#182-Implement method CppStringT::contains()

Completed. Validated.

Author: schmouk

cpp-strings-tests/cpp-strings-tests.cpp

@@ -714,6 +714,65 @@ namespace cppstringstests
 			Assert::AreEqual(pcs::CppWString(L"zyxwvutsrqp").c_str(), ws.center(10, L'#').c_str(), L"--16--");
 		}
 
+		TEST_METHOD(contains)
+		{
+			pcs::CppString text("Abcd. Efgh ij!");
+			for (std::size_t index = 0; index < text.size(); ++index) {
+				Assert::IsTrue(text.contains(text.substr(index)));
+				for (std::size_t count = 0; count < text.size() - index; ++count)
+					Assert::IsTrue(text.contains(text.substr(index, count)));
+			}
+			Assert::IsFalse(text.contains("zzz"cs));
+			Assert::IsFalse(text.contains("abc"cs));
+			Assert::IsFalse(text.contains("Abcd. Efgh ij!!"cs));
+			Assert::IsTrue(text.contains(""cs));
+
+			pcs::CppWString wtext(L"Abcd. Efgh ij!");
+			for (std::size_t index = 0; index < wtext.size(); ++index) {
+				Assert::IsTrue(wtext.contains(wtext.substr(index)));
+				for (std::size_t count = 0; count < text.size() - index; ++count)
+					Assert::IsTrue(wtext.contains(wtext.substr(index, count)));
+			}
+			Assert::IsFalse(wtext.contains(L"zzz"cs));
+			Assert::IsFalse(wtext.contains(L"abc"cs));
+			Assert::IsFalse(wtext.contains(L"Abcd. Efgh ij!!"cs));
+			Assert::IsTrue(wtext.contains(L""cs));
+
+
+			for (std::size_t index = 0; index < text.size(); ++index) {
+				Assert::IsTrue(text.contains(text.substr(index).c_str()));
+				for (std::size_t count = 0; count < text.size() - index; ++count)
+					Assert::IsTrue(text.contains(text.substr(index, count).c_str()));
+			}
+			Assert::IsFalse(text.contains("z"));
+			Assert::IsFalse(text.contains("a"));
+			Assert::IsFalse(text.contains("Abcd. Efgh ij!!"));
+			Assert::IsTrue(text.contains(""));
+			Assert::IsTrue(text.contains(nullptr));
+
+			for (std::size_t index = 0; index < wtext.size(); ++index) {
+				Assert::IsTrue(wtext.contains(wtext.substr(index).c_str()));
+				for (std::size_t count = 0; count < text.size() - index; ++count)
+					Assert::IsTrue(wtext.contains(wtext.substr(index, count).c_str()));
+			}
+			Assert::IsFalse(wtext.contains(L"zzz"));
+			Assert::IsFalse(wtext.contains(L"abc"));
+			Assert::IsFalse(wtext.contains(L"Abcd. Efgh ij!!"));
+			Assert::IsTrue(wtext.contains(L""));
+			Assert::IsTrue(wtext.contains(nullptr));
+
+
+			for (auto const ch : text)
+				Assert::IsTrue(text.contains(ch));
+			Assert::IsFalse(text.contains('z'));
+			Assert::IsFalse(text.contains('a'));
+
+			for (auto const wch : wtext)
+				Assert::IsTrue(wtext.contains(wch));
+			Assert::IsFalse(wtext.contains(L'z'));
+			Assert::IsFalse(wtext.contains(L'a'));
+		}
+
 		TEST_METHOD(count)
 		{
 			pcs::CppString s("abcabcabcdefabca bca bcabca");

cpp-strings/cppstrings.h

@@ -457,7 +457,7 @@ namespace pcs // i.e. "pythonic c++ strings"
 
 
         //---   contains()   --------------------------------------
-        /** \brief Returns true if this string contains the passed string or char.
+        /** \brief Returns true if this string contains the passed string, or false otherwise.
         *
         * This is the c++ implementation of Python keyword 'in' applied to strings.
         */
@@ -487,6 +487,32 @@ namespace pcs // i.e. "pythonic c++ strings"
 #endif
         }
 
+        /** \brief Returns true if this string contains the passed C-string, or false otherwise. */
+        inline const bool contains(const CharT* substr) const noexcept
+        {
+            if (substr == nullptr)
+                // just to avoid system error on invalid access
+                return true;
+
+#if (defined(_HAS_CXX23) && _HAS_CXX23) || (!defined(_HAS_CXX23) && __cplusplus >= 202302L)
+            // c++23 and above already defines this method
+            return MyBaseClass::contains(substr);
+#else
+            return contains(CppStringT(substr));
+#endif
+        }
+        /** \brief Returns true if this string contains the passed char, or false otherwise. */
+        const bool contains(const CharT& ch) const noexcept
+        {
+#if (defined(_HAS_CXX23) && _HAS_CXX23) || (!defined(_HAS_CXX23) && __cplusplus >= 202302L)
+            // c++23 and above already defines this method
+            return MyBaseClass::contains(ch);
+#else
+            // up to c++20, we have to implement this method
+            return std::ranges::any_of(*this, [ch](const value_type c) -> bool { return c == ch; });
+#endif
+        }
+
 
         //---   count()   -----------------------------------------
         /** \brief Returns the number of non-overlapping occurrences of substring sub in the range [start, end]. */