ssh: Minor simplification in SerialRangeSet

Instead of set.headMap(x).lastKey() use set.floorKey(x) and
instead of set.tailMap(x).firstKey() use set.ceilingKey(x).

Change-Id: I22f44cbe82b9ead06d6ff517d609dfdbc89a758c

diff --git a/org.eclipse.jgit.ssh.apache/src/org/eclipse/jgit/internal/signing/ssh/SerialRangeSet.java b/org.eclipse.jgit.ssh.apache/src/org/eclipse/jgit/internal/signing/ssh/SerialRangeSet.java
index 6a0cec8821a460c451ee771d82491d8432afc679..f4eb884239a8267926834c9df80e4c6692da3b6a 100644 (file)
--- a/org.eclipse.jgit.ssh.apache/src/org/eclipse/jgit/internal/signing/ssh/SerialRangeSet.java
+++ b/org.eclipse.jgit.ssh.apache/src/org/eclipse/jgit/internal/signing/ssh/SerialRangeSet.java
@@ -9,7 +9,6 @@
  */
 package org.eclipse.jgit.internal.signing.ssh;
 
-import java.util.SortedMap;
 import java.util.TreeMap;
 
 import org.eclipse.jgit.internal.transport.sshd.SshdText;
@@ -50,14 +49,14 @@ class SerialRangeSet {
                }
        }
 
-       // We use the same data structure as OpenSSH,; basically a
-       // TreeSet<SerialRange> of mutable elements. To get "mutability", the set is
-       // implemented as a TreeMap with the same elements as keys and values.
+       // We use the same data structure as OpenSSH; basically a TreeSet of mutable
+       // SerialRanges. To get "mutability", the set is implemented as a TreeMap
+       // with the same elements as keys and values.
        //
        // get(x) will return null if none of the serial numbers in the range x is
        // in the set, and some range (partially) overlapping with x otherwise.
        //
-       // containsKey will return true if there is any (partially) overlapping
+       // containsKey(x) will return true if there is any (partially) overlapping
        // range in the TreeMap.
        private final TreeMap<SerialRange, SerialRange> ranges = new TreeMap<>(
                        SerialRangeSet::compare);
@@ -117,21 +116,15 @@ class SerialRangeSet {
                }
                // No overlapping range exists: check for coalescing with the
                // previous/next range
-               SortedMap<SerialRange, SerialRange> head = ranges.headMap(newRange);
-               if (!head.isEmpty()) {
-                       SerialRange prev = head.lastKey();
-                       if (newRange.from() - prev.to() == 1) {
-                               ranges.remove(prev);
-                               newRange = new Range(prev.from(), newRange.to());
-                       }
+               SerialRange prev = ranges.floorKey(newRange);
+               if (prev != null && newRange.from() - prev.to() == 1) {
+                       ranges.remove(prev);
+                       newRange = new Range(prev.from(), newRange.to());
                }
-               SortedMap<SerialRange, SerialRange> tail = ranges.tailMap(newRange);
-               if (!tail.isEmpty()) {
-                       SerialRange next = tail.firstKey();
-                       if (next.from() - newRange.to() == 1) {
-                               ranges.remove(next);
-                               newRange = new Range(newRange.from(), next.to());
-                       }
+               SerialRange next = ranges.ceilingKey(newRange);
+               if (next != null && next.from() - newRange.to() == 1) {
+                       ranges.remove(next);
+                       newRange = new Range(newRange.from(), next.to());
                }
                ranges.put(newRange, newRange);
        }