StringParse.h

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef CXXUTILS_STRINGPARSE_H
#define CXXUTILS_STRINGPARSE_H
#include <string>
#include <vector>
#include <sstream>
#include <charconv>
#include <iostream>
#include <iomanip>

class StringParse: public std::vector<std::string> {
public:

  StringParse(const std::string& input) {
    std::istringstream instring(input);
    std::string token;
    while (instring >> token) this->push_back(token);
  }

  template <typename T> T piece(size_t num) const {
    if (num > this->size()) return {-1};
    std::string token = this->at(num-1);
    T result{-1};
    auto [ptr, ec] = std::from_chars(token.data(), token.data() + token.size(), result);
    if (ec == std::errc() && ptr == token.data() + token.size()) return result;
    if (ec == std::errc::invalid_argument || ptr != token.data() + token.size() ) return {-1}; //std::cout << "This number cannot be parsed.\n"; 
    if (ec == std::errc::result_out_of_range) return {-1}; //std::cout << "This number is out of range of the return type.\n";
    return {-1};
  }
};

template <> std::string StringParse::piece(size_t num) const {
    return num > this->size() ? std::string{} : this->at(num-1);
}
#endif