Test all supported vector widths (simdjson#25)

* test both vector species if on 512-bit-capable platform

* test both species on all platforms

Author: steveatgh

build.gradle

@@ -2,6 +2,7 @@ import me.champeau.jmh.JmhBytecodeGeneratorTask
 import org.gradle.internal.os.OperatingSystem
 import org.ajoberstar.grgit.Grgit
 import java.time.Duration
+import jdk.incubator.vector.ByteVector
 
 plugins {
     id 'java'
@@ -69,18 +70,37 @@ tasks.register('downloadTestData') {
     }
 }
 
-test {
+tasks.register('test256', Test) {
+    dependsOn downloadTestData
+    useJUnitPlatform()
+    jvmArgs += [
+            '--add-modules', 'jdk.incubator.vector',
+            '-Xmx2g',
+            '-Dorg.simdjson.species=256'
+    ]
+    testLogging {
+        events 'PASSED', 'SKIPPED', 'FAILED', 'STANDARD_OUT', 'STANDARD_ERROR'
+    }
+}
+
+tasks.register('test512', Test) {
     dependsOn downloadTestData
     useJUnitPlatform()
     jvmArgs += [
             '--add-modules', 'jdk.incubator.vector',
-            '-Xmx2g'
+            '-Xmx2g',
+            '-Dorg.simdjson.species=512'
     ]
     testLogging {
         events 'PASSED', 'SKIPPED', 'FAILED', 'STANDARD_OUT', 'STANDARD_ERROR'
     }
 }
 
+test {
+    dependsOn 'test256'
+    dependsOn 'test512'
+}
+
 tasks.withType(JmhBytecodeGeneratorTask).configureEach {
     jvmArgs.set(["--add-modules=jdk.incubator.vector"])
 }

gradle.properties

@@ -0,0 +1 @@
+org.gradle.jvmargs="--add-modules=jdk.incubator.vector"

src/main/java/org/simdjson/StructuralIndexer.java

@@ -12,7 +12,13 @@ class StructuralIndexer {
     static final int N_CHUNKS;
 
     static {
-        SPECIES = ByteVector.SPECIES_PREFERRED;
+        String species = System.getProperty("org.simdjson.species", "preferred");
+        SPECIES = switch(species) {
+            case "preferred" -> ByteVector.SPECIES_PREFERRED;
+            case "512" -> ByteVector.SPECIES_512;      
+            case "256" -> ByteVector.SPECIES_256;
+            default -> throw new IllegalArgumentException("Unsupported vector species: " + species);
+        };              
         N_CHUNKS = 64 / SPECIES.vectorByteSize();
         if (SPECIES != ByteVector.SPECIES_256 && SPECIES != ByteVector.SPECIES_512) {
             throw new IllegalArgumentException("Unsupported vector species: " + SPECIES);