【C++】cmdline——轻量级的C++命令行解析库

1、说明

cmdline是一个轻量级的c++命令行参数解析工具，全部源码只有一个cmdline.h头文件。

2、代码

20171210_命令行进行解析.cpp

// 20171210_命令行进行解析.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "cmdline.h"
#include <iostream>

using std::cout;
using std::string;
using std::endl;

int main(int argc, char *argv[])
{
    // 创建一个命令行解析器
    cmdline::parser a;
    // 加入指定类型的输入參数
    // 第一个參数：长名称
    // 第二个參数：短名称（‘\0‘表示没有短名称）
    // 第三个參数：參数描写叙述
    // 第四个參数：bool值，表示该參数是否必须存在（可选。默认值是false）
    // 第五个參数：參数的默认值（可选，当第四个參数为false时该參数有效）
    a.add<string>("host", 'h', "host name", true, "");
    // 第六个參数用来对參数加入额外的限制
    // 这里端口号被限制为必须是1到65535区间的值，通过cmdline::range(1, 65535)进行限制
    a.add<int>("port", 'p', "port number", true, 80, cmdline::range(1, 65535));
    // cmdline::oneof() 能够用来限制參数的可选值
    a.add<string>("type", 't', "protocol type", false, "http", cmdline::oneof<string>("http", "https", "ssh", "ftp"));
    // 也能够定义bool值
    // 通过调用不带类型的add方法
    a.add("gzip", '\0', "gzip when transfer");
    // 执行解析器
    // 仅仅有当全部的參数都有效时他才会返回
    //  假设有无效參数，解析器会输出错误消息。然后退出程序
    // 假设有‘--help‘或-?

    //这种帮助标识被指定，解析器输出帮助信息。然后退出程序
    a.parse_check(argc, argv);
    // 获取输入的參数值
    cout << a.get<string>("type") << "://"
        << a.get<string>("host") << ":"
        << a.get<int>("port") << endl;
    // bool值能够通过调用exsit()方法来推断
    if (a.exist("gzip")) cout << "gzip" << endl;

    return 0;
}

cmdline.h

/*
Copyright (c) 2009, Hideyuki Tanaka
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the <organization> nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY <copyright holder> ''AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <copyright holder> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#pragma once

#include <iostream>
#include <sstream>
#include <vector>
#include <map>
#include <string>
#include <stdexcept>
#include <typeinfo>
#include <cstring>
#include <algorithm>
//当编译器非gcc时,不包含cxxabi.h头文件
#ifdef __GNUC__
#include <cxxabi.h>
#endif
#include <cstdlib>

namespace cmdline {

    namespace detail {

        template <typename Target, typename Source, bool Same>
        class lexical_cast_t {
        public:
            static Target cast(const Source &arg) {
                Target ret;
                std::stringstream ss;
                if (!(ss << arg && ss >> ret && ss.eof()))
                    throw std::bad_cast();

                return ret;
            }
        };

        template <typename Target, typename Source>
        class lexical_cast_t<Target, Source, true> {
        public:
            static Target cast(const Source &arg) {
                return arg;
            }
        };

        template <typename Source>
        class lexical_cast_t<std::string, Source, false> {
        public:
            static std::string cast(const Source &arg) {
                std::ostringstream ss;
                ss << arg;
                return ss.str();
            }
        };

        template <typename Target>
        class lexical_cast_t<Target, std::string, false> {
        public:
            static Target cast(const std::string &arg) {
                Target ret;
                std::istringstream ss(arg);
                if (!(ss >> ret && ss.eof()))
                    throw std::bad_cast();
                return ret;
            }
        };

        template <typename T1, typename T2>
        struct is_same {
            static const bool value = false;
        };

        template <typename T>
        struct is_same<T, T> {
            static const bool value = true;
        };

        template<typename Target, typename Source>
        Target lexical_cast(const Source &arg)
        {
            return lexical_cast_t<Target, Source, detail::is_same<Target, Source>::value>::cast(arg);
        }

        static inline std::string demangle(const std::string &name)
        {
#ifdef _MSC_VER
            return name; // 为MSVC编译器时直接返回name
#elif defined(__GNUC__)
            // 为gcc编译器时还调用原来的代码
            int status = 0;
            char *p = abi::__cxa_demangle(name.c_str(), 0, 0, &status);
            std::string ret(p);
            free(p);
            return ret;
#else
            // 其他不支持的编译器需要自己实现这个方法
#error unexpected c complier (msc/gcc), Need to implement this method for demangle
#endif
        }

        template <class T>
        std::string readable_typename()
        {
            return demangle(typeid(T).name());
        }

        template <class T>
        std::string default_value(T def)
        {
            return detail::lexical_cast<std::string>(def);
        }

        template <>
        inline std::string readable_typename<std::string>()
        {
            return "string";
        }

    } // detail

      //-----

    class cmdline_error : public std::exception {
    public:
        cmdline_error(const std::string &msg) : msg(msg) {}
        ~cmdline_error() throw() {}
        const char *what() const throw() { return msg.c_str(); }
    private:
        std::string msg;
    };

    template <class T>
    struct default_reader {
        T operator()(const std::string &str) {
            return detail::lexical_cast<T>(str);
        }
    };

    template <class T>
    struct range_reader {
        range_reader(const T &low, const T &high) : low(low), high(high) {}
        T operator()(const std::string &s) const {
            T ret = default_reader<T>()(s);
            if (!(ret >= low && ret <= high)) throw cmdline::cmdline_error("range_error");
            return ret;
        }
    private:
        T low, high;
    };

    template <class T>
    range_reader<T> range(const T &low, const T &high)
    {
        return range_reader<T>(low, high);
    }

    template <class T>
    struct oneof_reader {
        T operator()(const std::string &s) {
            T ret = default_reader<T>()(s);
            if (std::find(alt.begin(), alt.end(), ret) == alt.end())
                throw cmdline_error("");
            return ret;
        }
        void add(const T &v) { alt.push_back(v); }
    private:
        std::vector<T> alt;
    };

    template <class T>
    oneof_reader<T> oneof(T a1)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5, T a6)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        ret.add(a6);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5, T a6, T a7)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        ret.add(a6);
        ret.add(a7);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5, T a6, T a7, T a8)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        ret.add(a6);
        ret.add(a7);
        ret.add(a8);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5, T a6, T a7, T a8, T a9)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        ret.add(a6);
        ret.add(a7);
        ret.add(a8);
        ret.add(a9);
        return ret;
    }

    template <class T>
    oneof_reader<T> oneof(T a1, T a2, T a3, T a4, T a5, T a6, T a7, T a8, T a9, T a10)
    {
        oneof_reader<T> ret;
        ret.add(a1);
        ret.add(a2);
        ret.add(a3);
        ret.add(a4);
        ret.add(a5);
        ret.add(a6);
        ret.add(a7);
        ret.add(a8);
        ret.add(a9);
        ret.add(a10);
        return ret;
    }

    //-----

    class parser {
    public:
        parser() {
        }
        ~parser() {
            for (std::map<std::string, option_base*>::iterator p = options.begin();
                p != options.end(); p++)
                delete p->second;
        }

        void add(const std::string &name,
            char short_name = 0,
            const std::string &desc = "") {
            if (options.count(name)) throw cmdline_error("multiple definition: " + name);
            options[name] = new option_without_value(name, short_name, desc);
            ordered.push_back(options[name]);
        }

        template <class T>
        void add(const std::string &name,
            char short_name = 0,
            const std::string &desc = "",
            bool need = true,
            const T def = T()) {
            add(name, short_name, desc, need, def, default_reader<T>());
        }

        template <class T, class F>
        void add(const std::string &name,
            char short_name = 0,
            const std::string &desc = "",
            bool need = true,
            const T def = T(),
            F reader = F()) {
            if (options.count(name)) throw cmdline_error("multiple definition: " + name);
            options[name] = new option_with_value_with_reader<T, F>(name, short_name, need, def, desc, reader);
            ordered.push_back(options[name]);
        }

        void footer(const std::string &f) {
            ftr = f;
        }

        void set_program_name(const std::string &name) {
            prog_name = name;
        }

        bool exist(const std::string &name) const {
            if (options.count(name) == 0) throw cmdline_error("there is no flag: --" + name);
            return options.find(name)->second->has_set();
        }

        template <class T>
        const T &get(const std::string &name) const {
            if (options.count(name) == 0) throw cmdline_error("there is no flag: --" + name);
            const option_with_value<T> *p = dynamic_cast<const option_with_value<T>*>(options.find(name)->second);
            if (p == NULL) throw cmdline_error("type mismatch flag '" + name + "'");
            return p->get();
        }

        const std::vector<std::string> &rest() const {
            return others;
        }

        bool parse(const std::string &arg) {
            std::vector<std::string> args;

            std::string buf;
            bool in_quote = false;
            for (std::string::size_type i = 0; i<arg.length(); i++) {
                if (arg[i] == '\"') {
                    in_quote = !in_quote;
                    continue;
                }

                if (arg[i] == ' ' && !in_quote) {
                    args.push_back(buf);
                    buf = "";
                    continue;
                }

                if (arg[i] == '\\') {
                    i++;
                    if (i >= arg.length()) {
                        errors.push_back("unexpected occurrence of '\\' at end of string");
                        return false;
                    }
                }

                buf += arg[i];
            }

            if (in_quote) {
                errors.push_back("quote is not closed");
                return false;
            }

            if (buf.length()>0)
                args.push_back(buf);

            for (size_t i = 0; i<args.size(); i++)
                std::cout << "\"" << args[i] << "\"" << std::endl;

            return parse(args);
        }

        bool parse(const std::vector<std::string> &args) {
            int argc = static_cast<int>(args.size());
            std::vector<const char*> argv(argc);

            for (int i = 0; i<argc; i++)
                argv[i] = args[i].c_str();

            return parse(argc, &argv[0]);
        }

        bool parse(int argc, const char * const argv[]) {
            errors.clear();
            others.clear();

            if (argc<1) {
                errors.push_back("argument number must be longer than 0");
                return false;
            }
            if (prog_name == "")
                prog_name = argv[0];

            std::map<char, std::string> lookup;
            for (std::map<std::string, option_base*>::iterator p = options.begin();
                p != options.end(); p++) {
                if (p->first.length() == 0) continue;
                char initial = p->second->short_name();
                if (initial) {
                    if (lookup.count(initial)>0) {
                        lookup[initial] = "";
                        errors.push_back(std::string("short option '") + initial + "' is ambiguous");
                        return false;
                    }
                    else lookup[initial] = p->first;
                }
            }

            for (int i = 1; i<argc; i++) {
                if (strncmp(argv[i], "--", 2) == 0) {
                    const char *p = strchr(argv[i] + 2, '=');
                    if (p) {
                        std::string name(argv[i] + 2, p);
                        std::string val(p + 1);
                        set_option(name, val);
                    }
                    else {
                        std::string name(argv[i] + 2);
                        if (options.count(name) == 0) {
                            errors.push_back("undefined option: --" + name);
                            continue;
                        }
                        if (options[name]->has_value()) {
                            if (i + 1 >= argc) {
                                errors.push_back("option needs value: --" + name);
                                continue;
                            }
                            else {
                                i++;
                                set_option(name, argv[i]);
                            }
                        }
                        else {
                            set_option(name);
                        }
                    }
                }
                else if (strncmp(argv[i], "-", 1) == 0) {
                    if (!argv[i][1]) continue;
                    char last = argv[i][1];
                    for (int j = 2; argv[i][j]; j++) {
                        last = argv[i][j];
                        if (lookup.count(argv[i][j - 1]) == 0) {
                            errors.push_back(std::string("undefined short option: -") + argv[i][j - 1]);
                            continue;
                        }
                        if (lookup[argv[i][j - 1]] == "") {
                            errors.push_back(std::string("ambiguous short option: -") + argv[i][j - 1]);
                            continue;
                        }
                        set_option(lookup[argv[i][j - 1]]);
                    }

                    if (lookup.count(last) == 0) {
                        errors.push_back(std::string("undefined short option: -") + last);
                        continue;
                    }
                    if (lookup[last] == "") {
                        errors.push_back(std::string("ambiguous short option: -") + last);
                        continue;
                    }

                    if (i + 1<argc && options[lookup[last]]->has_value()) {
                        set_option(lookup[last], argv[i + 1]);
                        i++;
                    }
                    else {
                        set_option(lookup[last]);
                    }
                }
                else {
                    others.push_back(argv[i]);
                }
            }

            for (std::map<std::string, option_base*>::iterator p = options.begin();
                p != options.end(); p++)
                if (!p->second->valid())
                    errors.push_back("need option: --" + std::string(p->first));

            return errors.size() == 0;
        }

        void parse_check(const std::string &arg) {
            if (!options.count("help"))
                add("help", '?', "print this message");
            check(0, parse(arg));
        }

        void parse_check(const std::vector<std::string> &args) {
            if (!options.count("help"))
                add("help", '?', "print this message");
            check(args.size(), parse(args));
        }

        void parse_check(int argc, char *argv[]) {
            if (!options.count("help"))
                add("help", '?', "print this message");
            check(argc, parse(argc, argv));
        }

        std::string error() const {
            return errors.size()>0 ? errors[0] : "";
        }

        std::string error_full() const {
            std::ostringstream oss;
            for (size_t i = 0; i<errors.size(); i++)
                oss << errors[i] << std::endl;
            return oss.str();
        }

        std::string usage() const {
            std::ostringstream oss;
            oss << "usage: " << prog_name << " ";
            for (size_t i = 0; i<ordered.size(); i++) {
                if (ordered[i]->must())
                    oss << ordered[i]->short_description() << " ";
            }

            oss << "[options] ... " << ftr << std::endl;
            oss << "options:" << std::endl;

            size_t max_width = 0;
            for (size_t i = 0; i<ordered.size(); i++) {
                max_width = std::max(max_width, ordered[i]->name().length());
            }
            for (size_t i = 0; i<ordered.size(); i++) {
                if (ordered[i]->short_name()) {
                    oss << "  -" << ordered[i]->short_name() << ", ";
                }
                else {
                    oss << "      ";
                }

                oss << "--" << ordered[i]->name();
                for (size_t j = ordered[i]->name().length(); j<max_width + 4; j++)
                    oss << ' ';
                oss << ordered[i]->description() << std::endl;
            }
            return oss.str();
        }

    private:

        void check(int argc, bool ok) {
            if ((argc == 1 && !ok) || exist("help")) {
                std::cerr << usage();
                exit(0);
            }

            if (!ok) {
                std::cerr << error() << std::endl << usage();
                exit(1);
            }
        }

        void set_option(const std::string &name) {
            if (options.count(name) == 0) {
                errors.push_back("undefined option: --" + name);
                return;
            }
            if (!options[name]->set()) {
                errors.push_back("option needs value: --" + name);
                return;
            }
        }

        void set_option(const std::string &name, const std::string &value) {
            if (options.count(name) == 0) {
                errors.push_back("undefined option: --" + name);
                return;
            }
            if (!options[name]->set(value)) {
                errors.push_back("option value is invalid: --" + name + "=" + value);
                return;
            }
        }

        class option_base {
        public:
            virtual ~option_base() {}

            virtual bool has_value() const = 0;
            virtual bool set() = 0;
            virtual bool set(const std::string &value) = 0;
            virtual bool has_set() const = 0;
            virtual bool valid() const = 0;
            virtual bool must() const = 0;

            virtual const std::string &name() const = 0;
            virtual char short_name() const = 0;
            virtual const std::string &description() const = 0;
            virtual std::string short_description() const = 0;
        };

        class option_without_value : public option_base {
        public:
            option_without_value(const std::string &name,
                char short_name,
                const std::string &desc)
                :nam(name), snam(short_name), desc(desc), has(false) {
            }
            ~option_without_value() {}

            bool has_value() const { return false; }

            bool set() {
                has = true;
                return true;
            }

            bool set(const std::string &) {
                return false;
            }

            bool has_set() const {
                return has;
            }

            bool valid() const {
                return true;
            }

            bool must() const {
                return false;
            }

            const std::string &name() const {
                return nam;
            }

            char short_name() const {
                return snam;
            }

            const std::string &description() const {
                return desc;
            }

            std::string short_description() const {
                return "--" + nam;
            }

        private:
            std::string nam;
            char snam;
            std::string desc;
            bool has;
        };

        template <class T>
        class option_with_value : public option_base {
        public:
            option_with_value(const std::string &name,
                char short_name,
                bool need,
                const T &def,
                const std::string &desc)
                : nam(name), snam(short_name), need(need), has(false)
                , def(def), actual(def) {
                this->desc = full_description(desc);
            }
            ~option_with_value() {}

            const T &get() const {
                return actual;
            }

            bool has_value() const { return true; }

            bool set() {
                return false;
            }

            bool set(const std::string &value) {
                try {
                    actual = read(value);
                    has = true;
                }
                catch (const std::exception &) {
                    return false;
                }
                return true;
            }

            bool has_set() const {
                return has;
            }

            bool valid() const {
                if (need && !has) return false;
                return true;
            }

            bool must() const {
                return need;
            }

            const std::string &name() const {
                return nam;
            }

            char short_name() const {
                return snam;
            }

            const std::string &description() const {
                return desc;
            }

            std::string short_description() const {
                return "--" + nam + "=" + detail::readable_typename<T>();
            }

        protected:
            std::string full_description(const std::string &desc) {
                return
                    desc + " (" + detail::readable_typename<T>() +
                    (need ? "" : " [=" + detail::default_value<T>(def) + "]")
                    + ")";
            }

            virtual T read(const std::string &s) = 0;

            std::string nam;
            char snam;
            bool need;
            std::string desc;

            bool has;
            T def;
            T actual;
        };

        template <class T, class F>
        class option_with_value_with_reader : public option_with_value<T> {
        public:
            option_with_value_with_reader(const std::string &name,
                char short_name,
                bool need,
                const T def,
                const std::string &desc,
                F reader)
                : option_with_value<T>(name, short_name, need, def, desc), reader(reader) {
            }

        private:
            T read(const std::string &s) {
                return reader(s);
            }

            F reader;
        };

        std::map<std::string, option_base*> options;
        std::vector<option_base*> ordered;
        std::string ftr;

        std::string prog_name;
        std::vector<std::string> others;

        std::vector<std::string> errors;
    };

} // cmdline

测试效果

>20171210_命令行进行解析.exe -p 8888 -h baidu.com -t ftp
ftp://baidu.com:8888

>20171210_命令行进行解析.exe -?
usage: 20171210_命令行进行解析.exe --host=string --port=int [options] ...
options:
  -h, --host    host name (string)
  -p, --port    port number (int)
  -t, --type    protocol type (string [=http])
      --gzip    gzip when transfer
  -?, --help    print this message

>20171210_命令行进行解析.exe -p 8888 -h baidu.com -t ftp
ftp://baidu.com:8888

>20171210_命令行进行解析.exe -p 8888 -h baidu.com --gzip
http://baidu.com:8888
gzip

3、参考

【C++】cmdline —— 轻量级的C++命令行解析库
http://www.mamicode.com/info-detail-1923374.html

c++:改造cmdline用于MSVC下的命令行参数解析
http://blog.csdn.net/10km/article/details/50982993