Android APIs
public class

Base64InputStream

extends FilterInputStream
java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ android.util.Base64InputStream

Class Overview

An InputStream that does Base64 decoding on the data read through it.

Summary

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Inherited Fields
From class java.io.FilterInputStream
Public Constructors
Base64InputStream(InputStream in, int flags)
An InputStream that performs Base64 decoding on the data read from the wrapped stream.
Public Methods
int available()
Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void close()
Closes this stream.
void mark(int readlimit)
Sets a mark position in this stream.
boolean markSupported()
Indicates whether this stream supports mark() and reset().
int read()
Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255.
int read(byte[] b, int off, int len)
Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset.
void reset()
Resets this stream to the last marked location.
long skip(long n)
Skips byteCount bytes in this stream.
[Expand]
Inherited Methods
From class java.io.FilterInputStream
From class java.io.InputStream
From class java.lang.Object
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Public Constructors

public Base64InputStream (InputStream in, int flags)

Added in API level 8

An InputStream that performs Base64 decoding on the data read from the wrapped stream.

Parameters
in InputStream: the InputStream to read the source data from
flags int: bit flags for controlling the decoder; see the constants in Base64

Public Methods

public int available ()

Added in API level 8

Returns an estimated number of bytes that can be read or skipped without blocking for more input.

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, 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 racy).

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 available.

Returns
int the estimated number of bytes available

public void close ()

Added in API level 8

Closes this stream. This implementation closes the filtered stream.

Throws
IOException

public void mark (int readlimit)

Added in API level 8

Sets a mark position in this stream. The parameter readlimit indicates how many bytes can be read before the mark is invalidated. Sending reset() will reposition this stream back to the marked position, provided that readlimit has not been surpassed.

This implementation sets a mark in the filtered stream.

Parameters
readlimit int: the number of bytes that can be read from this stream before the mark is invalidated.

public boolean markSupported ()

Added in API level 8

Indicates whether this stream supports mark() and reset(). This implementation returns whether or not the filtered stream supports marking.

Returns
boolean true if mark() and reset() are supported, false otherwise.

public int read ()

Added in API level 8

Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of this stream has been reached.

Returns
int the byte read or -1 if the end of the filtered stream has been reached.
Throws
IOException

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

Added in API level 8

Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset. Returns the number of bytes actually read or -1 if the end of the stream has been reached.

Parameters
b byte
off int
len int
Returns
int
Throws
IOException

public void reset ()

Added in API level 8

Resets this stream to the last marked location. This implementation resets the target stream.

public long skip (long n)

Added in API level 8

Skips byteCount bytes in this stream. Subsequent calls to read will not return these bytes unless reset is used. This implementation skips byteCount bytes in the filtered stream.

Parameters
n long
Returns
long the number of bytes actually skipped.
Throws
IOException