2 * Copyright (c) 1988, 1989, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * Routines to maintain a linked list of objects.
48 * Create a new node and add it to the given list after the given node.
52 * ln node after which to append the datum
56 * A new LstNode is created and linked in to the List. The lastPtr
57 * field of the List will be altered if ln is the last node in the
58 * list. lastPtr and firstPtr will alter if the list was empty and
62 Lst_Append(Lst *list, LstNode *ln, void *d)
66 nLNode = emalloc(sizeof(*nLNode));
70 nLNode->nextPtr = nLNode->prevPtr = NULL;
71 list->firstPtr = list->lastPtr = nLNode;
74 nLNode->nextPtr = ln->nextPtr;
77 if (nLNode->nextPtr != NULL) {
78 nLNode->nextPtr->prevPtr = nLNode;
81 if (ln == list->lastPtr) {
82 list->lastPtr = nLNode;
89 * Concatenate two lists. New elements are created to hold the data
90 * elements, if specified, but the elements themselves are not copied.
91 * If the elements should be duplicated to avoid confusion with another
92 * list, the Lst_Duplicate function should be called first.
95 * list1 The list to which list2 is to be appended
96 * list2 The list to append to list1
97 * flags LST_CONCNEW if LstNode's should be duplicated
98 * LST_CONCLINK if should just be relinked
101 * New elements are created and appended the first list.
104 Lst_Concat(Lst *list1, Lst *list2, int flags)
106 LstNode *ln; /* original LstNode */
107 LstNode *nln; /* new LstNode */
108 LstNode *last; /* the last element in the list. Keeps
109 * bookkeeping until the end */
111 if (list2->firstPtr == NULL)
114 if (flags == LST_CONCLINK) {
116 * Link the first element of the second list to the last
117 * element of the first list. If the first list isn't empty,
118 * we then link the last element of the list to the first
119 * element of the second list. The last element of the second
120 * list, if it exists, then becomes the last element of the
123 list2->firstPtr->prevPtr = list1->lastPtr;
124 if (list1->lastPtr != NULL)
125 list1->lastPtr->nextPtr = list2->firstPtr;
127 list1->firstPtr = list2->firstPtr;
128 list1->lastPtr = list2->lastPtr;
133 * The loop simply goes through the entire second list creating
134 * new LstNodes and filling in the nextPtr, and prevPtr to fit
135 * into list1 and its datum field from the datum field of the
136 * corresponding element in list2. The 'last' node follows the
137 * last of the new nodes along until the entire list2 has been
138 * appended. Only then does the bookkeeping catch up with the
139 * changes. During the first iteration of the loop, if 'last'
140 * is NULL, the first list must have been empty so the
141 * newly-created node is made the first node of the list.
143 for (last = list1->lastPtr, ln = list2->firstPtr;
146 nln = emalloc(sizeof(*nln));
147 nln->datum = ln->datum;
151 list1->firstPtr = nln;
158 * Finish bookkeeping. The last new element becomes the last
159 * element of list one.
161 list1->lastPtr = last;
162 last->nextPtr = NULL;
168 * Remove and return the datum at the head of the given list.
171 * The datum in the node at the head or (ick) NULL if the list
175 * The head node is removed from the list.
195 * Destroy a list and free all its resources. If the freeProc is
196 * given, it is called with the datum from each node in turn before
200 * The given list is freed in its entirety.
203 Lst_Destroy(Lst *list, FreeProc *freeProc)
207 if (list->firstPtr == NULL)
210 if (freeProc != NOFREE) {
211 while ((ln = list->firstPtr) != NULL) {
212 list->firstPtr = ln->nextPtr;
213 (*freeProc)(ln->datum);
217 while ((ln = list->firstPtr) != NULL) {
218 list->firstPtr = ln->nextPtr;
222 list->lastPtr = NULL;
227 * Duplicate an entire list. If a function to copy a void * is
228 * given, the individual client elements will be duplicated as well.
231 * dst the destination list (initialized)
232 * src the list to duplicate
233 * copyProc A function to duplicate each void
236 Lst_Duplicate(Lst *dst, Lst *src, DuplicateProc *copyProc)
242 if (copyProc != NOCOPY)
243 Lst_AtEnd(dst, (*copyProc)(ln->datum));
245 Lst_AtEnd(dst, ln->datum);
252 * Insert a new node with the given piece of data before the given
253 * node in the given list.
256 * l list to manipulate
257 * ln node before which to insert d
258 * d datum to be inserted
261 * the firstPtr field will be changed if ln is the first node in the
265 Lst_Insert(Lst *list, LstNode *ln, void *d)
267 LstNode *nLNode; /* new lnode for d */
269 nLNode = emalloc(sizeof(*nLNode));
273 nLNode->prevPtr = nLNode->nextPtr = NULL;
274 list->firstPtr = list->lastPtr = nLNode;
276 nLNode->prevPtr = ln->prevPtr;
277 nLNode->nextPtr = ln;
279 if (nLNode->prevPtr != NULL) {
280 nLNode->prevPtr->nextPtr = nLNode;
282 ln->prevPtr = nLNode;
284 if (ln == list->firstPtr) {
285 list->firstPtr = nLNode;
291 Lst_Member(Lst *list, void *d)
295 lNode = list->firstPtr;
301 if (lNode->datum == d) {
304 lNode = lNode->nextPtr;
305 } while (lNode != NULL && lNode != list->firstPtr);
312 * Remove the given node from the given list.
315 * The list's firstPtr will be set to NULL if ln is the last
316 * node on the list. firsPtr and lastPtr will be altered if ln is
317 * either the first or last node, respectively, on the list.
320 Lst_Remove(Lst *list, LstNode *ln)
323 * unlink it from the list
325 if (ln->nextPtr != NULL)
326 /* unlink from the backward chain */
327 ln->nextPtr->prevPtr = ln->prevPtr;
329 /* this was the last element */
330 list->lastPtr = ln->prevPtr;
332 if (ln->prevPtr != NULL)
333 /* unlink from the forward chain */
334 ln->prevPtr->nextPtr = ln->nextPtr;
336 /* this was the first element */
337 list->firstPtr = ln->nextPtr;
340 * note that the datum is unmolested. The caller must free it as
341 * necessary and as expected.