Add support for char[][] in copyArray()

CHANGELOG.md

@@ -12,6 +12,7 @@ HEAD
 * Add safe bool idiom in `JsonString`
 * Add support for NUL in string values (issue #1646)
 * Add support for arbitrary array rank in `copyArray()`
+* Add support for `char[][]` in `copyArray()`
 * Remove `DeserializationError == bool` and `DeserializationError != bool`
 * Renamed undocumented function `isUndefined()` to `isUnbound()`
 * Fix `JsonVariant::memoryUsage()` for raw strings

extras/tests/JsonArray/copyArray.cpp

@@ -32,6 +32,56 @@ TEST_CASE("copyArray()") {
     CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
   }
 
+  SECTION("const char*[] -> JsonArray") {
+    DynamicJsonDocument doc(4096);
+    JsonArray array = doc.to<JsonArray>();
+    char json[32];
+    const char* source[] = {"a", "b", "c"};
+
+    bool ok = copyArray(source, array);
+    CHECK(ok);
+
+    serializeJson(array, json);
+    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+  }
+
+  SECTION("const char[][] -> JsonArray") {
+    DynamicJsonDocument doc(4096);
+    JsonArray array = doc.to<JsonArray>();
+    char json[32];
+    char source[][2] = {"a", "b", "c"};
+
+    bool ok = copyArray(source, array);
+    CHECK(ok);
+
+    serializeJson(array, json);
+    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+  }
+
+  SECTION("const char[][] -> JsonDocument") {
+    DynamicJsonDocument doc(4096);
+    char json[32];
+    char source[][2] = {"a", "b", "c"};
+
+    bool ok = copyArray(source, doc);
+    CHECK(ok);
+
+    serializeJson(doc, json);
+    CHECK(std::string("[\"a\",\"b\",\"c\"]") == json);
+  }
+
+  SECTION("const char[][] -> MemberProxy") {
+    DynamicJsonDocument doc(4096);
+    char json[32];
+    char source[][2] = {"a", "b", "c"};
+
+    bool ok = copyArray(source, doc["data"]);
+    CHECK(ok);
+
+    serializeJson(doc, json);
+    CHECK(std::string("{\"data\":[\"a\",\"b\",\"c\"]}") == json);
+  }
+
   SECTION("int[] -> JsonDocument") {
     DynamicJsonDocument doc(4096);
     char json[32];
@@ -174,6 +224,23 @@ TEST_CASE("copyArray()") {
     CHECK("" == destination[3]);
   }
 
+  SECTION("JsonArray -> char[N][]") {
+    DynamicJsonDocument doc(4096);
+    char json[] = "[\"a12345\",\"b123456\",\"c1234567\"]";
+    DeserializationError err = deserializeJson(doc, json);
+    CHECK(err == DeserializationError::Ok);
+    JsonArray array = doc.as<JsonArray>();
+
+    char destination[4][8] = {{0}};
+    size_t result = copyArray(array, destination);
+
+    CHECK(3 == result);
+    CHECK(std::string("a12345") == destination[0]);
+    CHECK(std::string("b123456") == destination[1]);
+    CHECK(std::string("c123456") == destination[2]);  // truncated
+    CHECK(std::string("") == destination[3]);
+  }
+
   SECTION("JsonDocument -> int[]") {
     DynamicJsonDocument doc(4096);
     char json[] = "[1,2,3]";

src/ArduinoJson/Array/Utilities.hpp

@@ -36,6 +36,12 @@ copyArray(const T* src, size_t len, const TDestination& dst) {
   return ok;
 }
 
+// Special case for char[] which much be treated as const char*
+template <typename TDestination>
+inline bool copyArray(const char* src, size_t, const TDestination& dst) {
+  return dst.set(src);
+}
+
 // Copy array to a JsonDocument
 template <typename T>
 inline bool copyArray(const T& src, JsonDocument& dst) {
@@ -72,6 +78,18 @@ inline size_t copyArray(ArrayConstRef src, T* dst, size_t len) {
   return i;
 }
 
+// Special case for char[] which must be treated as a string
+template <size_t N>
+inline size_t copyArray(VariantConstRef src, char (&dst)[N]) {
+  String s = src;
+  size_t len = N - 1;
+  if (len > s.size())
+    len = s.size();
+  memcpy(dst, s.c_str(), len);
+  dst[len] = 0;
+  return 1;
+}
+
 // Copy a JsonDocument to an array
 // (JsonDocument doesn't implicitly convert to JsonArrayConst)
 template <typename TSource, typename T>