Class BitUtil
A variety of high efficiency bit twiddling routines.
This is a Lucene.NET INTERNAL API, use at your own risk
Inheritance
System.Object
BitUtil
Assembly: Lucene.Net.dll
Syntax
public sealed class BitUtil : object
Methods
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BitCount(Byte)
Return the number of bits sets in b.
Declaration
public static int BitCount(byte b)
Parameters
| Type |
Name |
Description |
| System.Byte |
b |
|
Returns
| Type |
Description |
| System.Int32 |
|
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BitList(Byte)
Return the list of bits which are set in b encoded as followed:
(i >>> (4 * n)) & 0x0F
is the offset of the n-th set bit of
the given byte plus one, or 0 if there are n or less bits set in the given
byte. For example
bitList(12)
returns 0x43:
0x43 & 0x0F
is 3, meaning the the first bit set is at offset 3-1 = 2,(0x43 >>> 4) & 0x0F
is 4, meaning there is a second bit set at offset 4-1=3,(0x43 >>> 8) & 0x0F
is 0, meaning there is no more bit set in this byte.
Declaration
public static int BitList(byte b)
Parameters
| Type |
Name |
Description |
| System.Byte |
b |
|
Returns
| Type |
Description |
| System.Int32 |
|
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NextHighestPowerOfTwo(Int32)
Returns the next highest power of two, or the current value if it's already a power of two or zero
Declaration
public static int NextHighestPowerOfTwo(int v)
Parameters
| Type |
Name |
Description |
| System.Int32 |
v |
|
Returns
| Type |
Description |
| System.Int32 |
|
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NextHighestPowerOfTwo(Int64)
Returns the next highest power of two, or the current value if it's already a power of two or zero
Declaration
public static long NextHighestPowerOfTwo(long v)
Parameters
| Type |
Name |
Description |
| System.Int64 |
v |
|
Returns
| Type |
Description |
| System.Int64 |
|
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Pop_AndNot(Int64[], Int64[], Int32, Int32)
Returns the popcount or cardinality of A & ~B.
Neither array is modified.
Declaration
public static long Pop_AndNot(long[] arr1, long[] arr2, int wordOffset, int numWords)
Parameters
| Type |
Name |
Description |
| System.Int64[] |
arr1 |
|
| System.Int64[] |
arr2 |
|
| System.Int32 |
wordOffset |
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| System.Int32 |
numWords |
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Returns
| Type |
Description |
| System.Int64 |
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Pop_Array(Int64[], Int32, Int32)
Returns the number of set bits in an array of s.
Declaration
public static long Pop_Array(long[] arr, int wordOffset, int numWords)
Parameters
| Type |
Name |
Description |
| System.Int64[] |
arr |
|
| System.Int32 |
wordOffset |
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| System.Int32 |
numWords |
|
Returns
| Type |
Description |
| System.Int64 |
|
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Pop_Intersect(Int64[], Int64[], Int32, Int32)
Returns the popcount or cardinality of the two sets after an intersection.
Neither array is modified.
Declaration
public static long Pop_Intersect(long[] arr1, long[] arr2, int wordOffset, int numWords)
Parameters
| Type |
Name |
Description |
| System.Int64[] |
arr1 |
|
| System.Int64[] |
arr2 |
|
| System.Int32 |
wordOffset |
|
| System.Int32 |
numWords |
|
Returns
| Type |
Description |
| System.Int64 |
|
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Pop_Union(Int64[], Int64[], Int32, Int32)
Returns the popcount or cardinality of the union of two sets.
Neither array is modified.
Declaration
public static long Pop_Union(long[] arr1, long[] arr2, int wordOffset, int numWords)
Parameters
| Type |
Name |
Description |
| System.Int64[] |
arr1 |
|
| System.Int64[] |
arr2 |
|
| System.Int32 |
wordOffset |
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| System.Int32 |
numWords |
|
Returns
| Type |
Description |
| System.Int64 |
|
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Pop_Xor(Int64[], Int64[], Int32, Int32)
Returns the popcount or cardinality of A ^ B
Neither array is modified.
Declaration
public static long Pop_Xor(long[] arr1, long[] arr2, int wordOffset, int numWords)
Parameters
| Type |
Name |
Description |
| System.Int64[] |
arr1 |
|
| System.Int64[] |
arr2 |
|
| System.Int32 |
wordOffset |
|
| System.Int32 |
numWords |
|
Returns
| Type |
Description |
| System.Int64 |
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