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#pragma once
#include <iostream>
#include <cassert>
#include <functional>
#include <vector>
#include <deque>
#include <unordered_map>
#include <string>
#include <cstring>
#include <getopt.h>
namespace dg {
using Handle = std::function<int()>;
class Options {
public:
/// @param name name of the option
/// @param has_arg kind of arguments that are used (no_argument, required_argument, optional_argument)
/// @param val identifies the option (see getopt documentation)
/// @param help_text help text for this option
/// @param handle lambda that is invoked when the option occures
void add(std::string const & name, int has_arg, int val, std::string const & help_text, Handle handle) {
add(name, has_arg, nullptr, val, help_text, handle);
}
/// @param name name of the option
/// @param has_arg kind of arguments that are used (no_argument, required_argument, optional_argument)
/// @param flag pointer that is set after the option occured
/// @param val value for the flag to be set
/// @param help_text help text for this option
/// @param handle lambda that is invoked when the option occures
void add(std::string const & name, int has_arg, int* flag, int val, std::string const & help_text, Handle handle) {
names.push_back(name);
// create a new option from the args
options.push_back({names.back().data(), has_arg, flag, val});
help_texts.push_back(help_text);
int index = val; // let val be the option's unique identifier
if (flag != nullptr) {
// flag is not null, so the val is not used as identifier
// so pick another one
index = num_flags++;
}
// store the handle
handles[index] = handle;
}
int process(int argc, char* argv[]) {
int ret = 0;
std::string shortopts;
for (auto const & option: options) {
if (option.flag != nullptr) {
continue;
}
shortopts += static_cast<char>(option.val);
switch (option.has_arg) {
case no_argument:
break;
case required_argument:
shortopts += ":";
break;
case optional_argument:
shortopts += "::";
break;
}
}
// add termination option
options.push_back({0, 0, 0, 0});
// handle arguments
while (true) {
int index = 0;
int key = getopt_long(argc, argv, shortopts.data(), options.data(), &index);
if (key == -1) {
break;
} else if (key == '?') {
return 1;
} else if (key == ':') {
return 1;
} else if (key == 0) {
// call flag's handle
ret = handles.at(index)();
} else {
// call option's handle
ret = handles.at(key)();
}
if(ret) {
return ret;
}
}
for (int i = optind; i < argc; ++i) {
args.push_back(argv[i]);
}
// remove terminating option
options.pop_back();
assert(options.size() == handles.size());
assert(options.size() == help_texts.size());
return 0;
}
const std::vector<std::string> arguments() const { return args; }
void help() {
std::size_t width = 0;
for(auto const & opt : options) {
if(opt.name == nullptr) {
continue; // skip terminating option
}
width = std::max(width, std::strlen(opt.name) + (opt.has_arg != no_argument ? 0 : 3));
}
width += 1;
int index = 0;
for(auto const & help_text : help_texts) {
if(index >= (int)options.size()) {
break;
}
auto const & opt = options.at(index);
std::string args;
switch(opt.has_arg) {
case required_argument:
args = "<x>";
break;
case optional_argument:
args = "[x]";
break;
case no_argument:
default:
break;
}
std::string padding;
std::size_t pad_size = width - (std::strlen(opt.name) + args.size());
padding.append(pad_size, ' ');
if(opt.val >= 33 && opt.val <= 126)
{
std::cout << " -" << static_cast<char>(opt.val) << ", --" << opt.name << " " << args << padding;
}
else
{
std::cout << " --" << opt.name << " " << args << padding;
}
std::cout << help_text << std::endl;
++index;
}
}
private:
std::size_t num_flags{};
std::vector<option> options{};
std::deque<std::string> names{};
std::vector<std::string> help_texts{};
std::vector<std::string> args;
std::unordered_map<int, Handle> handles{};
};
}
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