Speed up the craft definition handling (#8097)

The craft definition handling code that collects the names of the craftable nodes suffers from vector reallocation performance hits, slowing down instances with lots of crafting recipes (VanessaE's DreamBuilder and most public server some to my mind when thinking about this). As in each instance the size of the resulting vector is already known, add a reserve() call before the offending loops to allocate the needed chunk of memory within the result vector in one go, getting rid of the overhead.
minetest · Jan 13, 2019 · a51909b · a51909b
1 parent 5a00b11
commit a51909b
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/src/craftdef.cpp b/src/craftdef.cpp
@@ -112,6 +112,7 @@ static std::vector<std::string> craftGetItemNames(
 		const std::vector<std::string> &itemstrings, IGameDef *gamedef)
 {
 	std::vector<std::string> result;
+	result.reserve(itemstrings.size());
 	for (const auto &itemstring : itemstrings) {
 		result.push_back(craftGetItemName(itemstring, gamedef));
 	}
@@ -123,6 +124,7 @@ static std::vector<std::string> craftGetItemNames(
 		const std::vector<ItemStack> &items, IGameDef *gamedef)
 {
 	std::vector<std::string> result;
+	result.reserve(items.size());
 	for (const auto &item : items) {
 		result.push_back(item.name);
 	}
@@ -134,6 +136,7 @@ static std::vector<ItemStack> craftGetItems(
 		const std::vector<std::string> &items, IGameDef *gamedef)
 {
 	std::vector<ItemStack> result;
+	result.reserve(items.size());
 	for (const auto &item : items) {
 		result.emplace_back(std::string(item), (u16)1,
 			(u16)0, gamedef->getItemDefManager());