parse.hpp

/*****************************************************************//**
 * \file   parse.hpp
 * \brief  contains a template function to parse
 * comma-separated strings and store them in std::vector<T>.
 *
 * \author Xuhua Huang
 * \date   October 2021
 *********************************************************************/

#ifndef PARSE_STR_HPP
#define PARSE_STR_HPP

#ifndef _IOSTREAM_
#include <iostream>
#endif

#ifndef _INC_STDLIB
#include <stdlib.h>
#endif

#ifndef _VECTOR_
#include <vector>
#endif

#ifndef _SSTREAM_
#include <sstream>
#endif

namespace util {
namespace parse {

template <char c>
constexpr bool is_digit = (c >= '0' && c <= '9');

/**
 * Template to parse a delimiter-separated string.
 * The default delimiter is a comma ','
 * Ideal use case: convert such string to an integer array.
 */
template <typename T>
static const std::vector<T> parse_str(const std::string& str, char delimiter = ',') {
    std::vector<T> result;

    if (str.length() < 8E5) {
        std::stringstream ss(str);
        while (ss.good()) {
            std::string substr;
            getline(ss, substr, delimiter);
            if constexpr (std::is_same_v<T, std::string>) {
                result.push_back(substr);
            } else if constexpr (std::is_same_v<T, char>) {
                result.push_back(static_cast<char>(substr));
            } else if constexpr (std::is_same_v<T, int>) {
                result.push_back(stoi(substr));
            }
        }
    }

    return result;
}

/* Read digits from an integer and store in an array. */
static const std::vector<int> num_to_digits(int number) {
    std::vector<int> digits;

    if (number == 0) {
        digits.push_back(0);
    } else {
        while (number != 0) {
            int last = number % 10;
            digits.insert(digits.begin(), 1, last);
            number = (number - last) / 10;
        }
    }

    return digits;
}

} // namespace parse
} // namespace util

#endif