Add alternate XML format function for big files

Large XML files may cause memory errors with XSLT operations. Adding an alternate approach to simply replace the leading tabs with two spaces. This should allow the add-in to export even extremely large table data files as formatted XML. #389, fixes #474

Version Control.accda.src/modules/clsSourceParser.cls

@@ -940,8 +940,19 @@ Private Function SanitizeXML() As String
 
     Perf.OperationEnd
 
+    ' Check string length to determine which formatter to use.
+    ' (XSLT does a better job, but may fail on large sets of data)
+    If Len(strXML) < 30000 Then
+        ' Use XSLT to format the XML output.
+        this.strOutput = FormatXML(objXml)
+    Else
+        ' For very large XML strings like exporting data from large tables,
+        ' use an alternate simplified formatting function that avoids
+        ' the memory errors than can occur with XSLT.
+        this.strOutput = FormatXML2(objXml.XML)
+    End If
+
     ' Save the output
-    this.strOutput = FormatXML(objXml)
     SanitizeXML = this.strOutput
 
     ' Show stats if debug turned on.
@@ -1075,6 +1086,63 @@ Private Function FormatXML(objInput As MSXML2.DOMDocument60, _
 End Function
 
 
+'---------------------------------------------------------------------------------------
+' Procedure : FormatXML2
+' Author    : Adam Waller
+' Date      : 12/12/2023
+' Purpose   : Alternate approach to formatting XML for use in large data sets where
+'           : the XSL transformation may encounter memory errors.
+'---------------------------------------------------------------------------------------
+'
+Private Function FormatXML2(strInput As String) As String
+
+    Dim varLines As Variant
+    Dim varLine As Variant
+    Dim lngChar As Long
+
+    Perf.OperationStart "Format XML (alt)"
+
+    ' Split file into lines
+    varLines = Split(strInput, vbCrLf)
+
+    With New clsConcat
+        .AppendOnAdd = vbCrLf
+
+        ' Loop through lines
+        For Each varLine In varLines
+
+            ' Reset position
+            lngChar = 1
+
+            ' Loop through leading characters, watching for tabs.
+            Do While lngChar < Len(varLine)
+                ' See if this is
+                Select Case AscW(Mid(varLine, lngChar, 1))
+                    Case vbKeyTab   ' 9
+                        ' Increment tab counter
+                        lngChar = lngChar + 1
+                    Case Else
+                        ' Some other character.
+                        Exit Do
+                End Select
+            Loop
+
+            ' Add line with any indent
+            .Add Space$((lngChar - 1) * 2), Mid(varLine, lngChar)
+
+        Next varLine
+
+        ' Remove trailing vbCrLf and return result
+        .Remove 2
+        FormatXML2 = .GetStr
+
+    End With
+
+    Perf.OperationEnd
+
+End Function
+
+
 '---------------------------------------------------------------------------------------
 ' Procedure : Class_Terminate
 ' Author    : Adam Waller