org.vishia.util

Class ReadChars3Stream

java.lang.Object

org.vishia.util.ReadChars3Stream

public class ReadChars3Stream
extends java.lang.Object

This class helps to convert a special ASCII format in a byte[]. The input represents a 16-bit-word in memory with 3 chars.

The coding:

The first 2 chars contains bits 0..5 and bits 6..11. It is the (char - 0x30) & 0x3F. The last char contains bit 12..15, (char-0x30) & 0x0f. The bits (char-0x30)&x30 are a checksum over all other bits, with modulo 4. The value "&&&" marks the end of the stream.

This coding helps to transmit binary data with an ASCII medium.

At example "000" is the value 0, "@10" is the value 0x40. (bit 6=1).

Since:

created 1996, Java-source created 2009-09.

Constructor Summary

Constructors

Constructor and Description
ReadChars3Stream()

Method Summary

Modifier and Type	Method and Description
private static int	convert3Chars(java.lang.CharSequence s3, byte[] data, int ixData)
static java.lang.String	read(byte[] data, int idxStart, java.io.BufferedReader input) Reads 3-char coded input
static int[]	readNoExc(byte[] data, int idxStart, java.io.BufferedReader input) Reads 3-char coded input
static void	write(byte[] data, int from, int length, java.lang.Appendable out)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReadChars3Stream

public ReadChars3Stream()

Method Detail

read

public static java.lang.String read(byte[] data,
                                    int idxStart,
                                    java.io.BufferedReader input)
                             throws java.io.IOException

Reads 3-char coded input

Parameters:

data - Output array to write data.

idxStart - Start index in data to write

input - Input stream starting with a line containing 3-char-words. The terminated line should start with &&&.

Returns:

The following line after the byte data if there is a following line, elsewhere null.

Throws:

java.io.IOException - if any io-operation failed.

readNoExc

public static int[] readNoExc(byte[] data,
                              int idxStart,
                              java.io.BufferedReader input)
                       throws java.io.IOException

Reads 3-char coded input

Parameters:

data - Output array to write data.

idxStart - Start index in data to write

input - Input stream starting with a line containing 3-char-words. The terminated line should start with &&&.

Returns:

null if no error and the number of read bytes are exactly data.length. If not null, then [0] contains the number of read chars. More elements contains the positions of errors.

Throws:

java.io.IOException

convert3Chars

private static int convert3Chars(java.lang.CharSequence s3,
                                 byte[] data,
                                 int ixData)

write

public static void write(byte[] data,
                         int from,
                         int length,
                         java.lang.Appendable out)
                  throws java.io.IOException

Parameters:

data -

out -

Throws:

java.io.IOException