arraymap: fix tail removal (#21)

diffplug · Sep 11, 2023 · 31ce925 · 31ce925
2 parents 43d7048 + 301f071
commit 31ce925
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Showing 2 changed files with 26 additions and 1 deletion.
diff --git a/selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/ArrayMap.kt b/selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/ArrayMap.kt
@@ -61,7 +61,13 @@ class ArrayMap<K : Comparable<K>, V : Any>(private val data: Array<Any>) : Map<K
         ++currentDataIdx
       }
     }
-    check(toRemoveIdx == indicesToRemove.size) {
+    val tailRemoval =
+        if (indicesToRemove.contains((data.size / 2) - 1)) {
+          1
+        } else {
+          0
+        }
+    check(toRemoveIdx + tailRemoval == indicesToRemove.size) {
       "The indices weren't sorted or were too big: $indicesToRemove"
     }
     return ArrayMap<K, V>(newData as Array<Any>)

diff --git a/selfie-lib/src/commonTest/kotlin/com/diffplug/selfie/ArrayMapTest.kt b/selfie-lib/src/commonTest/kotlin/com/diffplug/selfie/ArrayMapTest.kt
@@ -18,6 +18,7 @@ package com.diffplug.selfie
 import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.matchers.shouldBe
 import kotlin.test.Test
+import kotlin.test.assertFails
 
 class ArrayMapTest {
   @Test
@@ -146,4 +147,22 @@ class ArrayMapTest {
     map shouldBe
         ArrayMap.empty<String, String>().plus(key2, value2).plus(key1, value1).plus(key3, value3)
   }
+
+  @Test
+  fun removeItemsWorks() {
+    val empty = ArrayMap.empty<String, String>()
+    val arrayMap = empty.plus("first", "1").plus("second", "2").plus("third", "3")
+    arrayMap.minusSortedIndices(listOf(2)) shouldBe mapOf("first" to "1", "second" to "2")
+    arrayMap.minusSortedIndices(listOf(0)) shouldBe mapOf("second" to "2", "third" to "3")
+    arrayMap.minusSortedIndices(listOf(1)) shouldBe mapOf("first" to "1", "third" to "3")
+
+    arrayMap.minusSortedIndices(listOf(0, 2)) shouldBe mapOf("second" to "2")
+
+    assertFails { arrayMap.minusSortedIndices(listOf(1, 0)) }.message shouldBe
+        "The indices weren't sorted or were too big: [1, 0]"
+    assertFails { arrayMap.minusSortedIndices(listOf(2, 1)) }.message shouldBe
+        "The indices weren't sorted or were too big: [2, 1]"
+    assertFails { arrayMap.minusSortedIndices(listOf(3)) }.message shouldBe
+        "The indices weren't sorted or were too big: [3]"
+  }
 }