How to truncate hl7 fields according to schema

For those interested. We copied part of the validation check, and updated with some options to truncate as per the schema.

It can be called with:

set tSC = ##class(User.Hl7RangeCheck).RangeChk(.pRequest)

Include EnsHL7

Class User.Hl7RangeCheck
{ ClassMethod RangeChk(ByRef pMsg As EnsLib.HL7.Message) As %Status
{
#dim pIndex as %Integer = 1
Set tSC=$$$OK , tSC2=$$$OK, tSC1=$$$OK
for 
{
set pSeg = pMsg.GetSegmentAt(pIndex)
quit:($ZSTRIP(##class(%String).LogicalToDisplay(pSeg), "<>W" ) = "") quit:(pSeg.Name = "") //$$$ERROR($$$EnsErrGeneral, "Cannot validate segment schemas without a segment name. Unable to validate segment "_$get(pSegNum)_".")
set hasSegNum = 1 - ($get(pSegNum)="")
quit:(pSeg.DocTypeCategory = "") //$$$ERROR($$$EnsErrGeneral, "Cannot validate segment schemas without a category. Unable to validate segment "_$S(hasSegNum:pSegNum_":",1:"")_pSeg.Name_".")
quit:($get($$$vaSchemaGbl(pSeg.DocTypeCategory, "SS", pSeg.Name)) = "") //$$$ERROR($$$EnsErrGeneral, "Unable to retrieve the schema to validate segment against. Unable to validate segment "_$S(hasSegNum:pSegNum_":",1:"")_pSeg.Name_".")
set schema = $$$vaSchemaGbl(pSeg.DocTypeCategory, "SS", pSeg.Name)
for fieldNum=1:1:$listlength(schema)
{
quit:(fieldNum > pSeg.Count)
set fieldDat = pSeg.GetValueAt(fieldNum, pSeg.Separators, .tSC2)
if ($$$ISERR(tSC2))
{
set tSC = $$$ADDSC(tSC, $$$ERROR($$$EnsErrGeneral, "Unable to retrieve field "_fieldNum_" from segment "_$S(hasSegNum:pSegNum_":",1:"")_pSeg.Name_"."))
quit ; can only continue with this field if no error in getting it
}
set fieldSchema = $listget(schema, fieldNum)
if '(((pSeg.Name = "MSH") || (pSeg.Name = "BHS") || (pSeg.Name = "FHS")) && ((fieldNum = 1) || (fieldNum = 2)))
{
set dat = $tr(fieldDat, pSeg.Separators, "") ; remove separators from field
}
else 
{
set dat = fieldDat
}
set data = (dat '= "") ; is anything left?
if (data)
{
//if not data structures, components, subcomponents, datatypes, and/or code tables
if ($listget(fieldSchema, 1) = "")
{ set len = $length(fieldDat)
if (($listget(fieldSchema, 4) '= "") && (len > $listget(fieldSchema, 4))) ; over length restriction
{
if '(((pSeg.Name = "MSH") || (pSeg.Name = "BHS") || (pSeg.Name = "FHS")) && (fieldNum = 2))
{
for rep=1:1:($length(fieldDat, pSeg.RS))
{
if ($length($p(fieldDat, pSeg.RS, rep)) > $listget(fieldSchema, 4))
{ 
set tSC = pMsg.SetValueAt(..Truncate(pMsg.GetValueAt(pSeg.Name_":"_fieldNum_"("_rep_")"),$listget(fieldSchema, 4)) , pSeg.Name_":"_fieldNum_"("_rep_")")
}
}
} }
}
else 
{
k info
set info("SegName") = pSeg.Name , info("fieldNum") = fieldNum, info("sep") = pSeg.Separators
set (info("rep"), info("comp"), info("subComp")) = 1
set:(hasSegNum) info("SegNum") = pSegNum
set info("hasSegNum") = hasSegNum if ($listget(fieldSchema, 1) '= "") ; there is a data structure for the field
{
set dataStruct = $listget(fieldSchema, 1)
set tSC = ..ValidateFieldDataStructure(.pMsg,fieldDat, dataStruct, .info)
}
}
}
} set pIndex = pIndex+1
}
return tSC
} ClassMethod ValidateFieldDataStructure(ByRef pMsg As EnsLib.HL7.Message, field As %String, struct As %String, ByRef info) As %Status [ Internal ]
{
set tSC = $$$OK, error = 0
set category = $p(struct, ":", 1)
set dataStruct = $p(struct, ":", 2)
quit:((category = "") || (dataStruct = "")) $$$ERROR($$$EnsErrGeneral, "Cannot find schema for data structure "_struct_". Unable to validate segment "_$S($get(info("SegNum"))'="":info("SegNum")_":",1:"")_info("SegName")_" field "_info("fieldNum")_" against this structure.")
set structure = $get($$$vaSchemaGbl(category, "DT", dataStruct))
quit:('$data(structure)) $$$ERROR($$$EnsErrGeneral, "Cannot find schema for data structure "_struct_". Unable to validate segment "_$S(info("hasSegNum"):info("SegNum")_":",1:"")_info("SegName")_" field "_info("fieldNum")_" against this structure.") if '(((info("SegName") = "MSH") || (info("SegName") = "BHS") || (info("SegName") = "FHS")) && (info("fieldNum") = 2))
{
for info("rep") = 1:1:$length(field, $$$RSSEP(info("sep")))
 {
set repeat = $piece(field, $$$RSSEP(info("sep")), info("rep"))
for info("comp")=1:1:$length(repeat, $$$CSSEP(info("sep")))
{
quit:(info("comp") > $listlength(structure))
set component = $piece(repeat, $$$CSSEP(info("sep")), info("comp"))
set dat = $tr(component, $$$SSSEP(info("sep"))) ; remove separators from field
set data = (dat '= "") ; is anything left?
if (data)
{
set len = $length(component)
if (($listget($listget(structure, info("comp")),3)'="") && (len > $listget($listget(structure, info("comp")),3))) ; over length restriction
{ 
set tSC = pMsg.SetValueAt(..Truncate(component,$listget($listget(structure, info("comp")),3)), info("SegName")_":"_info("fieldNum")_"("_info("rep")_")"_"."_info("comp"))
}
}
}
}
}
Return tSC
} ClassMethod Truncate(pString As %String, pNum As %Integer) As %String
{
#dim tString As %String = pString If ($LENGTH(pString) > pNum)
{
Set tString = $EXTRACT(pString,1,pNum)
} Return tString
} }