string: fix self-assignment, fixes #222

felixguendling · May 26, 2024 · ce041ab · ce041ab
1 parent 8255bcd
commit ce041ab
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Showing 3 changed files with 28 additions and 0 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -35,6 +35,7 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR
  -Wno-unsafe-buffer-usage
  -Wno-deprecated-declarations
  -Wno-ctad-maybe-unsupported
+ -Wno-self-assign-overloaded
  -Werror
  )
 elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")

diff --git a/include/cista/containers/string.h b/include/cista/containers/string.h
@@ -137,6 +137,9 @@ struct generic_string {
  }
 
  void move_from(generic_string&& s) noexcept {
+ if (&s == this) {
+ return;
+ }
  reset();
  std::memcpy(static_cast<void*>(this), &s, sizeof(*this));
  if constexpr (std::is_pointer_v<Ptr>) {
@@ -151,6 +154,9 @@ struct generic_string {
  }
 
  void copy_from(generic_string const& s) {
+ if (&s == this) {
+ return;
+ }
  reset();
  if (s.is_short()) {
  std::memcpy(static_cast<void*>(this), &s, sizeof(s));
@@ -434,6 +440,9 @@ struct basic_string : public generic_string<Ptr> {
  basic_string(basic_string&& o) { base::move_from(std::move(o)); }
 
  basic_string& operator=(basic_string const& o) {
+ if (&o == this) {
+ return *this;
+ }
  base::set_owning(o.data(), o.size());
  return *this;
  }

diff --git a/test/string_test.cc b/test/string_test.cc
@@ -18,6 +18,24 @@ constexpr auto const CORNER_CASE_LONG_16 = "0123456789123456";
 constexpr auto const LONG_STR = "hello world hello world";
 constexpr auto const SHORT_STR = "hello world";
 
+TEST_CASE("self assignment") {
+ // case short string
+ cista::raw::string test_short{"test_short"};
+ std::string output_short_pre{test_short};
+ test_short = test_short;
+ std::string output_short_post{test_short};
+ // test_short is empty now
+ CHECK(output_short_pre == output_short_post);
+
+ // case long string
+ cista::raw::string test_long{"test_long_12345678901234567890123456789012"};
+ std::string output_long_pre{test_long};
+ test_long = test_long;
+ std::string output_long_post{test_long};
+ // test_long is filled with 0x01 now
+ CHECK(output_long_pre == output_long_post);
+}
+
 TEST_CASE("string init") {
  auto s = string{};
  CHECK(!s.is_short());