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authorLinnea Gräf <nea@nea.moe>2024-08-28 19:04:24 +0200
committerLinnea Gräf <nea@nea.moe>2024-08-28 19:04:24 +0200
commitd2f240ff0ca0d27f417f837e706c781a98c31311 (patch)
tree0db7aff6cc14deaf36eed83889d59fd6b3a6f599 /src/main/kotlin/util/MutableMapWithMaxSize.kt
parenta6906308163aa3b2d18fa1dc1aa71ac9bbcc83ab (diff)
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Refactor source layout
Introduce compat source sets and move all kotlin sources to the main directory [no changelog]
Diffstat (limited to 'src/main/kotlin/util/MutableMapWithMaxSize.kt')
-rw-r--r--src/main/kotlin/util/MutableMapWithMaxSize.kt38
1 files changed, 38 insertions, 0 deletions
diff --git a/src/main/kotlin/util/MutableMapWithMaxSize.kt b/src/main/kotlin/util/MutableMapWithMaxSize.kt
new file mode 100644
index 0000000..067e652
--- /dev/null
+++ b/src/main/kotlin/util/MutableMapWithMaxSize.kt
@@ -0,0 +1,38 @@
+
+package moe.nea.firmament.util
+
+fun <K, V> mutableMapWithMaxSize(maxSize: Int): MutableMap<K, V> = object : LinkedHashMap<K, V>() {
+ override fun removeEldestEntry(eldest: MutableMap.MutableEntry<K, V>): Boolean {
+ return size > maxSize
+ }
+}
+
+fun <T, R> ((T) -> R).memoizeIdentity(maxCacheSize: Int): (T) -> R {
+ val memoized = { it: IdentityCharacteristics<T> ->
+ this(it.value)
+ }.memoize(maxCacheSize)
+ return { memoized(IdentityCharacteristics(it)) }
+}
+
+@PublishedApi
+internal val SENTINEL_NULL = java.lang.Object()
+
+/**
+ * Requires the map to only contain values of type [R] or [SENTINEL_NULL]. This is ensured if the map is only ever
+ * accessed via this function.
+ */
+inline fun <T, R> MutableMap<T, Any>.computeNullableFunction(key: T, crossinline func: () -> R): R {
+ val value = this.getOrPut(key) {
+ func() ?: SENTINEL_NULL
+ }
+ @Suppress("UNCHECKED_CAST")
+ return if (value === SENTINEL_NULL) null as R
+ else value as R
+}
+
+fun <T, R> ((T) -> R).memoize(maxCacheSize: Int): (T) -> R {
+ val map = mutableMapWithMaxSize<T, Any>(maxCacheSize)
+ return {
+ map.computeNullableFunction(it) { this@memoize(it) }
+ }
+}