Class BitUtil
- java.lang.Object
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- org.apache.lucene.util.BitUtil
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public final class BitUtil extends Object
A variety of high efficiency bit twiddling routines and encoders for primitives.- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description static ByteOrderNATIVE_BYTE_ORDERNative byte order.static VarHandleVH_BE_DOUBLEDeprecated.Better use little endian unless it is needed for backwards compatibility.static VarHandleVH_BE_FLOATDeprecated.Better use little endian unless it is needed for backwards compatibility.static VarHandleVH_BE_INTDeprecated.Better use little endian unless it is needed for backwards compatibility.static VarHandleVH_BE_LONGDeprecated.Better use little endian unless it is needed for backwards compatibility.static VarHandleVH_BE_SHORTDeprecated.Better use little endian unless it is needed for backwards compatibility.static VarHandleVH_LE_DOUBLEAVarHandleto read/write little endiandoublefrom a byte array.static VarHandleVH_LE_FLOATAVarHandleto read/write little endianfloatfrom a byte array.static VarHandleVH_LE_INTAVarHandleto read/write little endianintfrom a byte array.static VarHandleVH_LE_LONGAVarHandleto read/write little endianlongfrom a byte array.static VarHandleVH_LE_SHORTAVarHandleto read/write little endianshortfrom/to a byte array.static VarHandleVH_NATIVE_DOUBLEAVarHandleto read/write native endiandoublefrom a byte array.static VarHandleVH_NATIVE_FLOATAVarHandleto read/write native endianfloatfrom a byte array.static VarHandleVH_NATIVE_INTAVarHandleto read/write native endianintfrom a byte array.static VarHandleVH_NATIVE_LONGAVarHandleto read/write native endianlongfrom a byte array.static VarHandleVH_NATIVE_SHORTAVarHandleto read/write native endianshortfrom/to a byte array.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static longdeinterleave(long b)Extract just the even-bits value as a long from the bit-interleaved valuestatic longflipFlop(long b)flip flops odd with even bitsstatic longinterleave(int even, int odd)Interleaves the first 32 bits of each long valuestatic intnextHighestPowerOfTwo(int v)returns the next highest power of two, or the current value if it's already a power of two or zerostatic longnextHighestPowerOfTwo(long v)returns the next highest power of two, or the current value if it's already a power of two or zerostatic intzigZagDecode(int i)Decode an int previously encoded withzigZagEncode(int).static longzigZagDecode(long l)Decode a long previously encoded withzigZagEncode(long).static intzigZagEncode(int i)Same aszigZagEncode(long)but on integers.static longzigZagEncode(long l)Zig-zag encode the provided long.
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Field Detail
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NATIVE_BYTE_ORDER
public static final ByteOrder NATIVE_BYTE_ORDER
Native byte order.Warning: This constant is
ByteOrder.nativeOrder()only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), useByteOrder.nativeOrder().
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VH_LE_SHORT
public static final VarHandle VH_LE_SHORT
AVarHandleto read/write little endianshortfrom/to a byte array. Shape:short vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, short val)
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VH_LE_INT
public static final VarHandle VH_LE_INT
AVarHandleto read/write little endianintfrom a byte array. Shape:int vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, int val)
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VH_LE_LONG
public static final VarHandle VH_LE_LONG
AVarHandleto read/write little endianlongfrom a byte array. Shape:long vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, long val)
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VH_LE_FLOAT
public static final VarHandle VH_LE_FLOAT
AVarHandleto read/write little endianfloatfrom a byte array. Shape:float vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, float val)
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VH_LE_DOUBLE
public static final VarHandle VH_LE_DOUBLE
AVarHandleto read/write little endiandoublefrom a byte array. Shape:double vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, double val)
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VH_NATIVE_SHORT
public static final VarHandle VH_NATIVE_SHORT
AVarHandleto read/write native endianshortfrom/to a byte array. Shape:short vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, short val)Warning: This handle uses default order only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), use
ByteOrder.nativeOrder().
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VH_NATIVE_INT
public static final VarHandle VH_NATIVE_INT
AVarHandleto read/write native endianintfrom a byte array. Shape:int vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, int val)Warning: This handle uses default order only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), use
ByteOrder.nativeOrder().
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VH_NATIVE_LONG
public static final VarHandle VH_NATIVE_LONG
AVarHandleto read/write native endianlongfrom a byte array. Shape:long vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, long val)Warning: This handle uses default order only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), use
ByteOrder.nativeOrder().
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VH_NATIVE_FLOAT
public static final VarHandle VH_NATIVE_FLOAT
AVarHandleto read/write native endianfloatfrom a byte array. Shape:float vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, float val)Warning: This handle uses default order only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), use
ByteOrder.nativeOrder().
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VH_NATIVE_DOUBLE
public static final VarHandle VH_NATIVE_DOUBLE
AVarHandleto read/write native endiandoublefrom a byte array. Shape:double vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, double val)Warning: This handle uses default order only in production environments, during testing we randomize it. If you need to communicate with native APIs (e.g., Java's Panama API), use
ByteOrder.nativeOrder().
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VH_BE_SHORT
@Deprecated public static final VarHandle VH_BE_SHORT
Deprecated.Better use little endian unless it is needed for backwards compatibility.AVarHandleto read/write big endianshortfrom a byte array. Shape:short vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, short val)
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VH_BE_INT
@Deprecated public static final VarHandle VH_BE_INT
Deprecated.Better use little endian unless it is needed for backwards compatibility.AVarHandleto read/write big endianintfrom a byte array. Shape:int vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, int val)
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VH_BE_LONG
@Deprecated public static final VarHandle VH_BE_LONG
Deprecated.Better use little endian unless it is needed for backwards compatibility.AVarHandleto read/write big endianlongfrom a byte array. Shape:long vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, long val)
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VH_BE_FLOAT
@Deprecated public static final VarHandle VH_BE_FLOAT
Deprecated.Better use little endian unless it is needed for backwards compatibility.AVarHandleto read/write big endianfloatfrom a byte array. Shape:float vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, float val)
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VH_BE_DOUBLE
@Deprecated public static final VarHandle VH_BE_DOUBLE
Deprecated.Better use little endian unless it is needed for backwards compatibility.AVarHandleto read/write big endiandoublefrom a byte array. Shape:double vh.get(byte[] arr, int ofs)andvoid vh.set(byte[] arr, int ofs, double val)
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Method Detail
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nextHighestPowerOfTwo
public static int nextHighestPowerOfTwo(int v)
returns the next highest power of two, or the current value if it's already a power of two or zero
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nextHighestPowerOfTwo
public static long nextHighestPowerOfTwo(long v)
returns the next highest power of two, or the current value if it's already a power of two or zero
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interleave
public static long interleave(int even, int odd)Interleaves the first 32 bits of each long valueAdapted from: http://graphics.stanford.edu/~seander/bithacks.html#InterleaveBMN
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deinterleave
public static long deinterleave(long b)
Extract just the even-bits value as a long from the bit-interleaved value
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flipFlop
public static long flipFlop(long b)
flip flops odd with even bits
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zigZagEncode
public static int zigZagEncode(int i)
Same aszigZagEncode(long)but on integers.
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zigZagEncode
public static long zigZagEncode(long l)
Zig-zag encode the provided long. Assuming the input is a signed long whose absolute value can be stored onnbits, the returned value will be an unsigned long that can be stored onn+1bits.
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zigZagDecode
public static int zigZagDecode(int i)
Decode an int previously encoded withzigZagEncode(int).
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zigZagDecode
public static long zigZagDecode(long l)
Decode a long previously encoded withzigZagEncode(long).
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