RACF® gives control to IRRACX01 or IRRACX02 before compression of an ACEE if ACEEIEP is nonzero. This allows the exit to modify standard data before compression. More importantly, in the case of nonstandard data, the exit can build and return a range table describing the data areas RACF is to compress when it compresses the ACEE. This description is necessary because nonstandard data, by definition, follows no set format for how non-contiguous data areas are hooked together. The range table allows you to tell RACF the start point and end point of multiple non-contiguous areas which need to be saved. The format of a range table is defined in z/OS Security Server RACF Data Areas under the description of the ACXP mapping macro. Each data area pointed to by ACEEIEP, or by data areas chained off of ACEEIEP, should be included as a range in the range table (see Range table example). RACF moves the data specified in the range table to the contiguous area where it is stored. RACF also saves the range table in this contiguous area.

The range table is pointed to by X'8' into the exit parameter list. The exit should get the storage for the range table. When the exit provides a range table, RACF compression routines process the range table and ignore ACEEIEP. ICHRIX02 should FREEMAIN the data pointed by ACEEIEP.

At expansion time, the process is reversed. The exit gets the storage for the original data structure, establishes appropriate pointers, and copies the data indicated by the range table into the storage.

At expansion time, RACF gives control to IRRACX01, but not to IRRACX02. As a result, when RACF's caller is in SRB mode or cross memory mode, an installation cannot count on a range table to restore nonstandard data. In these cases, you should use ACEEIEP data in standard format instead of a range table.