Package com.google.common.hash
Class AbstractStreamingHasher
- java.lang.Object
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- com.google.common.hash.AbstractHasher
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- com.google.common.hash.AbstractStreamingHasher
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- All Implemented Interfaces:
Hasher
,PrimitiveSink
- Direct Known Subclasses:
Crc32cHashFunction.Crc32cHasher
,Murmur3_128HashFunction.Murmur3_128Hasher
,SipHashFunction.SipHasher
abstract class AbstractStreamingHasher extends AbstractHasher
A convenience base class for implementors ofHasher
; handles accumulating data until an entire "chunk" (of implementation-dependent length) is ready to be hashed.
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Field Summary
Fields Modifier and Type Field Description private java.nio.ByteBuffer
buffer
Buffer via which we pass data to the hash algorithm (the implementor)private int
bufferSize
Number of bytes to be filled before process() invocation(s).private int
chunkSize
Number of bytes processed per process() invocation.
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Constructor Summary
Constructors Modifier Constructor Description protected
AbstractStreamingHasher(int chunkSize)
Constructor for use by subclasses.protected
AbstractStreamingHasher(int chunkSize, int bufferSize)
Constructor for use by subclasses.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description HashCode
hash()
Computes a hash code based on the data that have been provided to this hasher.protected abstract HashCode
makeHash()
Computes a hash code based on the data that have been provided to this hasher.private void
munch()
private void
munchIfFull()
protected abstract void
process(java.nio.ByteBuffer bb)
Processes the available bytes of the buffer (at mostchunk
bytes).protected void
processRemaining(java.nio.ByteBuffer bb)
This is invoked for the last bytes of the input, which are not enough to fill a whole chunk.Hasher
putByte(byte b)
Puts a byte into this sink.Hasher
putBytes(byte[] bytes, int off, int len)
Puts a chunk of an array of bytes into this sink.Hasher
putBytes(java.nio.ByteBuffer readBuffer)
Puts the remaining bytes of a byte buffer into this sink.private Hasher
putBytesInternal(java.nio.ByteBuffer readBuffer)
Hasher
putChar(char c)
Puts a character into this sink.Hasher
putInt(int i)
Puts an int into this sink.Hasher
putLong(long l)
Puts a long into this sink.Hasher
putShort(short s)
Puts a short into this sink.-
Methods inherited from class com.google.common.hash.AbstractHasher
putBoolean, putBytes, putDouble, putFloat, putObject, putString, putUnencodedChars
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Field Detail
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buffer
private final java.nio.ByteBuffer buffer
Buffer via which we pass data to the hash algorithm (the implementor)
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bufferSize
private final int bufferSize
Number of bytes to be filled before process() invocation(s).
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chunkSize
private final int chunkSize
Number of bytes processed per process() invocation.
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Constructor Detail
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AbstractStreamingHasher
protected AbstractStreamingHasher(int chunkSize)
Constructor for use by subclasses. This hasher instance will process chunks of the specified size.- Parameters:
chunkSize
- the number of bytes available perprocess(ByteBuffer)
invocation; must be at least 4
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AbstractStreamingHasher
protected AbstractStreamingHasher(int chunkSize, int bufferSize)
Constructor for use by subclasses. This hasher instance will process chunks of the specified size, using an internal buffer ofbufferSize
size, which must be a multiple ofchunkSize
.- Parameters:
chunkSize
- the number of bytes available perprocess(ByteBuffer)
invocation; must be at least 4bufferSize
- the size of the internal buffer. Must be a multiple of chunkSize
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Method Detail
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process
protected abstract void process(java.nio.ByteBuffer bb)
Processes the available bytes of the buffer (at mostchunk
bytes).
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processRemaining
protected void processRemaining(java.nio.ByteBuffer bb)
This is invoked for the last bytes of the input, which are not enough to fill a whole chunk. The passedByteBuffer
is guaranteed to be non-empty.This implementation simply pads with zeros and delegates to
process(ByteBuffer)
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putBytes
public final Hasher putBytes(byte[] bytes, int off, int len)
Description copied from interface:PrimitiveSink
Puts a chunk of an array of bytes into this sink.bytes[off]
is the first byte written,bytes[off + len - 1]
is the last.- Specified by:
putBytes
in interfaceHasher
- Specified by:
putBytes
in interfacePrimitiveSink
- Overrides:
putBytes
in classAbstractHasher
- Parameters:
bytes
- a byte arrayoff
- the start offset in the arraylen
- the number of bytes to write- Returns:
- this instance
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putBytes
public final Hasher putBytes(java.nio.ByteBuffer readBuffer)
Description copied from interface:PrimitiveSink
Puts the remaining bytes of a byte buffer into this sink.bytes.position()
is the first byte written,bytes.limit() - 1
is the last. The position of the buffer will be equal to the limit when this method returns.- Specified by:
putBytes
in interfaceHasher
- Specified by:
putBytes
in interfacePrimitiveSink
- Overrides:
putBytes
in classAbstractHasher
- Parameters:
readBuffer
- a byte buffer- Returns:
- this instance
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putBytesInternal
private Hasher putBytesInternal(java.nio.ByteBuffer readBuffer)
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putByte
public final Hasher putByte(byte b)
Description copied from interface:PrimitiveSink
Puts a byte into this sink.- Parameters:
b
- a byte- Returns:
- this instance
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putShort
public final Hasher putShort(short s)
Description copied from interface:PrimitiveSink
Puts a short into this sink.- Specified by:
putShort
in interfaceHasher
- Specified by:
putShort
in interfacePrimitiveSink
- Overrides:
putShort
in classAbstractHasher
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putChar
public final Hasher putChar(char c)
Description copied from interface:PrimitiveSink
Puts a character into this sink.- Specified by:
putChar
in interfaceHasher
- Specified by:
putChar
in interfacePrimitiveSink
- Overrides:
putChar
in classAbstractHasher
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putInt
public final Hasher putInt(int i)
Description copied from interface:PrimitiveSink
Puts an int into this sink.- Specified by:
putInt
in interfaceHasher
- Specified by:
putInt
in interfacePrimitiveSink
- Overrides:
putInt
in classAbstractHasher
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putLong
public final Hasher putLong(long l)
Description copied from interface:PrimitiveSink
Puts a long into this sink.- Specified by:
putLong
in interfaceHasher
- Specified by:
putLong
in interfacePrimitiveSink
- Overrides:
putLong
in classAbstractHasher
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hash
public final HashCode hash()
Description copied from interface:Hasher
Computes a hash code based on the data that have been provided to this hasher. The result is unspecified if this method is called more than once on the same instance.
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makeHash
protected abstract HashCode makeHash()
Computes a hash code based on the data that have been provided to this hasher. This is called after all chunks are handled withprocess(java.nio.ByteBuffer)
and any leftover bytes that did not make a complete chunk are handled withprocessRemaining(java.nio.ByteBuffer)
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munchIfFull
private void munchIfFull()
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munch
private void munch()
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