A ByteArrayInputStream
contains
an internal buffer that contains bytes that
may be read from the stream. An internal
counter keeps track of the next byte to
be supplied by the read
method.
Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
See Also
Field Summary
protected byte[] | buf | An array of bytes that was provided by the creator of the stream. |
protected int | count | The index one greater than the last valid character in the input stream buffer. |
protected int | mark | The currently marked position in the stream. |
protected int | pos | The index of the next character to read from the input stream buffer. |
Public Constructor Summary
ByteArrayInputStream(byte[] buf)
Creates a
ByteArrayInputStream
so that it uses buf as its
buffer array. |
|
ByteArrayInputStream(byte[] buf, int offset, int length)
Creates
ByteArrayInputStream
that uses buf as its
buffer array. |
Public Method Summary
synchronized int |
available()
Returns the number of remaining bytes that can be read (or skipped over)
from this input stream.
|
void |
close()
Closing a ByteArrayInputStream has no effect.
|
void |
mark(int readAheadLimit)
Set the current marked position in the stream.
|
boolean |
markSupported()
Tests if this
InputStream supports mark/reset. |
synchronized int |
read()
Reads the next byte of data from this input stream.
|
synchronized int |
read(byte[] b, int off, int len)
Reads up to
len bytes of data into an array of bytes
from this input stream. |
synchronized void |
reset()
Resets the buffer to the marked position.
|
synchronized long |
skip(long n)
Skips
n bytes of input from this input stream. |
Inherited Method Summary
Fields
protected byte[] buf
An array of bytes that was provided
by the creator of the stream. Elements buf[0]
through buf[count-1]
are the
only bytes that can ever be read from the
stream; element buf[pos]
is
the next byte to be read.
protected int count
The index one greater than the last valid character in the input
stream buffer.
This value should always be nonnegative
and not larger than the length of buf
.
It is one greater than the position of
the last byte within buf
that
can ever be read from the input stream buffer.
protected int mark
The currently marked position in the stream.
ByteArrayInputStream objects are marked at position zero by
default when constructed. They may be marked at another
position within the buffer by the mark()
method.
The current buffer position is set to this point by the
reset()
method.
If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied).
protected int pos
The index of the next character to read from the input stream buffer.
This value should always be nonnegative
and not larger than the value of count
.
The next byte to be read from the input stream buffer
will be buf[pos]
.
Public Constructors
public ByteArrayInputStream (byte[] buf)
Creates a ByteArrayInputStream
so that it uses buf
as its
buffer array.
The buffer array is not copied.
The initial value of pos
is 0
and the initial value
of count
is the length of
buf
.
Parameters
buf | the input buffer. |
---|
public ByteArrayInputStream (byte[] buf, int offset, int length)
Creates ByteArrayInputStream
that uses buf
as its
buffer array. The initial value of pos
is offset
and the initial value
of count
is the minimum of offset+length
and buf.length
.
The buffer array is not copied. The buffer's mark is
set to the specified offset.
Parameters
buf | the input buffer. |
---|---|
offset | the offset in the buffer of the first byte to read. |
length | the maximum number of bytes to read from the buffer. |
Public Methods
public synchronized int available ()
Returns the number of remaining bytes that can be read (or skipped over) from this input stream.
The value returned is count - pos
,
which is the number of bytes remaining to be read from the input buffer.
Returns
- the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.
public void close ()
Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
Throws
IOException |
---|
public void mark (int readAheadLimit)
Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method.
If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied).
Note: The readAheadLimit
for this class
has no meaning.
Parameters
readAheadLimit | the maximum limit of bytes that can be read before the mark position becomes invalid. |
---|
public boolean markSupported ()
Tests if this InputStream
supports mark/reset. The
markSupported
method of ByteArrayInputStream
always returns true
.
Returns
true
if this stream instance supports the mark and reset methods;false
otherwise.
public synchronized int read ()
Reads the next byte of data from this 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 read
method
cannot block.
Returns
- the next byte of data, or
-1
if the end of the stream has been reached.
public synchronized int read (byte[] b, int off, int len)
Reads up to len
bytes of data into an array of bytes
from this input stream.
If pos
equals count
,
then -1
is returned to indicate
end of file. Otherwise, the number k
of bytes read is equal to the smaller of
len
and count-pos
.
If k
is positive, then bytes
buf[pos]
through buf[pos+k-1]
are copied into b[off]
through
b[off+k-1]
in the manner performed
by System.arraycopy
. The
value k
is added into pos
and k
is returned.
This read
method cannot block.
Parameters
b | the buffer into which the data is read. |
---|---|
off | the start offset in the destination array b |
len | the maximum number of bytes read. |
Returns
- 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.
Throws
NullPointerException | If b is null . |
---|---|
IndexOutOfBoundsException | If off is negative,
len is negative, or len is greater than
b.length - off
|
public synchronized void reset ()
Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor.
public synchronized long skip (long n)
Skips n
bytes of input from this input stream. Fewer
bytes might be skipped if the end of the input stream is reached.
The actual number k
of bytes to be skipped is equal to the smaller
of n
and count-pos
.
The value k
is added into pos
and k
is returned.
Parameters
n | the number of bytes to be skipped. |
---|
Returns
- the actual number of bytes skipped.