/*                              SCSIGetCommandLength.c                          */

/*

 * SCSIGetCommandLength.c

 * Copyright © 1992-94 Apple Computer Inc. All Rights Reserved.

 *

 * Use the command byte to determine the length of the SCSI Command. This will

 * work for all registered SCSI-II commands, but not for "vendor-specific"

 * commands, or commands outside of the registered range.  Returns zero

 * for "unknown" or one of the defined command lengths, 6, 10, or 12..

 *

 * Calling Sequence:

 *      unsigned short      SCSIGetCommandLength(

 *              const Ptr       cmdBlock

 *          );

 */

#include "MacSCSICommand.h"

unsigned short              SCSIGetCommandLength(

        const SCSI_CommandPtr   cmdBlock

    );

unsigned short

SCSIGetCommandLength(

        const SCSI_CommandPtr   cmdBlock

    )

{

        unsigned short          result;

        /*

         * Look at the "group code" in the command operation. Return a parameter

         * error for the reserved (3, 4) and vendor-specific command (6, 7)

         * command groups. Otherwise, set the command length from the group code

         * value as specified in the SCSI-II spec. Then, copy the command block

         * into the parameter block (this centralizes everything for debugging

         * convenience).

         */

        switch (cmdBlock->scsi[0] & 0xE0) {

        case (0 << 5):  result = 6;     break;

        case (1 << 5):

        case (2 << 5):  result = 10;    break;

        case (5 << 5):  result = 12;    break;

        default:        result = 0;     break;

        }

        return (result);

}