simple-squiggle

A restricted subset of Squiggle
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decoder.js (2201B)

      1 "use strict";
      2 
      3 Object.defineProperty(exports, "__esModule", {
      4   value: true
      5 });
      6 exports.decode = decode;
      7 
      8 function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }
      9 
     10 function _toArray(arr) { return Array.isArray(arr) ? arr : Array.from(arr); }
     11 
     12 function con(b) {
     13   if ((b & 0xc0) === 0x80) {
     14     return b & 0x3f;
     15   } else {
     16     throw new Error("invalid UTF-8 encoding");
     17   }
     18 }
     19 
     20 function code(min, n) {
     21   if (n < min || 0xd800 <= n && n < 0xe000 || n >= 0x10000) {
     22     throw new Error("invalid UTF-8 encoding");
     23   } else {
     24     return n;
     25   }
     26 }
     27 
     28 function decode(bytes) {
     29   return _decode(bytes).map(function (x) {
     30     return String.fromCharCode(x);
     31   }).join("");
     32 }
     33 
     34 function _decode(bytes) {
     35   if (bytes.length === 0) {
     36     return [];
     37   }
     38   /**
     39    * 1 byte
     40    */
     41 
     42 
     43   {
     44     var _bytes = _toArray(bytes),
     45         b1 = _bytes[0],
     46         bs = _bytes.slice(1);
     47 
     48     if (b1 < 0x80) {
     49       return [code(0x0, b1)].concat(_toConsumableArray(_decode(bs)));
     50     }
     51 
     52     if (b1 < 0xc0) {
     53       throw new Error("invalid UTF-8 encoding");
     54     }
     55   }
     56   /**
     57    * 2 bytes
     58    */
     59 
     60   {
     61     var _bytes2 = _toArray(bytes),
     62         _b = _bytes2[0],
     63         b2 = _bytes2[1],
     64         _bs = _bytes2.slice(2);
     65 
     66     if (_b < 0xe0) {
     67       return [code(0x80, ((_b & 0x1f) << 6) + con(b2))].concat(_toConsumableArray(_decode(_bs)));
     68     }
     69   }
     70   /**
     71    * 3 bytes
     72    */
     73 
     74   {
     75     var _bytes3 = _toArray(bytes),
     76         _b2 = _bytes3[0],
     77         _b3 = _bytes3[1],
     78         b3 = _bytes3[2],
     79         _bs2 = _bytes3.slice(3);
     80 
     81     if (_b2 < 0xf0) {
     82       return [code(0x800, ((_b2 & 0x0f) << 12) + (con(_b3) << 6) + con(b3))].concat(_toConsumableArray(_decode(_bs2)));
     83     }
     84   }
     85   /**
     86    * 4 bytes
     87    */
     88 
     89   {
     90     var _bytes4 = _toArray(bytes),
     91         _b4 = _bytes4[0],
     92         _b5 = _bytes4[1],
     93         _b6 = _bytes4[2],
     94         b4 = _bytes4[3],
     95         _bs3 = _bytes4.slice(4);
     96 
     97     if (_b4 < 0xf8) {
     98       return [code(0x10000, (((_b4 & 0x07) << 18) + con(_b5) << 12) + (con(_b6) << 6) + con(b4))].concat(_toConsumableArray(_decode(_bs3)));
     99     }
    100   }
    101   throw new Error("invalid UTF-8 encoding");
    102 }