[stdlib] Merge js-ir specific sources into common js sources

libraries/stdlib/js/runtime/BitMask.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.js
+
+internal typealias BitMask = IntArray
+
+private fun bitMaskWith(activeBit: Int): BitMask {
+    val numberIndex = activeBit shr 5
+    val intArray = IntArray(numberIndex + 1)
+    val positionInNumber = activeBit and 31
+    val numberWithSettledBit = 1 shl positionInNumber
+    intArray[numberIndex] = intArray[numberIndex] or numberWithSettledBit
+    return intArray
+}
+
+internal fun BitMask.isBitSet(possibleActiveBit: Int): Boolean {
+    val numberIndex = possibleActiveBit shr 5
+    if (numberIndex > size) return false
+    val positionInNumber = possibleActiveBit and 31
+    val numberWithSettledBit = 1 shl positionInNumber
+    return get(numberIndex) and numberWithSettledBit != 0
+}
+
+private fun compositeBitMask(capacity: Int, masks: Array<BitMask>): BitMask {
+    return IntArray(capacity) { i ->
+        var result = 0
+        for (mask in masks) {
+            if (i < mask.size) {
+                result = result or mask[i]
+            }
+        }
+        result
+    }
+}
+
+internal fun implement(interfaces: Array<dynamic>): BitMask {
+    var maxSize = 1
+    val masks = js("[]")
+
+    for (i in interfaces) {
+        var currentSize = maxSize
+        val imask: BitMask? = i.prototype.`$imask$` ?: i.`$imask$`
+
+        if (imask != null) {
+            masks.push(imask)
+            currentSize = imask.size
+        }
+
+        val iid: Int? = i.`$metadata$`.iid
+        val iidImask: BitMask? = iid?.let { bitMaskWith(it) }
+
+        if (iidImask != null) {
+            masks.push(iidImask)
+            currentSize = JsMath.max(currentSize, iidImask.size)
+        }
+
+        if (currentSize > maxSize) {
+            maxSize = currentSize
+        }
+    }
+
+    return compositeBitMask(maxSize, masks)
+}