APPBROWSER-341: Add ResizeNearest operator support

Change-Id: I1eefcb89b2185514f6eba8f3d0e7b126b20f7d8f
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/113856
Reviewed-by: Joel Liang <joel.liang@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
diff --git a/src/core/GLES_COMPUTE/kernels/GCScaleKernel.cpp b/src/core/GLES_COMPUTE/kernels/GCScaleKernel.cpp
new file mode 100644
index 0000000..7461c54
--- /dev/null
+++ b/src/core/GLES_COMPUTE/kernels/GCScaleKernel.cpp
@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2016, 2017 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 "arm_compute/core/GLES_COMPUTE/kernels/GCScaleKernel.h"
+
+#include "arm_compute/core/AccessWindowStatic.h"
+#include "arm_compute/core/Error.h"
+#include "arm_compute/core/GLES_COMPUTE/GCHelpers.h"
+#include "arm_compute/core/GLES_COMPUTE/GCKernelLibrary.h"
+#include "arm_compute/core/GLES_COMPUTE/IGCKernel.h"
+#include "arm_compute/core/GLES_COMPUTE/IGCTensor.h"
+#include "arm_compute/core/GLES_COMPUTE/OpenGLES.h"
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/TensorInfo.h"
+#include "arm_compute/core/Validate.h"
+
+#include <set>
+#include <string>
+
+using namespace arm_compute;
+
+BorderSize GCScaleKernel::border_size() const
+{
+    return BorderSize(1);
+}
+
+void GCScaleKernel::configure(const IGCTensor *input, IGCTensor *output, InterpolationPolicy policy, bool border_undefined, SamplingPolicy sampling_policy)
+{
+    ARM_COMPUTE_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 1, DataType::F16);
+    ARM_COMPUTE_ERROR_ON_NULLPTR(output);
+    ARM_COMPUTE_ERROR_ON_MISMATCHING_DATA_TYPES(input, output);
+    ARM_COMPUTE_ERROR_ON(output == input);
+    ARM_COMPUTE_ERROR_ON(policy != InterpolationPolicy::NEAREST_NEIGHBOR);
+    ARM_COMPUTE_UNUSED(sampling_policy);
+
+    _input  = input;
+    _output = output;
+
+    // Compute the ratio between source width/height and destination width/height
+    const auto wr = static_cast<float>(input->info()->dimension(0)) / static_cast<float>(output->info()->dimension(0));
+    const auto hr = static_cast<float>(input->info()->dimension(1)) / static_cast<float>(output->info()->dimension(1));
+
+    // Compute actual border size
+    BorderSize border = border_undefined ? BorderSize(0) : border_size();
+
+    // Area interpolation behaves as Nearest Neighbour in case of up-sampling
+    if(policy == InterpolationPolicy::AREA && wr <= 1.f && hr <= 1.f)
+    {
+        policy = InterpolationPolicy::NEAREST_NEIGHBOR;
+    }
+    else
+    {
+        ARM_COMPUTE_ERROR_ON(policy == InterpolationPolicy::AREA);
+    }
+
+    // Create kernel
+    std::set<std::string> build_opts;
+    build_opts.emplace("#define LOCAL_SIZE_X " + support::cpp11::to_string(1));
+    build_opts.emplace("#define LOCAL_SIZE_Y " + support::cpp11::to_string(1));
+    build_opts.emplace("#define LOCAL_SIZE_Z " + support::cpp11::to_string(1));
+
+    build_opts.emplace("#define DATA_TYPE_FP16");
+    build_opts.emplace("#define BORDER_SIZE " + support::cpp11::to_string(border.right));
+
+    // Configure kernel window
+    unsigned int num_elems_processed_per_iteration = 4;
+    unsigned int input_width_alignment             = 2;
+
+    // performance optimization for 2x upscaling with no border
+    if((fabs(wr - 0.5) < 1e-6) && (fabs(hr - 0.5) < 1e-6) && border_undefined)
+    {
+        num_elems_processed_per_iteration = 8;
+        input_width_alignment             = 4;
+        build_opts.emplace("#define SCALE_NEAREST_8X");
+    }
+    else
+    {
+        build_opts.emplace("#define SCALE_NEAREST_GENERIC");
+    }
+
+    std::string interpolation_name = string_from_interpolation_policy(policy); // NOLINT
+    std::transform(interpolation_name.begin(), interpolation_name.end(), interpolation_name.begin(), ::tolower);
+    std::string kernel_name = "scale_" + interpolation_name;
+    _kernel                 = GCKernelLibrary::get().create_kernel(kernel_name, build_opts);
+
+    Window win = calculate_max_window(*output->info(), Steps(num_elems_processed_per_iteration));
+
+    const ValidRegion &input_valid_region = input->info()->valid_region();
+
+    const int total_width   = border.left + input_valid_region.anchor[0] + input_valid_region.shape[0] + border.right;
+    const int padding_right = ceil_to_multiple(total_width, input_width_alignment) - border.left - input_valid_region.anchor[0] - input_valid_region.shape[0];
+
+    // Reads can occur within the valid region of the input
+    AccessWindowStatic input_access(input->info(),
+                                    input_valid_region.anchor[0] - border.left, input_valid_region.anchor[1] - border.top,
+                                    input_valid_region.anchor[0] + input_valid_region.shape[0] + padding_right,
+                                    input_valid_region.anchor[1] + input_valid_region.shape[1] + border.bottom);
+
+    AccessWindowHorizontal output_access(output->info(), 0, num_elems_processed_per_iteration);
+
+    update_window_and_padding(win, input_access, output_access);
+
+    output_access.set_valid_region(win, calculate_valid_region_scale(*(input->info()),
+                                                                     output->info()->tensor_shape(),
+                                                                     policy,
+                                                                     border,
+                                                                     border_undefined));
+
+    IGCKernel::configure(win);
+
+    // Set static kernel arguments
+    const float scale_x = static_cast<float>(input->info()->dimension(0)) / output->info()->dimension(0);
+    const float scale_y = static_cast<float>(input->info()->dimension(1)) / output->info()->dimension(1);
+
+    unsigned int idx = 2 * num_arguments_per_2D_tensor(); //Skip the tensor parameters
+    _kernel.set_argument<float>(idx++, static_cast<float>(input->info()->dimension(0)));
+    _kernel.set_argument<float>(idx++, static_cast<float>(input->info()->dimension(1)));
+    _kernel.set_argument(idx++, scale_x);
+    _kernel.set_argument(idx++, scale_y);
+}