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c906108c SS |
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 |