Package ucar.nc2.grib

Class GribNumbers

java.lang.Object

ucar.nc2.grib.GribNumbers

public final class GribNumbers
extends Object

Utilities for reading and interpreting GRIB bytes.

Field Summary

Fields

Modifier and Type	Field	Description
static int	MISSING	Grib uses this internally to mean missing
static int	UNDEFINED	If missing value is not defined use this value.
static double	UNDEFINEDD

Constructor Summary

Constructors

Constructor	Description
GribNumbers()

Method Summary

Modifier and Type	Method	Description
static int	convertSignedByte(byte v)	A signed byte has a sign bit then 1 15-bit value.
static int	convertSignedByte2(byte v)
static int	countBits(byte[] bitmap)
static float	float4(int a, int b, int c, int d)	Convert 4 bytes to a float.
static float	float4(RandomAccessFile raf)	Convert 4 bytes into a float value.
static int	int2(int a, int b)	convert 2 bytes to a signed integer.
static int	int2(RandomAccessFile raf)	Convert 2 bytes into a signed integer.
static int	int3(int a, int b, int c)	Convert 3 bytes to signed integer.
static int	int3(RandomAccessFile raf)	Convert 3 bytes into a signed integer.
static int	int4(int a, int b, int c, int d)	Convert 4 bytes into a signed integer.
static int	int4(RandomAccessFile raf)	Convert 4 bytes into a signed integer.
static long	int8(RandomAccessFile raf)	Convert 8 bytes into a signed long.
static boolean	isUndefined(double d)
static boolean	testBitIsSet(int value, int bit)	Test if the given bit is set in the test value.
static boolean	testGribBitIsSet(int value, int gribBitNumber)	Test if the given gribBitNumber is set in the test value.
static int	uint(RandomAccessFile raf)	Convert unsigned bytes into an integer.
static int	uint2(int a, int b)	convert 2 bytes to an unsigned integer.
static int	uint2(RandomAccessFile raf)	Convert 2 bytes into an unsigned integer.
static int	uint3(int a, int b, int c)	Convert 3 bytes into an unsigned int.
static int	uint3(RandomAccessFile raf)	Convert 3 bytes into an unsigned integer.

Methods inherited from class java.lang.Object

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

Field Detail

UNDEFINED

public static final int UNDEFINED

If missing value is not defined use this value.

See Also:

Constant Field Values

UNDEFINEDD

public static final double UNDEFINEDD

See Also:

Constant Field Values

MISSING

public static final int MISSING

Grib uses this internally to mean missing

See Also:

Constant Field Values

Constructor Detail

GribNumbers

public GribNumbers()

Method Detail

testGribBitIsSet

public static boolean testGribBitIsSet(int value,
                                       int gribBitNumber)

Test if the given gribBitNumber is set in the test value.

Parameters:

value - test the 8 bits in this value .

gribBitNumber - one based, starting from highest bit. Must be between 1-8.

Returns:

true if the given gribBitNumber is set.

testBitIsSet

public static boolean testBitIsSet(int value,
                                   int bit)

Test if the given bit is set in the test value.

Parameters:

value - test the 8 bits in this value .

bit - zero based, starting from highest bit. Must be between 0-7.

Returns:

true if the given bit is set.

isUndefined

public static boolean isUndefined(double d)

int2

public static int int2(RandomAccessFile raf)
                throws IOException

Convert 2 bytes into a signed integer.

Parameters:

raf - read from here

Returns:

integer value

Throws:

IOException - on read error

uint

public static int uint(RandomAccessFile raf)
                throws IOException

Convert unsigned bytes into an integer.

Parameters:

raf - read one byte from here

Returns:

integer value

Throws:

IOException - on read error

int2

public static int int2(int a,
                       int b)

convert 2 bytes to a signed integer.

Parameters:

a - first byte

b - second byte

Returns:

int

int3

public static int int3(RandomAccessFile raf)
                throws IOException

Convert 3 bytes into a signed integer.

Parameters:

raf - read from here

Returns:

integer value

Throws:

IOException - on read error

int3

public static int int3(int a,
                       int b,
                       int c)

Convert 3 bytes to signed integer.

Parameters:

a - first byte

b - second byte

c - third byte

Returns:

int

int4

public static int int4(RandomAccessFile raf)
                throws IOException

Convert 4 bytes into a signed integer.

Parameters:

raf - read from here

Returns:

integer value

Throws:

IOException - on read error

int4

public static int int4(int a,
                       int b,
                       int c,
                       int d)

Convert 4 bytes into a signed integer.

Parameters:

a - first byte

b - second byte

c - third byte

d - fourth byte

Returns:

int

uint2

public static int uint2(RandomAccessFile raf)
                 throws IOException

Convert 2 bytes into an unsigned integer.

Parameters:

raf - read from here

Returns:

integer value

Throws:

IOException - on read error

uint2

public static int uint2(int a,
                        int b)

convert 2 bytes to an unsigned integer.

Parameters:

a - first byte

b - second byte

Returns:

unsigned int

uint3

public static int uint3(RandomAccessFile raf)
                 throws IOException

Convert 3 bytes into an unsigned integer.

Parameters:

raf - read from here

Returns:

integer

Throws:

IOException - on read error

uint3

public static int uint3(int a,
                        int b,
                        int c)

Convert 3 bytes into an unsigned int.

Parameters:

a - first byte

b - second byte

c - third byte

Returns:

unsigned integer

float4

public static float float4(RandomAccessFile raf)
                    throws IOException

Convert 4 bytes into a float value.

Parameters:

raf - read from here

Returns:

float value

Throws:

IOException - on read error

float4

public static float float4(int a,
                           int b,
                           int c,
                           int d)

Convert 4 bytes to a float.

Parameters:

a - first byte

b - second byte

c - third byte

d - fourth byte

Returns:

float

int8

public static long int8(RandomAccessFile raf)
                 throws IOException

Convert 8 bytes into a signed long.

Parameters:

raf - RandomAccessFile

Returns:

long value

Throws:

IOException - on read error

convertSignedByte

public static int convertSignedByte(byte v)

A signed byte has a sign bit then 1 15-bit value. This is not twos complement (!)

Parameters:

v - convert byte to signed int

Returns:

signed int

convertSignedByte2

public static int convertSignedByte2(byte v)

countBits

public static int countBits(byte[] bitmap)