Merge and optimize applyOffset() and applyLimit()

h2/src/main/org/h2/result/LocalResult.java

@@ -386,11 +386,43 @@ public class LocalResult implements ResultInterface, ResultTarget {
                 }
             }
         }
-        applyOffset();
-        applyLimit();
+        applyOffsetAndLimit();
         reset();
     }
 
+    private void applyOffsetAndLimit() {
+        int offset = Math.max(this.offset, 0);
+        int limit = this.limit;
+        if (offset == 0 && limit < 0 || rowCount == 0) {
+            return;
+        }
+        boolean clearAll = offset >= rowCount || limit == 0;
+        if (!clearAll) {
+            int remaining = rowCount - offset;
+            limit = limit < 0 ? remaining : Math.min(remaining, limit);
+            if (offset == 0 && remaining <= limit) {
+                return;
+            }
+        } else {
+            limit = 0;
+        }
+        distinctRows = null;
+        rowCount = limit;
+        if (external == null) {
+            if (clearAll) {
+                rows.clear();
+                return;
+            }
+            // avoid copying the whole array for each row
+            rows = new ArrayList<>(rows.subList(offset, offset + limit));
+        } else {
+            if (clearAll) {
+                return;
+            }
+            diskOffset = offset;
+        }
+    }
+
     @Override
     public int getRowCount() {
         return rowCount;
@@ -410,24 +442,6 @@ public class LocalResult implements ResultInterface, ResultTarget {
         this.limit = limit;
     }
 
-    private void applyLimit() {
-        if (limit < 0) {
-            return;
-        }
-        if (external == null) {
-            if (rows.size() > limit) {
-                rows = new ArrayList<>(rows.subList(0, limit));
-                rowCount = limit;
-                distinctRows = null;
-            }
-        } else {
-            if (limit < rowCount) {
-                rowCount = limit;
-                distinctRows = null;
-            }
-        }
-    }
-
     @Override
     public boolean needToClose() {
         return external != null;
@@ -501,31 +515,6 @@ public class LocalResult implements ResultInterface, ResultTarget {
         this.offset = offset;
     }
 
-    private void applyOffset() {
-        if (offset <= 0) {
-            return;
-        }
-        if (external == null) {
-            if (offset >= rows.size()) {
-                rows.clear();
-                rowCount = 0;
-            } else {
-                // avoid copying the whole array for each row
-                int remove = Math.min(offset, rows.size());
-                rows = new ArrayList<>(rows.subList(remove, rows.size()));
-                rowCount -= remove;
-            }
-        } else {
-            if (offset >= rowCount) {
-                rowCount = 0;
-            } else {
-                diskOffset = offset;
-                rowCount -= offset;
-            }
-        }
-        distinctRows = null;
-    }
-
     @Override
     public String toString() {
         return super.toString() + " columns: " + visibleColumnCount +