SheetJS File Format Notes

Symbolic Link format

Files start with ID (0x49 0x44). Files are interpreted as plaintext in the system ANSI codepage.

This is a native file format of Multiplan and has been supported in all versions of Excel for Windows (to date). It is also used in the game “Warcraft III” and various mods including “Defense of the Ancients”.

Basics

Records

The file consists of a series of plaintext records. Records are separated by newline characters (both \r\n and \n newlines are accepted by newer versions of Excel, but generated files should prefer CRLF).

As stated in the Multiplan manual, “parsers must be prepared to ignore records and fields that they do not understand”. Loosely speaking, software can report error messages on each unsupported record but should read valid records.

Fields

A record consists of a record type and a series of fields. Each part of the record is separated by a single ; character.

The literal semicolon is encoded as two consecutive semicolons ;;. Example:

C;Y1;X1;K"abc;;def"

Global State

The Y and X fields set the current row / column before processing records. Parsing is stateful. Records that apply to a specific cell but do not have X or Y fields will use the global state:

F;M4;Y1;X1  <-- set current cell to A1
// current cell is A1
C;K"A1"     <-- set cell value to "A1"
F;M5;X2     <-- set current column to B (no Y -> row is unchanged)
// current cell is B1
C;K"C1";X3  <-- set current column to C, then assign value "C1"
// current cell is C1
C;K"C2";Y2  <-- set current row to 2, then assign value "C2"
// current cell is C2
F;M4        <-- set current cell style

This also means that records must be processed in order.

Encoding

In addition to the escaped semicolon, Excel understand two types of Encodings. They are not covered in the Multiplan documentation.

Raw Byte Trigrams

Trigrams matching the pattern \x1B[\x20-\x2F][\x30-\x3F] are decoded into a single byte whose high bits are taken from the second character and whose low bits are taken from the third character.

For example. "\x1B :" == "\x1B\x20\x3A encodes the byte "\x0A" (newline)

"\x1B#; encodes a literal semicolon.

Special Escapes

Excel also understands a set of special escapes that start with \x1BN. For clarity, the \x1BN part is not included in the table:

  0 1 2 3 4 5 6 7 8 9 A B C D E F
0_                                
1_                                
2_     * &       )           P    
3_                                
4_                                
5_                                
6_                                
7_                                
8_                         j      
9_                         z      
A_   ! " # ( %   ' H S c +     R  
B_ J 1 2 3 B 5 6 7   Q k ; < = > ?
C_ AA BA CA DA HA JA a KC AE BE CE HE AI BI CI HI
D_ b DN AO BO CO DO HO   i AU BU CU HU   l {
E_ Aa Ba Ca Da Ha Ja q Kc Ae Be Ce He Ai Bi Ci Hi
F_ s Dn Ao Bo Co Do Ho   y Au Bu Cu Hu   | Hy

For example, \x1BNj encodes byte 0x8C

Record Types

The following table lists the known record types.

Type Description Vintage
ID Header Multiplan
P Style Excel
F Format Multiplan
B Dimensions Multiplan
O Options Excel
NN Defined Name Multiplan
C Cell Multiplan
E EOF Multiplan
W Window Layout Multiplan
NE External Link Multiplan
NU Filename Substitution Multiplan
NL Chart External Link Excel

The supported fields for each type are listed in the relevant subsections. Excel supports every field that Multiplan supports.

Header (ID)

Files must start with the ID record.

Multiplan

The P field specifies the name of the program that generated the file. This record is not validated, although the typical value WXL is used in Excel.

Style (P)

Undocumented

The P record encodes data for multiple style tables, based on the fields. Each table is zero-indexed.

ID;PWXL;N;E
P;PGeneral
P;P0
P;P0.00
P;P#,##0

The 4 P records above are number format records. In the number format table, index 0 will be General, index 1 will be 0, etc.

Number Format Table

The P field indicates that the record specifies a number format. The value is an escaped number format similar to XLS encoding. ;; encodes a semicolon as used in a multi-part number format. For example:

P;P#,##0.00_);;[Red]\(#,##0.00\)

corresponds to the XLSX number format #,##0.00_);[Red]\(#,##0.00\)

Font Table

The four default fonts (normal, bold, italic, bold+italic) are specified with the F field. Other fonts are specified with the E field. It appears that Excel treats the fields as interchangeable, so either field type can be used.

Other supported fields are listed below:

Field Interpretation
F/E Font name
M Font size in twips
L Indexed color (from 1 to 64)
S Font Attributes (see table below)

The S field value is a list of attribute characters:

Value Interpretation
B Bold
I Italic
U Underline
S Strikeout

Format (F)

This record includes worksheet-level and cell-level formatting properties. The fields and interpretations vary based on position in the file.

Common Value Types

Multiplan “Cell Type” format codes:

Value Interpretation Multiplan name
D Default Def
C “Continuous” Cont
E Exponential Exp
F Fixed Point Fix
G General Gen
$ Currency Dollar
* Data Bar Cond Fmt Bar Graph
% Percentage Percent

Note that there is an error in the sylksum.doc documentation: C is a normal format (the spec claims it is “currency”)

Multiplan “Horizontal Alignment” format codes:

Value Interpretation XLS HorizAlign
D Default  
G General (text left, numbers right) 0x00 ALCGEN
L Left 0x01 ALCLEFT
C Center 0x02 ALCCTR
R Right 0x03 ALCRIGHT
X Fill 0x04 ALCFILL
- Unspecified 0xFF ALCNIL

Default Styling (immediately after P records)

The records in this area typically define high-level properties including the default format and column widths.

Field Interpretation
P# Default number format (index into table)
M# Default row height in twips
D_#_# Default cell type, decimals, horizontal alignment, column width

For example, the following record sets the default number format to index 0, the default cell type to “General”, the left cell alignment to left, the default column width to 8 characters, and the default row height to 32 pt:

F;P0;DG0L8;M640

Column Widths (immediately after O record)

The W field specifies widths for multiple columns and takes the form:

F;W# # # <-- 1-indexed start col, 1-indexed end col, width in characters

The first two parameters are the starting and ending column (1-indexed numbers) and the last parameter is the width as measured in characters. When specifying a single column width, the start and end should be equal:

F;W1 1 11 <-- column "A" is 11 characters wide
F;W2 3 6  <-- columns "B" and "C" are 6 characters wide

Cell Styling (interspersed with cell records)

Cell level styling is distinguished by the absence of the W, R, D and C fields or the presence of the X or Y fields.

X and Y fields modify the global state before applying formatting.

Field Interpretation
F_#_ Simple format: cell type, decimals, horizontal alignment
S... Style string (see below)
P# Number format (index into format table)

The style string can include the following attributes:

Value Interpretation
D Bold
I Italic
M# Font index
L Left Border
R Right Border
T Top Border
B Bottom Border
S Fill “gray125”

Row Heights and Styling (after column widths, before first cell of row)

The R field indicates that a format record applies to the specified row. In addition to the cell styling properties, the row height can be specified with the M field.

For example, the following record sets the height of row 5 to 19 pt and sets the font to index 78 of the font table:

F;R5;SM78;M380 <-- use index 78 of font table and set height to 19 pt for row 5

Column Styling (after column widths, before first cell of column)

The C field indicates that a format record applies to the specified column. As column widths are handled separately, the supported fields are identical to the cell-level styling fields:

F;C1;SM78 <-- use index 78 of font table for column 1 

Dimensions (B)

The bounds are not authoritative, and cells can exist outside of the range. As with XLSX/XLSB/XLS, Excel ignores this field and uses the actual cell records to determine the dimensions.

Multiplan

The Y and X fields specify the number of rows and columns respectively.

Undocumented

The D field specifies the worksheet dimensions, in the order r c R C with zero-indexed values. For example:

B;Y5;X3;D3 1 4 2

Multiplan will interpret the dimensions based on the Y and X field, assuming an origin of A1. This would be A1:C5 in the example.

Excel will use 3 1 4 2 which is B4:C5 (3 1 cell B4 and 4 2 cell E5)

Options (O)

This record includes a number of workbook-level settings

Excel

Field interpretations in quotes do not appear to be used in Excel 2019.

Field Interpretation
A# # XLS CalcIter / CalcDelta (enables iterative calculation)
C “Completion test at current cell”
P “Sheet is protected (but no password).”
L Use A1-style formulae (default is R1C1 formulae)
M Manual recalculation (XLS CalcMode 0)
R Precision as displayed (XLS CalcPrecision 0)
E “File is a macrosheet”

Undocumented

Field Interpretation
G# # XLS CalcIter / CalcDelta (does not enable iterative calculation)
V# Date system: (0 = 1900, 1/2/3/4 = 1904)
K# currently unknown (Value must be between 1 and 255)
D currently unknown
B currently unknown
S currently unknown (found in Warcraft III files)

Defined Name (NN)

The N field of the NN record is the name of the defined name.

The E field is the expression (interpreted as R1C1 or A1-style depending on the presence or absence of the L field in the O record.

NN;N_rng;ER4C3:R7C4            <-- name "_rng" reference to `$C$4:$D$7`
NN;N_arr;E{"a","b","c";;1,2,3} <-- name "_arr" excel array {"a","b","c";1,2,3}

Cell (C)

X and Y fields modify the global state before applying cell values.

The K field specifies the cell value. Numbers are specified as-is. Text should be wrapped in double quotes. Logical values are specified as TRUE/FALSE. Dates should be specified using the date codes after applying the appropriate number format (behavior identical to XLS):

ID;PWXL;N;E
P;PGeneral   <-- format 0 is "General"
P;Pm/d/yy    <-- format 1 specifies the default Date format
C;Y1;X1;K123 <-- set cell A1 value to the number 123
C;X2;K"123"  <-- set cell B1 value to the string "123"
C;X3;KTRUE   <-- set cell C1 value to the logical TRUE
F;Y2;P1      <-- move to cell C2, set number format to date
C;K44444     <-- set cell C2 value to the number 44444 (formatted date 9/5/21)
E

The E field specifies a formula. If the formula is included, it must be consistent with the worksheet expression style (A1 or R1C1) in the O record.

Comments

The A field of the C record can specify plaintext comments. They are encoded using the same text encoding in K fields.

C;Y4;X2;AHello! <-- sets comment on cell B4 to "Hello!"

comment.slk includes a few comments with newline encoding.

Shared Formulae

The S field of the C record signals that a cell is using a shared formula. The R and C fields are the 1-indexed row and column indices of the cell with the formula. The formula should be extracted from the original location and shifted to the current cell (relative references adjusted by the offset).

C;Y1;X1;K1          <-- cell A1=1
C;Y2;K2;ER[-1]C+1   <-- cell B1=A1+1 (both column and row relative)
C;Y3;K3;S;R2;C1     <-- cell C1=B1+1 (shifting formula from B1 +1 row)
C;X2;K3;S;R2;C1     <-- cell C2=B2+1 (shifting formula from B1 +1 row +1 col)

shared_formula.slk includes a few shared formulae.

EOF (E)

This must be the last record of the file. There are no fields.

References

The Multiplan manual (1982) includes an appendix covering the SYLK format.

sylksum.doc (1986) with author MCK, Microsoft was available on a Microsoft server. Public references to its existence date back to the 20th century.

Günter Born’s “The File Formats Handbook” expands upon sylksum.doc. While the core details are covered in official specs, the chart extension details are not covered in the public specifications.

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