Data Format Codes

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Data Format Codes

The data format codes are used in the OBJDESC.COMCOD, DESCRIP0.DATFMT, DESCRIP1.DESFMT, DESCRIP2.DESFMT, DESCRIP3.DESFMT, DESCRIP.DESFMT, PROCFORM.PRCFMT, PAKSPEC.DPAKFMT, PAKFORM.PAKFMT, and COMPFORM.COMPFMT record fields. These codes are integer values at least 32 bits long (because the codes are defined bit by bit, it is irrelevant whether these integers are considered to be signed or unsigned). The integer is expressed as a sequence of eight 4-bit nybbles, numbered from 0 to 7, the most significant nybble in the integer being number 0. The codes are structured in such a way that they can be interpreted by inspecting a hexadecimal printout.

The nybble specifications are as follows (LSB = Least Significant Bit, MSB = Most Significant Bit):

0 : Numeric types

1 : logical or Boolean

$\begin{picture}(40,2) \multiput(0,0)(5,0){9}{\line(0,1){2}} \put(0,2){\line(1,... ...){\makebox(5,2){false}} \multiput(25,0)(5,0){3}{\makebox(5,2){0}} \end{picture}$

size: 0 : same size as short integer
1 : same size as long integer
true-value: 0 : LSB is clear (0)
1 : LSB is set (1)
2 : MSB is set (1)
3 : MSB is clear (0)
false-value: 0 : LSB is clear (0)
1 : LSB is set (1)
2 : MSB is set (1)
3 : MSB is clear (0)

2 : byte

$\begin{picture}(40,2) \multiput(0,0)(5,0){9}{\line(0,1){2}} \put(0,2){\line(1,... ...0){\makebox(5,2){sign}} \multiput(15,0)(5,0){5}{\makebox(5,2){0}} \end{picture}$

sign: 0 : unsigned
1 : signed

3 : integer

$\begin{picture}(40,2) \multiput(0,0)(5,0){9}{\line(0,1){2}} \put(0,2){\line(1,... ...0){\makebox(5,2){size}} \multiput(20,0)(5,0){4}{\makebox(5,2){0}} \end{picture}$

sign: 0 : unsigned
1 : signed
size: 0 : short
1 : long

4 : floating-point

$\begin{picture}(40,2) \multiput(0,0)(5,0){9}{\line(0,1){2}} \put(0,2){\line(1,... ...0){\makebox(5,2){size}} \multiput(15,0)(5,0){5}{\makebox(5,2){0}} \end{picture}$

size: 0 : single precision
1 : double precision
2 : extended precision
3 : super-extended precision

5 : complex floating-point

$\begin{picture}(40,2) \multiput(0,0)(5,0){9}{\line(0,1){2}} \put(0,2){\line(1,... ...0){\makebox(5,2){size}} \multiput(15,0)(5,0){5}{\makebox(5,2){0}} \end{picture}$

size: 0 : single precision
1 : double precision
2 : extended precision
3 : super-extended precision

1 : Character types

Note that the string lengths given below include only the characters in the string proper, not including any header or trailer bytes.

0 : XDR string

$\begin{picture}(40,2) \multiput(0,0)(5,0){3}{\line(0,1){2}} \put(40,0){\line(0... ...ut(10,0){\makebox(30,2){maximum string\index{String type} length}} \end{picture}$

1 : fixed-length sequence of characters with no string length

$\begin{picture}(40,2) \multiput(0,0)(5,0){3}{\line(0,1){2}} \put(40,0){\line(0... ...0,0){\makebox(30,2){length of array or string\index{String type}}} \end{picture}$

2 : sequence of characters preceded by string length

$\begin{picture}(40,2) \multiput(0,0)(5,0){3}{\line(0,1){2}} \put(40,0){\line(0... ...ut(10,0){\makebox(30,2){maximum string\index{String type} length}} \end{picture}$

3 : sequence of characters followed by a null character

$\begin{picture}(40,2) \multiput(0,0)(5,0){3}{\line(0,1){2}} \put(40,0){\line(0... ...ut(10,0){\makebox(30,2){maximum string\index{String type} length}} \end{picture}$

4 : XDR counted string (IDL extension)

$\begin{picture}(40,2) \multiput(0,0)(5,0){3}{\line(0,1){2}} \put(40,0){\line(0... ...ut(10,0){\makebox(30,2){maximum string\index{String type} length}} \end{picture}$

2 : Structure types

$\begin{picture}(40,2) \multiput(0,0)(5,0){4}{\line(0,1){2}} \multiput(30,0)(5,... ...){\makebox(15,2){code}} \multiput(30,0)(5,0){2}{\makebox(5,2){0}} \end{picture}$

comp

number of components in the structure

code

unique code to identify the structure

0 :: a pair of bytes in (MSB, LSB) order which comprise a short integer
1 :: a quadruplet of long integers (used as nodes for AUDIT.TREE)

The following are common examples of the data format codes:

Hex

Decimal

01010000

16842752: logical with length of short integer (IDL logicals)
true = 1, false = 0

02000000

33554432: unsigned byte

02100000

34603008: signed byte

03000000

50331648: unsigned short integer

03100000

51380224: signed short integer

03010000

50397184: unsigned long integer

03110000

51445760: signed long integer

04000000

67108864: single precision floating-point

04100000

68157440: double precision floating-point

04200000

69206016: extended precision floating-point

05000000

83886080: single precision complex

05100000

84934656: double precision complex

05200000

85983232: extended precision complex

05300000

87031808: super-extended precision complex

10000001

268435457: XDR string, a maximum of one character long

10000050

268435536: XDR string, a maximum of 80 characters long

11000001

285212673: fixed-length string of 1 character

11000050

285212752: fixed-length string of 80 characters

13000050

318767184: Null-terminates string; max length is 80 characters

20200000

538968064: short integer (signed) from a 2-byte base (MSB,LSB)

20300100

540016896: four unsigned long integers (used as nodes in the AUDIT.TREE structure)

Next: Site Identifier Codes Up: Centrally Defined Codes Previous: Centrally Defined Codes Contents

Eric Nash 2003-09-25