CI_String.hpp

/*
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 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the appropriate papers when you publish your
 * work.  Good starting points are:
 *
 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
 * [4] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 * [5] Kuang & Gezelter, Mol. Phys., 110, 691-701 (2012).
 * [6] Lamichhane, Gezelter & Newman, J. Chem. Phys. 141, 134109 (2014).
 * [7] Lamichhane, Newman & Gezelter, J. Chem. Phys. 141, 134110 (2014).
 * [8] Bhattarai, Newman & Gezelter, Phys. Rev. B 99, 094106 (2019).
 */
 
#ifndef OPENMD_UTILS_CI_STRING_HPP
#define OPENMD_UTILS_CI_STRING_HPP
 
#include <cctype>
#include <cstddef>
#include <iostream>
#include <string>
 
namespace OpenMD::Utils {
 
  struct ci_char_traits : public std::char_traits<char> {
    static int compare(const char* s1_, const char* s2_,
                       std::size_t count_) noexcept {
      while (count_-- != 0) {
        if (std::toupper(*s1_) < std::toupper(*s2_)) return -1;
        if (std::toupper(*s1_) > std::toupper(*s2_)) return 1;
 
        ++s1_;
        ++s2_;
      }
 
      return 0;
    }
 
    static const char* find(const char* p_, std::size_t count_,
                            const char& ch_) noexcept {
      const auto CH {std::toupper(ch_)};
 
      while (count_-- != 0) {
        if (std::toupper(*p_) == CH) return p_;
 
        ++p_;
      }
 
      return nullptr;
    }
 
    static bool eq(char a, char b) noexcept {
      return std::toupper(a) == std::toupper(b);
    }
 
    static bool lt(char a, char b) noexcept {
      return std::toupper(a) < std::toupper(b);
    }
  };
 
  template<class OutputTraits, class InputTraits>
  inline std::basic_string<char, OutputTraits> traits_cast(
      const std::basic_string<char, InputTraits>& input) noexcept {
    std::basic_string<char, OutputTraits> ouput {input.data(), input.size()};
    return ouput;
  }
 
  inline std::ostream& operator<<(
      std::ostream& os, const std::basic_string<char, ci_char_traits>& str) {
    os << str.c_str();
    return os;
  }
 
  // Type alias for case-insensitive strings
  using ci_string = std::basic_string<char, ci_char_traits>;
}  // namespace OpenMD::Utils
 
#endif