[sis] 01/03: Override the most commonly used `transform(…)` variant for efficiency.

[desruisseaux]

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desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git

commit 5cc682122d8f5d4a3e5998ae5ddca9f3cca3e14c
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Mon Jan 31 11:51:44 2022 +0100

    Override the most commonly used `transform(…)` variant for efficiency.
---
 .../operation/transform/RotatedPole.java           | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git 
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
 
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
index 9a39db9..5026903 100644
--- 
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
+++ 
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
@@ -322,6 +322,36 @@ public class RotatedPole extends AbstractMathTransform2D 
implements Serializable
     }
 
     /**
+     * Converts a list of coordinate points. This method performs the same 
calculation than above
+     * {@link #transform(double[], int, double[], int, boolean)} method, but 
is overridden for efficiency.
+     *
+     * @throws TransformException if a point can not be converted.
+     */
+    @Override
+    public void transform(final double[] srcPts, int srcOff,
+                          final double[] dstPts, int dstOff, int numPts)
+            throws TransformException
+    {
+        if ((srcPts == dstPts && srcOff < dstOff) || getClass() != 
RotatedPole.class) {
+            super.transform(srcPts, srcOff, dstPts, dstOff, numPts);
+            return;
+        }
+        while (--numPts >= 0) {
+            double λ    = srcPts[srcOff++];
+            double φ    = srcPts[srcOff++];
+            double z    = sin(φ);
+            double cosφ = cos(φ);
+            double y    = sin(λ) * cosφ;
+            double x    = cos(λ) * cosφ;
+            double xt   =  cosφp * z - sinφp * x;
+            double zt   = -cosφp * x - sinφp * z;
+            double r    = fastHypot(xt, y);
+            dstPts[dstOff++] = atan2(y, xt);
+            dstPts[dstOff++] = atan2(zt, r);
+        }
+    }
+
+    /**
      * Returns the inverse transform of this object.
      *
      * @return the inverse of this transform.