Package org.apache.flink.types.variant

Class BinaryVariantUtil

  • @Internal
public class BinaryVariantUtil
extends Object
    This class defines constants related to the variant format and provides functions for manipulating variant binaries.

    A variant is made up of 2 binaries: value and metadata. A variant value consists of a one-byte header and a number of content bytes (can be zero). The header byte is divided into upper 6 bits (called "type info") and lower 2 bits (called "basic type"). The content format is explained in the below constants for all possible basic type and type info values.

    The variant metadata includes a version id and a dictionary of distinct strings (case-sensitive). Its binary format is: - Version: 1-byte unsigned integer. The only acceptable value is 1 currently. - Dictionary size: 4-byte little-endian unsigned integer. The number of keys in the dictionary. - Offsets: (size + 1) * 4-byte little-endian unsigned integers. `offsets[i]` represents the starting position of string i, counting starting from the address of `offsets[0]`. Strings must be stored contiguously, so we don’t need to store the string size, instead, we compute it with `offset[i + 1] - offset[i]`. - UTF-8 string data.