fix: optimization: PVS-Studio warning V831

Replaced 'at()' method with 'operator[]' to improve performance.

The 'at()' method performs bounds checking, which can introduce overhead. Using 'operator[]' bypasses this check and can improve performance when you are certain that the index is within bounds.

Reported by: PVS-Studio
Signed-off-by: Vyacheslav Ivanov <islavaivanov76@gmail.com>

src/audio/audio.cpp

@@ -253,7 +253,7 @@ speakerid_t audio::play(
     if (!sound->variants.empty()) {
         size_t index = rand() % (sound->variants.size() + 1);
         if (index < sound->variants.size()) {
-            sound = sound->variants.at(index).get();
+            sound = sound->variants[index].get();
         }
     }
     auto speaker_ptr = sound->newInstance(priority, channel);

src/graphics/ui/elements/Label.cpp

@@ -145,7 +145,7 @@ uint Label::getLineByYOffset(int offset) const {
 
 uint Label::getLineByTextIndex(size_t index) const {
     for (size_t i = 0; i < cache.lines.size(); i++) {
-        if (cache.lines.at(i).offset > index) {
+        if (cache.lines[i].offset > index) {
             return i-1;
         }
     }
@@ -195,7 +195,7 @@ void Label::draw(const DrawContext* pctx, Assets* assets) {
 
     if (multiline) {
         for (size_t i = 0; i < cache.lines.size(); i++) {
-            auto& line = cache.lines.at(i);
+            auto& line = cache.lines[i];
             size_t offset = line.offset;
             std::wstring_view view(text.c_str()+offset, text.length()-offset);
             if (i < cache.lines.size()-1) {

src/graphics/ui/gui_xml.cpp

@@ -286,7 +286,7 @@ static std::shared_ptr<UINode> readButton(UiXmlReader& reader, const xml::xmlele
 
     std::shared_ptr<Button> button;
     auto& elements = element->getElements();
-    if (!elements.empty() && elements.at(0)->getTag() != "#") {
+    if (!elements.empty() && elements[0]->getTag() != "#") {
         auto inner = reader.readUINode(element->getElements().at(0));
         if (inner != nullptr) {
             button = std::make_shared<Button>(inner, padding);

src/logic/scripting/lua/libconsole.cpp

@@ -75,7 +75,7 @@ static int l_get_command_info(lua::State* L) {
     
     lua::createtable(L, args.size(), 0);
     for (size_t i = 0; i < args.size(); i++) {
-        auto& arg = args.at(i);
+        auto& arg = args[i];
         lua::createtable(L, 0, 2);
         
         lua::pushstring(L, arg.name);

src/logic/scripting/lua/libpack.cpp

@@ -95,7 +95,7 @@ static int l_pack_get_info(lua::State* L, const ContentPack& pack, const Content
     if (!pack.dependencies.empty()) {
         lua::createtable(L, pack.dependencies.size(), 0);
         for (size_t i = 0; i < pack.dependencies.size(); i++) {
-            auto& dpack = pack.dependencies.at(i);
+            auto& dpack = pack.dependencies[i];
             std::string prefix;
             switch (dpack.level) {
                 case DependencyLevel::required: prefix = "!"; break;
@@ -142,7 +142,7 @@ static int l_pack_get_info(lua::State* L) {
         manager.scan();
         auto vec = manager.getAll({packid});
         if (!vec.empty()) {
-            return l_pack_get_info(L, vec.at(0), content);
+            return l_pack_get_info(L, vec[0], content);
         }
         return 0;
     }

src/util/listutil.cpp

@@ -7,7 +7,7 @@ std::string util::to_string(const std::vector<std::string>& vec) {
     std::stringstream ss;
     ss << "[";
     for (size_t i = 0; i < vec.size(); i++) {
-        ss << util::quote(vec.at(i));
+        ss << util::quote(vec[1]);
         if (i < vec.size()-1) {
             ss << ", ";
         }