Difference between revisions of "SpreadsheetML"

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| Label ranges [[http://www.bettersolutions.com/excel/EFC133/LE824631331.htm reference]] || || skipped || MS Office 2007 seems to have dropped support for this feature.
| Label ranges [[http://www.bettersolutions.com/excel/EFC133/LE824631331.htm reference]] || || skipped || MS Office 2007 seems to have dropped support for this feature.
| Data validation || || ||
| Data validation || || on hold || requires formula parser.
| Web queries || || ||
| Web queries || || ||

Revision as of 19:48, 10 May 2007

SpreadsheetML is the XML format used by Microsoft Excel 2007 and that is part of the Office Open XML specification.

SpreadsheetML Basics


A SpreadsheetML document is described at the top level by a workbook part ( /xl/workbook.xml ). The type of the work book type is


The workbook part contains document's metadata and one or more sheets. Each sheet can be a worksheet, a chart sheet, or a dialog sheet.

Both strings and formulas are stored in shared tables to avoid redundant storage and speed file I/O's.

Sample Files

Convenient locations to download sample files are here

Implementation Strategy

Eventually, the code handling SpreadsheetML import will merge with the existing Excel binary filter. As such, the new code needs to be designed with this in mind. It's always desirable to understand how the existing binary filter works when implementing the XML filter to make the future merging work less painful.

Code Organization

Source files for handling the SpreadsheetML format are located in inc/oox/xls and source/xls under module oox. A good place to start tracing the code would be ExcelFilter::Import and follow the calls it makes.

A substream in the XML package is called "fragment", and each fragment has an associated *fragment.hxx header file. For instance, the code for loading of the workbook.xml fragment is found in workbookfragment.hxx, and so on.

A nested element is called "context", and, like the fragments, each context has an associated *context.hxx. For instance, the code for parsing the <sheetData> element is found in sheetdatacontext.hxx.

The term workbook in this context refers to an entire document which includes worksheets and other document metadata, whereas the term worksheet refers to each individual sheet in the workbook.

The existing binary Excel filter is located in sc/source/filter/(inc|excel)/xi(page|view).(c|h)xx. The XclImpTabViewSettings class handles importing sheet's view settings, which corresponds to worksheet/sheetViews context in the XML format.

The UNO interface code is found in sc/source/ui/uno.

Global data

Workbook-wide global data are stored in GlobalData (struct), and handled by GlobalDataHelper (class) which holds reference to the GlobalData instance. All major classes should be derived from GlobalDataHelper to ensure availability of globals in all places.

GlobalData holds reference to ImportBase instance in order to be able to create new fragment handlers.

Different buffers hold the imported data from the fragments if it is needed later, e.g. the SharedStringsBuffer (sharedstringsbuffer.hxx) and the StylesBuffer (stylesbuffer.hxx). These buffers are always part of the GlobalDataHelper.

GlobalDataHelper (class)

It's important to be familar with the member methods of this class, because they are also available in most of XLSX import classes.

Handling Fragment

WorkbookFragment (class)

Handles loading of workbook.xml fragment. It loads the associated relationship file (xl/_rels/workbook.xml.rels) in the constructor.

Handling Context

In most cases the fragment handler will handle all nested contexts by itself to increase performance. For this, some helper classes have been implemented that do all needed work to deal with nested contexts (ContextHelper, FragmentBase, and ContextBase respectively in contexthelper.hxx, excelfragmentbase.hxx, and excelcontextbase.hxx). In general, for implementing a new fragment or context handler, the interface of the ContextHelper class from contexthelper.hxx has to be implemented. The classes FragmentBase (excelfragmentbase.hxx) and ContextBase (excelcontextbase.hxx) already provide default implementations of all virtual functions, but a derived class is free to implement them as well.

Relation (class)

Holds three string data for ID, Type and Target (need more info).

AddressConverter (class)

converts strings to addresses and ranges, and tracks invalid addresses (e.g. a not-importable cell at address ZZZ1000000). Later, this information will be used to generate a "Imported document contains data outside of sheet limits" warning box after loading. Header: addressconverter.hxx

UnitConverter (class)

provides basic unit conversion, including font dependent stuff such as calculating column width from a specific number of characters. Header: unitconverter.hxx


Feature Developer Status Comments/Missing
Framework, fragment handling cl/dr done
Workbook, worksheet fragment, sheet names tbe/dr in progress do not insert default sheets (issue 74668)
Simple cell contents (values, strings) dr in progress error cells
Shared strings fragment dr done
Styles fragment dr done
Simple cell formatting (alignment, protection, borders, fill) dr done
Builtin number formats dr in progress missing locales (issue 29949)
Font handling for cells tbe/dr in progress asian/complex scripts (issue 74754)
Cell styles (names, formatting) dr done
Column settings (format, width, outlines) tbe/dr/kohei in progress outlines, hidden, column width from font (issue 75447)
Row settings (format, height, outlines) tbe/dr/kohei in progress outlines, hidden, row borders (issue 74667)
Rich text in cells dr done
Scheme fragment, scheme colors dr done
Cell formulas, array formulas jody in progress almost ready to be committed.
Conditional formatting jody/kohei on hold blocks on formula parser.
External references/links kohei in progress parsing of externalLink fragments complete. The external link information is stored in ::oox::xls::ExtRefBuffer.
Print ranges, builtin defined names jody/kohei on hold blocks on formula parser implementation because a defined name can be any cell formula.
Page/print settings kohei in progress waiting on header/footer task to be completed.
Header/footer kohei in progress Header/footer height calculation still pending.
Column/row breaks kohei done
Sheet/document view settings kohei in progress not possible to set view settings during import; probably needs to create a buffer class to store imported view settings, and apply them after the import.
Cell hyperlinks kohei done because a cell hyperlink is a in-cell text field object in Calc, as opposed to a cell property in Excel, a hyperlink will not get imported when the cell is a value cell.
Label ranges [reference] skipped MS Office 2007 seems to have dropped support for this feature.
Data validation on hold requires formula parser.
Web queries
Pivot tables kohei
Drawing objects sj/dr
Charts dr
OLE objects, form controls sj/dr
Auto filter, user filter
Change tracking

External References

  • xl/workbook.xml contains externalReference tags that references relationship items in xl/_rels/workbook.xml.rels by rID.
  • xl/_rels/workbook.xml.rels contains path(s) to external link fragments, that are usually xl/externalLinks/externalLink*.xml.
  • xl/externalLinks/externalLink*.xml contains summary content information of the external book being referenced. It should provide enough information to display external cell's content. It also contains reference to the path to the external file by rID.
  • xl/externalLinks/_rels/externalLink*.xml.rels contains the path to the external file, stored by rID.

Inside a cell that contains an external cell reference, the format is given


as formula.

Page Settings

Refer to class XclPageData which is the data structure used by the existing binary filter. Here is the page for Calc's sheet properties.

See Also

  • sc module page for the implementation of Calc core.
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