bytedeco#391 In case of single dimension, do not calculate strides, s…

…o we save some multiplications

src/main/java/org/bytedeco/javacpp/indexer/Index.java

@@ -28,7 +28,9 @@
  */
 public abstract class Index {
 
-    public static Index ONE = create(1);
+    public static Index create(long size) {
+        return new OneIndex(size);
+    }
 
     public static Index create(long... sizes) {
         return new StrideIndex(sizes, defaultStrides(sizes));

src/main/java/org/bytedeco/javacpp/indexer/OneIndex.java

@@ -0,0 +1,40 @@
+package org.bytedeco.javacpp.indexer;
+
+public class OneIndex extends Index {
+
+    private final long[] sizes;
+
+    /**
+     * TODO
+     *
+     * @param size
+     */
+    protected OneIndex(long size) {
+        this.sizes = new long[]{size};
+    }
+
+    @Override
+    public long index(long i) {
+        return i;
+    }
+
+    @Override
+    public long index(long i, long j) {
+        return i;
+    }
+
+    @Override
+    public long index(long i, long j, long k) {
+        return i;
+    }
+
+    @Override
+    public long index(long... indices) {
+        return indices[0];
+    }
+
+    @Override
+    public long[] sizes() {
+        return sizes;
+    }
+}