resource-iterator: add ResourceIterator#associateTo & `ResourceIter…

…ator#associateByTo`

src/main/kotlin/Iterators.kt

@@ -151,6 +151,33 @@ fun <T, K, V> ResourceIterator<T>.associate(transform: (T) -> Pair<K, V>): Map<K
     asInternalSequence().associate(transform)
 }
 
+/**
+ * Analogy of the `Sequence<T>.associateByTo`.
+ */
+inline fun <T, K, M : MutableMap<in K, in T>> ResourceIterator<T>.associateByTo(
+    destination: M,
+    keySelector: (T) -> K
+): M =
+    use {
+        for (i in this) {
+            destination.put(keySelector(i), i)
+        }
+        return destination
+    }
+
+/**
+ * Analogy of the `Sequence<T>.associateTo`.
+ */
+inline fun <T, K, V, M : MutableMap<in K, in V>> ResourceIterator<T>.associateTo(
+    destination: M,
+    transform: (T) -> Pair<K, V>
+): M = use {
+    for (i in this) {
+        destination += transform(i)
+    }
+    return destination
+}
+
 /**
  * Returns a new map containing all key-value pairs from the given resource-iterator of pairs.
  *

src/test/kotlin/ResourceIteratorsTest.kt

@@ -494,4 +494,34 @@ internal class ResourceIteratorTest {
         Assertions.assertEquals(9, res)
         Assertions.assertEquals(1, onClose)
     }
+
+    @Test
+    fun `test associateByTo`() {
+        var onClose = 0
+        val res: MutableMap<String, Int> = resourceIteratorOf(42, 42, 4242, 424242) { onClose++ }
+            .associateByTo(mutableMapOf()) { it.toString() }
+        Assertions.assertEquals(
+            mapOf(
+                "42" to 42, "4242" to 4242, "424242" to 424242
+            ),
+            res
+        )
+        Assertions.assertEquals(1, onClose)
+    }
+
+    @Test
+    fun `test associateTo`() {
+        var onClose = 0
+        val res: MutableMap<Int, Int> = resourceIteratorOf(42, 42, 4242, 424242) { onClose++ }
+            .associateTo(mutableMapOf()) { a -> a / 2 to a * 2 }
+        Assertions.assertEquals(
+            mapOf(
+                21 to 84,
+                2121 to 8484,
+                212121 to 848484,
+            ),
+            res
+        )
+        Assertions.assertEquals(1, onClose)
+    }
 }