Package gnu.math

Class BitOps

java.lang.Object

gnu.math.BitOps

public class BitOps
extends Object

Implements logical (bit-wise) operations on infinite-precision integers. There are no BitOps object - all the functions here are static. The semantics used are the same as for Common Lisp.

Method Summary

Modifier and Type	Method	Description
static IntNum	and(IntNum x, int y)	Return the logical (bit-wise) "and" of an IntNum and an int.
static IntNum	and(IntNum x, IntNum y)	Return the logical (bit-wise) "and" of two IntNums.
static int	bitCount(int i)
static int	bitCount(int[] x, int len)
static int	bitCount(IntNum x)	Count one bits in an IntNum.
static IntNum	bitOp(int op, IntNum x, IntNum y)	Do one the the 16 possible bit-wise operations of two IntNums.
static boolean	bitValue(IntNum x, int bitno)	Return the value of a specified bit in an IntNum.
static IntNum	extract(IntNum x, int startBit, int endBit)	Extract a bit-field as an unsigned integer.
static IntNum	ior(IntNum x, IntNum y)	Return the logical (bit-wise) "(inclusive) or" of two IntNums.
static int	lowestBitSet(int i)
static int	lowestBitSet(IntNum x)
static IntNum	makeMask(int startBit, int endBit)	Create a mask with bits true form bits form startBit to endBit.
static IntNum	not(IntNum x)	Return the logical (bit-wise) negation of an IntNum.
static IntNum	reverseBits(IntNum x, int start, int end)
static void	setBitOp(IntNum result, int op, IntNum x, IntNum y)	Do one the the 16 possible bit-wise operations of two IntNums.
static IntNum	setBitValue(IntNum x, int bitno, int newValue)	Set the value of a specified bit in an IntNum.
static int	shift(int x, int count)
static long	shift(long x, int count)
static int	shiftUnsigned(int x, int count)
static long	shiftUnsigned(long x, int count)
static int	swappedOp(int op)	Return the boolean opcode (for bitOp) for swapped operands.
static boolean	test(IntNum x, int y)	Return true iff an IntNum and an int have any true bits in common.
static boolean	test(IntNum x, IntNum y)	Return true iff two IntNums have any true bits in common.
static IntNum	xor(IntNum x, IntNum y)	Return the logical (bit-wise) "exclusive or" of two IntNums.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

bitValue

public static boolean bitValue(IntNum x,
                               int bitno)

Return the value of a specified bit in an IntNum.

setBitValue

public static IntNum setBitValue(IntNum x,
                                 int bitno,
                                 int newValue)

Set the value of a specified bit in an IntNum.

test

public static boolean test(IntNum x,
                           int y)

Return true iff an IntNum and an int have any true bits in common.

test

public static boolean test(IntNum x,
                           IntNum y)

Return true iff two IntNums have any true bits in common.

and

public static IntNum and(IntNum x,
                         int y)

Return the logical (bit-wise) "and" of an IntNum and an int.

and

public static IntNum and(IntNum x,
                         IntNum y)

Return the logical (bit-wise) "and" of two IntNums.

ior

public static IntNum ior(IntNum x,
                         IntNum y)

Return the logical (bit-wise) "(inclusive) or" of two IntNums.

xor

public static IntNum xor(IntNum x,
                         IntNum y)

Return the logical (bit-wise) "exclusive or" of two IntNums.

not

public static IntNum not(IntNum x)

Return the logical (bit-wise) negation of an IntNum.

swappedOp

public static int swappedOp(int op)

Return the boolean opcode (for bitOp) for swapped operands. I.e. bitOp (swappedOp(op), x, y) == bitOp (op, y, x).

bitOp

public static IntNum bitOp(int op,
                           IntNum x,
                           IntNum y)

Do one the the 16 possible bit-wise operations of two IntNums.

setBitOp

public static void setBitOp(IntNum result,
                            int op,
                            IntNum x,
                            IntNum y)

Do one the the 16 possible bit-wise operations of two IntNums.

makeMask

public static IntNum makeMask(int startBit,
                              int endBit)

Create a mask with bits true form bits form startBit to endBit.

extract

public static IntNum extract(IntNum x,
                             int startBit,
                             int endBit)

Extract a bit-field as an unsigned integer.

lowestBitSet

public static int lowestBitSet(int i)

lowestBitSet

public static int lowestBitSet(IntNum x)

bitCount

public static int bitCount(int i)

bitCount

public static int bitCount(int[] x,
                           int len)

bitCount

public static int bitCount(IntNum x)

Count one bits in an IntNum. If argument is negative, count zero bits instead.

reverseBits

public static IntNum reverseBits(IntNum x,
                                 int start,
                                 int end)

shift

public static int shift(int x,
                        int count)

shiftUnsigned

public static int shiftUnsigned(int x,
                                int count)

shift

public static long shift(long x,
                         int count)

shiftUnsigned

public static long shiftUnsigned(long x,
                                 int count)