COMPMID-1235: Implements StridedSlice for CL

Change-Id: If2b44da31fae528c76be742b4b3a21fb0eb06b49
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/145284
Reviewed-by: Giuseppe Rossini <giuseppe.rossini@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/reference/StridedSlice.cpp b/tests/validation/reference/StridedSlice.cpp
new file mode 100644
index 0000000..ac02ce1
--- /dev/null
+++ b/tests/validation/reference/StridedSlice.cpp
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2018 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "StridedSlice.h"
+
+#include "arm_compute/core/utils/helpers/tensor_transform.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<T> strided_slice(const SimpleTensor<T> &src,
+                              Coordinates starts, Coordinates ends, BiStrides strides,
+                              int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask)
+{
+    using namespace arm_compute::helpers::tensor_transform;
+
+    // Validation checks
+    ARM_COMPUTE_ERROR_ON(src.shape().num_dimensions() > 4);
+    ARM_COMPUTE_ERROR_ON(starts.num_dimensions() > src.shape().num_dimensions());
+    ARM_COMPUTE_ERROR_ON(ends.num_dimensions() > src.shape().num_dimensions());
+    ARM_COMPUTE_ERROR_ON(strides.num_dimensions() > src.shape().num_dimensions());
+    for(unsigned int i = 0; i < strides.num_dimensions(); ++i)
+    {
+        ARM_COMPUTE_ERROR_ON(strides[i] == 0);
+    }
+
+    // Get source shape
+    const TensorShape &src_shape = src.shape();
+
+    // Get actual start, end coordinates and strides
+    const Coordinates final_strides = strided_slice_strides(src_shape, strides);
+    const Coordinates starts_abs    = strided_slice_absolute_start_coords(src_shape, starts, final_strides, begin_mask);
+    const Coordinates ends_abs      = strided_slice_absolute_end_coords(src_shape, starts_abs, ends, final_strides, end_mask, shrink_axis_mask);
+
+    // Get destination shape
+    const TensorShape dst_shape = compute_strided_slice_output_shape(src_shape, starts_abs, ends_abs, final_strides);
+
+    // Create destination tensor
+    SimpleTensor<T> dst{ dst_shape, src.data_type(), 1 };
+
+    // Perform strided slice
+    Window win;
+    win.use_tensor_dimensions(dst_shape);
+    execute_window_loop(win, [&](const Coordinates & id)
+    {
+        Coordinates offset;
+        for(unsigned int i = 0; i < id.num_dimensions(); ++i)
+        {
+            offset.set(i, starts_abs[i] + id[i] * final_strides[i]);
+        }
+        *reinterpret_cast<T *>(dst(id)) = *reinterpret_cast<const T *>(src(offset));
+    });
+
+    return dst;
+}
+
+template SimpleTensor<float> strided_slice(const SimpleTensor<float> &src,
+                                           Coordinates starts, Coordinates ends, BiStrides strides,
+                                           int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask);
+template SimpleTensor<half_float::half> strided_slice(const SimpleTensor<half_float::half> &src,
+                                                      Coordinates starts, Coordinates ends, BiStrides strides,
+                                                      int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/reference/StridedSlice.h b/tests/validation/reference/StridedSlice.h
new file mode 100644
index 0000000..805b7e6
--- /dev/null
+++ b/tests/validation/reference/StridedSlice.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef __ARM_COMPUTE_TEST_STRIDED_SLICE_H__
+#define __ARM_COMPUTE_TEST_STRIDED_SLICE_H__
+
+#include "tests/SimpleTensor.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<T> strided_slice(const SimpleTensor<T> &src,
+                              Coordinates starts, Coordinates ends, BiStrides strides,
+                              int32_t begin_mask, int32_t end_mask, int32_t shrink_axis_mask);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_TEST_STRIDED_SLICE_H__ */