* Prototype array view interface

* Buffer slicing and copying
* Test ArrayView constructors and copy/move assignment
* Test ArrayView::Slice, EnsureMutable, and some array attrs

Change-Id: Id4c1d7b95f958d207b443829a53078b3e7ac27f0

Author: wesm

CMakeLists.txt

@@ -574,7 +574,7 @@ if (UNIX)
   # Full lint
   add_custom_target(lint ${BUILD_SUPPORT_DIR}/cpplint.py
   --verbose=4
-  --filter=-whitespace/comments,-readability/todo,-build/header_guard,-build/include_order
+  --filter=-whitespace/comments,-readability/todo,-build/header_guard,-build/include_order,-build/c++11
     `find ${CMAKE_CURRENT_SOURCE_DIR}/src -name \\*.cc -or -name \\*.h`)
 endif (UNIX)
 
@@ -611,12 +611,12 @@ set(PANDAS_SRCS
   src/pandas/numpy_interop.cc
   src/pandas/pytypes.cc
   src/pandas/status.cc
-  src/pandas/types.cc
+  src/pandas/type.cc
 
   src/pandas/types/boolean.cc
+  src/pandas/types/common.cc
   src/pandas/types/category.cc
-  src/pandas/types/integer.cc
-  src/pandas/types/floating.cc
+  src/pandas/types/numeric.cc
 )
 
 add_library(pandas SHARED

src/pandas/CMakeLists.txt

@@ -11,6 +11,7 @@ install(FILES
 
 set(PANDAS_TEST_LINK_LIBS pandas_test_util ${PANDAS_MIN_TEST_LIBS})
 
+ADD_PANDAS_TEST(array-test)
 ADD_PANDAS_TEST(buffer-test)
 ADD_PANDAS_TEST(memory-test)
 ADD_PANDAS_TEST(util-test)

src/pandas/api.h

@@ -6,13 +6,11 @@
 
 #include "pandas/array.h"
 #include "pandas/dispatch.h"
-#include "pandas/types.h"
+#include "pandas/status.h"
+#include "pandas/type.h"
 
 #include "pandas/types/boolean.h"
 #include "pandas/types/category.h"
-#include "pandas/types/floating.h"
-#include "pandas/types/integer.h"
-
-#include "pandas/status.h"
+#include "pandas/types/numeric.h"
 
 #endif // PANDAS_API_H

src/pandas/array-test.cc

@@ -0,0 +1,150 @@
+// This file is a part of pandas. See LICENSE for details about reuse and
+// copyright holders
+
+// Test non-type specific array functionality
+
+#include <cstdint>
+#include <limits>
+#include <string>
+
+#include "gtest/gtest.h"
+
+#include "pandas/array.h"
+#include "pandas/buffer.h"
+#include "pandas/memory.h"
+#include "pandas/status.h"
+#include "pandas/test-util.h"
+#include "pandas/type.h"
+#include "pandas/types/numeric.h"
+
+using std::string;
+
+namespace pandas {
+
+class TestArray : public ::testing::Test {
+ public:
+  void SetUp() {
+    values_ = {0, 1, 2, 3, 4, 5, 6, 7};
+
+    auto buffer = std::make_shared<Buffer>(reinterpret_cast<const uint8_t*>(values_.data()),
+        values_.size() * sizeof(double));
+
+    array_ = std::make_shared<DoubleArray>(values_.size(), buffer);
+  }
+
+ protected:
+  std::shared_ptr<Array> array_;
+  std::vector<double> values_;
+};
+
+TEST_F(TestArray, Attrs) {
+  DoubleType ex_type;
+  ASSERT_TRUE(array_->type()->Equals(ex_type));
+  ASSERT_EQ(DataType::DOUBLE, array_->type_id());
+
+  ASSERT_EQ(values_.size(), array_->length());
+}
+
+// ----------------------------------------------------------------------
+// Array view object
+
+class TestArrayView : public ::testing::Test {
+ public:
+  using value_t = double;
+
+  void SetUp() {
+    values_ = {0, 1, 2, 3, 4, 5, 6, 7};
+
+    auto buffer = std::make_shared<Buffer>(reinterpret_cast<const uint8_t*>(values_.data()),
+        values_.size() * sizeof(value_t));
+
+    auto arr = std::make_shared<DoubleArray>(values_.size(), buffer);
+    view_ = ArrayView(arr);
+  }
+
+ protected:
+  ArrayView view_;
+  std::vector<value_t> values_;
+};
+
+TEST_F(TestArrayView, Ctors) {
+  ASSERT_EQ(1, view_.ref_count());
+  ASSERT_EQ(0, view_.offset());
+  ASSERT_EQ(values_.size(), view_.length());
+
+  // Copy ctor
+  ArrayView view2(view_);
+  ASSERT_EQ(2, view2.ref_count());
+  ASSERT_EQ(0, view_.offset());
+  ASSERT_EQ(values_.size(), view_.length());
+
+  // move ctor
+  ArrayView view3(view_.data(), 3);
+  ArrayView view4(std::move(view3));
+  ASSERT_EQ(3, view4.ref_count());
+  ASSERT_EQ(3, view3.offset());
+  ASSERT_EQ(values_.size() - 3, view3.length());
+
+  // With offset and length
+  ArrayView view5(view4.data(), 2, 4);
+  ASSERT_EQ(2, view5.offset());
+  ASSERT_EQ(4, view5.length());
+
+  // Copy assignment
+  ArrayView view6 = view5;
+  ASSERT_EQ(5, view4.ref_count());
+  ASSERT_EQ(2, view5.offset());
+  ASSERT_EQ(4, view5.length());
+
+  // Move assignment
+  ArrayView view7 = std::move(view6);
+  ASSERT_EQ(5, view4.ref_count());
+  ASSERT_EQ(2, view5.offset());
+  ASSERT_EQ(4, view5.length());
+}
+
+TEST_F(TestArrayView, EnsureMutable) {
+  // This only tests for one data type -- we will need to test more rigorously
+  // across all data types elsewhere
+
+  const Array* ap = view_.data().get();
+
+  ASSERT_OK(view_.EnsureMutable());
+  ASSERT_EQ(ap, view_.data().get());
+
+  ArrayView view2 = view_;
+
+  ASSERT_OK(view_.EnsureMutable());
+
+  // The views now have their own distinct copies of the array
+  ASSERT_NE(ap, view_.data().get());
+  ASSERT_EQ(ap, view2.data().get());
+
+  ASSERT_EQ(1, view_.ref_count());
+  ASSERT_EQ(1, view2.ref_count());
+}
+
+TEST_F(TestArrayView, Slice) {
+  ArrayView s1 = view_.Slice(3);
+  ASSERT_EQ(2, s1.ref_count());
+  ASSERT_EQ(3, s1.offset());
+  ASSERT_EQ(view_.length() - 3, s1.length());
+
+  ArrayView s2 = view_.Slice(2, 4);
+  ASSERT_EQ(3, s2.ref_count());
+  ASSERT_EQ(2, s2.offset());
+  ASSERT_EQ(4, s2.length());
+
+  // Slice of a slice
+  ArrayView s3 = s1.Slice(2);
+  ASSERT_EQ(4, s3.ref_count());
+  ASSERT_EQ(5, s3.offset());
+  ASSERT_EQ(view_.length() - 5, s3.length());
+
+  ArrayView s4 = s1.Slice(1, 2);
+  ASSERT_EQ(5, s4.ref_count());
+  ASSERT_EQ(4, s4.offset());
+  ASSERT_EQ(2, s4.length());
+}
+
+}  // namespace pandas

src/pandas/array.cc

@@ -3,7 +3,98 @@
 
 #include "pandas/array.h"
 #include "pandas/status.h"
+#include "pandas/type.h"
+#include "pandas/util/logging.h"
 
 namespace pandas {
 
+// ----------------------------------------------------------------------
+// Array
+
+Array::Array(const std::shared_ptr<DataType>& type, int64_t length)
+    : type_(type),
+      length_(length) {}
+
+Status Array::Copy(std::shared_ptr<Array>* out) const {
+  return Copy(0, length_, out);
+}
+
+// ----------------------------------------------------------------------
+// ArrayView
+
+ArrayView::ArrayView(const std::shared_ptr<Array>& data)
+    : data_(data),
+      offset_(0),
+      length_(data->length()) {}
+
+ArrayView::ArrayView(const std::shared_ptr<Array>& data, int64_t offset)
+    : data_(data),
+      offset_(offset),
+      length_(data->length() - offset) {
+  // Debugging sanity checks
+  PANDAS_DCHECK_GE(offset, 0);
+  PANDAS_DCHECK_LT(offset, data->length());
+}
+
+ArrayView::ArrayView(const std::shared_ptr<Array>& data, int64_t offset, int64_t length)
+    : data_(data),
+      offset_(offset),
+      length_(length) {
+  // Debugging sanity checks
+  PANDAS_DCHECK_GE(offset, 0);
+  PANDAS_DCHECK_LT(offset, data->length());
+  PANDAS_DCHECK_GE(length, 0);
+  PANDAS_DCHECK_LE(length, data->length() - offset);
+}
+
+// Copy ctor
+ArrayView::ArrayView(const ArrayView& other)
+    : data_(other.data_),
+      offset_(other.offset_),
+      length_(other.length_) {}
+
+// Move ctor
+ArrayView::ArrayView(ArrayView&& other)
+    : data_(std::move(other.data_)),
+      offset_(other.offset_),
+      length_(other.length_) {}
+
+// Copy assignment
+ArrayView& ArrayView::operator=(const ArrayView& other) {
+  data_ = other.data_;
+  offset_ = other.offset_;
+  length_ = other.length_;
+  return *this;
+}
+
+// Move assignment
+ArrayView& ArrayView::operator=(ArrayView&& other) {
+  data_ = std::move(other.data_);
+  offset_ = other.offset_;
+  length_ = other.length_;
+  return *this;
+}
+
+Status ArrayView::EnsureMutable() {
+  if (ref_count() > 1) {
+    std::shared_ptr<Array> copied_data;
+    RETURN_NOT_OK(data_->Copy(&copied_data));
+    data_ = copied_data;
+  }
+  return Status::OK();
+}
+
+ArrayView ArrayView::Slice(int64_t offset) {
+  return ArrayView(data_, offset_ + offset, length_ - offset);
+}
+
+ArrayView ArrayView::Slice(int64_t offset, int64_t length) {
+  return ArrayView(data_, offset_ + offset, length);
+}
+
+// Return the reference count for the underlying array
+int64_t ArrayView::ref_count() const {
+  return data_.use_count();
+}
+
 } // namespace pandas