in hpack/src/main/java/com/twitter/hpack/Decoder.java [463:473]
private void indexHeader(int index, HeaderListener headerListener) throws IOException {
if (index <= StaticTable.length) {
HeaderField headerField = StaticTable.getEntry(index);
addHeader(headerListener, headerField.name, headerField.value, false);
} else if (index - StaticTable.length <= dynamicTable.length()) {
HeaderField headerField = dynamicTable.getEntry(index - StaticTable.length);
addHeader(headerListener, headerField.name, headerField.value, false);
} else {
throw ILLEGAL_INDEX_VALUE;
}
}