Function get_dictionary_values 

fn get_dictionary_values(
    buf: &Buffer,
    batch: DictionaryBatch<'_>,
    schema: &Schema,
    dictionaries_by_id: &mut HashMap<i64, ArrayRef>,
    metadata: &MetadataVersion,
    require_alignment: bool,
    skip_validation: UnsafeFlag,
) -> Result<ArrayRef, ArrowError>

Given a dictionary batch IPC message/body along with the full state of a stream including schema, dictionary cache, metadata, and other flags, this function will parse the buffer into an array of dictionary values.