org.firebirdsql.gds

Class VaxEncoding

java.lang.Object

org.firebirdsql.gds.VaxEncoding

public final class VaxEncoding
extends java.lang.Object

Helper methods for decoding Vax style (little endian) integers as used by Firebird from byte arrays.

Since:

3.0

Author:

Mark Rotteveel

Method Summary

Modifier and Type	Method and Description
static void	encodeVaxInteger(java.io.OutputStream stream, int value) Encodes an integer using vax encoding into the output stream, length prefix is included.
static void	encodeVaxInteger2WithoutLength(java.io.OutputStream stream, int value) Encodes an integer using two byte vax encoding into the output stream, without length prefix.
static void	encodeVaxIntegerWithoutLength(java.io.OutputStream stream, int value) Encodes an integer using vax encoding into the output stream, without length prefix.
static void	encodeVaxLong(java.io.OutputStream stream, long value) Encodes a long using vax encoding into the output stream, length prefix is included.
static void	encodeVaxLongWithoutLength(java.io.OutputStream stream, long value) Encodes a long using vax encoding into the output stream, without length prefix.
static int	iscVaxInteger(byte[] buffer, int startPosition, int length) Reads Vax style integers from the supplied buffer, starting at startPosition and reading for length bytes.
static int	iscVaxInteger2(byte[] buffer, int startPosition) Variant of iscVaxInteger(byte[], int, int) specifically for two-byte integers.
static long	iscVaxLong(byte[] buffer, int startPosition, int length) Reads Vax style integers from the supplied buffer, starting at startPosition and reading for length bytes.

Methods inherited from class java.lang.Object

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

Method Detail

iscVaxInteger

public static int iscVaxInteger(byte[] buffer,
                                int startPosition,
                                int length)

Reads Vax style integers from the supplied buffer, starting at startPosition and reading for length bytes.

This method is useful for lengths up to 4 bytes (ie normal Java integers (int). For larger lengths it will return 0. Use iscVaxLong(byte[], int, int) for reading values with length up to 8 bytes. For decoding 2 byte integers, use iscVaxInteger2(byte[], int) for optimal performance.

Parameters:

buffer - The byte array from which the integer is to be retrieved

startPosition - The offset starting position from which to start retrieving byte values

length - number of bytes to read

Returns:

The integer value retrieved from the bytes

See Also:

iscVaxLong(byte[], int, int), iscVaxInteger2(byte[], int)

encodeVaxInteger

public static void encodeVaxInteger(java.io.OutputStream stream,
                                    int value)
                             throws java.io.IOException

Encodes an integer using vax encoding into the output stream, length prefix is included.

Parameters:

stream - Output stream to write

value - Value to encode

Throws:

java.io.IOException

encodeVaxIntegerWithoutLength

public static void encodeVaxIntegerWithoutLength(java.io.OutputStream stream,
                                                 int value)
                                          throws java.io.IOException

Encodes an integer using vax encoding into the output stream, without length prefix.

Parameters:

stream - Output stream to write

value - Value to encode

Throws:

java.io.IOException

iscVaxLong

public static long iscVaxLong(byte[] buffer,
                              int startPosition,
                              int length)

Reads Vax style integers from the supplied buffer, starting at startPosition and reading for length bytes.

This method is useful for lengths up to 8 bytes (ie normal Java longs (long). For larger lengths it will return 0.

Parameters:

buffer - The byte array from which the integer is to be retrieved

startPosition - The offset starting position from which to start retrieving byte values

length - number of bytes to read

Returns:

The integer value retrieved from the bytes

See Also:

iscVaxInteger(byte[], int, int), iscVaxInteger2(byte[], int)

encodeVaxLong

public static void encodeVaxLong(java.io.OutputStream stream,
                                 long value)
                          throws java.io.IOException

Encodes a long using vax encoding into the output stream, length prefix is included.

Parameters:

stream - Output stream to write

value - Value to encode

Throws:

java.io.IOException

encodeVaxLongWithoutLength

public static void encodeVaxLongWithoutLength(java.io.OutputStream stream,
                                              long value)
                                       throws java.io.IOException

Encodes a long using vax encoding into the output stream, without length prefix.

Parameters:

stream - Output stream to write

value - Value to encode

Throws:

java.io.IOException

iscVaxInteger2

public static int iscVaxInteger2(byte[] buffer,
                                 int startPosition)

Variant of iscVaxInteger(byte[], int, int) specifically for two-byte integers.

Parameters:

buffer - The byte array from which the integer is to be retrieved

startPosition - The offset starting position from which to start retrieving byte values

Returns:

The integer value retrieved from the bytes

See Also:

iscVaxInteger(byte[], int, int), iscVaxLong(byte[], int, int)

encodeVaxInteger2WithoutLength

public static void encodeVaxInteger2WithoutLength(java.io.OutputStream stream,
                                                  int value)
                                           throws java.io.IOException

Encodes an integer using two byte vax encoding into the output stream, without length prefix.

Parameters:

stream - Output stream to write

value - Value to encode

Throws:

java.io.IOException