deserialize CPC sketches from Java

cpc/test/CMakeLists.txt

@@ -23,12 +23,12 @@ set_target_properties(cpc_test PROPERTIES
   CXX_STANDARD_REQUIRED YES
 )
 
-#file(TO_CMAKE_PATH "${CMAKE_CURRENT_SOURCE_DIR}" CPC_TEST_BINARY_PATH)
-#string(APPEND CPC_TEST_BINARY_PATH "/")
-#target_compile_definitions(cpc_test
-#  PRIVATE
-#    TEST_BINARY_INPUT_PATH="${CPC_TEST_BINARY_PATH}"
-#)
+file(TO_CMAKE_PATH "${CMAKE_CURRENT_SOURCE_DIR}" CPC_TEST_BINARY_PATH)
+string(APPEND CPC_TEST_BINARY_PATH "/")
+target_compile_definitions(cpc_test
+  PRIVATE
+    TEST_BINARY_INPUT_PATH="${CPC_TEST_BINARY_PATH}"
+)
 
 add_test(
   NAME cpc_test
@@ -42,3 +42,10 @@ target_sources(cpc_test
     compression_test.cpp
     cpc_sketch_allocation_test.cpp
 )
+
+if (SERDE_COMPAT)
+target_sources(cpc_test
+  PRIVATE
+    cpc_sketch_deserialize_from_java_test.cpp
+)
+endif()

cpc/test/cpc_sketch_deserialize_from_java_test.cpp

@@ -0,0 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <catch2/catch.hpp>
+#include <fstream>
+#include <cpc_sketch.hpp>
+
+namespace datasketches {
+
+static std::string testBinaryInputPath = std::string(TEST_BINARY_INPUT_PATH) + "../../java/";
+
+TEST_CASE("cpc sketch", "[serde_compat]") {
+  unsigned n_arr[] = {0, 100, 200, 2000, 20000};
+  for (unsigned n: n_arr) {
+    std::ifstream is;
+    is.exceptions(std::ios::failbit | std::ios::badbit);
+    is.open(testBinaryInputPath + "cpc_n" + std::to_string(n) + ".sk", std::ios::binary);
+    auto sketch = cpc_sketch::deserialize(is);
+    REQUIRE(sketch.is_empty() == (n == 0));
+    REQUIRE(sketch.get_estimate() == Approx(n).margin(n * 0.02));
+  }
+}
+
+} /* namespace datasketches */