/*- *----------------------------------------------------------------------- * Lst_Concat -- * Concatenate two lists. New elements are created to hold the data * elements but the elements themselves are not copied. * If the elements themselves should be duplicated to avoid * confusion with another list, the Lst_Duplicate function * should be called first. * * Side Effects: * New elements are created and appended to the first list. *----------------------------------------------------------------------- */ void Lst_Concat(Lst l1, Lst l2) { LstNode ln; /* original LstNode */ LstNode nln; /* new LstNode */ LstNode last; /* the last element in the list. Keeps * bookkeeping until the end */ if (l2->firstPtr != NULL) { /* The loop simply goes through the entire second list creating * new LstNodes and filling in the nextPtr, and prevPtr to fit * into l1 and its datum field from the datum field of the * corresponding element in l2. The 'last' node follows the * last of the new nodes along until the entire l2 has been * appended. Only then does the bookkeeping catch up with the * changes. During the first iteration of the loop, if 'last' * is NULL, the first list must have been empty so the * newly-created node is made the first node of the list. */ for (last = l1->lastPtr, ln = l2->firstPtr; ln != NULL; ln = ln->nextPtr) { PAlloc(nln, LstNode); nln->datum = ln->datum; if (last != NULL) last->nextPtr = nln; else l1->firstPtr = nln; nln->prevPtr = last; last = nln; } /* Finish bookkeeping. The last new element becomes the last * element of l1. */ l1->lastPtr = last; last->nextPtr = NULL; } }
/*- *----------------------------------------------------------------------- * Lst_Append -- * Create a new node and add it to the given list after the given node. * * Side Effects: * A new ListNode is created and linked in to the List. The lastPtr * field of the List will be altered if ln is the last node in the * list. lastPtr and firstPtr will alter if the list was empty and * ln was NULL. * *----------------------------------------------------------------------- */ void Lst_Append(Lst l, LstNode after, void *d) { LstNode nLNode; if (after == NULL && !Lst_IsEmpty(l)) return; if (after != NULL && Lst_IsEmpty(l)) return; PAlloc(nLNode, LstNode); nLNode->datum = d; if (after == NULL) { nLNode->nextPtr = nLNode->prevPtr = NULL; l->firstPtr = l->lastPtr = nLNode; } else { nLNode->prevPtr = after; nLNode->nextPtr = after->nextPtr; after->nextPtr = nLNode; if (nLNode->nextPtr != NULL) nLNode->nextPtr->prevPtr = nLNode; if (after == l->lastPtr) l->lastPtr = nLNode; } }
/*- *----------------------------------------------------------------------- * Lst_Insert -- * Insert a new node with the given piece of data before the given * node in the given list. * * Side Effects: * the firstPtr field will be changed if ln is the first node in the * list. * *----------------------------------------------------------------------- */ void Lst_Insert(Lst l, LstNode before, void *d) { LstNode nLNode; if (before == NULL && !Lst_IsEmpty(l)) return; if (before != NULL && Lst_IsEmpty(l)) return; PAlloc(nLNode, LstNode); nLNode->datum = d; if (before == NULL) { nLNode->prevPtr = nLNode->nextPtr = NULL; l->firstPtr = l->lastPtr = nLNode; } else { nLNode->prevPtr = before->prevPtr; nLNode->nextPtr = before; if (nLNode->prevPtr != NULL) nLNode->prevPtr->nextPtr = nLNode; before->prevPtr = nLNode; if (before == l->firstPtr) l->firstPtr = nLNode; } }
/*- *----------------------------------------------------------------------- * Lst_Init -- * Create and initialize a new list. * * Input: * circ TRUE if the list should be made circular * * Results: * The created list. * * Side Effects: * A list is created, what else? * *----------------------------------------------------------------------- */ Lst Lst_Init(Boolean circ) { List nList; PAlloc (nList, List); nList->firstPtr = NULL; nList->lastPtr = NULL; nList->isOpen = FALSE; nList->isCirc = circ; nList->atEnd = Unknown; return (nList); }
void Lst_AtEnd(Lst l, void *d) { LstNode ln; PAlloc(ln, LstNode); ln->datum = d; ln->prevPtr = l->lastPtr; ln->nextPtr = NULL; if (l->lastPtr == NULL) l->firstPtr = ln; else l->lastPtr->nextPtr = ln; l->lastPtr = ln; }
/*- *----------------------------------------------------------------------- * Lst_InsertBefore -- * Insert a new node with the given piece of data before the given * node in the given list. * * Input: * l list to manipulate * ln node before which to insert d * d datum to be inserted * * Results: * SUCCESS or FAILURE. * * Side Effects: * the firstPtr field will be changed if ln is the first node in the * list. * *----------------------------------------------------------------------- */ ReturnStatus Lst_InsertBefore(Lst l, LstNode ln, void *d) { ListNode nLNode; /* new lnode for d */ ListNode lNode = ln; List list = l; /* * check validity of arguments */ if (LstValid (l) && (LstIsEmpty (l) && ln == NULL)) goto ok; if (!LstValid (l) || LstIsEmpty (l) || !LstNodeValid (ln, l)) { return (FAILURE); } ok: PAlloc (nLNode, ListNode); nLNode->datum = d; nLNode->useCount = nLNode->flags = 0; if (ln == NULL) { if (list->isCirc) { nLNode->prevPtr = nLNode->nextPtr = nLNode; } else { nLNode->prevPtr = nLNode->nextPtr = NULL; } list->firstPtr = list->lastPtr = nLNode; } else { nLNode->prevPtr = lNode->prevPtr; nLNode->nextPtr = lNode; if (nLNode->prevPtr != NULL) { nLNode->prevPtr->nextPtr = nLNode; } lNode->prevPtr = nLNode; if (lNode == list->firstPtr) { list->firstPtr = nLNode; } } return (SUCCESS); }
/*- *----------------------------------------------------------------------- * Lst_InsertAfter -- * Create a new node and add it to the given list after the given node. * * Input: * l affected list * ln node after which to append the datum * d said datum * * Results: * SUCCESS if all went well. * * Side Effects: * A new ListNode is created and linked in to the List. The lastPtr * field of the List will be altered if ln is the last node in the * list. lastPtr and firstPtr will alter if the list was empty and * ln was NILLNODE. * *----------------------------------------------------------------------- */ ReturnStatus Lst_InsertAfter(Lst l, LstNode ln, ClientData d) { List list; ListNode lNode; ListNode nLNode; if (LstValid (l) && (ln == NILLNODE && LstIsEmpty (l))) { goto ok; } if (!LstValid (l) || LstIsEmpty (l) || ! LstNodeValid (ln, l)) { return (FAILURE); } ok: list = l; lNode = ln; PAlloc (nLNode, ListNode); nLNode->datum = d; nLNode->useCount = nLNode->flags = 0; if (lNode == NilListNode) { if (list->isCirc) { nLNode->nextPtr = nLNode->prevPtr = nLNode; } else { nLNode->nextPtr = nLNode->prevPtr = NilListNode; } list->firstPtr = list->lastPtr = nLNode; } else { nLNode->prevPtr = lNode; nLNode->nextPtr = lNode->nextPtr; lNode->nextPtr = nLNode; if (nLNode->nextPtr != NilListNode) { nLNode->nextPtr->prevPtr = nLNode; } if (lNode == list->lastPtr) { list->lastPtr = nLNode; } } return (SUCCESS); }
/*- *----------------------------------------------------------------------- * Lst_Concat -- * Concatenate two lists. New elements are created to hold the data * elements, if specified, but the elements themselves are not copied. * If the elements should be duplicated to avoid confusion with another * list, the Lst_Duplicate function should be called first. * If LST_CONCLINK is specified, the second list is destroyed since * its pointers have been corrupted and the list is no longer useable. * * Input: * l1 The list to which l2 is to be appended * l2 The list to append to l1 * flags LST_CONCNEW if LstNode's should be duplicated * LST_CONCLINK if should just be relinked * * Results: * SUCCESS if all went well. FAILURE otherwise. * * Side Effects: * New elements are created and appended the first list. *----------------------------------------------------------------------- */ ReturnStatus Lst_Concat(Lst l1, Lst l2, int flags) { ListNode ln; /* original LstNode */ ListNode nln; /* new LstNode */ ListNode last; /* the last element in the list. Keeps * bookkeeping until the end */ List list1 = l1; List list2 = l2; if (!LstValid (l1) || !LstValid (l2)) { return (FAILURE); } if (flags == LST_CONCLINK) { if (list2->firstPtr != NULL) { /* * We set the nextPtr of the * last element of list two to be NIL to make the loop easier and * so we don't need an extra case should the first list turn * out to be non-circular -- the final element will already point * to NIL space and the first element will be untouched if it * existed before and will also point to NIL space if it didn't. */ list2->lastPtr->nextPtr = NULL; /* * So long as the second list isn't empty, we just link the * first element of the second list to the last element of the * first list. If the first list isn't empty, we then link the * last element of the list to the first element of the second list * The last element of the second list, if it exists, then becomes * the last element of the first list. */ list2->firstPtr->prevPtr = list1->lastPtr; if (list1->lastPtr != NULL) { list1->lastPtr->nextPtr = list2->firstPtr; } else { list1->firstPtr = list2->firstPtr; } list1->lastPtr = list2->lastPtr; } if (list1->isCirc && list1->firstPtr != NULL) { /* * If the first list is supposed to be circular and it is (now) * non-empty, we must make sure it's circular by linking the * first element to the last and vice versa */ list1->firstPtr->prevPtr = list1->lastPtr; list1->lastPtr->nextPtr = list1->firstPtr; } free(l2); } else if (list2->firstPtr != NULL) { /* * We set the nextPtr of the last element of list 2 to be nil to make * the loop less difficult. The loop simply goes through the entire * second list creating new LstNodes and filling in the nextPtr, and * prevPtr to fit into l1 and its datum field from the * datum field of the corresponding element in l2. The 'last' node * follows the last of the new nodes along until the entire l2 has * been appended. Only then does the bookkeeping catch up with the * changes. During the first iteration of the loop, if 'last' is nil, * the first list must have been empty so the newly-created node is * made the first node of the list. */ list2->lastPtr->nextPtr = NULL; for (last = list1->lastPtr, ln = list2->firstPtr; ln != NULL; ln = ln->nextPtr) { PAlloc (nln, ListNode); nln->datum = ln->datum; if (last != NULL) { last->nextPtr = nln; } else { list1->firstPtr = nln; } nln->prevPtr = last; nln->flags = nln->useCount = 0; last = nln; } /* * Finish bookkeeping. The last new element becomes the last element * of list one. */ list1->lastPtr = last; /* * The circularity of both list one and list two must be corrected * for -- list one because of the new nodes added to it; list two * because of the alteration of list2->lastPtr's nextPtr to ease the * above for loop. */ if (list1->isCirc) { list1->lastPtr->nextPtr = list1->firstPtr; list1->firstPtr->prevPtr = list1->lastPtr; } else { last->nextPtr = NULL; } if (list2->isCirc) { list2->lastPtr->nextPtr = list2->firstPtr; } } return (SUCCESS); }