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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22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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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 *-----------------------------------------------------------------------
50 * Create a new node and add it to the given list after the given node.
54 * ln node after which to append the datum
58 * A new LstNode is created and linked in to the List. The lastPtr
59 * field of the List will be altered if ln is the last node in the
60 * list. lastPtr and firstPtr will alter if the list was empty and
63 *-----------------------------------------------------------------------
66 Lst_Append(Lst *list, LstNode *ln, void *d)
70 nLNode = emalloc(sizeof(*nLNode));
74 nLNode->nextPtr = nLNode->prevPtr = NULL;
75 list->firstPtr = list->lastPtr = nLNode;
78 nLNode->nextPtr = ln->nextPtr;
81 if (nLNode->nextPtr != NULL) {
82 nLNode->nextPtr->prevPtr = nLNode;
85 if (ln == list->lastPtr) {
86 list->lastPtr = nLNode;
92 *-----------------------------------------------------------------------
94 * Concatenate two lists. New elements are created to hold the data
95 * elements, if specified, but the elements themselves are not copied.
96 * If the elements should be duplicated to avoid confusion with another
97 * list, the Lst_Duplicate function should be called first.
100 * SUCCESS if all went well. FAILURE otherwise.
103 * list1 The list to which list2 is to be appended
104 * list2 The list to append to list1
105 * flags LST_CONCNEW if LstNode's should be duplicated
106 * LST_CONCLINK if should just be relinked
109 * New elements are created and appended the the first list.
110 *-----------------------------------------------------------------------
113 Lst_Concat(Lst *list1, Lst *list2, int flags)
115 LstNode *ln; /* original LstNode */
116 LstNode *nln; /* new LstNode */
117 LstNode *last; /* the last element in the list. Keeps
118 * bookkeeping until the end */
120 if (list2->firstPtr == NULL)
123 if (flags == LST_CONCLINK) {
125 * Link the first element of the second list to the last element of the
126 * first list. If the first list isn't empty, we then link the
127 * last element of the list to the first element of the second list
128 * The last element of the second list, if it exists, then becomes
129 * the last element of the first list.
131 list2->firstPtr->prevPtr = list1->lastPtr;
132 if (list1->lastPtr != NULL)
133 list1->lastPtr->nextPtr = list2->firstPtr;
135 list1->firstPtr = list2->firstPtr;
136 list1->lastPtr = list2->lastPtr;
141 * The loop simply goes through the entire
142 * second list creating new LstNodes and filling in the nextPtr, and
143 * prevPtr to fit into list1 and its datum field from the
144 * datum field of the corresponding element in list2. The 'last' node
145 * follows the last of the new nodes along until the entire list2 has
146 * been appended. Only then does the bookkeeping catch up with the
147 * changes. During the first iteration of the loop, if 'last' is NULL,
148 * the first list must have been empty so the newly-created node is
149 * made the first node of the list.
151 for (last = list1->lastPtr, ln = list2->firstPtr;
155 nln = emalloc(sizeof(*nln));
156 nln->datum = ln->datum;
160 list1->firstPtr = nln;
167 * Finish bookkeeping. The last new element becomes the last element
170 list1->lastPtr = last;
171 last->nextPtr = NULL;
176 *-----------------------------------------------------------------------
178 * Remove and return the datum at the head of the given list.
181 * The datum in the node at the head or (ick) NULL if the list
185 * The head node is removed from the list.
187 *-----------------------------------------------------------------------
206 *-----------------------------------------------------------------------
208 * Destroy a list and free all its resources. If the freeProc is
209 * given, it is called with the datum from each node in turn before
216 * The given list is freed in its entirety.
218 *-----------------------------------------------------------------------
221 Lst_Destroy(Lst *list, FreeProc *freeProc)
225 if (list->firstPtr == NULL)
228 if (freeProc != NOFREE) {
229 while ((ln = list->firstPtr) != NULL) {
230 list->firstPtr = ln->nextPtr;
231 (*freeProc)(ln->datum);
235 while ((ln = list->firstPtr) != NULL) {
236 list->firstPtr = ln->nextPtr;
240 list->lastPtr = NULL;
244 *-----------------------------------------------------------------------
246 * Duplicate an entire list. If a function to copy a void * is
247 * given, the individual client elements will be duplicated as well.
250 * dst the destination list (initialized)
251 * src the list to duplicate
252 * copyProc A function to duplicate each void
254 *-----------------------------------------------------------------------
257 Lst_Duplicate(Lst *dst, Lst *src, DuplicateProc *copyProc)
263 if (copyProc != NOCOPY)
264 Lst_AtEnd(dst, (*copyProc)(ln->datum));
266 Lst_AtEnd(dst, ln->datum);
272 *-----------------------------------------------------------------------
274 * Insert a new node with the given piece of data before the given
275 * node in the given list.
278 * l list to manipulate
279 * ln node before which to insert d
280 * d datum to be inserted
283 * the firstPtr field will be changed if ln is the first node in the
286 *-----------------------------------------------------------------------
289 Lst_Insert(Lst *list, LstNode *ln, void *d)
291 LstNode *nLNode; /* new lnode for d */
293 nLNode = emalloc(sizeof(*nLNode));
297 nLNode->prevPtr = nLNode->nextPtr = NULL;
298 list->firstPtr = list->lastPtr = nLNode;
300 nLNode->prevPtr = ln->prevPtr;
301 nLNode->nextPtr = ln;
303 if (nLNode->prevPtr != NULL) {
304 nLNode->prevPtr->nextPtr = nLNode;
306 ln->prevPtr = nLNode;
308 if (ln == list->firstPtr) {
309 list->firstPtr = nLNode;
315 Lst_Member(Lst *list, void *d)
319 lNode = list->firstPtr;
325 if (lNode->datum == d) {
328 lNode = lNode->nextPtr;
329 } while (lNode != NULL && lNode != list->firstPtr);
335 *-----------------------------------------------------------------------
337 * Remove the given node from the given list.
340 * SUCCESS or FAILURE.
343 * The list's firstPtr will be set to NULL if ln is the last
344 * node on the list. firsPtr and lastPtr will be altered if ln is
345 * either the first or last node, respectively, on the list.
347 *-----------------------------------------------------------------------
350 Lst_Remove(Lst *list, LstNode *ln)
353 * unlink it from the list
355 if (ln->nextPtr != NULL)
356 /* unlink from the backward chain */
357 ln->nextPtr->prevPtr = ln->prevPtr;
359 /* this was the last element */
360 list->lastPtr = ln->prevPtr;
362 if (ln->prevPtr != NULL)
363 /* unlink from the forward chain */
364 ln->prevPtr->nextPtr = ln->nextPtr;
366 /* this was the first element */
367 list->firstPtr = ln->nextPtr;
370 * note that the datum is unmolested. The caller must free it as
371 * necessary and as expected.