Add CStringArray::join() method (#2668)

SmingHub · Sep 25, 2023 · 69685b1 · 69685b1
1 parent 1d4f0cc
commit 69685b1
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diff --git a/Sming/Core/Data/CStringArray.cpp b/Sming/Core/Data/CStringArray.cpp
@@ -168,3 +168,25 @@ unsigned CStringArray::count() const
 	}
 	return stringCount;
 }
+
+String CStringArray::join(const String& separator) const
+{
+	if(isNull()) {
+		return nullptr;
+	}
+	unsigned len = length();
+	if(len == 0) {
+		return "";
+	}
+	len -= count(); // NUL separators
+	len += separator.length() * (stringCount - 1);
+	String s;
+	s.reserve(len);
+	for(auto it = begin(); it != end(); ++it) {
+		if(it.index() != 0) {
+			s += separator;
+		}
+		s += *it;
+	}
+	return s;
+}
diff --git a/Sming/Core/Data/CStringArray.h b/Sming/Core/Data/CStringArray.h
@@ -246,6 +246,15 @@ class CStringArray : private String
 	*/
 	unsigned count() const;
 
+	/**
+	 * @brief Get contents of array as delimited string
+	 * @param separator What to join elements with
+	 * @retval String
+	 *
+	 * e.g. CStringArray(F("a\0b\0c")).join() returns "a,b,c"
+	 */
+	String join(const String& separator = ",") const;
+
 	/**
 	 * @name Iterator support (forward only)
 	 * @{

diff --git a/tests/HostTests/modules/CStringArray.cpp b/tests/HostTests/modules/CStringArray.cpp
@@ -213,6 +213,25 @@ class CStringArrayTest : public TestGroup
 			REQUIRE(csa.back() == nullptr);
 			REQUIRE(!csa.popBack());
 		}
+
+		TEST_CASE("join")
+		{
+			CStringArray csa;
+			REQUIRE(!csa.join());
+
+			csa = "";
+			REQUIRE(csa.join() == "");
+
+			csa.add("a");
+			REQUIRE(csa.join() == "a");
+
+			csa.add("");
+			REQUIRE(csa.join() == "a,");
+
+			csa.add(F("test\0again"));
+			REQUIRE_EQ(csa.join("}+{"), "a}+{}+{test}+{again");
+			REQUIRE_EQ(csa.join(nullptr), "atestagain");
+		}
 	}
 };