| 1 | /* |
| 2 | * (c) Copyright 1990-1996 OPEN SOFTWARE FOUNDATION, INC. |
| 3 | * (c) Copyright 1990-1996 HEWLETT-PACKARD COMPANY |
| 4 | * (c) Copyright 1990-1996 DIGITAL EQUIPMENT CORPORATION |
| 5 | * (c) Copyright 1991, 1992 Siemens-Nixdorf Information Systems |
| 6 | * To anyone who acknowledges that this file is provided "AS IS" without |
| 7 | * any express or implied warranty: permission to use, copy, modify, and |
| 8 | * distribute this file for any purpose is hereby granted without fee, |
| 9 | * provided that the above copyright notices and this notice appears in |
| 10 | * all source code copies, and that none of the names listed above be used |
| 11 | * in advertising or publicity pertaining to distribution of the software |
| 12 | * without specific, written prior permission. None of these organizations |
| 13 | * makes any representations about the suitability of this software for |
| 14 | * any purpose. |
| 15 | */ |
| 16 | /* |
| 17 | * Header file for generic list functions operating on singly linked |
| 18 | * null-terminated lists. Items may not be REMOVED from the list! The |
| 19 | * intent is that the list can be traversed (for read-only operations) |
| 20 | * without locking, since insertion is "safe" (though not truely |
| 21 | * atomic). THIS ASSUMES THAT THE HARDWARE MAKES WRITES VISIBLE TO READS |
| 22 | * IN THE ORDER IN WHICH THEY OCCURRED! WITHOUT SUCH READ/WRITE |
| 23 | * ORDERING, IT MAY BE NECESSARY TO INSERT "BARRIERS" TO PRODUCE THE |
| 24 | * REQUIRED VISIBILITY! |
| 25 | */ |
| 26 | |
| 27 | #ifndef CMA_LIST |
| 28 | #define CMA_LIST |
| 29 | |
| 30 | /* |
| 31 | * INCLUDE FILES |
| 32 | */ |
| 33 | |
| 34 | #include <cma.h> |
| 35 | |
| 36 | /* |
| 37 | * CONSTANTS AND MACROS |
| 38 | */ |
| 39 | |
| 40 | #define cma__c_null_list ((cma__t_list *)cma_c_null_ptr) |
| 41 | |
| 42 | /* |
| 43 | * Test whether a list is empty. Return cma_c_true if so, else |
| 44 | * cma_c_false. |
| 45 | */ |
| 46 | #define cma__list_empty(head) ((head)->link == cma__c_null_list) |
| 47 | |
| 48 | /* |
| 49 | * Initialize a queue header to empty. |
| 50 | */ |
| 51 | #define cma__list_init(head) (void)((head)->link = cma__c_null_list) |
| 52 | |
| 53 | /* |
| 54 | * Insert an element in a list following the specified item (or at the |
| 55 | * beginning of the list if "list" is the list head). NOTE: insertion |
| 56 | * operations should be interlocked by the caller! |
| 57 | */ |
| 58 | #define cma__list_insert(element,list) (void)( \ |
| 59 | (element)->link = (list)->link, \ |
| 60 | (list)->link = (element)) |
| 61 | |
| 62 | /* |
| 63 | * Return the next item in a list (or the first, if the address is of the |
| 64 | * list header) |
| 65 | */ |
| 66 | #define cma__list_next(element) ((element)->link) |
| 67 | |
| 68 | /* |
| 69 | * TYPEDEFS |
| 70 | */ |
| 71 | |
| 72 | typedef struct CMA__T_LIST { |
| 73 | struct CMA__T_LIST *link; /* Forward link */ |
| 74 | } cma__t_list; |
| 75 | |
| 76 | /* |
| 77 | * GLOBAL DATA |
| 78 | */ |
| 79 | |
| 80 | /* |
| 81 | * INTERNAL INTERFACES |
| 82 | */ |
| 83 | |
| 84 | #endif |