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com.tangosol.io
Class Base64OutputStream

java.lang.Object
java.io.OutputStream
com.tangosol.io.Base64OutputStream

All Implemented Interfaces:

OutputStreaming, java.io.Closeable, java.io.Flushable

public class Base64OutputStream

extends java.io.OutputStream

implements OutputStreaming

Writes binary data into a Writer using IETF RFC 2045 Base64 Content Transfer Encoding. If the Base64OutputStream is not the first to write data into the Writer, it may be desired to write a line feed before Base64 data. According to the specification, Base64 data cannot exceed 76 characters per line. Be careful to avoid calling flush() except when a stream of Base64 content is complete.

Author:

cp 2000.09.06

Field Summary

protected static char[]	BASE64_ALPHABET Base64 encodes into this "alphabet" of 64 characters.
protected static char	BASE64_LF The Base64 line feed character.
protected static char	BASE64_PAD The Base64 padding character.
protected static int	GROUPS_PER_LINE The number of Base64 character groups in one line.
protected byte[]	m_abAccum Accumulated bytes.
protected char[]	m_achGroup An array that is used to send 4 characters at a time to the underlying Writer object.
protected int	m_cAccum The number of bytes accumulated (0, 1, 2 or 3).
protected int	m_cLineGroups The number of groups left to write in the current line.
protected boolean	m_fBreakLines True if lines are to be broken by BASE64_LF;
protected boolean	m_fClosed True after close is invoked.
protected java.io.Writer	m_writer The Writer object to which the Base64 encoded data is written.

Constructor Summary

Base64OutputStream(java.io.Writer writer)
Construct a Base64OutputStream on a Writer object.

Base64OutputStream(java.io.Writer writer, boolean fBreakLines)
Construct a Base64OutputStream on a Writer object and specifying a line-break option.

Method Summary

void	close() Close the stream, flushing any accumulated bytes.
static char[]	encode(byte[] ab) Encode the passed binary data using Base64 encoding.
static char[]	encode(byte[] ab, boolean fBreakLines) Encode the passed binary data using Base64 encoding.
static char[]	encode(byte[] ab, int ofb, int cb, boolean fBreakLines) Encode the passed binary data using Base64 encoding.
void	flush() Close the stream, flushing any accumulated bytes.
protected void	flushAccumulator() Flushes the bytes accumulated by the write(int) method.
void	write(byte[] ab, int ofb, int cb) Writes len bytes from the specified byte array starting at offset off to this output stream.
void	write(int b) Writes the specified byte to this output stream.

Methods inherited from class java.io.OutputStream

write

Methods inherited from interface com.tangosol.io.OutputStreaming

write

Field Detail

BASE64_ALPHABET

protected static final char[] BASE64_ALPHABET

Base64 encodes into this "alphabet" of 64 characters.

BASE64_PAD

protected static final char BASE64_PAD

The Base64 padding character. Base64 is encoded into 4-character chunks; if the last chunk does not contain 4 characters, it is filled with this padding character.

See Also:

Constant Field Values

BASE64_LF

protected static final char BASE64_LF

The Base64 line feed character. Base64 is encoded into 76-character lines unless .

See Also:

Constant Field Values

GROUPS_PER_LINE

protected static final int GROUPS_PER_LINE

The number of Base64 character groups in one line. This number prevents a line from exceeding 76 characters.

See Also:

Constant Field Values

m_fClosed

protected boolean m_fClosed

True after close is invoked.

m_writer

protected java.io.Writer m_writer

The Writer object to which the Base64 encoded data is written.

m_fBreakLines

protected boolean m_fBreakLines

True if lines are to be broken by BASE64_LF;

m_cLineGroups

protected int m_cLineGroups

The number of groups left to write in the current line.

m_abAccum

protected byte[] m_abAccum

Accumulated bytes.

m_cAccum

protected int m_cAccum

The number of bytes accumulated (0, 1, 2 or 3).

m_achGroup

protected char[] m_achGroup

An array that is used to send 4 characters at a time to the underlying Writer object.

Constructor Detail

Base64OutputStream

public Base64OutputStream(java.io.Writer writer)

Construct a Base64OutputStream on a Writer object.

Parameters:

writer - the Writer to write the Base64 encoded data to

Base64OutputStream

public Base64OutputStream(java.io.Writer writer,
                          boolean fBreakLines)

Construct a Base64OutputStream on a Writer object and specifying a line-break option.

Parameters:

writer - the Writer to write the Base64 encoded data to

fBreakLines - true to break the output into 76-character lines

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes the specified byte to this output stream.

Specified by:

write in interface OutputStreaming

Specified by:

write in class java.io.OutputStream

Parameters:

b - the byte.

Throws:

java.io.IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.

write

public void write(byte[] ab,
                  int ofb,
                  int cb)
           throws java.io.IOException

Writes len bytes from the specified byte array starting at offset off to this output stream.

If b is null, a NullPointerException is thrown.

If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown.

Specified by:

write in interface OutputStreaming

Overrides:

write in class java.io.OutputStream

Parameters:

ab - the data

ofb - the start offset in the data

cb - the number of bytes to write

Throws:

java.io.IOException - if an I/O error occurs. In particular, an IOException is thrown if the output stream is closed.

flush

public void flush()
           throws java.io.IOException

Close the stream, flushing any accumulated bytes. The underlying writer is not closed.

Specified by:

flush in interface OutputStreaming

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

Throws:

java.io.IOException - if an I/O error occurs

close

public void close()
           throws java.io.IOException

Close the stream, flushing any accumulated bytes. The underlying writer is not closed.

Specified by:

close in interface OutputStreaming

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException - if an I/O error occurs

flushAccumulator

protected void flushAccumulator()
                         throws java.io.IOException

Flushes the bytes accumulated by the write(int) method.

Throws:

java.io.IOException - if an I/O error occurs

encode

public static char[] encode(byte[] ab)

Encode the passed binary data using Base64 encoding.

Parameters:

ab - the array containing the bytes to encode

Returns:

the encoded data as a char array

encode

public static char[] encode(byte[] ab,
                            boolean fBreakLines)

Encode the passed binary data using Base64 encoding.

Parameters:

ab - the array containing the bytes to encode

fBreakLines - true to break the output into 76-character lines

Returns:

the encoded data as a char array

encode

public static char[] encode(byte[] ab,
                            int ofb,
                            int cb,
                            boolean fBreakLines)

Encode the passed binary data using Base64 encoding.

Parameters:

ab - the array containing the bytes to encode

ofb - the start offset in the byte array

cb - the number of bytes to encode

fBreakLines - true to break the output into 76-character lines

Returns:

the encoded data as a char array

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