Package org.eclipse.jgit.lfs.lib

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:

Serialized Form

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
static AbbreviatedLongObjectId	fromLongObjectId(AnyLongObjectId id)	Convert an AbbreviatedObjectId from an AnyObjectId.
static AbbreviatedLongObjectId	fromString(byte[] buf, int offset, int end)	Convert an AbbreviatedObjectId from hex characters (US-ASCII).
static AbbreviatedLongObjectId	fromString(String str)	Convert an AbbreviatedLongObjectId from hex characters.
int	getFirstByte()	Get the first byte of this id
int	hashCode()
boolean	isComplete()	Check if this id is complete
static boolean	isId(String id)	Test a string of characters to verify it is a hex format.
int	length()	Get length
String	name()	name.
int	prefixCompare(byte[] bs, int p)	Compare this abbreviation to a network-byte-order LongObjectId.
int	prefixCompare(long[] bs, int p)	Compare this abbreviation to a network-byte-order LongObjectId.
int	prefixCompare(AnyLongObjectId other)	Compares this abbreviation to a full object id.
LongObjectId	toLongObjectId()	Convert to LongObjectId
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

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