@hashgraph/sdk/lib/encoding/hex.cjs

Hiero SDK

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.decode = decode;
exports.encode = encode;
exports.hexZeroPadded = hexZeroPadded;
exports.isHexString = isHexString;
// SPDX-License-Identifier: Apache-2.0

/**
 * @param {Uint8Array} data
 * @returns {string}
 */
function encode(data) {
  return Buffer.from(data).toString("hex");
}

/**
 * @param {string} text
 * @returns {Uint8Array}
 */
function decode(text) {
  const str = text.startsWith("0x") ? text.substring(2) : text;
  if (str.length % 2 !== 0) {
    throw new Error("Invalid hex string: Must have an even number of characters.");
  }
  if (/[^0-9a-fA-F]/.test(str)) {
    throw new Error("Invalid hex string: Contains non-hexadecimal characters.");
  }
  const bytes = new Uint8Array(str.length / 2);
  for (let i = 0; i < str.length; i += 2) {
    const byte = parseInt(str.substring(i, i + 2), 16);
    bytes[i / 2] = byte;
  }
  return Buffer.from(str, "hex");
}

/**
 * Check if a string is a valid hexadecimal string
 * @param {string} text - The string to check
 * @returns {boolean} - True if the string is a valid hex string, false otherwise
 */
function isHexString(text) {
  if (typeof text !== "string") {
    return false;
  }
  const str = text.startsWith("0x") ? text.substring(2) : text;

  // Check if the string is empty after removing 0x prefix
  if (str.length === 0) {
    return false;
  }

  // Check if the string has even length (hex pairs)
  if (str.length % 2 !== 0) {
    return false;
  }

  // Check if all characters are valid hex digits
  const hexRegex = /^[0-9a-fA-F]+$/;
  return hexRegex.test(str);
}

/**
 * Encode with a specified length. Supports zero padding if the most significant byte is 0
 *
 * https://github.com/ethers-io/ethers.js/blob/master/packages/bytes/src.ts/index.ts#L315
 *
 * @param {Uint8Array} value
 * @param {number} length
 * @returns {string}
 */
function hexZeroPadded(value, length) {
  const HexCharacters = "0123456789abcdef";

  // https://github.com/ethers-io/ethers.js/blob/master/packages/bytes/src.ts/index.ts#L243
  let result = "0x";
  for (let i = 0; i < value.length; i++) {
    let v = value[i];
    result += HexCharacters[(v & 0xf0) >> 4] + HexCharacters[v & 0x0f];
  }

  // https://github.com/ethers-io/ethers.js/blob/master/packages/bytes/src.ts/index.ts#L315
  if (result.length > 2 * length + 2) {
    console.log("result out of range", "result");
  }
  while (result.length < 2 * length + 2) {
    result = "0x0" + result.substring(2);
  }
  return result.substring(2);
}