Class BinaryDeltaInputStream

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    public class BinaryDeltaInputStream
    extends InputStream
    An InputStream that applies a binary delta to a base on the fly.

    Delta application to a base needs random access to the base data. The delta is expressed as a sequence of copy and insert instructions. A copy instruction has the form "COPY fromOffset length" and says "copy length bytes from the base, starting at offset fromOffset, to the result". An insert instruction has the form "INSERT length" followed by length bytes and says "copy the next length bytes from the delta to the result".

    These instructions are generated using a content-defined chunking algorithm (currently C git uses the standard Rabin variant; but there are others that could be used) that identifies equal chunks. It is entirely possible that a later copy instruction has a fromOffset that is before the fromOffset of an earlier copy instruction.

    This makes it impossible to stream the base.

    JGit is limited to 2GB maximum size for the base since array indices are signed 32bit values.