From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Thu, 24 Nov 2022 01:21:32 +0100
Subject: [PATCH] SIMD support

License: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)
Gale - https://galemc.org

This patch is based on the following patch:
"Add SIMD utilities"
By: Kevin Raneri <kevin.raneri@gmail.com>
As part of: Pufferfish (https://github.com/pufferfish-gg/Pufferfish)
Licensed under: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html)

diff --git a/src/main/java/gg/pufferfish/pufferfish/simd/SIMDChecker.java b/src/main/java/gg/pufferfish/pufferfish/simd/SIMDChecker.java
new file mode 100644
index 0000000000000000000000000000000000000000..90d87374e9dddd79aeca3e05f9cd6c82eb3aad27
--- /dev/null
+++ b/src/main/java/gg/pufferfish/pufferfish/simd/SIMDChecker.java
@@ -0,0 +1,48 @@
+// Gale - Pufferfish - SIMD support
+
+package gg.pufferfish.pufferfish.simd;
+
+import jdk.incubator.vector.FloatVector;
+import jdk.incubator.vector.IntVector;
+import jdk.incubator.vector.VectorSpecies;
+
+/**
+ * Basically, java is annoying and we have to push this out to its own class.
+ */
+@Deprecated
+public class SIMDChecker {
+
+    public static void initialize() {
+        if (SIMDDetection.isInitialized()) {
+            return;
+        }
+        SIMDDetection.setInitialized();
+        try {
+            int javaVersion = SIMDDetection.getJavaVersion();
+            if (javaVersion < 17) {
+                return;
+            }
+            SIMDDetection.supportingJavaVersion = true;
+            SIMDDetection.testRunStarted = true;
+
+            VectorSpecies<Integer> ISPEC = IntVector.SPECIES_PREFERRED;
+            VectorSpecies<Float> FSPEC = FloatVector.SPECIES_PREFERRED;
+
+            SIMDDetection.intVectorBitSize = ISPEC.vectorBitSize();
+            SIMDDetection.floatVectorBitSize = FSPEC.vectorBitSize();
+
+            SIMDDetection.intElementSize = ISPEC.elementSize();
+            SIMDDetection.floatElementSize = FSPEC.elementSize();
+
+            SIMDDetection.testRunCompleted = true;
+
+            if (ISPEC.elementSize() < 2 || FSPEC.elementSize() < 2) {
+                SIMDDetection.unsupportingLaneSize = true;
+                return;
+            }
+
+            SIMDDetection.isEnabled = true;
+        } catch (Throwable ignored) {} // Basically, we don't do anything. This lets us detect if it's not functional and disable it.
+    }
+
+}
diff --git a/src/main/java/gg/pufferfish/pufferfish/simd/SIMDDetection.java b/src/main/java/gg/pufferfish/pufferfish/simd/SIMDDetection.java
new file mode 100644
index 0000000000000000000000000000000000000000..b19b6bc85cb08a49f064a4ecb88af858a9a22fe7
--- /dev/null
+++ b/src/main/java/gg/pufferfish/pufferfish/simd/SIMDDetection.java
@@ -0,0 +1,78 @@
+// Gale - Pufferfish - SIMD support
+
+package gg.pufferfish.pufferfish.simd;
+
+public class SIMDDetection {
+
+    private static boolean isInitialized = false;
+    static int intVectorBitSize;
+    static int floatVectorBitSize;
+    static int intElementSize;
+    static int floatElementSize;
+    static boolean supportingJavaVersion;
+    static boolean testRunStarted;
+    static boolean testRunCompleted;
+    static boolean unsupportingLaneSize;
+    static boolean isEnabled;
+
+    @SuppressWarnings("deprecation")
+    public static void initialize() {
+        try {
+            SIMDChecker.initialize();
+        } catch (Throwable ignored) {}
+    }
+
+    static void setInitialized() {
+        isInitialized = true;
+    }
+
+    public static boolean isInitialized() {
+        return isInitialized;
+    }
+
+    public static int intVectorBitSize() {
+        return intVectorBitSize;
+    }
+
+    public static int floatVectorBitSize() {
+        return floatVectorBitSize;
+    }
+
+    public static int intElementSize() {
+        return intElementSize;
+    }
+
+    public static int floatElementSize() {
+        return floatElementSize;
+    }
+
+    public static boolean supportingJavaVersion() {
+        return supportingJavaVersion;
+    }
+
+    public static boolean testRunCompleted() {
+        return testRunCompleted;
+    }
+
+    public static boolean unsupportingLaneSize() {
+        return unsupportingLaneSize;
+    }
+
+    public static boolean isEnabled() {
+        return isEnabled;
+    }
+
+    public static int getJavaVersion() {
+        // https://stackoverflow.com/a/2591122
+        String version = System.getProperty("java.version");
+        if(version.startsWith("1.")) {
+            version = version.substring(2, 3);
+        } else {
+            int dot = version.indexOf(".");
+            if(dot != -1) { version = version.substring(0, dot); }
+        }
+        version = version.split("-")[0]; // Azul is stupid
+        return Integer.parseInt(version);
+    }
+
+}