From c4ae56ef42c57077fe6242a6a3bb58f82add9029 Mon Sep 17 00:00:00 2001
From: =?utf8?q?=EB=B0=95=EC=A2=85=ED=98=84/=EB=8F=99=EC=9E=91=EC=A0=9C?=
 =?utf8?q?=EC=96=B4Lab=28SR=29/Staff=20Engineer/=EC=82=BC=EC=84=B1?=
 =?utf8?q?=EC=A0=84=EC=9E=90?= <jh1302.park@samsung.com>
Date: Thu, 31 May 2018 17:43:27 +0900
Subject: [PATCH] [Pure CL] Introduce Const Tensor View (#1474)

This commit introduces ConstView class to make it easy to write generic
const operand updates.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>
---
 .../src/internal/nnapi/tensor/ConstView.h          | 69 ++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 runtimes/pure_arm_compute/src/internal/nnapi/tensor/ConstView.h

diff --git a/runtimes/pure_arm_compute/src/internal/nnapi/tensor/ConstView.h b/runtimes/pure_arm_compute/src/internal/nnapi/tensor/ConstView.h
new file mode 100644
index 0000000..085f715
--- /dev/null
+++ b/runtimes/pure_arm_compute/src/internal/nnapi/tensor/ConstView.h
@@ -0,0 +1,69 @@
+#ifndef __INTERNAL_NNAPI_TENSOR_CONST_VIEW_H__
+#define __INTERNAL_NNAPI_TENSOR_CONST_VIEW_H__
+
+#include "util/tensor/Shape.h"
+#include "util/tensor/Index.h"
+
+namespace internal
+{
+namespace nnapi
+{
+namespace tensor
+{
+
+template <typename T> class ConstView
+{
+public:
+  ConstView(const ::nnfw::util::tensor::Shape &shape, const uint8_t *ptr, size_t len)
+      : _shape{shape}, _ptr{ptr}, _len{len}
+  {
+    // DO NOTHING
+  }
+
+public:
+  const nnfw::util::tensor::Shape &shape(void) const { return _shape; }
+
+private:
+  // TODO Make this as a helper function, and share it for both View<T> and ConstView<T>
+  uint32_t offset_of(const nnfw::util::tensor::Index &index) const
+  {
+    if (_shape.rank() == 0)
+    {
+      return 0;
+    }
+
+    uint32_t offset = index.at(0);
+
+    // Stride decreases as axis increases in NNAPI
+    for (uint32_t axis = 1; axis < _shape.rank(); ++axis)
+    {
+      offset *= _shape.dim(axis);
+      offset += index.at(axis);
+    }
+
+    return offset;
+  }
+
+public:
+  T at(const nnfw::util::tensor::Index &index) const
+  {
+    const auto offset = offset_of(index);
+
+    const T *arr = reinterpret_cast<const T *>(_ptr);
+
+    return arr[offset];
+  }
+
+private:
+  const nnfw::util::tensor::Shape _shape;
+
+private:
+  const uint8_t *const _ptr;
+  const size_t _len;
+};
+
+} // namespace tensor
+} // namespace nnapi
+} // namespace internal
+
+#endif // __INTERNAL_NNAPI_TENSOR_CONST_VIEW_H__
-- 
2.7.4