it.unimi.dsi.big.util
Class SemiExternalGammaBigList
java.lang.Object
java.util.AbstractCollection<Long>
it.unimi.dsi.fastutil.longs.AbstractLongCollection
it.unimi.dsi.fastutil.longs.AbstractLongBigList
it.unimi.dsi.big.util.SemiExternalGammaBigList
- All Implemented Interfaces:
- BigList<Long>, LongBigList, LongCollection, LongIterable, LongStack, Size64, Stack<Long>, Comparable<BigList<? extends Long>>, Iterable<Long>, Collection<Long>
public class SemiExternalGammaBigList
- extends AbstractLongBigList
Provides semi-external random access to a big list
of γ-encoded integers.
This class is a semi-external LongBigList
that
MG4J uses to access files containing frequencies.
Instead, this class accesses frequencies in their
compressed forms, and provides entry points for random access to each long. At construction
time, entry points are computed with a certain step, which is the number of longs
accessible from each entry point, or, equivalently, the maximum number of longs that will
be necessary to read to access a given long.
Warning: This class is not thread safe, and needs to be synchronised to be used in a
multithreaded environment.
- Since:
- 2.0
- Author:
- Fabien Campagne, Sebastiano Vigna
Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongBigList |
add, add, add, addAll, addAll, addAll, addAll, addAll, addAll, addAll, addElements, addElements, compareTo, contains, ensureIndex, ensureRestrictedIndex, equals, get, getElements, getLong, hashCode, indexOf, indexOf, iterator, lastIndexOf, lastIndexOf, listIterator, listIterator, listIterator, peek, peekLong, pop, popLong, push, push, rem, remove, remove, removeElements, removeLong, removeLong, set, set, set, size, size, size, subList, top, topLong, toString |
Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLongCollection |
add, contains, containsAll, containsAll, isEmpty, longIterator, rem, remove, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toLongArray, toLongArray |
Methods inherited from interface it.unimi.dsi.fastutil.Stack |
isEmpty |
DEFAULT_STEP
public static final int DEFAULT_STEP
- See Also:
- Constant Field Values
SemiExternalGammaBigList
public SemiExternalGammaBigList(InputBitStream longs,
int step,
long numLongs)
throws IOException
- Creates a new semi-external list.
- Parameters:
longs
- a bit stream containing γ-encoded longs.step
- the step used to build random-access entry points, or -1 to get DEFAULT_STEP
; note that
a step causing more than 231 slots will be silently increased.numLongs
- the overall number of offsets (i.e., the number of terms).
- Throws:
IOException
SemiExternalGammaBigList
public SemiExternalGammaBigList(InputBitStream longs)
throws IOException
- Creates a new semi-external list.
This quick-and-dirty constructor estimates the number of longs by checking
for an EOFException
.
- Parameters:
longs
- a bit stream containing γ-encoded longs.
- Throws:
IOException
getLong
public final long getLong(long index)
size64
public long size64()