org.opennms.protocols.snmp.asn1

Class BerEncoder

java.lang.Object

org.opennms.protocols.snmp.asn1.BerEncoder

All Implemented Interfaces:

AsnEncoder

public class BerEncoder
extends java.lang.Object
implements AsnEncoder

The BerEncoder class is used to implement the AsnEncoder interface for the Basic Encoding Rules (BER). The encoding rules are used to encode and decode SNMP values using BER.

Version:

1.1.1.1

Author:

OpenNMS, Brian Weaver

Field Summary

Fields

Modifier and Type	Field and Description
private static byte	CONSTRUCTOR Defines the BER constructor id
private static byte	EXTENSION_ID Defines the BER extension "value" that is used to mark an extension type.
private static byte	HIGH_BIT Defines the "high bit" that is the sign extension bit for a 8-bit signed value.
private static byte	LONG_LENGTH Defines the ASN.1 long length marker for the Basic Encoding Rule (BER)

Constructor Summary

Constructors

Constructor and Description
BerEncoder()

Method Summary

Methods

Modifier and Type	Method and Description
int	buildHeader(byte[] buf, int startOffset, byte asnType, int asnLength) The buildHeader() method is used to encode an ASN.1 header into the specified byte buffer.
int	buildInteger32(byte[] buf, int startOffset, byte asnType, int asnInt32) The buildInteger32() method is used to encode an ASN.1 32-bit signed integer into the specified byte buffer.
int	buildLength(byte[] buf, int startOffset, int asnLength) The buildLength() method is used to encode an ASN.1 length into the specified byte buffer.
int	buildNull(byte[] buf, int startOffset, byte asnType) The buildNull() method is used to encode an ASN.1 NULL value into the specified byte buffer.
int	buildObjectId(byte[] buf, int startOffset, byte asnType, int[] oids) The buildObjectId() method is used to encode an ASN.1 object id value into the specified byte buffer.
int	buildString(byte[] buf, int startOffset, byte asnType, byte[] opaque) The buildString() method is used to encode an ASN.1 string value into the specified byte buffer.
int	buildUInteger32(byte[] buf, int startOffset, byte asnType, long asnUInt32) The buildUInteger32() method is used to encode an ASN.1 32-bit unsigned integer into the specified byte buffer.
int	buildUInteger64(byte[] buf, int startOffset, byte asnType, java.math.BigInteger asnUInt64) The buildUInteger64() method is used to encode an ASN.1 64-bit unsigned integer into the specified byte buffer.
protected static int	byteToInt(byte b) Converts a primitive byte to a primitive long using "unsigned" logic.
protected static long	byteToLong(byte b) Converts a primitive byte to a primitive long.
protected static boolean	isConstructor(byte b) Used to determine if the ASN.1 type is a constructor.
protected static boolean	isExtensionId(byte b) Used to test if the ASN.1 type is an extension.
java.lang.Object[]	parseHeader(byte[] buf, int startOffset) The parseHeader() method is used to decode an ASN.1 header from the specified buffer.
java.lang.Object[]	parseInteger32(byte[] buf, int startOffset) The parseInteger32() method is used to decode an ASN.1 32-bit signed integer from the specified buffer.
java.lang.Object[]	parseLength(byte[] buf, int startOffset) The parseLength() method is used to decode an ASN.1 length from the specified buffer.
java.lang.Object[]	parseNull(byte[] buf, int startOffset) The parseNull() method is used to decode an ASN.1 Null value from the specified buffer.
java.lang.Object[]	parseObjectId(byte[] buf, int startOffset) The parseObjectId() method is used to decode an ASN.1 Object Identifer from the specified buffer.
java.lang.Object[]	parseString(byte[] buf, int startOffset) The parseString() method is used to decode an ASN.1 opaque string from the specified buffer.
java.lang.Object[]	parseUInteger32(byte[] buf, int startOffset) The parseUInteger32() method is used to decode an ASN.1 32-bit unsigned integer from the specified buffer.
java.lang.Object[]	parseUInteger64(byte[] buf, int startOffset) The parseUInteger64() method is used to decode an ASN.1 64-bit unsigned integer from the specified buffer.
protected static void	rotate(byte[] buf, int begin, int pivot, int end) Rotates a give buffer area marked by begin, pivot, and end.

Methods inherited from class java.lang.Object

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

Field Detail

LONG_LENGTH

private static final byte LONG_LENGTH

Defines the ASN.1 long length marker for the Basic Encoding Rule (BER)

See Also:

Constant Field Values

HIGH_BIT

private static final byte HIGH_BIT

Defines the "high bit" that is the sign extension bit for a 8-bit signed value.

See Also:

Constant Field Values

EXTENSION_ID

private static final byte EXTENSION_ID

Defines the BER extension "value" that is used to mark an extension type.

See Also:

Constant Field Values

CONSTRUCTOR

private static final byte CONSTRUCTOR

Defines the BER constructor id

See Also:

Constant Field Values

Constructor Detail

BerEncoder

public BerEncoder()

Method Detail

byteToInt

protected static int byteToInt(byte b)

Converts a primitive byte to a primitive long using "unsigned" logic.

Parameters:

b - The 8-bit value to convert

Returns:

Returns the 32-bit converted value

byteToLong

protected static long byteToLong(byte b)

Converts a primitive byte to a primitive long. The byte is converted using "unsigned" logic

Parameters:

b - The 8-bit value to convert

Returns:

Returns the 64-bit converted value

isConstructor

protected static boolean isConstructor(byte b)

Used to determine if the ASN.1 type is a constructor.

Parameters:

b - The ASN.1 type

Returns:

True if the ASN.1 type is a constructor, otherwise a false is returned.

isExtensionId

protected static boolean isExtensionId(byte b)

Used to test if the ASN.1 type is an extension.

Parameters:

b - The ASN.1 type.

Returns:

True if the ASN.1 type is an extension. False if the ASN.1 type is not an extension.

rotate

protected static void rotate(byte[] buf,
          int begin,
          int pivot,
          int end)
                      throws java.lang.ArrayIndexOutOfBoundsException

Rotates a give buffer area marked by begin, pivot, and end. The pivot marks the point where the bytes between [pivot..end) are moved to the position marked by begin. The bytes between [begin..pivot) are shifted such that begin is at [begin+(end-pivot)].

Parameters:

buf - The buffer containing the data to rotate

begin - The start of the rotation

pivot - The pivot point for the rotation

end - The end of the rotational buffer

Throws:

java.lang.ArrayIndexOutOfBoundsException - Thrown if an access exception occurs

buildLength

public int buildLength(byte[] buf,
              int startOffset,
              int asnLength)
                throws AsnEncodingException

The buildLength() method is used to encode an ASN.1 length into the specified byte buffer. The method is defined in the AsnEncoder interface.

Specified by:

buildLength in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnLength - The length to be encoded.

Returns:

Returns the new offset for the next encoding routine. If the startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseLength

public java.lang.Object[] parseLength(byte[] buf,
                             int startOffset)
                               throws AsnDecodingException

The parseLength() method is used to decode an ASN.1 length from the specified buffer. The method is defined to support the AsnEncoder interface.

Specified by:

parseLength in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset and the decoded length. The first object is an Integer object and contains the new offset for the next object in buf. The second object is an Integer and contains the actual decoded length.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildHeader

public int buildHeader(byte[] buf,
              int startOffset,
              byte asnType,
              int asnLength)
                throws AsnEncodingException

The buildHeader() method is used to encode an ASN.1 header into the specified byte buffer. The method is defined to support the AsnEncoder interface. This method is dependant on the buildLength() method.

Specified by:

buildHeader in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

asnLength - The length to be encoded.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseHeader

public java.lang.Object[] parseHeader(byte[] buf,
                             int startOffset)
                               throws AsnDecodingException

The parseHeader() method is used to decode an ASN.1 header from the specified buffer. The method is defined to support the AsnEncoder interface. The method also calls the parseLength() method.

Specified by:

parseHeader in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset, ASN.1 type, and decoded length. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is an Integer and contains the actual decoded length.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildInteger32

public int buildInteger32(byte[] buf,
                 int startOffset,
                 byte asnType,
                 int asnInt32)
                   throws AsnEncodingException

The buildInteger32() method is used to encode an ASN.1 32-bit signed integer into the specified byte buffer.

Specified by:

buildInteger32 in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

asnInt32 - The 32-bit signed integer to encode.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseInteger32

public java.lang.Object[] parseInteger32(byte[] buf,
                                int startOffset)
                                  throws AsnDecodingException

The parseInteger32() method is used to decode an ASN.1 32-bit signed integer from the specified buffer.

Specified by:

parseInteger32 in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset, ASN.1 type, and value. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is an Integer and contains the actual decoded value.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildUInteger32

public int buildUInteger32(byte[] buf,
                  int startOffset,
                  byte asnType,
                  long asnUInt32)
                    throws AsnEncodingException

The buildUInteger32() method is used to encode an ASN.1 32-bit unsigned integer into the specified byte buffer.

Specified by:

buildUInteger32 in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

asnUInt32 - The 32-bit unsigned integer to encode.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseUInteger32

public java.lang.Object[] parseUInteger32(byte[] buf,
                                 int startOffset)
                                   throws AsnDecodingException

The parseUInteger32() method is used to decode an ASN.1 32-bit unsigned integer from the specified buffer.

Specified by:

parseUInteger32 in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset, ASN.1 type, and value. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is a Long object and contains the actual decoded value.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildUInteger64

public int buildUInteger64(byte[] buf,
                  int startOffset,
                  byte asnType,
                  java.math.BigInteger asnUInt64)
                    throws AsnEncodingException

The buildUInteger64() method is used to encode an ASN.1 64-bit unsigned integer into the specified byte buffer.

Specified by:

buildUInteger64 in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

asnUInt64 - The 64-bit unsigned integer to encode.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseUInteger64

public java.lang.Object[] parseUInteger64(byte[] buf,
                                 int startOffset)
                                   throws AsnDecodingException

The parseUInteger64() method is used to decode an ASN.1 64-bit unsigned integer from the specified buffer.

Specified by:

parseUInteger64 in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset, ASN.1 type, and value. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is a Long object and contains the actual decoded value.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildNull

public int buildNull(byte[] buf,
            int startOffset,
            byte asnType)
              throws AsnEncodingException

The buildNull() method is used to encode an ASN.1 NULL value into the specified byte buffer.

Specified by:

buildNull in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseNull

public java.lang.Object[] parseNull(byte[] buf,
                           int startOffset)
                             throws AsnDecodingException

The parseNull() method is used to decode an ASN.1 Null value from the specified buffer. Since there is no "null" value only the new offset and ASN.1 type are returned.

Specified by:

parseNull in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset and the ASN.1 type. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildString

public int buildString(byte[] buf,
              int startOffset,
              byte asnType,
              byte[] opaque)
                throws AsnEncodingException

The buildString() method is used to encode an ASN.1 string value into the specified byte buffer.

Specified by:

buildString in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

opaque - An array of bytes to encode into the string.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseString

public java.lang.Object[] parseString(byte[] buf,
                             int startOffset)
                               throws AsnDecodingException

The parseString() method is used to decode an ASN.1 opaque string from the specified buffer.

Specified by:

parseString in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset and ASN.1 type, and byte array. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is an array of primitive bytes.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.

buildObjectId

public int buildObjectId(byte[] buf,
                int startOffset,
                byte asnType,
                int[] oids)
                  throws AsnEncodingException

The buildObjectId() method is used to encode an ASN.1 object id value into the specified byte buffer.

Specified by:

buildObjectId in interface AsnEncoder

Parameters:

buf - The output buffer of encoded bytes.

startOffset - The offset from the start of the buffer where the method should start writing the encoded data.

asnType - The ASN.1 type to place in the buffer

oids - An array of integers to encode.

Returns:

Returns the new offset for the next encoding routine. If startOffset is subtracted from the return value then the length of the encoded data can be determined.

Throws:

AsnEncodingException - Thrown if an error occurs encoding the datatype.

parseObjectId

public java.lang.Object[] parseObjectId(byte[] buf,
                               int startOffset)
                                 throws AsnDecodingException

The parseObjectId() method is used to decode an ASN.1 Object Identifer from the specified buffer.

Specified by:

parseObjectId in interface AsnEncoder

Parameters:

buf - The input buffer

startOffset - The offset to start decoding in the buffer

Returns:

Returns an Object array that contains the new offset and ASN.1 type, and ObjectId array. The first object is an Integer object and contains the new offset for the next object in buf. The second object is a Byte object that represents the decoded ASN.1 Type. The third object is an array of primitive integers.

Throws:

AsnDecodingException - Thrown if an error occurs decoding the buffer.