Default slice shift, i.e. 1L << shift, denoting slice size in MiB:

• 64bit machines -> 30 = 1024 MiB
• 32bit machines -> 29 = 512 MiB

In case the default is too much of-used up address-space, one may choose other values:

• 29 -> 512 MiB
• 28 -> 256 MiB
• 27 -> 128 MiB
• 26 -> 64 MiB

Overrides java.io.InputStream.available.

Doc from java.io.InputStream.available.

See remaining() for an accurate variant.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on 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.

Note that while some implementations of InputStream will return the total number of bytes in the stream, many will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream.

A subclass's implementation of this method may choose to throw an IOException if this input stream has been closed by invoking the close() method.

Returns:int

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking or 0 when it reaches the end of the input stream.

Annotations

@Override

Exceptions

IOException:

if a buffer slice operation failed.

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

Doc from java.io.InputStream.close.

Closes this input stream and releases any system resources associated with the stream.

Annotations

@Override

Exceptions

IOException:

if an I/O error occurs.

Return the mapped ByteBuffer slice at the current position().

Due to the nature of using sliced buffers mapping the whole region, user has to determine whether the returned buffer covers the desired region and may fetch the nextSlice() until satisfied.
It is also possible to repeat this operation after reposition the stream via position(long) or skip(long) to a position within the next block, similar to nextSlice().

Exceptions

IOException:

if a buffer slice operation failed.

Similar to OutputStream#flush(), synchronizes all mapped buffers from local storage via MappedByteBuffer#force() as well as the FileChannel#force(boolean) w/o metaData.

Parameters

metaData:boolean

TODO

Exceptions

IOException:

if this stream has been closed.

Return the used CacheMode.

If a desired CacheMode is not available, it may fall back to an available one at runtime, see CacheMode#FLUSH_PRE_HARD.
This evaluation only happens if the CacheMode != CacheMode#FLUSH_NONE and while attempting to flush an unused buffer slice.

Returns a new MappedByteBufferOutputStream instance sharing all resources of this input stream, including all buffer slices.

Exceptions

IllegalStateException:

if attempting to set the FileResizeOp to a different value than before

IOException:

if this instance was opened w/ FileChannel.MapMode#READ_ONLY or if this stream has been closed.

Return synchronous mode.

Returns the total size in bytes of the InputStream

  0 <= position() <= length()

Overrides java.io.InputStream.mark.

Doc from java.io.InputStream.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 arguments tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

The general contract of mark is that, if the method markSupported returns true, the stream somehow remembers all the bytes read after the call to mark and stands ready to supply those same bytes again if and whenever the method reset is called. However, the stream is not required to remember any data at all if more than readlimit bytes are read from the stream before reset is called.

Marking a closed stream should not have any effect on the stream.

Parameter readLimit is not used in this implementation, since the whole file is memory mapped and no read limitation occurs.

Parameters

readlimit:int

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

Annotations

@Override

Overrides java.io.InputStream.markSupported.

Doc from java.io.InputStream.markSupported.

Tests if this input stream supports the mark and reset methods. Whether or not mark and reset are supported is an invariant property of a particular input stream instance.

Returns:boolean

true if this stream instance supports the mark and reset methods; false otherwise.

Annotations

@Override

Return the next mapped ByteBuffer slice from the current position(), implicitly setting position(long) to the start of the returned next slice, see currentSlice().

If no subsequent slice is available, null is being returned.

Exceptions

IOException:

if a buffer slice operation failed.

Notify this instance that the underlying FileChannel's size has been changed and adjusting this instances buffer slices and states accordingly.

Should be called by user API when aware of such event.

Parameters

newTotalSize:long

the new total size

Exceptions

IOException:

if a buffer slice operation failed

Returns the absolute position of the InputStream.

  0 <= position() <= length()

Exceptions

IOException:

if a buffer slice operation failed.

Sets the absolute position of the InputStream to newPosition.

  0 <= position() <= length()

Parameters

newPosition:long

The new position, which must be non-negative and ≤ length().

Returns:MappedByteBufferInputStream

this instance

Exceptions

IOException:

if a buffer slice operation failed or stream is closed.

Implements abstract java.io.InputStream.read.

Doc from java.io.InputStream.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.

Overrides java.io.InputStream.read.

Doc from java.io.InputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off-1] and elements b[off+len] through b[b.length-1] are unaffected.

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 the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.

Perform similar to read(byte[], int, int) with ByteBuffer instead of byte array.

Parameters

b:ByteBuffer

the ByteBuffer sink, data is written at current ByteBuffer#position()

len:int

the number of bytes to read

Returns:int

the number of bytes read, -1 for EOS

Exceptions

IOException:

if a buffer slice operation failed or stream has been closed.

Returns the number of remaining available bytes of the InputStream, i.e. length() - position().

  0 <= position() <= length()

In contrast to InputStream's available() method, this method returns the proper return type long.

Exceptions

IOException:

if a buffer slice operation failed.

Overrides java.io.InputStream.reset.

Doc from java.io.InputStream.reset.

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

The general contract of reset is:

• If the method markSupported returns true, then:
  • If the method mark has not been called since the stream was created, or the number of bytes read from the stream since mark was last called is larger than the argument to mark at that last call, then an IOException might be thrown.
  • If such an IOException is not thrown, then the stream is reset to a state such that all the bytes read since the most recent call to mark (or since the start of the file, if mark has not been called) will be resupplied to subsequent callers of the read method, followed by any bytes that otherwise would have been the next input data as of the time of the call to reset.
• If the method markSupported returns false, then:
  • The call to reset may throw an IOException.
  • If an IOException is not thrown, then the stream is reset to a fixed state that depends on the particular type of the input stream and how it was created. The bytes that will be supplied to subsequent callers of the read method depend on the particular type of the input stream.

Annotations

@Override

Exceptions

IOException:

if this stream has not been marked, a buffer slice operation failed or stream has been closed.

Parameters

fileResizeOp:MappedByteBufferInputStream.FileResizeOp

the new FileResizeOp.

Exceptions

IllegalStateException:

if attempting to set the FileResizeOp to a different value than before

Resize the underlying FileChannel's size and adjusting this instance via accordingly.

User must have a FileResizeOp registered before.

Implementation calls notifyLengthChange(long) after FileResizeOp#setLength(long).

Parameters

newTotalSize:long

the new total size

Exceptions

IOException:

if no FileResizeOp has been registered or if a buffer slice operation failed

Enable or disable synchronous mode.

If synchronous mode is enabled, mapped buffers will be flushed if resized, written to or closing in read-write mapping mode.

If synchronous mode is enabled, FileChannel#force(boolean) is issued if resizing or closing and not in read-only mapping mode.

Parameters

s:boolean

true to enable synchronous mode

Overrides java.io.InputStream.skip.

Doc from java.io.InputStream.skip.

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, the skip method for class InputStream always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently.

Parameters

n:long

the number of bytes to be skipped.

Returns:long

the actual number of bytes skipped which might be zero.

Annotations

@Override

Exceptions

IOException:

if a buffer slice operation failed or stream is closed.