Class SparseBitSet.AndStrategy

java.lang.Object

com.zaxxer.sparsebits.SparseBitSet.AbstractStrategy

com.zaxxer.sparsebits.SparseBitSet.AndStrategy

Enclosing class:

SparseBitSet

protected static class SparseBitSet.AndStrategy
extends SparseBitSet.AbstractStrategy

And of two sets. Where the a set is zero, it remains zero (i.e., without entries or with zero words). Similarly, where the b set is zero, the a becomes zero (i.e., without entries).

If level1 of the a set is longer than level1 of the bit set b, then the unmatched virtual "entries" of the b set (beyond the actual length of b) corresponding to these are all false, hence the result of the "and" operation will be to make all these entries in this set to become false--hence just remove them, and then scan only those entries that could match entries in the bit setb. This clearing of the remainder of the a set is accomplished by selecting both F_OP_X_EQ_F and X_OP_F_EQ_F.

and| 0 1
  0| 0 0
  1| 0 1 

Since:

1.6

Version:

1.0, 2009-03-17

Field Summary

Fields inherited from class SparseBitSet.AbstractStrategy

F_OP_F_EQ_F, F_OP_X_EQ_F, X_OP_F_EQ_F, X_OP_F_EQ_X

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AndStrategy()

Method Summary

Modifier and Type	Method	Description
protected boolean	block(int base, int u3, int v3, long[] a3, long[] b3)	Deals with a part of a block that consists of whole words, starting with the given first index, and ending with the word before the last index.
protected int	properties()	Properties of this strategy.
protected boolean	start(SparseBitSet b)	Instances of this class are to be serially reusable.
protected boolean	word(int base, int u3, long[] a3, long[] b3, long mask)	Deal with a scan that include a partial word within a level3 block.

Methods inherited from class SparseBitSet.AbstractStrategy

finish, isZeroBlock

Methods inherited from class Object

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

Constructor Details

AndStrategy

protected AndStrategy()

Method Details

properties

protected int properties()

Description copied from class: SparseBitSet.AbstractStrategy

Properties of this strategy.

Specified by:

properties in class SparseBitSet.AbstractStrategy

Returns:

the int containing the bits representing the properties of this strategy

start

protected boolean start(SparseBitSet b)

Description copied from class: SparseBitSet.AbstractStrategy

Instances of this class are to be serially reusable. To start a particular use, an instance is (re-)started by calling this method. It is passed the reference to the other bit set (usually to allow a check on whether it is null or not, so as to simplify the implementation of the block() method.

Specified by:

start in class SparseBitSet.AbstractStrategy

Parameters:

b - the "other" set, for whatever checking is needed.

Returns:

true -> if the cache should be set to zero

word

protected boolean word(int base,
 int u3,
 long[] a3,
 long[] b3,
 long mask)

Description copied from class: SparseBitSet.AbstractStrategy

Deal with a scan that include a partial word within a level3 block. All that is required is that the result be stored (if needed) into the given a set block at the correct position, and that the operation only affect those bits selected by 1 bits in the mask.

Specified by:

word in class SparseBitSet.AbstractStrategy

Parameters:

base - the base index of the block (to be used if needed)

u3 - the index of the word within block

a3 - the level3 block from the a set.

b3 - the (nominal) level3 block from the b set (not null).

mask - for the (partial) word

Returns:

true if the resulting word is zero

block

protected boolean block(int base,
 int u3,
 int v3,
 long[] a3,
 long[] b3)

Description copied from class: SparseBitSet.AbstractStrategy

Deals with a part of a block that consists of whole words, starting with the given first index, and ending with the word before the last index. For the words processed, the return value should indicate whether all those resulting words were zero, or not.

Specified by:

block in class SparseBitSet.AbstractStrategy

Parameters:

base - the base index of the block (to be used if needed)

u3 - the index of the first word within block to process

v3 - the index of the last word, which may be within block

a3 - the level3 block from the a set.

b3 - the (nominal) level3 block from the b set (not null).

Returns:

true if the words scanned within the level3 block were all zero