JS实现手动将String转换为utf8格式的arraybuffer

Posted 2022-11-09 btxlc

function code2utf8(uni) 
  let uni2 = uni.toString(2)
  if (uni < 128) 
    return uni.toString(16);
   else if (uni < 2048) 
    uni2 = (‘00000000000000000‘ + uni2).slice(-11);
    const s1 =  parseInt("110" + uni2.substring(0, 5), 2);
    const s2 =  parseInt("10" + uni2.substring(5), 2);
    return s1.toString(16) + ‘,‘ + s2.toString(16)
   else 
    uni2 = (‘00000000000000000‘ + uni2).slice(-16);
    const s1 = parseInt(‘1110‘ + uni2.substring(0, 4),2 );
    const s2 = parseInt(‘10‘ + uni2.substring(4, 10), 2 );
    const s3 = parseInt(‘10‘ + uni2.substring(10), 2);
    return s1.toString(16) + ‘,‘ + s2.toString(16) + ‘,‘ + s3.toString(16)
  


function string2buffer(str) 
  let val = ""
  for (let i = 0; i < str.length; i++) 
    val += ‘,‘ + code2utf8(str.charCodeAt(i))
  
  val += ‘,00‘;
  console.log(val);
  // 将16进制转化为ArrayBuffer
  return new Uint8Array(val.match(/[\da-f]2/gi).map(function (h) 
    return parseInt(h, 16)
  )).buffer