Package org.aoju.bus.core.io.buffer

Class Buffer.UnsafeCursor

java.lang.Object

org.aoju.bus.core.io.buffer.Buffer.UnsafeCursor

All Implemented Interfaces:

Closeable, AutoCloseable

Enclosing class:

Buffer

public static final class Buffer.UnsafeCursor
extends Object
implements Closeable

不安全的游标

Field Summary

Fields

Modifier and Type	Field	Description
Buffer	buffer
byte[]	data
int	end
long	offset
boolean	readWrite
int	start

Constructor Summary

Constructors

Constructor	Description
UnsafeCursor()

Method Summary

Modifier and Type	Method	Description
void	close()
final long	expandBuffer(int minByteCount)	Grow the buffer by adding a contiguous range of capacity in a single segment.
int	next()	Seeks to the next range of bytes, advancing the offset by end - start.
long	resizeBuffer(long newSize)	Change the size of the buffer so that it equals newSize by either adding new capacity at the end or truncating the buffer at the end.
int	seek(long offset)	Reposition the cursor so that the data at offset is readable at data[start].

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

buffer

public Buffer buffer

readWrite

public boolean readWrite

offset

public long offset

data

public byte[] data

start

public int start

end

public int end

Constructor Details

UnsafeCursor

public UnsafeCursor()

Method Details

next

public int next()

Seeks to the next range of bytes, advancing the offset by end - start. Returns the size of the readable range (at least 1), or -1 if we have reached the end of the buffer and there are no more bytes to read.

seek

public int seek(long offset)

Reposition the cursor so that the data at offset is readable at data[start]. Returns the number of bytes readable in data (at least 1), or -1 if there are no data to read.

resizeBuffer

public long resizeBuffer(long newSize)

Change the size of the buffer so that it equals newSize by either adding new capacity at the end or truncating the buffer at the end. Newly added capacity may span multiple segments.

As a side-effect this cursor will seek. If the buffer is being enlarged it will move offset to the first byte of newly-added capacity. This is the size of the buffer prior to the resizeBuffer() call. If the buffer is being shrunk it will move offset to the end of the buffer.

Warning: it is the caller’s responsibility to write new data to every byte of the newly-allocated capacity. Failure to do so may cause serious security problems as the data in the returned buffers is not zero filled. Buffers may contain dirty pooled segments that hold very sensitive data from other parts of the current process.

Returns:

the previous size of the buffer.

expandBuffer

public final long expandBuffer(int minByteCount)

Grow the buffer by adding a contiguous range of capacity in a single segment. This adds at least minByteCount bytes but may add up to a full segment of additional capacity.

As a side-effect this cursor will seek. It will move offset to the first byte of newly-added capacity. This is the size of the buffer prior to the expandBuffer() call.

If minByteCount bytes are available in the buffer's current tail segment that will be used; otherwise another segment will be allocated and appended. In either case this returns the number of bytes of capacity added to this buffer.

Warning: it is the caller’s responsibility to either write new data to every byte of the newly-allocated capacity, or to shrink the buffer to the data written. Failure to do so may cause serious security problems as the data in the returned buffers is not zero filled. Buffers may contain dirty pooled segments that hold very sensitive data from other parts of the current process.

Parameters:

minByteCount - the size of the contiguous capacity. Must be positive and not greater than the capacity size of a single segment (8 KiB).

Returns:

the number of bytes expanded by. Not less than minByteCount.

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable