IVGCVSW-3878 Add reference workload for SLICE

* Added reference workload implementation and layer tests
  for all supported tensor dimensions (1d, 2d, 3d, 4d)

Signed-off-by: Aron Virginas-Tar <Aron.Virginas-Tar@arm.com>
Change-Id: I40eb300828933e9183027281105d1a7e597d1569

1 files changed, 95 insertions, 0 deletions

diff --git a/src/backends/reference/workloads/Slice.cpp b/src/backends/reference/workloads/Slice.cpp
new file mode 100644
index 0000000000..c7ca3b156e
--- /dev/null
+++ b/src/backends/reference/workloads/Slice.cpp
@@ -0,0 +1,95 @@
+//
+// Copyright © 2019 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "Slice.hpp"
+
+#include <boost/assert.hpp>
+#include <boost/core/ignore_unused.hpp>
+#include <boost/numeric/conversion/cast.hpp>
+
+namespace armnn
+{
+
+void Slice(const TensorInfo& inputInfo,
+           const SliceDescriptor& descriptor,
+           const void* inputData,
+           void* outputData,
+           unsigned int dataTypeSize)
+{
+    const TensorShape& inputShape = inputInfo.GetShape();
+    const unsigned int numDims    = inputShape.GetNumDimensions();
+
+    BOOST_ASSERT(descriptor.m_Begin.size() == numDims);
+    BOOST_ASSERT(descriptor.m_Size.size()  == numDims);
+
+    constexpr unsigned int maxNumDims = 4;
+    BOOST_ASSERT(numDims <= maxNumDims);
+
+    std::vector<unsigned int> paddedInput(4);
+    std::vector<unsigned int> paddedBegin(4);
+    std::vector<unsigned int> paddedSize (4);
+
+    const unsigned int numPaddingDims = maxNumDims - numDims;
+    for (unsigned int i = 0u; i < maxNumDims; ++i)
+    {
+        if (i < numPaddingDims)
+        {
+            paddedInput[i] = 1u;
+            paddedBegin[i] = 0u;
+            paddedSize[i]  = 1u;
+        }
+        else
+        {
+            const unsigned int j = i - numPaddingDims;
+            paddedInput[i] = inputShape[j];
+            paddedBegin[i] = descriptor.m_Begin[j];
+            paddedSize[i]  = descriptor.m_Size[j];
+        }
+    }
+
+    unsigned int dim0 = paddedInput[0];
+    unsigned int dim1 = paddedInput[1];
+    unsigned int dim2 = paddedInput[2];
+    unsigned int dim3 = paddedInput[3];
+
+    unsigned int begin0 = paddedBegin[0];
+    unsigned int begin1 = paddedBegin[1];
+    unsigned int begin2 = paddedBegin[2];
+    unsigned int begin3 = paddedBegin[3];
+
+    unsigned int size0  = paddedSize[0];
+    unsigned int size1  = paddedSize[1];
+    unsigned int size2  = paddedSize[2];
+    unsigned int size3  = paddedSize[3];
+
+    BOOST_ASSERT(begin0 + size0 <= dim0);
+    BOOST_ASSERT(begin1 + size1 <= dim1);
+    BOOST_ASSERT(begin2 + size2 <= dim2);
+    BOOST_ASSERT(begin3 + size3 <= dim3);
+
+    const unsigned char* input = reinterpret_cast<const unsigned char*>(inputData);
+    unsigned char* output      = reinterpret_cast<unsigned char*>(outputData);
+
+    boost::ignore_unused(dim0);
+    for (unsigned int idx0 = begin0; idx0 < begin0 + size0; ++idx0)
+    {
+        for (unsigned int idx1 = begin1; idx1 < begin1 + size1; ++idx1)
+        {
+            for (unsigned int idx2 = begin2; idx2 < begin2 + size2; ++idx2)
+            {
+                for (unsigned int idx3 = begin3; idx3 < begin3 + size3; ++idx3)
+                {
+                    const unsigned int inputOffset =
+                        (((idx0 * dim1 + idx1) * dim2 + idx2) * dim3 + idx3) * dataTypeSize;
+
+                    ::memcpy(output, input + inputOffset, dataTypeSize);
+                    output += dataTypeSize;
+                }
+            }
+        }
+    }
+}
+
+} // namespace armnn