implemented frontend including separate message system; started to implement backend

yjs-poll/node_modules/lib0/prng/Xoroshiro128plus.js

@@ -0,0 +1,111 @@
+/**
+ * @module prng
+ */
+
+import { Xorshift32 } from './Xorshift32.js'
+import * as binary from '../binary.js'
+
+/**
+ * This is a variant of xoroshiro128plus - the fastest full-period generator passing BigCrush without systematic failures.
+ *
+ * This implementation follows the idea of the original xoroshiro128plus implementation,
+ * but is optimized for the JavaScript runtime. I.e.
+ * * The operations are performed on 32bit integers (the original implementation works with 64bit values).
+ * * The initial 128bit state is computed based on a 32bit seed and Xorshift32.
+ * * This implementation returns two 32bit values based on the 64bit value that is computed by xoroshiro128plus.
+ *   Caution: The last addition step works slightly different than in the original implementation - the add carry of the
+ *   first 32bit addition is not carried over to the last 32bit.
+ *
+ * [Reference implementation](http://vigna.di.unimi.it/xorshift/xoroshiro128plus.c)
+ */
+export class Xoroshiro128plus {
+  /**
+   * @param {number} seed Unsigned 32 bit number
+   */
+  constructor (seed) {
+    this.seed = seed
+    // This is a variant of Xoroshiro128plus to fill the initial state
+    const xorshift32 = new Xorshift32(seed)
+    this.state = new Uint32Array(4)
+    for (let i = 0; i < 4; i++) {
+      this.state[i] = xorshift32.next() * binary.BITS32
+    }
+    this._fresh = true
+  }
+
+  /**
+   * @return {number} Float/Double in [0,1)
+   */
+  next () {
+    const state = this.state
+    if (this._fresh) {
+      this._fresh = false
+      return ((state[0] + state[2]) >>> 0) / (binary.BITS32 + 1)
+    } else {
+      this._fresh = true
+      const s0 = state[0]
+      const s1 = state[1]
+      const s2 = state[2] ^ s0
+      const s3 = state[3] ^ s1
+      // function js_rotl (x, k) {
+      //   k = k - 32
+      //   const x1 = x[0]
+      //   const x2 = x[1]
+      //   x[0] = x2 << k | x1 >>> (32 - k)
+      //   x[1] = x1 << k | x2 >>> (32 - k)
+      // }
+      // rotl(s0, 55) // k = 23 = 55 - 32; j = 9 =  32 - 23
+      state[0] = (s1 << 23 | s0 >>> 9) ^ s2 ^ (s2 << 14 | s3 >>> 18)
+      state[1] = (s0 << 23 | s1 >>> 9) ^ s3 ^ (s3 << 14)
+      // rol(s1, 36) // k = 4 = 36 - 32; j = 23 = 32 - 9
+      state[2] = s3 << 4 | s2 >>> 28
+      state[3] = s2 << 4 | s3 >>> 28
+      return (((state[1] + state[3]) >>> 0) / (binary.BITS32 + 1))
+    }
+  }
+}
+
+/*
+// Reference implementation
+// Source: http://vigna.di.unimi.it/xorshift/xoroshiro128plus.c
+// By David Blackman and Sebastiano Vigna
+// Who published the reference implementation under Public Domain (CC0)
+
+#include <stdint.h>
+#include <stdio.h>
+
+uint64_t s[2];
+
+static inline uint64_t rotl(const uint64_t x, int k) {
+    return (x << k) | (x >> (64 - k));
+}
+
+uint64_t next(void) {
+    const uint64_t s0 = s[0];
+    uint64_t s1 = s[1];
+    s1 ^= s0;
+    s[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14); // a, b
+    s[1] = rotl(s1, 36); // c
+    return (s[0] + s[1]) & 0xFFFFFFFF;
+}
+
+int main(void)
+{
+    int i;
+    s[0] = 1111 | (1337ul << 32);
+    s[1] = 1234 | (9999ul << 32);
+
+    printf("1000 outputs of genrand_int31()\n");
+    for (i=0; i<100; i++) {
+        printf("%10lu ", i);
+        printf("%10lu ", next());
+        printf("- %10lu ", s[0] >> 32);
+        printf("%10lu ", (s[0] << 32) >> 32);
+        printf("%10lu ", s[1] >> 32);
+        printf("%10lu ", (s[1] << 32) >> 32);
+        printf("\n");
+        // if (i%5==4) printf("\n");
+    }
+    return 0;
+}
+*/