STAF - Data Structures or Tables

  Data communication between the PAMs and STAF and between the PAMs is handled by way of defined data structures which are called tables. These are defined as variable length arrays of C-structs using C/C++ structure definitions. In STAF we deal with two distinct table entities: (1) table types, which are defined in idl files having the same name as the table, in the PKG/inc subdirectory or at run time using TDM, and (2) tables themselves. You can have as many tables of a given type as you like. They can even have the same name if they are in different datasets (directories).

The table type and table feature of STAF permits repetitive use of previously defined table types for specific, run time applications. An example of this would be a single TPC pixel table type for one super-sector with 24 tables for each of the 24 TPC super-sectors. Tables may be created and placed in the same or in different STAF datasets, provided the usual precautions are taken to avoid naming conflicts.

Table type idl definition files are located in the PKG/inc subdirectories for SL97b. The maximum number of rows (memory allocation) and the number of rows actually used during processing may be set or changed (increased or decreased) during run time either using the TDM ASP commands or using programming statements in the PAM source code. The necessary Fortran include files and the C/C++ *.h files for these structures are generated automatically by the STAR Library make procedures.

The most common method in STAF for defining table types is with the table idl file. See for example the TPC track table type definition tpt_track.idl. The table idl files contain the filename identifier and other comments, followed by the declaration and definitions of variables. Note in the example that one-dimensional arrays are allowed and how these are declared. Table types are public and may be used by any other PKG in the STAR Library.

Table types may be declared in STAR at run time using the tdm/newtable command. When this ASP is used to declare a new table type the variable declarations are embedded in the command line. Examples of these commands are given in the following tutorials.

The list of allowed variable types in STAF SL97b are:

   IDL             ANSI-C          C++               FORTRAN 77
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   short           short           short             INTEGER*2
   unsigned short  unsigned short  unsigned short    INTEGER*2
   long            long            long              INTEGER*4
   unsigned long   unsigned long   unsigned long     INTEGER*4
   char            char            char              CHARACTER*1
   octet           unsigned char   unsigned char     LOGICAL*1
   float           float           float             REAL*4
   double          double          double            REAL*8
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Except for the creation of new table types, STAF commands refer to table names as illustrated in the following tutorials.