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36 * @(#)lstInt.h 8.1 (Berkeley) 6/6/93
41 * Internals for the list library
48 typedef struct ListNode {
49 struct ListNode *prevPtr; /* previous element in list */
50 struct ListNode *nextPtr; /* next in list */
51 short useCount:8, /* Count of functions using the node.
52 * node may not be deleted until count
54 flags:8; /* Node status flags */
55 ClientData datum; /* datum associated with this element */
58 * Flags required for synchronization
60 #define LN_DELETED 0x0001 /* List node should be removed when done */
62 #define NilListNode ((ListNode)-1)
65 Head, Middle, Tail, Unknown
69 ListNode firstPtr; /* first node in list */
70 ListNode lastPtr; /* last node in list */
71 Boolean isCirc; /* true if the list should be considered
74 * fields for sequential access
76 Where atEnd; /* Where in the list the last access was */
77 Boolean isOpen; /* true if list has been Lst_Open'ed */
78 ListNode curPtr; /* current node, if open. NilListNode if
80 ListNode prevPtr; /* Previous node, if open. Used by
84 #define NilList ((List)-1)
87 * PAlloc (var, ptype) --
88 * Allocate a pointer-typedef structure 'ptype' into the variable 'var'
90 #define PAlloc(var,ptype) var = (ptype) malloc (sizeof (*var))
94 * Return TRUE if the list l is valid
96 #define LstValid(l) (((Lst)l == NILLST) ? FALSE : TRUE)
99 * LstNodeValid (ln, l) --
100 * Return TRUE if the LstNode ln is valid with respect to l
102 #define LstNodeValid(ln, l) ((((LstNode)ln) == NILLNODE) ? FALSE : TRUE)
106 * TRUE if the list l is empty.
108 #define LstIsEmpty(l) (((List)l)->firstPtr == NilListNode)