1 files changed, 11 insertions, 3 deletions
diff --git a/RoughlyEnoughItems-api/src/main/java/me/shedaniel/rei/utils/CollectionUtils.java b/RoughlyEnoughItems-api/src/main/java/me/shedaniel/rei/utils/CollectionUtils.java
index 1060a6bdc..fd4cac467 100644
--- a/RoughlyEnoughItems-api/src/main/java/me/shedaniel/rei/utils/CollectionUtils.java
+++ b/RoughlyEnoughItems-api/src/main/java/me/shedaniel/rei/utils/CollectionUtils.java
@@ -26,15 +26,15 @@ package me.shedaniel.rei.utils;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.common.collect.UnmodifiableIterator;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
 import me.shedaniel.rei.api.EntryStack;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.api.Environment;
 import net.minecraft.util.Mth;
 
 import java.util.*;
-import java.util.function.Function;
-import java.util.function.Predicate;
-import java.util.function.Supplier;
+import java.util.function.*;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -162,6 +162,14 @@ public class CollectionUtils {
         return l;
     }
     
+    public static <T> IntList mapToInt(Collection<T> list, ToIntFunction<T> function) {
+        IntList l = new IntArrayList(list.size() + 1);
+        for (T t : list) {
+            l.add(function.applyAsInt(t));
+        }
+        return l;
+    }
+    
     public static <T, R> List<R> mapParallel(Collection<T> list, Function<T, R> function) {
         return list.parallelStream().map(function).collect(Collectors.toList());
     }