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#pragma once
#include <iostream>
#include <cassert>
#include <functional>
#include <vector>
#include <unordered_map>
#include <string>
#include <getopt.h>
namespace dg {
using Handle = std::function<void()>;
class Options {
public:
Options();
/// @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 handle lambda that is invoked when the option occures
void add(std::string const & name, int has_arg, int val, Handle 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 handle lambda that is invoked when the option occures
void add(std::string const & name, int has_arg, int* flag, int val, Handle handle);
bool process(int argc, char* argv[]);
const std::vector<std::string> arguments() const { return args; }
private:
std::size_t num_flags;
std::vector<option> options;
std::vector<std::string> args;
std::unordered_map<int, Handle> handles;
};
Options::Options()
: num_flags{}
, options{}
, handles{} {
}
void Options::add(std::string const & name, int has_arg, int val, Handle handle) {
add(name, has_arg, nullptr, val, handle);
}
void Options::add(std::string const & name, int has_arg, int* flag, int val, Handle handle) {
int index = val; // let val be the option's unique identifier
options.push_back({name.data(), has_arg, flag, val});
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;
}
bool Options::process(int argc, char* argv[]) {
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 false;
} else if (key == ':') {
return false;
} else if (key == 0) {
// call flag's handle
handles.at(index)();
} else {
// call option's handle
handles.at(key)();
}
}
for (int i = optind; i < argc; ++i) {
args.push_back(argv[i]);
}
// remove terminating option
options.pop_back();
assert(options.size() == handles.size());
return true;
}
}
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