JS ArrayBuffer 类型转换及拼接_js arraybuffer 拼接

1 转换

1 字符串转为ArrayBuffer

// 字符串转为ArrayBuffer对象，参数为字符串
const str2ab = function(str) {
  var buf = new ArrayBuffer(str.length * 2); // 每个字符占用2个字节
  var bufView = new Uint16Array(buf);
  for (var i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}
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2.ArrayBuffer转字符串

// ArrayBuffer转为字符串，参数为ArrayBuffer对象, 字符串编码为一个字节
const ab2str = function (buf) {
  return String.fromCharCode.apply(null, new Uint8Array(buf));
}

// ArrayBuffer转为字符串，参数为ArrayBuffer对象字符串编码为js默认编码
const ab2strU16 = function (buf) {
  return String.fromCharCode.apply(null, new Uint16Array(buf));
}
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3.ArrayBuffer与十六进制的互相转换

/**
 * 十六进制转 bytearray
 */
var hex2ab = function(hex){
  var typedArray = new Uint8Array(hex.match(/[\da-f]{2}/gi).map(function (h) {
    return parseInt(h, 16)
  }))

  var buffer = typedArray.buffer
  return buffer
}

 // ArrayBuffer转16进度字符串示例
const ab2hex = function (buffer) {
  var hexArr = Array.prototype.map.call(
    new Uint8Array(buffer),
    function (bit) {
      return ('00' + bit.toString(16)).slice(-2)
    }
  )
  return hexArr.join('');
}
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2拼接

function concatenate(resultConstructor, ...arrays) {
    let totalLength = 0;
    for (let arr of arrays) {
        totalLength += arr.length;
    }
    let result = new resultConstructor(totalLength);
    let offset = 0;
    for (let arr of arrays) {
        result.set(arr, offset);
        offset += arr.length;
    }
    return result;
}
使用：
totalmsg = concatenate(Uint8Array, totalmsg, submsg)

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