Implement IntArrayView::split for dicttoolkit.

Bug: 10059681
Change-Id: Ic29e79d049bb532727cf5cb1e529fec5d35156ed

native/jni/src/utils/int_array_view.h

@@ -133,6 +133,29 @@ class IntArrayView {
         return std::vector<int>(begin(), end());
     }
 
+    std::vector<IntArrayView> split(const int separator, const int limit = S_INT_MAX) const {
+        if (limit <= 0) {
+            return std::vector<IntArrayView>();
+        }
+        std::vector<IntArrayView> result;
+        if (limit == 1) {
+            result.emplace_back(mPtr, mSize);
+            return result;
+        }
+        size_t startIndex = 0;
+        for (size_t i = 0; i < mSize; ++i) {
+            if (mPtr[i] == separator) {
+                result.emplace_back(mPtr + startIndex, i - startIndex);
+                startIndex = i + 1;
+                if (result.size() >= static_cast<size_t>(limit - 1)) {
+                    break;
+                }
+            }
+        }
+        result.emplace_back(mPtr + startIndex, mSize - startIndex);
+        return result;
+    }
+
  private:
     DISALLOW_ASSIGNMENT_OPERATOR(IntArrayView);
 

native/jni/tests/utils/int_array_view_test.cpp

@@ -151,5 +151,52 @@ TEST(IntArrayViewTest, TestToVector) {
     EXPECT_EQ(std::vector<int>(), CodePointArrayView().toVector());
 }
 
+TEST(IntArrayViewTest, TestSplit) {
+    EXPECT_TRUE(IntArrayView().split(0, 0).empty());
+    {
+        const auto intArrayViews = IntArrayView().split(0, 1);
+        EXPECT_EQ(1u, intArrayViews.size());
+        EXPECT_TRUE(intArrayViews[0].empty());
+    }
+    {
+        const auto intArrayViews = IntArrayView().split(0, 100);
+        EXPECT_EQ(1u, intArrayViews.size());
+        EXPECT_TRUE(intArrayViews[0].empty());
+    }
+
+    const std::vector<int> intVector = {1, 2, 3, 3, 2, 3};
+    const IntArrayView intArrayView(intVector);
+    {
+        const auto intArrayViews = intArrayView.split(2);
+        EXPECT_EQ(3u, intArrayViews.size());
+        EXPECT_EQ(std::vector<int>({1}), intArrayViews[0].toVector());
+        EXPECT_EQ(std::vector<int>({3, 3}), intArrayViews[1].toVector());
+        EXPECT_EQ(std::vector<int>({3}), intArrayViews[2].toVector());
+    }
+    {
+        const auto intArrayViews = intArrayView.split(2, 2);
+        EXPECT_EQ(2u, intArrayViews.size());
+        EXPECT_EQ(std::vector<int>({1}), intArrayViews[0].toVector());
+        EXPECT_EQ(std::vector<int>({3, 3, 2, 3}), intArrayViews[1].toVector());
+    }
+    {
+        const auto intArrayViews = intArrayView.split(2, 1);
+        EXPECT_EQ(1u, intArrayViews.size());
+        EXPECT_EQ(intVector, intArrayViews[0].toVector());
+    }
+    {
+        const auto intArrayViews = intArrayView.split(2, 0);
+        EXPECT_EQ(0u, intArrayViews.size());
+    }
+    {
+        const auto intArrayViews = intArrayView.split(3);
+        EXPECT_EQ(4u, intArrayViews.size());
+        EXPECT_EQ(std::vector<int>({1, 2}), intArrayViews[0].toVector());
+        EXPECT_EQ(std::vector<int>(), intArrayViews[1].toVector());
+        EXPECT_EQ(std::vector<int>({2}), intArrayViews[2].toVector());
+        EXPECT_EQ(std::vector<int>(), intArrayViews[3].toVector());
+    }
+}
+
 }  // namespace
 }  // namespace latinime