1 // Copyright 2016 Google Inc. All Rights Reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 // iterator.h: Const forward iterators for VectorMap and VectorDup that help
16 // access data in architecture specific way, e.g. 4 elements at a time for NEON.
17
18 #ifndef GEMMLOWP_INTERNAL_ITERATOR_H_
19 #define GEMMLOWP_INTERNAL_ITERATOR_H_
20
21 namespace gemmlowp {
22
23 enum class VectorShape;
24
25 // ConstIterator is a forward only constant iterator that can be made
26 // architecture specific e.g. to return 4 values at once for NEON.
27 template <typename VectorType> class ConstIterator {
28 // Unused default case.
29 };
30
31 template <typename tScalar, VectorShape tShape> class VectorMap;
32
33 template <typename tScalar, VectorShape tShape>
34 class ConstIterator<VectorMap<tScalar, tShape>> {
35 public:
36 typedef tScalar Scalar;
ConstIterator(const VectorMap<tScalar,tShape> & vector_map)37 ConstIterator(const VectorMap<tScalar, tShape>& vector_map)
38 : pointer_(vector_map.data()) {}
39 const Scalar operator*() const { return *pointer_; }
get()40 const Scalar* get() const { return pointer_; }
41 ConstIterator& operator+=(int inc) { pointer_ += inc; return *this; }
42 private:
43 const Scalar* pointer_;
44 };
45
46 template <typename tScalar, VectorShape tShape>
const_iterator(const VectorMap<tScalar,tShape> & vector_map)47 ConstIterator<VectorMap<tScalar, tShape>> const_iterator(
48 const VectorMap<tScalar, tShape>& vector_map) {
49 return ConstIterator<VectorMap<tScalar, tShape>>(vector_map);
50 }
51
52 template <typename tScalar, VectorShape tShape> class VectorDup;
53
54 template <typename tScalar, VectorShape tShape>
55 class ConstIterator<VectorDup<tScalar, tShape>> {
56 public:
57 typedef tScalar Scalar;
ConstIterator(const VectorDup<tScalar,tShape> & vector_dup)58 ConstIterator(const VectorDup<tScalar, tShape>& vector_dup)
59 : data_(vector_dup(0)) {}
60 const Scalar operator*() const { return data_; }
get()61 const Scalar* get() const { return &data_; }
62 ConstIterator& operator+=(int inc) { return *this; }
63 private:
64 Scalar data_;
65 };
66
67 template <typename tScalar, VectorShape tShape>
const_iterator(const VectorDup<tScalar,tShape> & vector_map)68 ConstIterator<VectorDup<tScalar, tShape>> const_iterator(
69 const VectorDup<tScalar, tShape>& vector_map) {
70 return ConstIterator<VectorDup<tScalar, tShape>>(vector_map);
71 }
72
73 } // namespace gemmlowp
74
75 #endif // GEMMLOWP_INTERNAL_ITERATOR_H_
76