Proper zeroing-out mapped bytes (that could potentially be dirty), and only the bytes that are required to be zero by tier state invariants; refactorings and renamings

2021-09-13 01:26:12 +00:00 · 2015-10-03 01:38:35 +03:00
parent 05f94965be
commit 71599fd4eb
4 changed files with 104 additions and 61 deletions
@@ -0,0 +1,76 @@
+/*
+ *      Copyright (C) 2015  higherfrequencytrading.com
+ *
+ *      This program is free software: you can redistribute it and/or modify
+ *      it under the terms of the GNU Lesser General Public License as published by
+ *      the Free Software Foundation, either version 3 of the License.
+ *
+ *      This program is distributed in the hope that it will be useful,
+ *      but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *      GNU Lesser General Public License for more details.
+ *
+ *      You should have received a copy of the GNU Lesser General Public License
+ *      along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.openhft.chronicle.hash.impl;
+
+import static net.openhft.lang.io.NativeBytes.UNSAFE;
+
+/**
+ * The reason why this is not a data value generated class, and offsets are allocated by
+ * hand -- this functionality is accessed concurrently from many threads, and data value generated
+ * classes are stateful - so need to keep an instance in thread local that seems to be overall more
+ * pain than gain.
+ */
+public enum TierCountersArea {
+    ;
+
+    public static final long NEXT_TIER_INDEX_OFFSET = 0L;
+    public static final long PREV_TIER_INDEX_OFFSET = NEXT_TIER_INDEX_OFFSET + 8L;
+    public static final long NEXT_POS_TO_SEARCH_FROM_TIERED_OFFSET = PREV_TIER_INDEX_OFFSET + 8L;
+    public static final long SEGMENT_INDEX_OFFSET = NEXT_POS_TO_SEARCH_FROM_TIERED_OFFSET + 8L;
+    public static final long TIER_OFFSET = SEGMENT_INDEX_OFFSET + 4L;
+
+    public static long nextTierIndex(long address) {
+        return UNSAFE.getLong(address + NEXT_TIER_INDEX_OFFSET);
+    }
+
+    public static void nextTierIndex(long address, long nextTierIndex) {
+        UNSAFE.putLong(address + NEXT_TIER_INDEX_OFFSET, nextTierIndex);
+    }
+
+    public static long nextPosToSearchFromTiered(long address) {
+        return UNSAFE.getLong(address + NEXT_POS_TO_SEARCH_FROM_TIERED_OFFSET);
+    }
+
+    public static void nextPosToSearchFromTiered(long address, long nextPosToSearchFrom) {
+        UNSAFE.putLong(address + NEXT_POS_TO_SEARCH_FROM_TIERED_OFFSET,
+                nextPosToSearchFrom);
+    }
+
+    public static long prevTierIndex(long address) {
+        return UNSAFE.getLong(address + PREV_TIER_INDEX_OFFSET);
+    }
+
+    public static void prevTierIndex(long address, long prevTierIndex) {
+        UNSAFE.putLong(address + PREV_TIER_INDEX_OFFSET, prevTierIndex);
+    }
+
+    public static int segmentIndex(long address) {
+        return UNSAFE.getInt(address + SEGMENT_INDEX_OFFSET);
+    }
+
+    public static void segmentIndex(long address, int segmentIndex) {
+        UNSAFE.putInt(address + SEGMENT_INDEX_OFFSET, segmentIndex);
+    }
+
+    public static int tier(long address) {
+        return UNSAFE.getInt(address + TIER_OFFSET);
+    }
+
+    public static void tier(long address, int tier) {
+        UNSAFE.putInt(address + TIER_OFFSET, tier);
+    }
+}