More constexpr tests

test/constexpr_tests.hpp

@@ -0,0 +1,153 @@
+#include <string>
+#include <boost/static_string/static_string.hpp>
+
+// char_traits aren't constexpr until c++17
+#ifndef BOOST_STATIC_STRING_CPP17_CONSTEXPR_USED
+struct cxper_char_traits
+{
+  using char_type = char;
+  using int_type = int;
+  using state_type = mbstate_t;
+
+  static constexpr void assign(char_type& c1, const char_type& c2) noexcept {}
+  static constexpr bool eq(char_type c1, char_type c2) noexcept { return true; }
+  static constexpr bool lt(char_type c1, char_type c2) noexcept { return true; }
+
+  static constexpr int compare(const char_type* s1, const char_type* s2, size_t n) { return 0; }
+  static constexpr size_t length(const char_type* s) { return 0; }
+  static constexpr const char_type* find(const char_type* s, size_t n,
+                                         const char_type& a)
+  {
+    return 0;
+  }
+  static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n) { return s1; }
+  static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n) { return s1; }
+  static constexpr char_type* assign(char_type* s, size_t n, char_type a) { return s; }
+};
+#else
+using cxper_char_traits = std::char_traits<char>;
+#endif
+using cstatic_string = boost::static_string::basic_static_string<50, char, cxper_char_traits>;
+
+inline
+constexpr 
+bool 
+testConstantEvaluation()
+{
+#ifdef BOOST_STATIC_STRING_CPP20_CONSTEXPR_USED
+  // c++20 constexpr tests
+  return true;
+#elif defined(BOOST_STATIC_STRING_CPP17_CONSTEXPR_USED)
+  // c++17 constexpr tests
+  return true;
+#elif defined(BOOST_STATIC_STRING_CPP14_CONSTEXPR_USED)
+  // c++14 constexpr tests
+
+  // ctors
+  cstatic_string a;
+  cstatic_string b(1, 'a');
+  cstatic_string c(b, 0);
+  cstatic_string d(b, 0, 1);
+  cstatic_string e("a", 1);
+  cstatic_string f("a");
+  //cstatic_string g(f.begin(), f.end());
+  cstatic_string h(f);
+  cstatic_string i({'a'});
+
+  // assignment
+  a = b;
+  a = "a";
+  a = 'a';
+  a = {'a'};
+
+  // assign
+  a.assign(b);
+  a.assign(b, 0, 1);
+  a.assign("a", 1);
+  a.assign("a");
+  a.assign(b.begin(), b.end());
+  a.assign({'a'});
+  a.assign(1, 'a');
+
+  // element access
+  {
+    auto j = a.at(0);
+  }
+  {
+    auto j = a[0];
+  }
+  {
+    auto j = a.front();
+  }
+  {
+    auto j = a.back();
+  }
+  {
+    auto j = a.data();
+  }
+  {
+    auto j = a.c_str();
+  }
+  {
+    auto j = a.begin();
+  }
+  {
+    auto j = a.cbegin();
+  }
+  {
+    auto j = a.end();
+  }
+  {
+    auto j = a.cend();
+  }
+  /*
+  {
+    auto j = a.rbegin();
+  }
+  {
+    auto j = a.crbegin();
+  }
+  {
+    auto j = a.rend();
+  }
+  {
+    auto j = a.crend();
+  }*/
+
+  // capacity and size
+  auto j = cstatic_string().size() +
+    cstatic_string().empty() +
+    cstatic_string().length() +
+    cstatic_string().max_size() +
+    cstatic_string().capacity();
+
+  // clear
+  a.clear();
+
+  // insert
+  a.insert(a.begin(), 1, 'a');
+  // cannot have a pointer outside the same array due to UB
+  a.insert(0, a.begin());
+  a.insert(0, a.begin(), 1);
+  a.insert(a.begin(), 'a');
+  a.insert(a.begin(), {'a'});
+
+  // erase
+  a.erase();
+  a.erase(a.begin());
+  a.erase(a.begin(), a.end());
+
+  // push
+  a.push_back('a');
+  a.pop_back();
+
+  return true;
+#elif defined(BOOST_STATIC_STRING_CPP11_CONSTEXPR_USED)
+  // c++11 constexpr tests
+  return cstatic_string().size() + 
+    cstatic_string().empty() + 
+    cstatic_string().length() + 
+    cstatic_string().max_size() + 
+    cstatic_string().capacity();
+#endif
+}