# Package org.apache.lucene.util.packed

Packed integer arrays and streams.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  PackedInts.Decoder | A decoder for packed integers.
  PackedInts.Encoder | An encoder for packed integers.
  PackedInts.Mutable | A packed integer array that can be modified.
  PackedInts.Reader | A read-only random access array of positive integers.
  PackedInts.ReaderIterator | Run-once iterator interface, to decode previously saved PackedInts.

- Class Summary
  Class | Description
  --- | ---
  AppendingLongBuffer | Utility class to buffer a list of signed longs in memory.
  BlockPackedReader | Provides random access to a stream written with `BlockPackedWriter`.
  BlockPackedReaderIterator | Reader for sequences of longs written with `BlockPackedWriter`.
  BlockPackedWriter | A writer for large sequences of longs.
  GrowableWriter | Implements `PackedInts.Mutable`, but grows the bit count of the underlying packed ints on-demand.
  MonotonicAppendingLongBuffer | Utility class to buffer signed longs in memory, which is optimized for the case where the sequence is monotonic, although it can encode any sequence of arbitrary longs.
  MonotonicBlockPackedReader | Provides random access to a stream written with `MonotonicBlockPackedWriter`.
  MonotonicBlockPackedWriter | A writer for large monotonically increasing sequences of positive longs.
  PackedDataInput | A `DataInput` wrapper to read unaligned, variable-length packed integers.
  PackedDataOutput | A `DataOutput` wrapper to write unaligned, variable-length packed integers.
  PackedInts | Simplistic compression for array of unsigned long values.
  PackedInts.FormatAndBits | Simple class that holds a format and a number of bits per value.
  PackedInts.Header | Header identifying the structure of a packed integer array.
  PackedInts.NullReader | A `PackedInts.Reader` which has all its values equal to 0 (bitsPerValue = 0).
  PackedInts.Writer | A write-once Writer.

- Enum Summary
  Enum | Description
  --- | ---
  PackedInts.Format | A format to write packed ints.

## Package org.apache.lucene.util.packed Description

Packed integer arrays and streams.

The packed package provides

- sequential and random access capable arrays of positive longs,
- routines for efficient serialization and deserialization of streams of packed integers.

The implementations provide different trade-offs between memory usage and access speed. The standard usage scenario is replacing large int or long arrays in order to reduce the memory footprint.

The main access point is the `PackedInts` factory.

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