protected final int getNumUndefinedBytesAfter(DataTypeComponent dtc) {
		if (!isShowingUndefinedBytes()) {
			throw new UnsupportedOperationException();
		}
		if (!(viewComposite instanceof Structure struct)) {
			throw new UnsupportedOperationException();
		}
		if (struct.isPackingEnabled()) {
			throw new UnsupportedOperationException();
		}

		// TODO: May  need special logic if dtc is zero-length component
		int length = getLength();
		int nextCompOffset = dtc.getEndOffset() + 1;
		if (nextCompOffset >= length) {
			return 0;
		}
		DataTypeComponent nextDefinedDtc =
			struct.getDefinedComponentAtOrAfterOffset(nextCompOffset);
		int nextDefinedOffset = (nextDefinedDtc == null) ? length : nextDefinedDtc.getOffset();
		return Math.max(0, nextDefinedOffset - nextCompOffset); // prevent negative return value
	}
Get the number of undefined bytes after the specified component.
The viewComposite must be a non-packed structure.
@param dtc datatype component
@return number of undefined bytes after non-packed structure component or -1 if no additional
defined components exist which will impead component growth or placement.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/CompEditorModel.java