test-triam-base-contract/src/contractinput.js

Low level triam smart cotnract support library

import {default as xdr} from "./generated/stellar-xdr_generated";
import clone from 'lodash/clone';
import padEnd from 'lodash/padEnd';
import trimEnd from 'lodash/trimEnd';

/**
 * ContractInput class represents an input of contract operations
 *
 * @constructor
 * @param {string} funcName - The function name.
 * @param {Array} contractParams - The contract parameters.
 */
export class ContractInput {

  constructor(funcName, contractParams) {
    this.funcName = funcName;
    
    let paramsJson = JSON.stringify(contractParams);
    // array of Buffer
    let ab = str2ab(paramsJson);
    // buffer
    let buf = toBuffer(ab);
    this.contractParams = buf;
  }

  /**
   * Returns an contractInput object from its XDR object representation.
   * @param {xdr.ContractInput} contractInputXdr - The contractInput xdr object.
   * @returns {ContractInput}
   */
  static fromOperation(contractInputXdr) {
    let funcName, contractParams;
    funcName = contractInputXdr.funcName().toString('ascii');

    // to array
    let buf = contractInputXdr.contractParams();
    let ab = toArrayBuffer(buf);
    let str = ab2str(ab);
    contractParams = JSON.parse(str);


    return new this(funcName, contractParams);
    }
}
function ab2str(buf)  {
  return String.fromCharCode.apply (null, new Uint16Array (buf));
};

function str2ab(str) {
  let buf = new ArrayBuffer (str.length * 2); // 2 bytes for each char
  let bufView = new Uint16Array (buf);
  for (let i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt (i);
  }
  return buf;
}


function toArrayBuffer(buf) {
  let ab = new ArrayBuffer (buf.length);
  let view = new Uint8Array (ab);
  for (let i = 0; i < buf.length; ++i) {
    view[i] = buf[i];
  }
  return ab;
}

function toBuffer(ab){
  let buf = new Buffer (ab.byteLength);
  let view = new Uint8Array (ab);
  for (let i = 0; i < buf.length; ++i) {
    buf[i] = view[i];
  }
  return buf;
}