MICROSOFT EXCEL BINARY FILE FORMAT          ----------------------------------       Mark O'Brien          Microsoft Corporation        18-Feb-1988Table of Contents-----------------  Introduction  General BIFF Record Format  Rows and Columns Within BIFF  Cell Table - Concepts  Cell Records  Record Types  Cell Attributes  Order of Records  Finding Values From BIFF Files  Excel Formulas  Expression Evaluation  Unary Operators  Binary Operators  Operand Tokens - Constant  Operand Tokens - Classes  Operand Tokens - Base  Control Tokens  Function Operators  Reserved Ptg's  Scanning a Parsed Expression  Excel Function Table  Command Equivalent Function Table  List of Ptg'sIntroduction------------  BIFF (BInary File Format) is the file format in which Excel  documents are saved on disk.  A BIFF file is a complete  description of an Excel document.  BIFF was designed to satisfy the following goals:   - Easy to understand and use   - Easy to expand the file format for future needs   - Files should save and load quickly  BIFF files consist of sequences of variable-length records.  There are many different types of BIFF records.  For example,  one record type describes a formula entered into a cell;  one describes the size and location of a window into a document;  another describes a picture format.General BIFF Record Format--------------------------  Although different BIFF record types contain different  information, every record follows the same basic format:   - Record type.  This tells us what kind of data     the record contains (e.g. a formula, a window, or     a picture format).   - Record length.  This tells us how long the data     contained in the record is.  The length of a record     depends on the type of data it contains.  For example,     a window record may always be the same length,     containing just the size and location of a window, while     a formula record varies in length, depending on the     length of the formula itself.   - Record data.  This is the variable-length portion of     the record containing the actual data.  All BIFF records are in the following format:   Offset     Length   Contents   ------     ------   --------   0   word    record type   2   word    length of data portion   4   varies     data portion of record  The data portion of a BIFF record must be no longer than 2080  bytes long.  Thus, counting the record type and length fields,  the maximum length of a BIFF record is 2084 bytes.  Within this document, all numbers are decimal numbers unless they are  preceded by "0x", in which case they are hexadecimal.  Some portions of BIFF records are marked as RESERVED.  These portions  are unavailable for application use.  If they are marked "RESERVED -  must be zero", then a BIFF-related application should ensure that  their contents are always filled with zeros. If they are marked  simply RESERVED, then they do not need to be set to any particular  value.Rows and Columns Within BIFF----------------------------  Within BIFF files, rows and columns are always stored zero-based,  rather than one-based as they appear on the screen.  For example,  cell A1 is stored as row 0, column 0; cell B3 is row 2, column 1.Cell Table - Concepts---------------------  Microsoft Excel uses a sparse cell table to reduce memory  requirements as much as possible.  Cells that don't have values or  formulas in them, have default format attributes, and are not  referenced in any other formulas, are undefined cells and do not  have any memory allocated for them.  For example, if a worksheet has a value in cell A3 and the formula  =A3+A4 in cell B10, then the only defined cells on the worksheet are  A3, A4, and B10.  No other cells need to exist.  Entire rows can be  undefined, if they have no defined cells in them.  In this case,  only rows 3, 4, and 10 are defined.Cell Records------------  The term "cell record" refers to a BIFF record that defines a  cell on an Excel document.  A cell record is one of the following  types:   BLANK   INTEGER   NUMBER   LABEL   BOOLERR   FORMULA  The following records can occur in conjunction with cell records:   CONTINUE   ARRAY   TABLE   TABLE2Record Types------------  Here are the record types defined in BIFF.  The record type  and record length fields have been omitted from the descriptions,  but they are present in every record.BOF record - beginning of file (type = 9)  Offset  Name    Size Contents  ------  ----    ---- --------  4   vers    2   version number  6   dt   2  document type          0x10 = worksheet          0x40 = macro sheet  Description   The BOF must be the first record in every BIFF file. The   version number for Excel documents is currently 2; Microsoft   may change this number in the future, as BIFF is modified for   future needs.   Currently defined version numbers are:      Value   Name    Meaning      -----   ----    -------      2   versExcel   Excel document      3   versMP   Multiplan document   All other version numbers are reserved for future use by   Microsoft.   The high byte of the version number contains flag bits.   Current flag values are:      Mask Name    Meaning      ---- ----    -------      0x0100  bitFMP   =1 if the BIFF file is a              Multiplan document      0xFE00      RESERVED for future use -           must be zeros   The dt field specifies whether the document is a worksheet or   a macro sheet.  Chart BIFF files are different and are not   described in this document.FILEPASS record - file password key (type = 47)  Description   The FILEPASS record is used for an Excel document which was   saved with a password in the File Save As command.  If this   record appears, it must directly follow the BOF record.  All   subsequent BIFF records will be encrypted, so you cannot read   a password-protected BIFF file.   Note that this record specifies a file password, as opposed   to the PASSWORD record, which specifies a document password.INDEX record - ROW record index (type = 11)  Offset  Name    Size Contents  ------  ----    ---- --------  4   ibRtName 4  absolute file position of the          first NAME record  8   rwMic    2  first row that exists          on the document  10  rwMac    2  last row that exists          on the document, plus 1  12  rgibRw   var array of absolute file positions          of the blocks of ROW records  Description   The INDEX record is used to optimize searching through a file   for a particular cell or name.  This record is optional; if   it occurs, it must occur directly after the document's   FILEPASS record.  If the document has no FILEPASS record,   then the INDEX record must occur directly after the BOF record.   The ibRtName field gives the absolute file offset (0 =   beginning of file) of the first NAME record.  rwMic and rwMac   are the range of defined rows in the document.  The rgibRw   field is an array of 4-byte absolute file offsets to the   document's ROW records.   Excel always writes an INDEX record when it saves a BIFF   file. If you are writing a BIFF file, you should probably not   attempt to write an INDEX record.   The INDEX record is explained more fully in the section   "Finding Values From BIFF Files."CALCCOUNT record - iteration count (type = 12)  Offset  Name    Size Contents  ------  ----    ---- --------  4   cIter    2  iteration count  Description   The CALCCOUNT record specifies the iteration count   as set in the Options Calculation command.CALCMODE record - calculation mode (type = 13)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fAutoRecalc  2  calculation mode          =0 for manual          =1 for automatic          =-1 for automatic, no tables  Description   The CALCMODE record specifies the calculation mode   as set in the Options Calculation command.PRECISION record - precision (type = 14)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fFullPrec   2   document precision          =1 for full precision          =0 for precision as displayed  Description   The PRECISION record specifies the precision   as set in the Options Calculation command.REFMODE record - reference mode (type = 15)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fRefA1   2  reference mode          =1 for A1 mode          =0 for R1C1 mode  Description   The REFMODE record specifies the reference mode   as set in the Options Desktop command.DELTA record - maximum iteration change (type = 16)  Offset  Name    Size Contents  ------  ----    ---- --------  4   numDelta 8  maximum change for iteration  Description   The DELTA record specifies the maximum change for an   iterative model, as set in the Options Calculation command.   The number is in 8-byte IEEE floating point format.ITERATION record - iteration flag (type = 17)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fIter    2  iteration flag          =1 for iteration on          =0 for iteration off  Description   The ITERATION record specifes the state of iteration   as set in the Options Calculation command.1904 record - date system (type = 34)  Offset  Name    Size Contents  ------  ----    ---- --------  4   f1904    2  =1 if the document uses the 1904             date system          =0 otherwise  Description   The 1904 record specifies the date system used in an Excel   document, as specified in the Options Calculation command.BACKUP record - file backup option (type = 64)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fBackupFile  2  =1 if Excel should save a backup             version of the file when it is             saved          =0 otherwise  Description   The BACKUP record specifies whether or not Excel should save   backup versions of a BIFF file, as specified in the "Create   Backup File" checkbox in the Save As dialog box.PRINT ROW HEADERS record - print row headers flag (type = 42)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fPrintRwCol  2  =1 if we should print row and             column headers when printing             the document          =0 otherwise  Description   The PRINT ROW HEADERS record controls whether or not Excel   prints row and column headers when printing the document.PRINT GRIDLINES record - print gridlines flag (type = 43)  Offset  Name    Size Contents  ------  ----    ---- --------  4   fPrintGrid  2   =1 if we should print gridlines             when printing the document          =0 otherwise  Description   The PRINT GRIDLINES record controls whether or not Excel   prints gridlines when printing the document.HORIZONTAL PAGE BREAKS record - row page breaks (type = 27)  Offset  Name    Size Contents  ------  ----    ---- --------  4   cbrk    2   number of page breaks  6   rgrw    var  array of rows  Description   The HORIZONTAL PAGE BREAKS record contains a list of explicit   row page breaks.  The cbrk field contains the number of page   breaks.  rgrw is an array of 2-byte integers specifying   rows.  Excel sets a page break before each row in the list.   The rows must be sorted in increasing order.VERTICAL PAGE BREAKS record - column page breaks (type = 26)  Offset  Name    Size Contents  ------  ----    ---- --------  4   cbrk    2   number of page breaks  6   rgcol    var array of columns  Description   The VERTICAL PAGE BREAKS record contains a list of explicit   column page breaks.  The cbrk field contains the number of   page breaks.  rgcol is an array of 2-byte integers specifying   columns.  Excel sets a page break before each column in the   list.  The columns must be sorted in increasing order.DEFAULT ROW HEIGHT record - default row height (type = 37)  Offset  Name    Size Contents  ------  ----    ---- --------  4   miyRwGhost  2   default row height  Description   The DEFAULT ROW HEIGHT record specifies the height of all   undefined rows in the document.  The miyRwGhost field   contains the row height in units of 1/20 of a point.   This record does not affect the row heights of any rows   that are explicitly defined.