string、ArrayBuffy相互转换-蒲公英云

string、ArrayBuffy相互转换

字符串转ArrayBuff：

//字符串转ArrayBuff
            strToArrayBuffer(s) { 
              var i = s.length;
              var n = 0;
              var ba = new Array()
              for (var j = 0; j < i;) { 
                var c = s.codePointAt(j);
                if (c < 128) { 
                  ba[n++] = c;
                  j++;
                }
                else if ((c > 127) && (c < 2048)) { 
                  ba[n++] = (c >> 6) | 192;
                  ba[n++] = (c & 63) | 128;
                  j++;
                }
                else if ((c > 2047) && (c < 65536)) { 
                  ba[n++] = (c >> 12) | 224;
                  ba[n++] = ((c >> 6) & 63) | 128;
                  ba[n++] = (c & 63) | 128;
                  j++;
                }
                else { 
                  ba[n++] = (c >> 18) | 240;
                  ba[n++] = ((c >> 12) & 63) | 128;
                  ba[n++] = ((c >> 6) & 63) | 128;
                  ba[n++] = (c & 63) | 128;
                  j+=2;
                }
              }
              return new Uint8Array(ba);
            }

ArrayBuff转字符串：

Utf8ArrayToStr(array) { 
                var out, i, len, c;
                var char2, char3;
                out = "";
                len = array.length;
                i = 0;
                while(i < len) { 
                c = array[i++];
                switch(c >> 4)
                {  
                  case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
                    // 0xxxxxxx
                    out += String.fromCharCode(c);
                    break;
                  case 12: case 13:
                    // 110x xxxx 10xx xxxx
                    char2 = array[i++];
                    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
                    break;
                  case 14:
                    // 1110 xxxx 10xx xxxx 10xx xxxx
                    char2 = array[i++];
                    char3 = array[i++];
                    out += String.fromCharCode(((c & 0x0F) << 12) |
                                   ((char2 & 0x3F) << 6) |
                                   ((char3 & 0x3F) << 0));
                    break;
                }
                }
                return out;
            }