coreValuesCipher.js

"use strict";

function assert(...express) {
  const l = express.length;
  const msg = (typeof express[l - 1] === 'string') ? express[l - 1] : 'Assert Error';
  for (let b of express) {
    if (!b) {
      throw new Error(msg);
    }
  }
}

function randBin() {
  return Math.random() >= 0.5;
}

const values = '富强民主文明和谐自由平等公正法治爱国敬业诚信友善';

function str2utf8(str) {
  const notEncoded = /[A-Za-z\d\-_.!~*'()]/g;
  const str1 = str.replace(notEncoded, c => c.codePointAt(0).toString(16));
  let str2 = encodeURIComponent(str1);
  return str2.replace(/%/g, '').toUpperCase();
}

function utf82str(utfs) {
  assert(typeof utfs === 'string', 'utfs Error');
  const l = utfs.length;
  assert((l & 1) === 0);
  const split = [];
  for (let i = 0; i < l; i++) {
    if ((i & 1) === 0) {
      split.push('%');
    }
    split.push(utfs[i]);
  }
  return decodeURIComponent(split.join(''));
}

function hex2duo(hexs) {
  // duodecimal in array of number
  // '0'.. '9' -> 0.. 9
  // 'A'.. 'F' -> 10, c - 10    a2fFlag = 10
  //          or 11, c - 6      a2fFlag = 11
  assert(typeof hexs === 'string')
  const duo = [];
  for (let c of hexs) {
    const n = Number.parseInt(c, 16);
    if (n < 10) {
      duo.push(n);
    } else {
      if (randBin()) {
        duo.push(10);
        duo.push(n - 10);
      } else {
        duo.push(11);
        duo.push(n - 6);
      }
    }
  }
  return duo;
}

function duo2hex(duo) {
  assert(duo instanceof Array);
  const hex = [];
  const l = duo.length;
  let i = 0;
  while (i < l) {
    if (duo[i] < 10) {
      hex.push(duo[i]);
    } else {
      if (duo[i] === 10) {
        i++;
        hex.push(duo[i] + 10);
      } else {
        i++;
        hex.push(duo[i] + 6);
      }
    }
    i++;
  }
  // noinspection JSCheckFunctionSignatures
  return hex.map(v => v.toString(16).toUpperCase()).join('');
}


function duo2values(duo) {
  return duo.map(d => values[2 * d] + values[2 * d + 1]).join('');
}

function valuesDecode(cipher) {
  const duo = [];
  for (let c of cipher) {
    const i = values.indexOf(c);
    if (i === -1) {
    } else if (i & 1) {
    } else {
      duo.push(i >> 1);
    }
  }
  const hexs = duo2hex(duo);
  assert((hexs.length & 1) === 0);
  let str;
  try {
    str = utf82str(hexs);
  } catch (e) {
    throw e;
  }
  return str;
}

function valuesEncode(str) {
  return duo2values(hex2duo(str2utf8(str)));
}

module.exports = {
  coreValuesEncode: valuesEncode, coreValuesDecode: valuesDecode
}