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1 // Copyright 2015 The Gemmlowp Authors. 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 // map.h: a minimalist view-existing-buffer-as-a-matrix class,
16 // which is how gemmlowp interfaces with external matrix data.
17 
18 #ifndef GEMMLOWP_PUBLIC_MAP_H_
19 #define GEMMLOWP_PUBLIC_MAP_H_
20 
21 #include "../internal/common.h"
22 
23 namespace gemmlowp {
24 
25 // The two storage orders allowed to map buffers as matrices: ColMajor
26 // means column-major, RowMajor means row-major.
27 enum class MapOrder { ColMajor, RowMajor };
28 
29 // A MatrixMap is a view of an existing buffer as a matrix. It does not own
30 // the buffer.
31 template <typename tScalar, MapOrder tOrder>
32 class MatrixMap {
33  public:
34   typedef tScalar Scalar;
35   static constexpr MapOrder kOrder = tOrder;
36 
37  protected:
38   Scalar* data_;  // not owned.
39   int rows_, cols_, stride_;
40 
41  public:
MatrixMap()42   MatrixMap() : data_(nullptr), rows_(0), cols_(0), stride_(0) {}
MatrixMap(Scalar * data,int rows,int cols)43   MatrixMap(Scalar* data, int rows, int cols)
44       : data_(data),
45         rows_(rows),
46         cols_(cols),
47         stride_(kOrder == MapOrder::ColMajor ? rows : cols) {}
MatrixMap(Scalar * data,int rows,int cols,int stride)48   MatrixMap(Scalar* data, int rows, int cols, int stride)
49       : data_(data), rows_(rows), cols_(cols), stride_(stride) {}
MatrixMap(const MatrixMap & other)50   MatrixMap(const MatrixMap& other)
51       : data_(other.data_),
52         rows_(other.rows_),
53         cols_(other.cols_),
54         stride_(other.stride_) {}
55 
rows()56   int rows() const { return rows_; }
cols()57   int cols() const { return cols_; }
stride()58   int stride() const { return stride_; }
rows_stride()59   int rows_stride() const { return kOrder == MapOrder::ColMajor ? 1 : stride_; }
cols_stride()60   int cols_stride() const { return kOrder == MapOrder::RowMajor ? 1 : stride_; }
data()61   Scalar* data() const { return data_; }
data(int row,int col)62   Scalar* data(int row, int col) const {
63     return data_ + row * rows_stride() + col * cols_stride();
64   }
operator()65   Scalar& operator()(int row, int col) const { return *data(row, col); }
66 
block(int start_row,int start_col,int block_rows,int block_cols)67   MatrixMap block(int start_row, int start_col, int block_rows,
68                   int block_cols) const {
69     assert(start_row >= 0);
70     assert(start_row + block_rows <= rows_);
71     assert(start_col >= 0);
72     assert(start_col + block_cols <= cols_);
73 
74     return MatrixMap(data(start_row, start_col), block_rows, block_cols,
75                      stride_);
76   }
77 };
78 
79 enum class VectorShape { Col, Row };
80 
81 // A VectorMap is a view of an existing buffer as a vector. It does not own
82 // the buffer.
83 template <typename tScalar, VectorShape tShape>
84 class VectorMap {
85  public:
86   typedef tScalar Scalar;
87   static constexpr VectorShape kShape = tShape;
88 
89  protected:
90   Scalar* data_;  // not owned.
91   int size_;
92 
93  public:
VectorMap()94   VectorMap() : data_(nullptr), size_(0) {}
VectorMap(Scalar * data,int size)95   VectorMap(Scalar* data, int size) : data_(data), size_(size) {}
VectorMap(const VectorMap & other)96   VectorMap(const VectorMap& other) : data_(other.data_), size_(other.size_) {}
97 
size()98   int size() const { return size_; }
data()99   Scalar* data() const { return data_; }
data(int index)100   Scalar* data(int index) const { return data_ + index; }
operator()101   Scalar& operator()(int index) const { return *data(index); }
102 
block(int start,int len)103   VectorMap block(int start, int len) const {
104     assert(start >= 0);
105     assert(start + len <= size_);
106 
107     return VectorMap(data(start), len);
108   }
109 };
110 
111 // A VectorDup is a (duplicated value) vector where all components are the same.
112 template <typename tScalar, VectorShape tShape>
113 class VectorDup {
114  public:
115   typedef tScalar Scalar;
116   static constexpr VectorShape kShape = tShape;
117 
118  protected:
119   Scalar data_;
120   int size_;
121 
122  public:
VectorDup()123   VectorDup() : data_(0), size_(0) {}
VectorDup(Scalar data,int size)124   VectorDup(Scalar data, int size) : data_(data), size_(size) {}
VectorDup(const VectorDup & other)125   VectorDup(const VectorDup& other) : data_(other.data_), size_(other.size_) {}
126 
size()127   int size() const { return size_; }
operator()128   Scalar& operator()(int) const { return data_; }
129 
block(int start,int len)130   VectorDup block(int start, int len) const {
131     assert(start >= 0);
132     assert(start + len <= size_);
133 
134     (void)start;
135     return VectorDup(data_, len);
136   }
137 };
138 
139 }  // namespace gemmlowp
140 
141 #endif  // GEMMLOWP_PUBLIC_MAP_H_
142