com.objsys.asn1j.runtime

Class Asn1NasUtil

java.lang.Object

com.objsys.asn1j.runtime.Asn1NasUtil

public class Asn1NasUtil
extends java.lang.Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Asn1NasUtil.ARFCNRange

Field Summary

Fields

Modifier and Type	Field and Description
static int	FREQ_LIST_FMT_BITMAP0 Enumeration of the formats supported for ARFCN encoding.
static int	FREQ_LIST_FMT_RANGE_1024
static int	FREQ_LIST_FMT_RANGE_128
static int	FREQ_LIST_FMT_RANGE_256
static int	FREQ_LIST_FMT_RANGE_512
static int	FREQ_LIST_FMT_VAR_BITMAP

Constructor Summary

Constructors

Constructor and Description
Asn1NasUtil()

Method Summary

Modifier and Type	Method and Description
static int[]	decodeARFCN(int format, byte[] data, int numbits) Decode a list of ARFCN (frequency list) that have been encoded as described in 44.018 10.5.2.13 Frequency List and Annex J.
static void	encodeARFCN(int[] arfcns, int format, int range, int f0, Asn1BitString data) Encode a list of ARFCN (frequency list).
static Asn1NasUtil.ARFCNRange	getARFCNRange(int[] arfcns) Determines the minimum range for the given list of ARFCNs according to 44.018 Annex F.

Methods inherited from class java.lang.Object

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

Field Detail

FREQ_LIST_FMT_BITMAP0

public static final int FREQ_LIST_FMT_BITMAP0

Enumeration of the formats supported for ARFCN encoding. These correspond to the formats described in 44.018 for the Frequency List IE and in Appendix J.

See Also:

Constant Field Values

FREQ_LIST_FMT_RANGE_1024

public static final int FREQ_LIST_FMT_RANGE_1024

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Constant Field Values

FREQ_LIST_FMT_RANGE_512

public static final int FREQ_LIST_FMT_RANGE_512

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Constant Field Values

FREQ_LIST_FMT_RANGE_256

public static final int FREQ_LIST_FMT_RANGE_256

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Constant Field Values

FREQ_LIST_FMT_RANGE_128

public static final int FREQ_LIST_FMT_RANGE_128

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Constant Field Values

FREQ_LIST_FMT_VAR_BITMAP

public static final int FREQ_LIST_FMT_VAR_BITMAP

See Also:

Constant Field Values

Constructor Detail

Asn1NasUtil

public Asn1NasUtil()

Method Detail

decodeARFCN

public static int[] decodeARFCN(int format,
                                byte[] data,
                                int numbits)

Decode a list of ARFCN (frequency list) that have been encoded as described in 44.018 10.5.2.13 Frequency List and Annex J.

Parameters:

format - The format in which the ARFCNs have been encoded. One of the FREQ_LIST_FMT_* constants.

data - The encoding of the ARFCNs. This only includes the bits that actually encode the ARFCNs and not the bits that indicate the choice of the format. For example, in the Frequency List IE, format range 1024, data begins with bit 3 of octet 3.

numbits - The number of bits to be decoded.

Returns:

A a newly allocated array, holding the ARFCN values.

encodeARFCN

public static void encodeARFCN(int[] arfcns,
                               int format,
                               int range,
                               int f0,
                               Asn1BitString data)

Encode a list of ARFCN (frequency list). The given ARFCNs will be encoded as described in 44.018 10.5.2.13 Frequency List and Annex J. The encoding of the ARFCNs is set into the given Asn1BitString, data. If data's byte array is too small, a new array of the correct size is created. In some cases, ARFCNs are encoded into a fixed number of bits (e.g. Cell Channel Description). In such cases, size the array to that size before calling this method, and then set numbits to the fixed size after calling this method. If necessary, ensure the extra bits are zeroed. Let usedOctets be the actual number of octets used. Then data.numbits will be set to the following value, depending on the format: format value of data.numbits ------------ ---------------- bitmap0 usedOctets * 8 - 4 range 1024 usedOctets * 8 - 5 range 512 usedOctets * 8 - 7 range 256 usedOctets * 8 - 7 range 128 usedOctets * 8 - 7 var bitmap usedOctets * 8 - 7 These values of numbits are designed so that the resulting bit string will align to a byte boundary given the known offset that the string will begin at in the overall encoding of the containing IE (e.g. to make the entire Frequency List IE be a multiple of 8 bits). Any of the numbits bits that are not actually needed to encode the given list of ARFCNs in the given format will be set to 0.

Parameters:

arfcns - Array of ARFCNs to be encoded. The values must be distinct. Their ordering does not matter.

format - The format to apply to the encoding. One of the FREQ_LIST_FMT_* constants. It is an error if the given ARFCNs cannot be encoded in the given format. For bitmap0, all ARFCNs must be in the range 1..124. For range formats 512, 256, and 128, the ARFCNs have a corresponding minimum range of less than or equal to 512, 256, and 128, respectively.

range - The minimum range of the given arfcns. The minimum range R is the smallest value such that there is some value in the set, F0, such that every value in the set can be expressed as: (F0 + N) % 1024 for some N in [0, R-1] getARFCNRange can be used to obtain the minimum range and a value for F0. This argument is not used for format bitmap0.

f0 - An ARFCN from the list serving as F0 for the given range. This argument is not used for format bitmap0.

data - Receives the encoded ARFCNs (includes the F0/orig_arfcn fields.)

getARFCNRange

public static Asn1NasUtil.ARFCNRange getARFCNRange(int[] arfcns)

Determines the minimum range for the given list of ARFCNs according to 44.018 Annex F. Each ARFCN must be unique and less than 1024. The range of an empty list of ARFCNs is 0.

Parameters:

arfcns - array of ARFCNs

Returns:

Returns an ARFCNRange with: f0, and ARFCN from the array to use as F0. range, The minimum range. A value chosen such that all ARFCNs in the array satisfy: arfcn = (F0 + N ) mod 1024 for some N in [0, range-1]