argsParser.h

/*
 * Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef TENSORRT_ARGS_PARSER_H
#define TENSORRT_ARGS_PARSER_H

#include <string>
#include <vector>
#ifdef _MSC_VER
#include "..\common\windows\getopt.h"
#else
#include <getopt.h>
#endif
#include <iostream>

namespace samplesCommon
{

//!
//! \brief The SampleParams structure groups the basic parameters required by
//!        all sample networks.
//!
struct SampleParams
{
    int batchSize{1};                  //!< Number of inputs in a batch
    int dlaCore{-1};                   //!< Specify the DLA core to run network on.
    bool int8{false};                  //!< Allow runnning the network in Int8 mode.
    bool fp16{false};                  //!< Allow running the network in FP16 mode.
    std::vector<std::string> dataDirs; //!< Directory paths where sample data files are stored
    std::vector<std::string> inputTensorNames;
    std::vector<std::string> outputTensorNames;
};

//!
//! \brief The CaffeSampleParams structure groups the additional parameters required by
//!         networks that use caffe
//!
// 在SampleParams的基礎上加上caffe特有的參數
struct CaffeSampleParams : public SampleParams
{
    std::string prototxtFileName; //!< Filename of prototxt design file of a network
    std::string weightsFileName;  //!< Filename of trained weights file of a network
    std::string meanFileName;     //!< Filename of mean file of a network
};

//!
//! \brief The OnnxSampleParams structure groups the additional parameters required by
//!         networks that use ONNX
//!
struct OnnxSampleParams : public SampleParams
{
    std::string onnxFileName; //!< Filename of ONNX file of a network
};

//!
//! \brief The UffSampleParams structure groups the additional parameters required by
//!         networks that use Uff
//!
struct UffSampleParams : public SampleParams
{
    std::string uffFileName; //!< Filename of uff file of a network
};

//!
//! /brief Struct to maintain command-line arguments.
//!
//parseArgs解析完命令行的參數後，會把得到的資訊存入此結構體內
struct Args
{
    bool runInInt8{false};
    bool runInFp16{false};
    bool help{false};
    int useDLACore{-1};
    int batch{1};
    std::vector<std::string> dataDirs;
    //？
    bool useILoop{false};
};

//!
//! \brief Populates the Args struct with the provided command-line parameters.
//!
//! \throw invalid_argument if any of the arguments are not valid
//!
//! \return boolean If return value is true, execution can continue, otherwise program should exit
//!
//解析argv，將所得到的資訊存入args這個struct Args型別的變數內
inline bool parseArgs(Args& args, int argc, char* argv[])
{
    //無窮迴圈。等到參數解析完了，arg會自動變成-1，接著跳出迴圈
    while (1)
    {
        int arg;
        static struct option long_options[] = {{"help", no_argument, 0, 'h'}, {"datadir", required_argument, 0, 'd'},
            {"int8", no_argument, 0, 'i'}, {"fp16", no_argument, 0, 'f'}, {"useILoop", no_argument, 0, 'l'},
            {"useDLACore", required_argument, 0, 'u'}, {"batch", required_argument, 0, 'b'}, {nullptr, 0, nullptr, 0}};
        int option_index = 0;
        // getopt_long用於解析傳入的參數，定義於Linux系統自帶的getopt.h，
        // 亦或是samples/common/windows/getopt.c
        // 在getopt_long被呼叫的過程中，option_index會隨之變化，代表該次解析的是long_options裡的第幾個參數
        //getopt_long的回傳值是struct option裡最後一個元素，即'h','d','i','f','l','u','b'或0
        //注意到d後面跟著一個冒號，這代表-d後面還跟著一個參數
        //為何這裡optstring只有'h','d','i','u'，少了'f','l','b'及0?
        arg = getopt_long(argc, argv, "hd:iu", long_options, &option_index);
        // 如果所有可選參數都解析完了，則getopt_long回傳-1
        if (arg == -1)
        {
            break;
        }

        switch (arg)
        {
        //parseArgs的參數args傳入時是空的，在這個block裡依不同情況來為args設值
        case 'h': args.help = true; return true;
        case 'd':
            //optarg定義於samples/common/windows/getopt.c，由getopt_long間接地被賦值，表示可選參數
            //-d後跟著的參數會被解析到optarg內
            if (optarg)
            {
                args.dataDirs.push_back(optarg);
            }
            else
            {
                std::cerr << "ERROR: --datadir requires option argument" << std::endl;
                return false;
            }
            break;
        case 'i': args.runInInt8 = true; break;
        //'f'不在optstring內，能被解析出來？
        case 'f': args.runInFp16 = true; break;
        //？
        //'l'不在optstring內，能被解析出來？
        case 'l': args.useILoop = true; break;
        case 'u':
            //在optstring中，u後面沒加冒號，為何這裡可以有參數？
            if (optarg)
            {
                args.useDLACore = std::stoi(optarg);
            }
            break;
        case 'b':
            //'b'不在optstring內，能被解析出來？
            if (optarg)
            {
                args.batch = std::stoi(optarg);
            }
            break;
        //如果傳入的參數不是上面的任一個，則程序執行失敗
        default: return false;
        }
    }
    return true;
}

} // namespace samplesCommon

#endif // TENSORRT_ARGS_PARSER_H

namespace

代碼中定義了名為samplesCommon的namespace。關於namespace，詳見C++ namespace。

struct的繼承

CaffeSampleParams結構體是繼承自SampleParams結構體，
關於struct的繼承，詳見C++ struct的繼承。

caffe特有參數

prototxtFileName：預期的參數是以.prototxt結尾的檔名，代表網路結構定義
weightsFileName：預期的參數是以.caffemodel結尾的檔名，代表網路權重
meanFileName：預期的參數是以.binaryproto結尾的檔名，代表圖像的平均值

UFF格式

摘自4.3.1. Example 1: Adding A Custom Layer To A TensorFlow Model：

In order to run a TensorFlow network with TensorRT, you must first convert it to the UFF format.

UFF格式似乎是為了將TensorFlow與TensorRT的模型互相轉換而定義的一種中間表示方式？

不需要typedef struct xxx yyy？

記得在C語言中，定義完一個struct之後，我們通常還會加上typedef，用以簡化之後與該struct相關的代碼。但是在argsParser.h中，定義完Args這個結構體後，我們卻可以直接在parseArgs函數裡使用它，這是為什麼呢？詳見C++ typedef struct v.s. struct。