ensureAvailableLength method

void ensureAvailableLength(int length)

Ensures that the buffer has space for N more bytes.

If buffer does not have enough space and isExpanding is false, will throw RawWriterException.

Implementation

void ensureAvailableLength(int length) {
  // See whether old buffer has enough capacity.
  final oldByteData = this._byteData;
  final minCapacity = this._length + length;
  if (oldByteData.lengthInBytes >= minCapacity) {
    return;
  }

  if (!isExpanding) {
    throw RawWriterException(
        "ensureAvailaleLength($length) was called, but only ${oldByteData.lengthInBytes - this._length} bytes is available");
  }

  // Choose a new capacity that's a power of 2.
  var newCapacity = 64;
  while (newCapacity < minCapacity) {
    newCapacity *= 2;
  }

  // Switch to the new buffer.
  _byteData = new ByteData(newCapacity);
  final oldIndex = this._length;
  this._length = 0;

  // Write contents of the old buffer.
  //
  // We write the whole buffer so we eliminate complex bugs when index is
  // non-monotonic or data is written directly.
  writeByteData(oldByteData);

  this._length = oldIndex;
}