Package com.automation_pros.odva.cip.data

Class DataResolver

java.lang.Object

com.automation_pros.odva.cip.data.DataResolver

public class DataResolver
extends java.lang.Object

Data extraction helper, with support for selected transforms.

The class follows path segments into an array or structure or other base data instance, possibly concluding with a bit index.

A static method starts from a given CipTree instance.

Field Summary

Fields

Modifier and Type	Field	Description
int	bit	Bit index that applies to the subscripted element of data, or, if already a CipBOOL, the bit used to produce that CipBOOL.
PathSegment	bitHost	The selector that yielded a hosted bit.
BaseDataType<?>	data	Innermost data instance not including subscripts or any bit index.
BaseDataType<?>	data0	Outermost data instance.
BaseDataType<?>	data1	Fully subscripted/bit selected data instance.
int[]	dims	Dimensions of data extracted for convenience.
boolean	hasDebug
boolean	hasTrace
int[]	indices	Accumulated subscripts that apply to data.
protected BaseDataType<?>[]	indirectobjs	The indirection values that were extracted from the context at the indirection selectors encountered.
protected int[]	indirects	The nesting levels at which indirection selectors were encountered.
int	priorBytes	The number of bytes of bytes between the start of data0 and data.
java.lang.Long	unusedParasiteBits	When a hosted bit, holds the unused bits of that host.

Constructor Summary

Constructors

Constructor	Description
DataResolver(DataContext ctx, BaseDataType<?> root, java.util.List<PathSegment> path, int nesting)	Given a data element and a path containing zero or more selector segments, resolve the selectors to locate a specific subelement.

Method Summary

Modifier and Type	Method	Description
BaseDataType<?>	asSubscripted()	Obtain the data with the resolved indices encapsulated.
static DataResolver	follow(CipTree tree, java.util.List<PathSegment> path)	Follows a path into a CipTree hierarchy, and if it stops on a DataWrapper, continues drilling into that item's data.
static DataDefinitionSeg	followTransform(DataDefinitionSeg outer, PathSegment seg, DataContext ctx)	Helper that identifies supported transform symbols and returns the corresponding data type definition segment.
int	getOffset()	Obtain the resolved element's byte offset within the outermost data object's complete payload.
static boolean	isStringable(DataDefinitionSeg outer, DataContext ctx)	Helper that examines a data definition segment and determines if it is a structure that fits a Logix-style string type (.LEN and .DATA).
static void	main(java.lang.String[] args)
boolean	newSubscript()	Determine if any indirect subscript has changed in the path to the data.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

data0

public final BaseDataType<?> data0

Outermost data instance.

data

public BaseDataType<?> data

Innermost data instance not including subscripts or any bit index.

data1

public final BaseDataType<?> data1

Fully subscripted/bit selected data instance.

dims

public int[] dims

Dimensions of data extracted for convenience.

indices

public int[] indices

Accumulated subscripts that apply to data. These are always zero-based. Member offsets are applied as these are accumulated.

bit

public int bit

Bit index that applies to the subscripted element of data, or, if already a CipBOOL, the bit used to produce that CipBOOL.

bitHost

public PathSegment bitHost

The selector that yielded a hosted bit.

unusedParasiteBits

public java.lang.Long unusedParasiteBits

When a hosted bit, holds the unused bits of that host.

priorBytes

public int priorBytes

The number of bytes of bytes between the start of data0 and data. Updated whenever traversal follows a structure member.

indirects

protected int[] indirects

The nesting levels at which indirection selectors were encountered.

indirectobjs

protected BaseDataType<?>[] indirectobjs

The indirection values that were extracted from the context at the indirection selectors encountered. Always corresponds 1:1 with indirects.

hasDebug

public final boolean hasDebug

hasTrace

public final boolean hasTrace

Constructor Detail

DataResolver

public DataResolver(DataContext ctx,
                    BaseDataType<?> root,
                    java.util.List<PathSegment> path,
                    int nesting)

Given a data element and a path containing zero or more selector segments, resolve the selectors to locate a specific subelement.

Parameters:

ctx - The reference to use for indirect subscripts, if any

root - The starting data element

path - The selectors to follow

nesting - The number of leading segments to skip

Method Detail

follow

public static DataResolver follow(CipTree tree,
                                  java.util.List<PathSegment> path)

Follows a path into a CipTree hierarchy, and if it stops on a DataWrapper, continues drilling into that item's data.

Parameters:

tree -

path -

Returns:

isStringable

public static boolean isStringable(DataDefinitionSeg outer,
                                   DataContext ctx)

Helper that examines a data definition segment and determines if it is a structure that fits a Logix-style string type (.LEN and .DATA).

Parameters:

outer -

ctx -

Returns:

followTransform

public static DataDefinitionSeg followTransform(DataDefinitionSeg outer,
                                                PathSegment seg,
                                                DataContext ctx)

Helper that identifies supported transform symbols and returns the corresponding data type definition segment.

Parameters:

outer -

seg -

ctx -

Returns:

newSubscript

public boolean newSubscript()

Determine if any indirect subscript has changed in the path to the data.

Returns:

True if callers need to re-resolve the path.

getOffset

public int getOffset()

Obtain the resolved element's byte offset within the outermost data object's complete payload. Not valid when variable-length elements are prior to the resolved element, nor when accessing individual bits.

Returns:

Byte offset or -1 when invalid.

asSubscripted

public BaseDataType<?> asSubscripted()

Obtain the data with the resolved indices encapsulated. Needed to properly support assemblies containing elements of arrays or structures.

Returns:

A data item that is a view into the final resolved data item. If no indices nor bit number are present, then this will be the same object as returned in .data.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

main

public static void main(java.lang.String[] args)