Allow getting size of dynamic format arg store (#4270)

fmtlib · Dec 19, 2024 · 7c50da5 · 7c50da5
1 parent 873670b
commit 7c50da5
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diff --git a/include/fmt/args.h b/include/fmt/args.h
@@ -210,6 +210,9 @@ template <typename Context> class dynamic_format_arg_store {
     data_.reserve(new_cap);
     named_info_.reserve(new_cap_named);
   }
+
+  /// Returns the number of elements in the store.
+  size_t size() const noexcept { return data_.size(); }
 };
 
 FMT_END_NAMESPACE

diff --git a/test/args-test.cc b/test/args-test.cc
@@ -186,3 +186,17 @@ TEST(args_test, move_constructor) {
   store.reset();
   EXPECT_EQ(fmt::vformat("{} {} {a1}", moved_store), "42 foo foo");
 }
+
+TEST(args_test, size) {
+  fmt::dynamic_format_arg_store<fmt::format_context> store;
+  EXPECT_EQ(store.size(), 0);
+
+  store.push_back(42);
+  EXPECT_EQ(store.size(), 1);
+
+  store.push_back("Molybdenum");
+  EXPECT_EQ(store.size(), 2);
+
+  store.clear();
+  EXPECT_EQ(store.size(), 0);
+}