FB_XmlControl Function Block

Organizes parsing and composing of XML data. Data can be treated as STRING or char array. Buffer size of file can be set via GVL_Param_TcUnit (xUnitBufferSize)

Variables

Name	Type	Default
`XmlBuffer`	FB_StreamBuffer
`TagListBuffer`	FB_StreamBuffer
`Tags`	T_MaxString
`TagListSeekBuffer`	FB_StreamBuffer
`TagsSeek`	STRING
`TagBuffer`	FB_StreamBuffer
`Tag`	T_MaxString
`TagOpen`	BOOL
`Select`	UDINT
`SearchPosition`	UDINT
`TAG_OPEN`	STRING(1)	`'<'`
`TAG_CLOSE`	STRING(1)	`'>'`
`END_TAG_CLOSE`	STRING(2)	`'/>'`
`SPACE`	STRING(1)	`' '`
`EQUALS`	STRING(1)	`'='`
`QUOTE`	STRING(1)	`'"'`
`BACK_SLASH`	STRING(1)	`'\'`
`FORWARD_SLASH`	STRING(1)	`'/'`
`OPEN_COMMENT`	STRING(5)	`'<!-- '`
`CLOSE_COMMENT`	STRING(4)	`' -->'`
`TAB`	STRING(2)	`'$T'`
`CR_LF`	STRING(4)	`'$R$N'`

Methods

ClearBuffer PUBLIC

Clears the contents of the entire buffer.

Implementation

SearchPosition := 0;
TagListSeekBuffer.Length := 0;
XmlBuffer.Length := 0;
TagsSeek := '';
Tag := '';

CloseTag PUBLIC

Closes a Tag: XML: <MyTag />'

Implementation

IF TagOpen THEN
    XmlBuffer.Append := END_TAG_CLOSE;
    Select := TagListBuffer.FindBack(SearchString := FORWARD_SLASH);
    ClosedTag := TagListBuffer.CutOff(StartPos := Select);
    TagOpen := FALSE;
ELSE
    Select := TagListBuffer.FindBack(SearchString := FORWARD_SLASH);
    ClosedTag := TagListBuffer.CutOff(StartPos := Select);
    XmlBuffer.Append := TAG_OPEN;
    XmlBuffer.Append := ClosedTag;
    XmlBuffer.Append := TAG_CLOSE;
END_IF

CloseTag := ClosedTag;

NewComment PUBLIC

Adds a comment XML:  XML.NewComment(Comment: = 'MyComment');

Parameters

Name	Type	Description
`Comment`	T_MaxString

Implementation

IF TagOpen THEN
    XmlBuffer.Append := TAG_CLOSE;
    TagOpen := FALSE;
END_IF;
XmlBuffer.Append := OPEN_COMMENT;
XmlBuffer.Append := Comment;
XmlBuffer.Append := CLOSE_COMMENT;

NewParameter PUBLIC

Must be called after opening a new tag XML.NewParameter(Name: = 'ParaName', Value: = 'Value');

Parameters

Name	Type	Description
`Name`	T_MaxString
`Value`	T_MaxString

Implementation

XmlBuffer.Append := SPACE;
XmlBuffer.Append := Name;
XmlBuffer.Append := EQUALS;
XmlBuffer.Append := QUOTE;
XmlBuffer.Append := Value;
XmlBuffer.Append := QUOTE;

NewTag PUBLIC

Creates a new Tag: XML: <MyTag> XML.NewTag(Name: = 'MyTag');

Parameters

Name	Type	Description
`Name`	T_MaxString

Implementation

IF TagOpen THEN
    XmlBuffer.Append := TAG_CLOSE;
END_IF;
XmlBuffer.Append := TAG_OPEN;
XmlBuffer.Append := Name;
TagOpen := TRUE;
TagListBuffer.Append := FORWARD_SLASH;
TagListBuffer.Append := Name;

NewTagData PUBLIC

Parameters

Name	Type	Description
`Data`	T_MaxString

Implementation

XmlBuffer.Append := TAG_CLOSE;
XmlBuffer.Append := Data;
TagOpen := FALSE;

SetBuffer PUBLIC

Parameters

Name	Type	Description
`PointerToBuffer`	POINTER TO BYTE	ADR(..)
`SizeOfBuffer`	UDINT	SIZEOF(..)

Implementation

XmlBuffer.SetBuffer(PointerToBufferAddress:= PointerToBuffer, SizeOfBuffer := SizeOfBuffer);
TagListBuffer.SetBuffer(PointerToBufferAddress := ADR(Tags), SizeOfBuffer := SIZEOF(Tags));
TagListSeekBuffer.SetBuffer(PointerToBufferAddress := ADR(TagsSeek), SizeOfBuffer := SIZEOF(TagsSeek));
TagBuffer.SetBuffer(PointerToBufferAddress := ADR(Tag), SizeOfBuffer := SIZEOF(Tag));

ToStartBuffer PUBLIC

Jump to the beginning of the XML data XML.ToStartBuffer();

Implementation

SearchPosition := 0;
TagListSeekBuffer.Length := 0;
TagsSeek := '';
Tag := '';

WriteDocumentHeader PUBLIC

Add your own preffered fileheader like: XML: <?xml version="1.0" encoding="UTF-8"?> Start with calling this method before appending any other tags! XML.WriteDocumentHeader('<?xml version="1.0" encoding="UTF-8"?>');

Parameters

Name	Type	Description
`Header`	T_MaxString

Implementation

XmlBuffer.Append := Header;

Properties

Length : UDINT GET

Declaration source

(*
    Organizes parsing and composing of XML data. Data can be treated as STRING or char array.
    Buffer size of file can be set via GVL_Param_TcUnit (xUnitBufferSize)
*)
FUNCTION_BLOCK FB_XmlControl
VAR
    XmlBuffer : FB_StreamBuffer;
    TagListBuffer : FB_StreamBuffer;
    Tags : T_MaxString;
    TagListSeekBuffer : FB_StreamBuffer;
    TagsSeek : STRING;
    TagBuffer : FB_StreamBuffer;
    Tag : T_MaxString;
    TagOpen: BOOL;
    Select : UDINT;
    SearchPosition : UDINT; 
END_VAR
VAR CONSTANT
    TAG_OPEN : STRING(1) := '<';
    TAG_CLOSE : STRING(1) := '>';
    END_TAG_CLOSE : STRING(2) := '/>';
    SPACE : STRING(1) := ' ';
    EQUALS : STRING(1) := '=';
    QUOTE : STRING(1) := '"';
    BACK_SLASH : STRING(1) := '\';
    FORWARD_SLASH : STRING(1) := '/';
    OPEN_COMMENT : STRING(5) := '<!-- ';
    CLOSE_COMMENT : STRING(4) := ' -->';
    TAB : STRING(2) := '$T';
    CR_LF : STRING(4) := '$R$N';

    // $OD : ASCII code for carriage return (CR)
    // $$ : to add a $R
    // $' : to add ' (apostrophe)
    // $L or $l : line feed
    // $N or $n : new line
    // $P or $p : next page
    // $R or $r : end of line
END_VAR