initial commit

lib/Helpers.ts

@@ -0,0 +1,54 @@
+const DEC2HEX = (() => {
+  const alphabet = '0123456789abcdef';
+  const dec2hex16 = [...alphabet];
+  const dec2hex256 = new Array<string> (256);
+
+  for (let i = 0; i < 256; i++) {
+    dec2hex256[i] = `${dec2hex16[(i >>> 4) & 0xF]}${dec2hex16[i & 0xF]}`;
+  }
+
+  return dec2hex256;
+})();
+
+const HEX2DEC = (() => {
+  const hex2dec: Record<string, number> = {};
+
+  for ( let i = 0; i < 256; i++ ) {
+    const hex = DEC2HEX[i];
+    const firstLower = hex[0];
+    const firstUpper = firstLower.toUpperCase();
+    const lastLower = hex[1];
+    const lastUpper = lastLower.toUpperCase();
+
+    hex2dec[hex] = i;
+    hex2dec[`${firstLower}${lastUpper}`] = i;
+    hex2dec[`${firstUpper}${lastLower}`] = i;
+    hex2dec[`${firstUpper}${lastUpper}`] = i;
+  }
+
+  return hex2dec;
+})();
+
+export function uint8ArrayConcat(arrays: Uint8Array[]) {
+  const totalLength = arrays.reduce((acc, arr) => acc + arr.length, 0);
+  const result = new Uint8Array(totalLength);
+
+  let offset = 0;
+  for(const array of arrays) {
+    result.set(array, offset);
+    offset += array.length;
+  }
+
+  return result;
+}
+
+export function hexToUint8Array(hexString: string, maxLength?: number): Uint8Array {
+  const length = maxLength ?? hexString.length / 2;
+  const result = new Uint8Array(length);
+
+  for (let i = 0; i < length; i++) {
+    result[i] = HEX2DEC[hexString.slice (i * 2, (i * 2) + 2)];
+  }
+
+  return result;
+}