JNI bit cast (#7493)

In #7373 logical_cast is renamed to bit_cast. That breaks JNI, and this fixes it. Authors: - Robert (Bobby) Evans (@revans2) - Nghia Truong (@ttnghia) Approvers: - Raza Jafri (@razajafri) - Jason Lowe (@jlowe) - Alessandro Bellina (@abellina) URL: #7493
rapidsai · Mar 3, 2021 · c69b6f8 · c69b6f8
1 parent 5bd6f94
commit c69b6f8
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Showing 3 changed files with 23 additions and 8 deletions.
diff --git a/java/src/main/java/ai/rapids/cudf/ColumnView.java b/java/src/main/java/ai/rapids/cudf/ColumnView.java
@@ -1304,9 +1304,24 @@ public ColumnVector castTo(DType type) {
    * types must match.
    * @param type the type you want to go to.
    * @return a ColumnView that cannot outlive the Column that owns the actual data it points to.
+   * @deprecated this has changed to bit_cast in C++ so use that name instead
    */
+  @Deprecated
   public ColumnView logicalCastTo(DType type) {
-    return new ColumnView(logicalCastTo(getNativeView(),
+    return bitCastTo(type);
+  }
+
+  /**
+   * Zero-copy cast between types with the same underlying length.
+   *
+   * Similar to bit_cast in C++. This will take the underlying data and create new metadata
+   * so it is interpreted as a new type. Not all types are supported the width of the
+   * types must match.
+   * @param type the type you want to go to.
+   * @return a ColumnView that cannot outlive the Column that owns the actual data it points to.
+   */
+  public ColumnView bitCastTo(DType type) {
+    return new ColumnView(bitCastTo(getNativeView(),
         type.typeId.getNativeId(), type.getScale()));
   }
 
@@ -2607,7 +2622,7 @@ private static native long stringReplaceWithBackrefs(long columnView, String pat
 
   private static native long castTo(long nativeHandle, int type, int scale);
 
-  private static native long logicalCastTo(long nativeHandle, int type, int scale);
+  private static native long bitCastTo(long nativeHandle, int type, int scale);
 
   private static native long byteListCast(long nativeHandle, boolean config);
 

diff --git a/java/src/main/native/src/ColumnViewJni.cpp b/java/src/main/native/src/ColumnViewJni.cpp
@@ -760,16 +760,16 @@ JNIEXPORT jlong JNICALL Java_ai_rapids_cudf_ColumnView_castTo(JNIEnv *env, jclas
   CATCH_STD(env, 0);
 }
 
-JNIEXPORT jlong JNICALL Java_ai_rapids_cudf_ColumnView_logicalCastTo(JNIEnv *env, jclass,
-                                                                     jlong handle, jint type,
-                                                                     jint scale) {
+JNIEXPORT jlong JNICALL Java_ai_rapids_cudf_ColumnView_bitCastTo(JNIEnv *env, jclass,
+                                                                 jlong handle, jint type,
+                                                                 jint scale) {
   JNI_NULL_CHECK(env, handle, "native handle is null", 0);
   try {
     cudf::jni::auto_set_device(env);
     cudf::column_view *column = reinterpret_cast<cudf::column_view *>(handle);
     cudf::data_type n_data_type = cudf::jni::make_data_type(type, scale);
     std::unique_ptr<cudf::column_view> result = std::make_unique<cudf::column_view>();
-    *result = cudf::logical_cast(*column, n_data_type);
+    *result = cudf::bit_cast(*column, n_data_type);
     return reinterpret_cast<jlong>(result.release());
   }
   CATCH_STD(env, 0);

diff --git a/java/src/test/java/ai/rapids/cudf/ColumnVectorTest.java b/java/src/test/java/ai/rapids/cudf/ColumnVectorTest.java
@@ -2061,10 +2061,10 @@ void emptyStringColumnFindReplaceAll() {
   }
 
   @Test
-  void testLogicalCast() {
+  void testBitCast() {
     try (ColumnVector cv = ColumnVector.decimalFromLongs(-2, 1L, 2L, 100L, 552L);
          ColumnVector expected = ColumnVector.fromLongs(1L, 2L, 100L, 552L);
-         ColumnView casted = cv.logicalCastTo(DType.INT64)) {
+         ColumnView casted = cv.bitCastTo(DType.INT64)) {
       assertColumnsAreEqual(expected, casted);
     }
   }