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JDK-4830125 : RFE: adding partial support for unsigned primitive integers and huge (128 bits)

Details
Type:
Enhancement
Submit Date:
2003-03-11
Status:
Closed
Updated Date:
2003-03-11
Project Name:
JDK
Resolved Date:
2003-03-11
Component:
core-libs
OS:
windows_2000
Sub-Component:
java.lang
CPU:
x86
Priority:
P4
Resolution:
Duplicate
Affected Versions:
1.4.1
Fixed Versions:

Related Reports
Duplicate:

Sub Tasks

Description

Name: rmT116609			Date: 03/10/2003


DESCRIPTION OF THE REQUEST :
Java primitive number are byte (8 bits signed), short (16 bits signed), int (32 bits signed) and long (64 bits signed). In some case we have to use unsigned number to make some computation and it will be good to support this case. Some says we have to add ubyte, ushort, uint and ulong : I think this is the maximum case. But for the moment may be it will be judicious to add support of unsigned as a part of primitive wraping (i.e. in objects Byte, Short, Integer, Long).
It may be the time for java to add capability to optimal arithmetic with 128 bits integers because 64 bits will make 128 bits operation as fast as actual 64 bits. we propose the keyword 'huge' and also the class Huge. Moreover algorithm like digest (SHA, MD5) and cryptography need to make operation on block of 128 bits size !

It is clear that operation like "+", "-" and equality ("==" or "!=") give the same result if we suppose primitive signed or unsigned. But for "*", "/" and comparing ("<", ">", "<=", ">=") the result are false.
The problem is somethat difficult for "*" and "/".

Let us only propose a partial solution for comparing

So we can add

-- for class Byte
public (native) static int compareUnsigned(byte byteAsUnsigned1, byte byteAsUnsigned2)
public int compareToUnsigned(Byte anotherByteAsUnsigned)

-- for class Short
public (native) static int compareUnsigned(short shortAsUnsigned1, short shortAsUnsigned2)
public int compareToUnsigned(Short anotherShortAsUnsigned)

-- for class Integer
public (native) static int compareUnsigned(int intAsUnsigned1, int intAsUnsigned2)
public int compareToUnsigned(Integer anotherIntegerAsUnsigned)

-- for class Long
public (native) static int compareUnsigned(long longAsUnsigned1, long longAsUnsigned2)
public int compareToUnsigned(Long anotherLongAsUnsigned)

-- for class Huge
public (native) static int compareUnsigned(huge hugeAsUnsigned1, huge hugeAsUnsigned2)
public int compareToUnsigned(Huge anotherHugeAsUnsigned)

-- for class Math

public static byte  minUnsigned(byte  ua, byte  ub)
public static short minUnsigned(short ua, short ub)
public static int   minUnsigned(int   ua, int   ub)
public static long  minUnsigned(long  ua, long  ub)
public static huge  minUnsigned(huge  ua, huge  ub)

public static byte  maxUnsigned(byte  ua, byte  ub)
public static short maxUnsigned(short ua, short ub)
public static int   maxUnsigned(int   ua, int   ub)
public static long  maxUnsigned(long  ua, long  ub)
public static huge  maxUnsigned(huge  ua, huge  ub)

Except for "+", "-", "==", "!=", ">>>" and "<<", there is no specific support of unsigned primitive integers in java


CUSTOMER SUBMITTED WORKAROUND :
use short      for unsigned byte
use int        for unsigned short
use long       for unsigned int
use BigInteger for unsigned long
use BigInteger for huge
use BigInteger for unsigned huge
(Review ID: 182199) 
======================================================================

                                    

Comments
EVALUATION

Generally a duplicate of 4504839; 128 bit operations can be done with BigInteger.

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2003-03-10



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