public static class AssetFileDescriptor.AutoCloseInputStream extends ParcelFileDescriptor.AutoCloseInputStream
ParcelFileDescritor.close()for you when the stream is closed.
|Constructor and Description|
|Modifier and Type||Method and Description|
Returns an estimated number of bytes that can be read or skipped without blocking for more input.
Sets a mark position in this InputStream.
Indicates whether this stream supports the
Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
Reads at most
Resets this stream to the last marked location.
Skips at most
public int available() throws IOException
Note that this method provides such a weak guarantee that it is not very useful in practice.
Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.
Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".
Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.
It is particularly important to realize that you must not use this method to
size a container and assume that you can read the entirety of the stream without needing
to resize the container. Such callers should probably write everything they read to a
ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're
reading from a file,
File.length() returns the current length of the file (though
assuming the file's length can't change may be incorrect, reading a file is inherently
The default implementation of this method in
InputStream always returns 0.
Subclasses should override this method if they are able to indicate the number of bytes
public int read() throws IOException
public int read(byte buffer, int offset, int count) throws IOException
lengthbytes from this stream and stores them in the byte array
buffer- the byte array in which to store the bytes read.
offset- the initial position in
bufferto store the bytes read from this stream.
count- the maximum number of bytes to store in
IOException- if the stream is closed or another IOException occurs.
public int read(byte buffer) throws IOException
read(buffer, 0, buffer.length).
public long skip(long count) throws IOException
nbytes in this stream. This method does nothing and returns 0 if
nis negative, but some subclasses may throw.
Note the "at most" in the description of this method: this method may choose to skip fewer bytes than requested. Callers should always check the return value.
This default implementation reads bytes into a temporary buffer. Concrete subclasses should provide their own implementation.
public void mark(int readlimit)
readlimitindicates how many bytes can be read before the mark is invalidated. Sending
reset()will reposition the stream back to the marked position provided
readLimithas not been surpassed.
This default implementation does nothing and concrete subclasses must provide their own implementation.
public boolean markSupported()
reset()methods. The default implementation returns
public void reset() throws IOException
IOExceptionif the number of bytes read since the mark has been set is greater than the limit provided to
mark, or if no mark has been set.
This implementation always throws an
IOException and concrete
subclasses should provide the proper implementation.