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java.lang.Objectit.unimi.dsi.sux4j.mph.Hashes
public class Hashes
Basic hash functions.
Method Summary | |
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static long |
jenkins(BitVector bv)
Jenkins 64-bit hashing. |
static long |
jenkins(BitVector bv,
long seed)
Jenkins 64-bit hashing. |
static void |
jenkins(BitVector bv,
long seed,
long[] h)
Jenkins 64-bit hashing (all three values produced). |
static long |
jenkins(BitVector bv,
long prefixLength,
long[] aa,
long[] bb,
long[] cc)
Constant-time Jenkins 64-bit hashing for any prefix. |
static void |
jenkins(BitVector bv,
long prefixLength,
long[] aa,
long[] bb,
long[] cc,
long[] h)
Constant-time Jenkins 64-bit hashing for any prefix (all three values produced). |
static void |
jenkins(long[] triple,
long seed,
long[] h)
Jenkins 64-bit hashing (all three values produced) for a triple of longs. |
static long[][] |
preprocessJenkins(BitVector bv,
long seed)
Preprocesses a bit vector so that Jenkins 64-bit hashing can be computed in constant time on all prefixes. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
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public static void jenkins(BitVector bv, long seed, long[] h)
This code is based on the lookup8.c, and in particular on the version consuming 64 bits at a time, but it has been slightly modified to work correctly with any bit vector length (not just multiples of 64). Moreover, we return all three values generated by the algorithm.
bv
- a bit vector.seed
- a seed for the hash.h
- a triple of long values in which the three generated hashes will be saved.public static long jenkins(BitVector bv, long seed)
bv
- a bit vector.seed
- a seed for the hash.
jenkins(BitVector, long, long[])
.public static long jenkins(BitVector bv)
bv
- a bit vector.
jenkins(BitVector, long, long[])
with seed 0.public static long[][] preprocessJenkins(BitVector bv, long seed)
bv
- a bit vector.seed
- a seed for the hash.
a
, b
and c
during the hash computation; these vector must be passed to jenkins(BitVector, long, long[], long[], long[])
(and analogous functions) in this order.jenkins(BitVector)
public static void jenkins(BitVector bv, long prefixLength, long[] aa, long[] bb, long[] cc, long[] h)
bv
- a bit vector.prefixLength
- the length of the prefix of bv
over which the hash must be computed.aa
- the first state array returned by preprocessJenkins(BitVector, long)
.bb
- the second state array returned by preprocessJenkins(BitVector, long)
.cc
- the third state array returned by preprocessJenkins(BitVector, long)
.h
- a triple of long values in which the three generated hashes will be saved.public static long jenkins(BitVector bv, long prefixLength, long[] aa, long[] bb, long[] cc)
bv
- a bit vector.prefixLength
- the length of the prefix of bv
over which the hash must be computed.aa
- the first state array returned by preprocessJenkins(BitVector, long)
.bb
- the second state array returned by preprocessJenkins(BitVector, long)
.cc
- the third state array returned by preprocessJenkins(BitVector, long)
.
jenkins(BitVector, long, long[], long[], long[], long[])
.public static void jenkins(long[] triple, long seed, long[] h)
triple
- three longs.seed
- a seed for the hash.h
- a triple of long values in which the three generated hashes will be saved.
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