2 // Copyright © 2017 Arm Ltd. All rights reserved.
3 // SPDX-License-Identifier: MIT
5 #include "MnistDatabase.hpp"
7 #include <armnn/Logging.hpp>
9 #include <boost/numeric/conversion/cast.hpp>
10 #include <boost/assert.hpp>
14 constexpr int g_kMnistImageByteSize = 28 * 28;
16 void EndianSwap(unsigned int &x)
18 x = (x >> 24) | ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | (x << 24);
21 MnistDatabase::MnistDatabase(const std::string& binaryFileDirectory, bool scaleValues)
22 : m_BinaryDirectory(binaryFileDirectory)
23 , m_ScaleValues(scaleValues)
27 std::unique_ptr<MnistDatabase::TTestCaseData> MnistDatabase::GetTestCaseData(unsigned int testCaseId)
29 std::vector<unsigned char> I(g_kMnistImageByteSize);
30 unsigned int label = 0;
32 std::string imagePath = m_BinaryDirectory + std::string("t10k-images.idx3-ubyte");
33 std::string labelPath = m_BinaryDirectory + std::string("t10k-labels.idx1-ubyte");
35 std::ifstream imageStream(imagePath, std::ios::binary);
36 std::ifstream labelStream(labelPath, std::ios::binary);
38 if (!imageStream.is_open())
40 ARMNN_LOG(fatal) << "Failed to load " << imagePath;
43 if (!labelStream.is_open())
45 ARMNN_LOG(fatal) << "Failed to load " << imagePath;
49 unsigned int magic, num, row, col;
51 // Checks the files have the correct header.
52 imageStream.read(reinterpret_cast<char*>(&magic), sizeof(magic));
53 if (magic != 0x03080000)
55 ARMNN_LOG(fatal) << "Failed to read " << imagePath;
58 labelStream.read(reinterpret_cast<char*>(&magic), sizeof(magic));
59 if (magic != 0x01080000)
61 ARMNN_LOG(fatal) << "Failed to read " << labelPath;
65 // Endian swaps the image and label file - all the integers in the files are stored in MSB first(high endian)
66 // format, hence it needs to flip the bytes of the header if using it on Intel processors or low-endian machines
67 labelStream.read(reinterpret_cast<char*>(&num), sizeof(num));
68 imageStream.read(reinterpret_cast<char*>(&num), sizeof(num));
70 imageStream.read(reinterpret_cast<char*>(&row), sizeof(row));
72 imageStream.read(reinterpret_cast<char*>(&col), sizeof(col));
75 // Reads image and label into memory.
76 imageStream.seekg(testCaseId * g_kMnistImageByteSize, std::ios_base::cur);
77 imageStream.read(reinterpret_cast<char*>(&I[0]), g_kMnistImageByteSize);
78 labelStream.seekg(testCaseId, std::ios_base::cur);
79 labelStream.read(reinterpret_cast<char*>(&label), 1);
81 if (!imageStream.good())
83 ARMNN_LOG(fatal) << "Failed to read " << imagePath;
86 if (!labelStream.good())
88 ARMNN_LOG(fatal) << "Failed to read " << labelPath;
92 std::vector<float> inputImageData;
93 inputImageData.resize(g_kMnistImageByteSize);
95 for (unsigned int i = 0; i < col * row; ++i)
97 inputImageData[i] = boost::numeric_cast<float>(I[i]);
101 inputImageData[i] /= 255.0f;
105 return std::make_unique<TTestCaseData>(label, std::move(inputImageData));