common/alstring.cpp

   1
   2 #include "config.h"
   3
   4 #include "alstring.h"
   5
   6 #include <algorithm>
   7 #include <cctype>
   8 #include <cwctype>
   9 #include <cstring>
  10 #include <string>
  11
  12
  13 namespace al {
  14
  15 int case_compare(const std::string_view str0, const std::string_view str1) noexcept
  16 {
  17     using Traits = std::string_view::traits_type;
  18
  19     auto ch0 = str0.cbegin();
  20     auto ch1 = str1.cbegin();
  21     auto ch1end = ch1 + std::min(str0.size(), str1.size());
  22     while(ch1 != ch1end)
  23     {
  24         const int u0{std::toupper(Traits::to_int_type(*ch0))};
  25         const int u1{std::toupper(Traits::to_int_type(*ch1))};
  26         if(const int diff{u0-u1}) return diff;
  27         ++ch0; ++ch1;
  28     }
  29
  30     if(str0.size() < str1.size()) return -1;
  31     if(str0.size() > str1.size()) return 1;
  32     return 0;
  33 }
  34
  35 int case_compare(const std::wstring_view str0, const std::wstring_view str1) noexcept
  36 {
  37     using Traits = std::wstring_view::traits_type;
  38
  39     auto ch0 = str0.cbegin();
  40     auto ch1 = str1.cbegin();
  41     auto ch1end = ch1 + std::min(str0.size(), str1.size());
  42     while(ch1 != ch1end)
  43     {
  44         const auto u0 = std::towupper(Traits::to_int_type(*ch0));
  45         const auto u1 = std::towupper(Traits::to_int_type(*ch1));
  46         if(const auto diff = static_cast<int>(u0-u1)) return diff;
  47         ++ch0; ++ch1;
  48     }
  49
  50     if(str0.size() < str1.size()) return -1;
  51     if(str0.size() > str1.size()) return 1;
  52     return 0;
  53 }
  54
  55 int strcasecmp(const char *str0, const char *str1) noexcept
  56 { return case_compare(str0, str1); }
  57
  58 int strncasecmp(const char *str0, const char *str1, std::size_t len) noexcept
  59 {
  60     return case_compare(std::string_view{str0, std::min(std::strlen(str0), len)},
  61         std::string_view{str1, std::min(std::strlen(str1), len)});
  62 }
  63
  64 } // namespace al