Fix joinToString with initial empty string.

CesiumGS · Apr 5, 2024 · 3d7ff14 · 3d7ff14
1 parent 1a6b1f8
commit 3d7ff14
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Showing 2 changed files with 31 additions and 18 deletions.
diff --git a/CesiumUtility/include/CesiumUtility/joinToString.h b/CesiumUtility/include/CesiumUtility/joinToString.h
@@ -17,16 +17,17 @@ namespace CesiumUtility {
 template <class TIterator>
 std::string
 joinToString(TIterator begin, TIterator end, const std::string& separator) {
+  if (begin == end)
+    return std::string();
+
+  std::string first = *begin;
+
   return std::accumulate(
-      begin,
+      ++begin,
       end,
-      std::string(),
+      std::move(first),
       [&separator](const std::string& acc, const std::string& element) {
-        if (!acc.empty()) {
-          return acc + separator + element;
-        } else {
-          return element;
-        }
+        return acc + separator + element;
       });
 }
 
@@ -41,16 +42,6 @@ joinToString(TIterator begin, TIterator end, const std::string& separator) {
  */
 template <class TCollection>
 std::string joinToString(TCollection collection, const std::string& separator) {
-  return std::accumulate(
-      collection.cbegin(),
-      collection.cend(),
-      std::string(),
-      [&separator](const std::string& acc, const std::string& element) {
-        if (!acc.empty()) {
-          return acc + separator + element;
-        } else {
-          return element;
-        }
-      });
+  return joinToString(collection.cbegin(), collection.cend(), separator);
 }
 } // namespace CesiumUtility
diff --git a/CesiumUtility/test/TestJoinToString.cpp b/CesiumUtility/test/TestJoinToString.cpp
@@ -0,0 +1,22 @@
+#include <CesiumUtility/joinToString.h>
+
+#include <catch2/catch.hpp>
+
+using namespace CesiumUtility;
+
+TEST_CASE("joinToString") {
+  CHECK(
+      joinToString(std::vector<std::string>{"test", "this"}, "--") ==
+      "test--this");
+  CHECK(
+      joinToString(std::vector<std::string>{"test", "this", "thing"}, " ") ==
+      "test this thing");
+  CHECK(
+      joinToString(std::vector<std::string>{"test", "this", "thing"}, "") ==
+      "testthisthing");
+  CHECK(joinToString(std::vector<std::string>{"test"}, "--") == "test");
+  CHECK(joinToString(std::vector<std::string>{""}, "--") == "");
+  CHECK(joinToString(std::vector<std::string>{"", "aa", ""}, "--") == "--aa--");
+  CHECK(joinToString(std::vector<std::string>{"", ""}, "--") == "--");
+  CHECK(joinToString(std::vector<std::string>{}, "--") == "");
+}