Apache POI - Common 5.3.0 · org.apache.poi.poifs.crypt.ChunkedCipherInputStream

Modifier and Type	Field and Description
private final byte[]	chunk
private final int	chunkBits
private boolean	chunkIsValid
private final int	chunkSize
private final Cipher	cipher
private int	lastIndex
private final byte[]	plain
private long	pos
private final long	size

Access	Constructor and Description
public	ChunkedCipherInputStream(InputStream stream, long size, int chunkSize)
public	ChunkedCipherInputStream(InputStream stream, long size, int chunkSize, int initialPos)

Method Summary

Modifier and Type	Method and Description
public int	available() Overrides org.apache.poi.util.LittleEndianInputStream.available. Implements org.apache.poi.util.LittleEndianInput.available. Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
protected byte[]	Returns: the chunk bytes getChunk()
protected int	getChunkMask()
protected byte[]	Returns: the plain bytes getPlain()
public long	Returns: the absolute position in the stream getPos()
public final Cipher	initCipherForBlock(int block)
protected abstract Cipher	initCipherForBlock(Cipher existing, int block)
protected int	invokeCipher(int totalBytes, boolean doFinal) Helper function for overriding the cipher invocation, i.e. XOR doesn't use a cipher and uses its own implementation
public synchronized void	mark(int the maximum limit of bytes that can be read before the mark position becomes invalid. readlimit) Overrides org.apache.poi.util.LittleEndianInputStream.mark. Marks the current position in this input stream.
public boolean	markSupported() Overrides java.io.FilterInputStream.markSupported. Tests if this input stream supports the `mark` and `reset` methods.
private void	nextChunk()
public int	read() Overrides java.io.FilterInputStream.read. Reads the next byte of data from the input stream.
public int	read(byte[] the buffer into which the data is read. b, int the start offset in array `b` at which the data is written. off, int the maximum number of bytes to read. len) Overrides org.apache.poi.util.LittleEndianInputStream.read. Reads up to `len` bytes of data from this input stream into an array of bytes.
private int	read(byte[] b, int off, int len, boolean readPlain)
public void	readPlain(byte[] the byte array to receive the bytes b, int the start offset into the byte array off, int the amount of bytes to fill len) Overrides org.apache.poi.util.LittleEndianInputStream.readPlain. Implements org.apache.poi.util.LittleEndianInput.readPlain. Used when BIFF header fields (sid, size) are being read.
private int	Returns: the remaining byte until EOF remainingBytes() Helper method for forbidden available call - we know the size beforehand, so it's ok ...
public synchronized void	reset() Overrides org.apache.poi.util.LittleEndianInputStream.reset. Repositions this stream to the position at the time the `mark` method was last called on this input stream.
public void	setNextRecordSize(int the size of the next record recordSize) Some ciphers (actually just XOR) are based on the record size, which needs to be set before decryption
public long	skip(final long the number of bytes to be skipped. n) Overrides java.io.FilterInputStream.skip. Skips over and discards `n` bytes of data from the input stream.

Inherited from org.apache.poi.util.LittleEndianInputStream:: getReadIndex readByte readDouble readFloat readFully readFully readInt readLong readShort readUByte readUInt readUShort skipFully

chunk	back to summary
private final byte[] chunk

chunkBits	back to summary
private final int chunkBits

chunkIsValid	back to summary
private boolean chunkIsValid

chunkSize	back to summary
private final int chunkSize

cipher	back to summary
private final Cipher cipher

lastIndex	back to summary
private int lastIndex

plain	back to summary
private final byte[] plain

pos	back to summary
private long pos

size	back to summary
private final long size

ChunkedCipherInputStream	back to summary
public ChunkedCipherInputStream(InputStream stream, long size, int chunkSize) throws GeneralSecurityException

ChunkedCipherInputStream	back to summary
public ChunkedCipherInputStream(InputStream stream, long size, int chunkSize, int initialPos) throws GeneralSecurityException

Method Detail

available	back to summary
public int available() Overrides org.apache.poi.util.LittleEndianInputStream.available. Implements org.apache.poi.util.LittleEndianInput.available. Doc from java.io.FilterInputStream.available. Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes. Returns:int an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking. Annotations @Override

available

back to summary

public int available()

Overrides org.apache.poi.util.LittleEndianInputStream.available.

Implements org.apache.poi.util.LittleEndianInput.available.

Doc from java.io.FilterInputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Returns:int

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.

Annotations

@Override

getChunk	back to summary
protected byte[] getChunk() Returns:byte[] the chunk bytes

getChunkMask	back to summary
protected int getChunkMask()

getPlain	back to summary
protected byte[] getPlain() Returns:byte[] the plain bytes

getPos	back to summary
public long getPos() Returns:long the absolute position in the stream

initCipherForBlock	back to summary
public final Cipher initCipherForBlock(int block) throws IOException, GeneralSecurityException

initCipherForBlock	back to summary
protected abstract Cipher initCipherForBlock(Cipher existing, int block) throws GeneralSecurityException

invokeCipher	back to summary
protected int invokeCipher(int totalBytes, boolean doFinal) throws GeneralSecurityException Helper function for overriding the cipher invocation, i.e. XOR doesn't use a cipher and uses its own implementation

mark back to summary

mark	back to summary
public synchronized void mark(int readlimit) Overrides org.apache.poi.util.LittleEndianInputStream.mark. Doc from java.io.FilterInputStream.mark. Marks the current position in this input stream. A subsequent call to the `reset` method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. The `readlimit` argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated. Parameters readlimit:int the maximum limit of bytes that can be read before the mark position becomes invalid. Annotations @Override

public synchronized void mark(int readlimit)

Overrides org.apache.poi.util.LittleEndianInputStream.mark.

Doc from java.io.FilterInputStream.mark.

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

The readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

Parameters

readlimit:int: the maximum limit of bytes that can be read before the mark position becomes invalid.

Annotations

@Override

markSupported back to summary

markSupported	back to summary
public boolean markSupported() Overrides java.io.FilterInputStream.markSupported. Doc from java.io.FilterInputStream.markSupported. Tests if this input stream supports the `mark` and `reset` methods. Returns:boolean `true` if this stream type supports the `mark` and `reset` method; `false` otherwise. Annotations @Override

public boolean markSupported()

Overrides java.io.FilterInputStream.markSupported.

Doc from java.io.FilterInputStream.markSupported.

Tests if this input stream supports the mark and reset methods.

Returns:boolean

true if this stream type supports the mark and reset method; false otherwise.

Annotations

@Override

nextChunk	back to summary
private void nextChunk() throws GeneralSecurityException, IOException

read back to summary

read	back to summary
public int read() throws IOException Overrides java.io.FilterInputStream.read. Doc from java.io.FilterInputStream.read. Reads the next byte of data from the input stream. The value byte is returned as an `int` in the range `0` to `255`. If no byte is available because the end of the stream has been reached, the value `-1` is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown. Returns:int the next byte of data, or `-1` if the end of the stream is reached. Annotations @Override Exceptions IOException: if an I/O error occurs.

public int read() throws IOException

Overrides java.io.FilterInputStream.read.

Doc from java.io.FilterInputStream.read.

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Returns:int

the next byte of data, or -1 if the end of the stream is reached.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

read back to summary

read	back to summary
public int read(byte[] b, int off, int len) throws IOException Overrides org.apache.poi.util.LittleEndianInputStream.read. Doc from java.io.FilterInputStream.read. Reads up to `len` bytes of data from this input stream into an array of bytes. If `len` is not zero, the method blocks until some input is available; otherwise, no bytes are read and `0` is returned. Parameters b:byte[] the buffer into which the data is read. off:int the start offset in array `b` at which the data is written. len:int the maximum number of bytes to read. Returns:int the total number of bytes read into the buffer, or `-1` if there is no more data because the end of the stream has been reached. Annotations @Override Exceptions IOException: if an I/O error occurs.

public int read(byte[] b, int off, int len) throws IOException

Overrides org.apache.poi.util.LittleEndianInputStream.read.

Doc from java.io.FilterInputStream.read.

Reads up to len bytes of data from this input stream into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned.

Parameters

b:byte[]: the buffer into which the data is read.
off:int: the start offset in array b at which the data is written.
len:int: the maximum number of bytes to read.

Returns:int

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs.

read	back to summary
private int read(byte[] b, int off, int len, boolean readPlain) throws IOException

readPlain back to summary

readPlain	back to summary
public void readPlain(byte[] b, int off, int len) Overrides org.apache.poi.util.LittleEndianInputStream.readPlain. Implements org.apache.poi.util.LittleEndianInput.readPlain. Used when BIFF header fields (sid, size) are being read. The internal `Cipher` instance must step even when unencrypted bytes are read Parameters b:byte[] Doc from org.apache.poi.util.LittleEndianInput.readPlain. the byte array to receive the bytes off:int Doc from org.apache.poi.util.LittleEndianInput.readPlain. the start offset into the byte array len:int Doc from org.apache.poi.util.LittleEndianInput.readPlain. the amount of bytes to fill Annotations @Override

public void readPlain(byte[] b, int off, int len)

Overrides org.apache.poi.util.LittleEndianInputStream.readPlain.

Implements org.apache.poi.util.LittleEndianInput.readPlain.

Used when BIFF header fields (sid, size) are being read. The internal Cipher instance must step even when unencrypted bytes are read

Parameters

b:byte[]

Doc from org.apache.poi.util.LittleEndianInput.readPlain.

the byte array to receive the bytes

off:int

Doc from org.apache.poi.util.LittleEndianInput.readPlain.

the start offset into the byte array

len:int

Doc from org.apache.poi.util.LittleEndianInput.readPlain.

the amount of bytes to fill

Annotations

@Override

remainingBytes	back to summary
private int remainingBytes() Helper method for forbidden available call - we know the size beforehand, so it's ok ... Returns:int the remaining byte until EOF

remainingBytes

back to summary

private int remainingBytes()

Helper method for forbidden available call - we know the size beforehand, so it's ok ...

Returns:int: the remaining byte until EOF

reset back to summary

reset	back to summary
public synchronized void reset() Overrides org.apache.poi.util.LittleEndianInputStream.reset. Doc from java.io.FilterInputStream.reset. Repositions this stream to the position at the time the `mark` method was last called on this input stream. Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser. Annotations @Override

public synchronized void reset()

Overrides org.apache.poi.util.LittleEndianInputStream.reset.

Doc from java.io.FilterInputStream.reset.

Repositions this stream to the position at the time the mark method was last called on this input stream.

Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.

Annotations

@Override

setNextRecordSize	back to summary
public void setNextRecordSize(int recordSize) Some ciphers (actually just XOR) are based on the record size, which needs to be set before decryption Parameters recordSize:int the size of the next record

setNextRecordSize

back to summary

public void setNextRecordSize(int recordSize)

Some ciphers (actually just XOR) are based on the record size, which needs to be set before decryption

Parameters

recordSize:int: the size of the next record

skip back to summary

skip	back to summary
public long skip(final long n) Overrides java.io.FilterInputStream.skip. Doc from java.io.FilterInputStream.skip. Skips over and discards `n` bytes of data from the input stream. The `skip` method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly `0`. The actual number of bytes skipped is returned. Parameters n:long the number of bytes to be skipped. Returns:long the actual number of bytes skipped. Annotations @Override

public long skip(final long n)

Overrides java.io.FilterInputStream.skip.

Doc from java.io.FilterInputStream.skip.

Skips over and discards n bytes of data from the input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number of bytes skipped is returned.

Parameters

n:long: the number of bytes to be skipped.

Returns:long

the actual number of bytes skipped.

Annotations

@Override

public abstract Class ChunkedCipherInputStream

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