org.apache.xerces.impl.io

Class UCSReader


public class UCSReader
extends Reader

Reader for UCS-2 and UCS-4 encodings. (i.e., encodings from ISO-10646-UCS-(2|4)).
Version:
$Id: UCSReader.java,v 1.5 2004/10/04 22:07:41 mrglavas Exp $
Author:
Neil Graham, IBM

Field Summary

static int
DEFAULT_BUFFER_SIZE
Default byte buffer size (8192, larger than that of ASCIIReader since it's reasonable to surmise that the average UCS-4-encoded file should be 4 times as large as the average ASCII-encoded file).
static short
UCS2BE
static short
UCS2LE
static short
UCS4BE
static short
UCS4LE
protected byte[]
fBuffer
Byte buffer.
protected short
fEncoding
protected InputStream
fInputStream
Input stream.

Constructor Summary

UCSReader(InputStream inputStream, int size, short encoding)
Constructs an ASCII reader from the specified input stream and buffer size.
UCSReader(InputStream inputStream, short encoding)
Constructs an ASCII reader from the specified input stream using the default buffer size.

Method Summary

void
close()
Close the stream.
void
mark(int readAheadLimit)
Mark the present position in the stream.
boolean
markSupported()
Tell whether this stream supports the mark() operation.
int
read()
Read a single character.
int
read(ch[] , int offset, int length)
Read characters into a portion of an array.
boolean
ready()
Tell whether this stream is ready to be read.
void
reset()
Reset the stream.
long
skip(long n)
Skip characters.

Field Details

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE
Default byte buffer size (8192, larger than that of ASCIIReader since it's reasonable to surmise that the average UCS-4-encoded file should be 4 times as large as the average ASCII-encoded file).
Field Value:
8192

UCS2BE

public static final short UCS2BE
Field Value:
2

UCS2LE

public static final short UCS2LE
Field Value:
1

UCS4BE

public static final short UCS4BE
Field Value:
8

UCS4LE

public static final short UCS4LE
Field Value:
4

fBuffer

protected byte[] fBuffer
Byte buffer.

fEncoding

protected short fEncoding

fInputStream

protected InputStream fInputStream
Input stream.

Constructor Details

UCSReader

public UCSReader(InputStream inputStream,
                 int size,
                 short encoding)
Constructs an ASCII reader from the specified input stream and buffer size. The Endian-ness and whether this is UCS-2 or UCS-4 needs also to be known in advance.
Parameters:
inputStream - The input stream.
size - The initial buffer size.
encoding - One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.

UCSReader

public UCSReader(InputStream inputStream,
                 short encoding)
Constructs an ASCII reader from the specified input stream using the default buffer size. The Endian-ness and whether this is UCS-2 or UCS-4 needs also to be known in advance.
Parameters:
inputStream - The input stream.
encoding - One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.

Method Details

close

public void close()
            throws IOException
Close the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

mark

public void mark(int readAheadLimit)
            throws IOException
Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation.
Parameters:
readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.

markSupported

public boolean markSupported()
Tell whether this stream supports the mark() operation.

read

public int read()
            throws IOException
Read a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.

Subclasses that intend to support efficient single-character input should override this method.

Returns:
The character read, as an integer in the range 0 to 127 (0x00-0x7f), or -1 if the end of the stream has been reached

read

public int read(ch[] ,
                int offset,
                int length)
            throws IOException
Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.
Parameters:
offset - Offset at which to start storing characters
length - Maximum number of characters to read
Returns:
The number of characters read, or -1 if the end of the stream has been reached

ready

public boolean ready()
            throws IOException
Tell whether this stream is ready to be read.
Returns:
True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

reset

public void reset()
            throws IOException
Reset the stream. If the stream has been marked, then attempt to reposition it at the mark. If the stream has not been marked, then attempt to reset it in some way appropriate to the particular stream, for example by repositioning it to its starting point. Not all character-input streams support the reset() operation, and some support reset() without supporting mark().

skip

public long skip(long n)
            throws IOException
Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.
Parameters:
n - The number of characters to skip
Returns:
The number of characters actually skipped

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