add indexOfFirst and indexOfLast to EntityBag and family. Also, add g…

…oToFirst and goToLast to EntityBagIterator
Quillraven · Dec 23, 2024 · 1246b77 · 1246b77
1 parent c765d1f
commit 1246b77
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diff --git a/src/commonMain/kotlin/com/github/quillraven/fleks/collection/EntityBagIterator.kt b/src/commonMain/kotlin/com/github/quillraven/fleks/collection/EntityBagIterator.kt
@@ -63,4 +63,32 @@ data class EntityBagIterator(private val bag: EntityBag) {
     fun reset() {
         currentIdx = 0
     }
+
+    /**
+     * Moves the iterator to the first [Entity] matching the given [predicate] and returns it.
+     * If there is no such [Entity] then the iterator is reset and [Entity.NONE] is returned instead.
+     */
+    fun goToFirst(predicate: (Entity) -> Boolean): Entity {
+        currentIdx = bag.indexOfFirst(predicate)
+        if (currentIdx == -1) {
+            reset()
+            return Entity.NONE
+        }
+
+        return bag[currentIdx]
+    }
+
+    /**
+     * Moves the iterator to the last [Entity] matching the given [predicate] and returns it.
+     * If there is no such [Entity] then the iterator is reset and [Entity.NONE] is returned instead.
+     */
+    fun goToLast(predicate: (Entity) -> Boolean): Entity {
+        currentIdx = bag.indexOfLast(predicate)
+        if (currentIdx == -1) {
+            reset()
+            return Entity.NONE
+        }
+
+        return bag[currentIdx]
+    }
 }
diff --git a/src/commonMain/kotlin/com/github/quillraven/fleks/collection/entityBag.kt b/src/commonMain/kotlin/com/github/quillraven/fleks/collection/entityBag.kt
@@ -118,6 +118,18 @@ interface EntityBag {
      */
     fun count(predicate: (Entity) -> Boolean): Int
 
+    /**
+     * Returns the index of the first [Entity] matching the given [predicate],
+     * or -1 if the bag does not contain such an [Entity].
+     */
+    fun indexOfFirst(predicate: (Entity) -> Boolean): Int
+
+    /**
+     * Returns the index of the last [Entity] matching the given [predicate],
+     * or -1 if the bag does not contain such an [Entity].
+     */
+    fun indexOfLast(predicate: (Entity) -> Boolean): Int
+
     /**
      * Returns a [List] containing only [entities][Entity] matching the given [predicate].
      */

diff --git a/src/commonMain/kotlin/com/github/quillraven/fleks/collection/mutableEntityBag.kt b/src/commonMain/kotlin/com/github/quillraven/fleks/collection/mutableEntityBag.kt
@@ -295,6 +295,34 @@ class MutableEntityBag(
         return result
     }
 
+    /**
+     * Returns the index of the first [Entity] matching the given [predicate],
+     * or -1 if the bag does not contain such an [Entity].
+     */
+    override inline fun indexOfFirst(predicate: (Entity) -> Boolean): Int {
+        for (i in 0 until size) {
+            val entity = values[i]
+            if (predicate(entity)) {
+                return i
+            }
+        }
+        return -1
+    }
+
+    /**
+     * Returns the index of the last [Entity] matching the given [predicate],
+     * or -1 if the bag does not contain such an [Entity].
+     */
+    override inline fun indexOfLast(predicate: (Entity) -> Boolean): Int {
+        for (i in size - 1 downTo 0) {
+            val entity = values[i]
+            if (predicate(entity)) {
+                return i
+            }
+        }
+        return -1
+    }
+
     /**
      * Returns a [List] containing only [entities][Entity] matching the given [predicate].
      */

diff --git a/src/commonMain/kotlin/com/github/quillraven/fleks/family.kt b/src/commonMain/kotlin/com/github/quillraven/fleks/family.kt
@@ -259,6 +259,24 @@ data class Family(
      */
     fun count(predicate: (Entity) -> Boolean): Int = mutableEntities.count(predicate)
 
+    /**
+     * Returns the index of the first [Entity] matching the given [predicate],
+     * or -1 if the family does not contain such an [Entity].
+     */
+    fun indexOfFirst(predicate: (Entity) -> Boolean): Int = mutableEntities.indexOfFirst(predicate)
+
+    /**
+     * Returns the index of the last [Entity] matching the given [predicate],
+     * or -1 if the family does not contain such an [Entity].
+     */
+    fun indexOfLast(predicate: (Entity) -> Boolean): Int = mutableEntities.indexOfLast(predicate)
+
+    /**
+     * Creates an [EntityBagIterator] for the family. If the family gets updated
+     * during iteration then [EntityBagIterator.reset] must be called to guarantee correct iterator behavior.
+     */
+    fun iterator(): EntityBagIterator = EntityBagIterator(mutableEntities)
+
     /**
      * Returns a [Map] containing key-value pairs provided by the [transform] function applied to
      * each [entity][Entity] of the family.

diff --git a/src/commonTest/kotlin/com/github/quillraven/fleks/FamilyBagFunctionsTest.kt b/src/commonTest/kotlin/com/github/quillraven/fleks/FamilyBagFunctionsTest.kt
@@ -449,4 +449,11 @@ class FamilyBagFunctionsTest {
         assertEquals(entityBagOf(testEntity1, testEntity2), testFamily.take(2))
         assertEquals(entityBagOf(testEntity1, testEntity2), testFamily.take(3))
     }
+
+    @Test
+    fun testIndexOf() {
+        assertEquals(0, testFamily.indexOfFirst { it.id == 0 })
+        assertEquals(1, testFamily.indexOfLast { it.id == 1 })
+        assertEquals(-1, testFamily.indexOfLast { it.id == 99 })
+    }
 }
diff --git a/src/commonTest/kotlin/com/github/quillraven/fleks/collection/EntityBagIteratorTest.kt b/src/commonTest/kotlin/com/github/quillraven/fleks/collection/EntityBagIteratorTest.kt
@@ -25,9 +25,9 @@ class EntityBagIteratorTest {
     @Test
     fun `test iterator on bag with single entity`() {
         val entity = Entity(1, 0u)
-        val emptyBag = mutableEntityBagOf(entity)
+        val testBag = mutableEntityBagOf(entity)
 
-        val iterator = emptyBag.iterator()
+        val iterator = testBag.iterator()
 
         assertTrue(iterator.hasNext())
         assertFalse(iterator.hasPrevious())
@@ -49,9 +49,9 @@ class EntityBagIteratorTest {
     fun `test iterator on bag with two entities`() {
         val entity1 = Entity(1, 0u)
         val entity2 = Entity(2, 0u)
-        val emptyBag = mutableEntityBagOf(entity1, entity2)
+        val testBag = mutableEntityBagOf(entity1, entity2)
 
-        val iterator = emptyBag.iterator()
+        val iterator = testBag.iterator()
 
         assertTrue(iterator.hasNext())
         assertFalse(iterator.hasPrevious())
@@ -72,4 +72,34 @@ class EntityBagIteratorTest {
         assertEquals(entity2, iterator.previous(loop = true))
     }
 
+    @Test
+    fun `test goToFirst`() {
+        val entity1 = Entity(1, 0u)
+        val entity2 = Entity(2, 0u)
+        val entity3 = Entity(2, 1u) // same id on purpose to check that goTo stops at first entity
+        val testBag = mutableEntityBagOf(entity1, entity2, entity3)
+
+        val iterator = testBag.iterator()
+
+        assertEquals(entity2, iterator.goToFirst { e -> e.id == 2 })
+        assertEquals(entity1, iterator.previous())
+        assertEquals(Entity.NONE, iterator.goToFirst { e -> e.id == 3 })
+        assertEquals(entity1, iterator.next())
+    }
+
+    @Test
+    fun `test goToLast`() {
+        val entity1 = Entity(1, 0u)
+        val entity2 = Entity(2, 0u)
+        val entity3 = Entity(2, 1u) // same id on purpose to check that goTo stops at first entity
+        val testBag = mutableEntityBagOf(entity1, entity2, entity3)
+
+        val iterator = testBag.iterator()
+
+        assertEquals(entity3, iterator.goToLast { e -> e.id == 2 })
+        assertEquals(entity2, iterator.previous())
+        assertEquals(Entity.NONE, iterator.goToLast { e -> e.id == 3 })
+        assertEquals(entity1, iterator.next())
+    }
+
 }