var rng = require('./lib/rng'); var bytesToUuid = require('./lib/bytesToUuid');

function v4(options, buf, offset) {

var i = buf && offset || 0;

if (typeof(options) == 'string') {
  buf = options === 'binary' ? new Array(16) : null;
  options = null;
}
options = options || {};

var rnds = options.random || (options.rng || rng)();

// Per 4.4, set bits for version and `clock_seq_hi_and_reserved`
rnds[6] = (rnds[6] & 0x0f) | 0x40;
rnds[8] = (rnds[8] & 0x3f) | 0x80;

// Copy bytes to buffer, if provided
if (buf) {
  for (var ii = 0; ii < 16; ++ii) {
    buf[i + ii] = rnds[ii];
  }
}

return buf || bytesToUuid(rnds);

}

module.exports = v4;