Class AbbreviatedLongObjectId

java.lang.Object
org.eclipse.jgit.lfs.lib.AbbreviatedLongObjectId
All Implemented Interfaces:
Serializable
public final class AbbreviatedLongObjectId extends Object implements Serializable
A prefix abbreviation of an LongObjectId.

Enable abbreviating SHA-256 strings used by Git LFS, using sufficient leading digits from the LongObjectId name to still be unique within the repository the string was generated from. These ids are likely to be unique for a useful period of time, especially if they contain at least 6-10 hex digits.

This class converts the hex string into a binary form, to make it more efficient for matching against an object. Ported to SHA-256 from AbbreviatedObjectId

Since:
4.3
See Also:

  • Method Details

    • isId

      public static final boolean isId(String id)
      Test a string of characters to verify it is a hex format.

      If true the string can be parsed with fromString(String).

      Parameters:
      id - the string to test.
      Returns:
      true if the string can converted into an AbbreviatedObjectId.

    • fromString

      public static final AbbreviatedLongObjectId fromString(byte[] buf, int offset, int end)
      Convert an AbbreviatedObjectId from hex characters (US-ASCII).
      Parameters:
      buf - the US-ASCII buffer to read from.
      offset - position to read the first character from.
      end - one past the last position to read (end-offset is the length of the string).
      Returns:
      the converted object id.

    • fromLongObjectId

      public static final AbbreviatedLongObjectId fromLongObjectId(AnyLongObjectId id)
      Convert an AbbreviatedObjectId from an AnyObjectId.

      This method copies over all bits of the Id, and is therefore complete (see isComplete()).

      Parameters:
      id - the ObjectId to convert from.
      Returns:
      the converted object id.

    • fromString

      public static final AbbreviatedLongObjectId fromString(String str)
      Convert an AbbreviatedLongObjectId from hex characters.
      Parameters:
      str - the string to read from. Must be <= 64 characters.
      Returns:
      the converted object id.

    • length

      public int length()
      Get length
      Returns:
      number of hex digits appearing in this id.

    • isComplete

      public boolean isComplete()
      Check if this id is complete
      Returns:
      true if this ObjectId is actually a complete id.

    • toLongObjectId

      public LongObjectId toLongObjectId()
      Convert to LongObjectId
      Returns:
      a complete ObjectId; null if isComplete() is false.

    • prefixCompare

      public final int prefixCompare(AnyLongObjectId other)
      Compares this abbreviation to a full object id.
      Parameters:
      other - the other object id.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • prefixCompare

      public final int prefixCompare(byte[] bs, int p)
      Compare this abbreviation to a network-byte-order LongObjectId.
      Parameters:
      bs - array containing the other LongObjectId in network byte order.
      p - position within bs to start the compare at. At least 32 bytes, starting at this position are required.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • prefixCompare

      public final int prefixCompare(long[] bs, int p)
      Compare this abbreviation to a network-byte-order LongObjectId.
      Parameters:
      bs - array containing the other LongObjectId in network byte order.
      p - position within bs to start the compare at. At least 4 longs, starting at this position are required.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • getFirstByte

      public final int getFirstByte()
      Get the first byte of this id
      Returns:
      value for a fan-out style map, only valid of length >= 2.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • name

      public final String name()

      name.

      Returns:
      string form of the abbreviation, in lower case hexadecimal.

    • toString

      public String toString()
      Overrides:
      toString in class Object