global: private xpub support part 2

website_next/wallets/derive/bytes.js

@@ -0,0 +1,92 @@
+/**
+ * @param {number} length
+ */
+export function createBytes(length) {
+  return new Uint8Array(length);
+}
+
+/**
+ * @param {Uint8Array[]} parts
+ */
+export function concatBytes(parts) {
+  const length = parts.reduce((total, part) => total + part.length, 0);
+  const bytes = createBytes(length);
+  let offset = 0;
+
+  for (const part of parts) {
+    bytes.set(part, offset);
+    offset += part.length;
+  }
+
+  return bytes;
+}
+
+/**
+ * @param {Uint8Array} bytes
+ * @param {number} start
+ */
+export function readUint32(bytes, start) {
+  return (
+    bytes[start] * 0x1000000 +
+    bytes[start + 1] * 0x10000 +
+    bytes[start + 2] * 0x100 +
+    bytes[start + 3]
+  );
+}
+
+/**
+ * @param {number} value
+ */
+export function writeUint32(value) {
+  const bytes = createBytes(4);
+
+  bytes[0] = value >>> 24;
+  bytes[1] = value >>> 16;
+  bytes[2] = value >>> 8;
+  bytes[3] = value;
+
+  return bytes;
+}
+
+/**
+ * @param {Uint8Array} bytes
+ */
+export function bytesToBigInt(bytes) {
+  let value = 0n;
+
+  for (const byte of bytes) {
+    value = (value << 8n) + BigInt(byte);
+  }
+
+  return value;
+}
+
+/**
+ * @param {bigint} value
+ * @param {number} length
+ */
+export function bigIntToBytes(value, length) {
+  const bytes = createBytes(length);
+  let remaining = value;
+
+  for (let i = length - 1; i >= 0; i -= 1) {
+    bytes[i] = Number(remaining & 0xffn);
+    remaining >>= 8n;
+  }
+
+  return bytes;
+}
+
+/**
+ * @param {Uint8Array} left
+ * @param {Uint8Array} right
+ */
+export function bytesEqual(left, right) {
+  if (left.length !== right.length) return false;
+
+  for (let i = 0; i < left.length; i += 1) {
+    if (left[i] !== right[i]) return false;
+  }
+
+  return true;
+}