Source: codecBytes.js

  1. /** @fileOverview Bit array codec implementations.
  2.  *
  3.  * @author Emily Stark
  4.  * @author Mike Hamburg
  5.  * @author Dan Boneh
  6.  */
  8. /**
  9.  * Arrays of bytes
  10.  * @namespace
  11.  */
  12. sjcl.codec.bytes = {
  13.   /** Convert from a bitArray to an array of bytes. */
  14.   fromBits: function (arr) {
  15.     var out = [], bl = sjcl.bitArray.bitLength(arr), i, tmp;
  16.     for (i=0; i<bl/8; i++) {
  17.       if ((i&3) === 0) {
  18.         tmp = arr[i/4];
  19.       }
  20.       out.push(tmp >>> 24);
  21.       tmp <<= 8;
  22.     }
  23.     return out;
  24.   },
  25.   /** Convert from an array of bytes to a bitArray. */
  26.   toBits: function (bytes) {
  27.     var out = [], i, tmp=0;
  28.     for (i=0; i<bytes.length; i++) {
  29.       tmp = tmp << 8 | bytes[i];
  30.       if ((i&3) === 3) {
  31.         out.push(tmp);
  32.         tmp = 0;
  33.       }
  34.     }
  35.     if (i&3) {
  36.       out.push(sjcl.bitArray.partial(8*(i&3), tmp));
  37.     }
  38.     return out;
  39.   }
  40. };