working create-new-world

2026-03-08 04:41:51 +09:00 · 2021-10-28 17:32:09 +09:00
parent 1dc7d46c39
commit 3bd7e740d4
6 changed files with 191 additions and 24 deletions
--- a/src/net/torvald/random/XXHash64.java
+++ b/src/net/torvald/random/XXHash64.java
@@ -0,0 +1,123 @@
+package net.torvald.random;
+
+import net.torvald.UnsafeHelper;
+
+/**
+ * Code from https://richardstartin.github.io/posts/xxhash
+ * https://github.com/richardstartin/xxhash-benchmark
+ * Created by minjaesong on 2021-10-28.
+ */
+public class XXHash64 {
+
+    static final long PRIME64_1 = 0x9E3779B185EBCA87L;
+    static final long PRIME64_2 = 0xC2B2AE3D27D4EB4FL;
+    static final long PRIME64_3 = 0x165667B19E3779F9L;
+    static final long PRIME64_4 = 0x85EBCA77C2B2AE63L;
+    static final long PRIME64_5 = 0x27D4EB2F165667C5L;
+
+    public static long hash(byte[] input, long seed) {
+        long hash;
+        long remaining = input.length;
+        int offset = 0;
+
+        if (remaining >= 32) {
+            long v1 = seed + PRIME64_1 + PRIME64_2;
+            long v2 = seed + PRIME64_2;
+            long v3 = seed;
+            long v4 = seed - PRIME64_1;
+
+            do {
+                v1 += getLong(input, offset) * PRIME64_2;
+                v1 = Long.rotateLeft(v1, 31);
+                v1 *= PRIME64_1;
+
+                v2 += getLong(input, offset + 8) * PRIME64_2;
+                v2 = Long.rotateLeft(v2, 31);
+                v2 *= PRIME64_1;
+
+                v3 += getLong(input, offset + 16) * PRIME64_2;
+                v3 = Long.rotateLeft(v3, 31);
+                v3 *= PRIME64_1;
+
+                v4 += getLong(input, offset + 24) * PRIME64_2;
+                v4 = Long.rotateLeft(v4, 31);
+                v4 *= PRIME64_1;
+
+                offset += 32;
+                remaining -= 32;
+            } while (remaining >= 32);
+
+            hash = Long.rotateLeft(v1, 1)
+                    + Long.rotateLeft(v2, 7)
+                    + Long.rotateLeft(v3, 12)
+                    + Long.rotateLeft(v4, 18);
+
+            v1 *= PRIME64_2;
+            v1 = Long.rotateLeft(v1, 31);
+            v1 *= PRIME64_1;
+            hash ^= v1;
+            hash = hash * PRIME64_1 + PRIME64_4;
+
+            v2 *= PRIME64_2;
+            v2 = Long.rotateLeft(v2, 31);
+            v2 *= PRIME64_1;
+            hash ^= v2;
+            hash = hash * PRIME64_1 + PRIME64_4;
+
+            v3 *= PRIME64_2;
+            v3 = Long.rotateLeft(v3, 31);
+            v3 *= PRIME64_1;
+            hash ^= v3;
+            hash = hash * PRIME64_1 + PRIME64_4;
+
+            v4 *= PRIME64_2;
+            v4 = Long.rotateLeft(v4, 31);
+            v4 *= PRIME64_1;
+            hash ^= v4;
+            hash = hash * PRIME64_1 + PRIME64_4;
+        } else {
+            hash = seed + PRIME64_5;
+        }
+
+        hash += input.length;
+
+        while (remaining >= 8) {
+            long k1 = getLong(input, offset);
+            k1 *= PRIME64_2;
+            k1 = Long.rotateLeft(k1, 31);
+            k1 *= PRIME64_1;
+            hash ^= k1;
+            hash = Long.rotateLeft(hash, 27) * PRIME64_1 + PRIME64_4;
+            offset += 8;
+            remaining -= 8;
+        }
+
+        if (remaining >= 4) {
+            hash ^= getInt(input, offset) * PRIME64_1;
+            hash = Long.rotateLeft(hash, 23) * PRIME64_2 + PRIME64_3;
+            offset += 4;
+            remaining -= 4;
+        }
+
+        while (remaining != 0) {
+            hash ^= input[offset] * PRIME64_5;
+            hash = Long.rotateLeft(hash, 11) * PRIME64_1;
+            --remaining;
+            ++offset;
+        }
+
+        hash ^= hash >>> 33;
+        hash *= PRIME64_2;
+        hash ^= hash >>> 29;
+        hash *= PRIME64_3;
+        hash ^= hash >>> 32;
+        return hash;
+    }
+
+    protected static long getLong(byte[] data, int offset) {
+        return UnsafeHelper.INSTANCE.getUnsafe().getLong(data, offset + UnsafeHelper.INSTANCE.getArrayOffset(data));
+    }
+    protected static int getInt(byte[] data, int offset) {
+        return UnsafeHelper.INSTANCE.getUnsafe().getInt(data, offset + UnsafeHelper.INSTANCE.getArrayOffset(data));
+    }
+}