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author | Linnea Gräf <nea@nea.moe> | 2024-08-28 19:04:24 +0200 |
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committer | Linnea Gräf <nea@nea.moe> | 2024-08-28 19:04:24 +0200 |
commit | d2f240ff0ca0d27f417f837e706c781a98c31311 (patch) | |
tree | 0db7aff6cc14deaf36eed83889d59fd6b3a6f599 /src/main/kotlin/util/MutableMapWithMaxSize.kt | |
parent | a6906308163aa3b2d18fa1dc1aa71ac9bbcc83ab (diff) | |
download | firmament-d2f240ff0ca0d27f417f837e706c781a98c31311.tar.gz firmament-d2f240ff0ca0d27f417f837e706c781a98c31311.tar.bz2 firmament-d2f240ff0ca0d27f417f837e706c781a98c31311.zip |
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.kt | 38 |
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) } + } +} |