return UnsignedLongs.compare(aPrefix, bPrefix);
}
}
+ // unsigned asc null last
+ public static final class UnsignedPrefixComparatorNullLast extends
RadixSortSupport {
+ @Override public boolean sortDescending() { return false; }
+ @Override public boolean sortSigned() { return false; }
+ @Override public NullOrder nullOrder() { return NullOrder.LAST; }
+ public int compare(long aPrefix, long bPrefix) {
+ if (aPrefix == 0L && bPrefix == 0L) {
+ return 0;
+ }
+ if (aPrefix == 0L) {
+ return 1;
+ } else if (bPrefix == 0L) {
+ return -1;
+ }
+ return UnsignedLongs.compare(aPrefix, bPrefix);
+ }
+ }
+
+ // unsigned desc null first
+ public static final class UnsignedPrefixComparatorDescNullFirst extends
RadixSortSupport {
+ @Override public boolean sortDescending() { return true; }
+ @Override public boolean sortSigned() { return false; }
+ @Override public NullOrder nullOrder() { return NullOrder.FIRST; }
+ public int compare(long bPrefix, long aPrefix) {
+ if (aPrefix == 0L && bPrefix == 0L) {
+ return 0;
+ }
+ if (bPrefix == 0L) {
+ return -1;
+ } else if (aPrefix == 0L) {
+ return 1;
+ }
+ return UnsignedLongs.compare(aPrefix, bPrefix);
+ }
+ }
+
+ // unsigned desc null last (default)
public static final class UnsignedPrefixComparatorDesc extends
RadixSortSupport {
@Override public boolean sortDescending() { return true; }
@Override public boolean sortSigned() { return false; }
- @Override
+ @Override public NullOrder nullOrder() { return NullOrder.LAST; }
public int compare(long bPrefix, long aPrefix) {
+ if (aPrefix == 0L && bPrefix == 0L) {
+ return 0;
+ }
+ if (bPrefix == 0L) {
+ return 1;
+ } else if (aPrefix == 0L) {
+ return -1;
+ }
return UnsignedLongs.compare(aPrefix, bPrefix);
}
}
+ // signed asc null first (default)
public static final class SignedPrefixComparator extends
RadixSortSupport {
@Override public boolean sortDescending() { return false; }
@Override public boolean sortSigned() { return true; }
- @Override
+ @Override public NullOrder nullOrder() { return NullOrder.FIRST; }
+ public int compare(long a, long b) {
+ if (a == Long.MIN_VALUE && b == Long.MIN_VALUE) {
+ return 0;
+ }
+ if (a == Long.MIN_VALUE) {
+ return -1;
+ } else if (b == Long.MIN_VALUE) {
+ return 1;
+ }
+ return (a < b) ? -1 : (a > b) ? 1 : 0;
+ }
+ }
+
+ // signed asc null last
+ public static final class SignedPrefixComparatorNullLast extends
RadixSortSupport {
+ @Override public boolean sortDescending() { return false; }
+ @Override public boolean sortSigned() { return true; }
+ @Override public NullOrder nullOrder() { return NullOrder.LAST; }
public int compare(long a, long b) {
+ if (a == Long.MIN_VALUE && b == Long.MIN_VALUE) {
+ return 0;
+ }
+ if (a == Long.MIN_VALUE) {
+ return 1;
+ } else if (b == Long.MIN_VALUE) {
+ return -1;
+ }
+ return (a < b) ? -1 : (a > b) ? 1 : 0;
+ }
+ }
+
+ // signed desc null first
+ public static final class SignedPrefixComparatorDescNullFirst extends
RadixSortSupport {
+ @Override public boolean sortDescending() { return true; }
+ @Override public boolean sortSigned() { return true; }
+ @Override public NullOrder nullOrder() { return NullOrder.FIRST; }
+ public int compare(long b, long a) {
+ if (a == Long.MIN_VALUE && b == Long.MIN_VALUE) {
--- End diff --
The fact that MIN_VALUE could be also literal min value was also my concern
too. I will check what I can in SortOrder.scala. Thanks!
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