implemented frontend including separate message system; started to implement backend

yjs-poll/node_modules/lib0/hash/rabin-uncached.js

@@ -0,0 +1,68 @@
+/**
+ * It is not recommended to use this package. This is the uncached implementation of the rabin
+ * fingerprint algorithm. However, it can be used to verify the `rabin.js` implementation.
+ *
+ * @module rabin-uncached
+ */
+
+import * as math from '../math.js'
+import * as buffer from '../buffer.js'
+
+export class RabinUncachedEncoder {
+  /**
+   * @param {Uint8Array} m assert(m[0] === 1)
+   */
+  constructor (m) {
+    this.m = m
+    this.blen = m.byteLength
+    this.bs = new Uint8Array(this.blen)
+    /**
+     * This describes the position of the most significant byte (starts with 0 and increases with
+     * shift)
+     */
+    this.bpos = 0
+  }
+
+  /**
+   * Add/Xor/Substract bytes.
+   *
+   * Discards bytes that are out of range.
+   * @todo put this in function or inline
+   *
+   * @param {Uint8Array} cs
+   */
+  add (cs) {
+    const copyLen = math.min(this.blen, cs.byteLength)
+    // copy from right to left until max is reached
+    for (let i = 0; i < copyLen; i++) {
+      this.bs[(this.bpos + this.blen - i - 1) % this.blen] ^= cs[cs.byteLength - i - 1]
+    }
+  }
+
+  /**
+   * @param {number} byte
+   */
+  write (byte) {
+    // [0,m1,m2,b]
+    //  x            <- bpos
+    // Shift one byte to the left, add b
+    this.bs[this.bpos] = byte
+    this.bpos = (this.bpos + 1) % this.blen
+    // mod
+    for (let i = 7; i >= 0; i--) {
+      if (((this.bs[this.bpos] >>> i) & 1) === 1) {
+        this.add(buffer.shiftNBitsLeft(this.m, i))
+      }
+    }
+    // if (this.bs[this.bpos] !== 0) { error.unexpectedCase() }
+    // assert(this.bs[this.bpos] === 0)
+  }
+
+  getFingerprint () {
+    const result = new Uint8Array(this.blen - 1)
+    for (let i = 0; i < result.byteLength; i++) {
+      result[i] = this.bs[(this.bpos + i + 1) % this.blen]
+    }
+    return result
+  }
+}