/* * alpm_list.c * * Copyright (c) 2006-2011 Pacman Development Team <pacman-dev@archlinux.org> * Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <stdlib.h> #include <string.h> /* libalpm */ #include "alpm_list.h" /* check exported library symbols with: nm -C -D <lib> */ #define SYMEXPORT __attribute__((visibility("default"))) #define SYMHIDDEN __attribute__((visibility("internal"))) /** * @addtogroup alpm_list List Functions * @brief Functions to manipulate alpm_list_t lists. * * These functions are designed to create, destroy, and modify lists of * type alpm_list_t. This is an internal list type used by libalpm that is * publicly exposed for use by frontends if desired. * * @{ */ /* Allocation */ /** * @brief Free a list, but not the contained data. * * @param list the list to free */ void SYMEXPORT alpm_list_free(alpm_list_t *list) { alpm_list_t *it = list; while(it) { alpm_list_t *tmp = it->next; free(it); it = tmp; } } /** * @brief Free the internal data of a list structure. * * @param list the list to free * @param fn a free function for the internal data */ void SYMEXPORT alpm_list_free_inner(alpm_list_t *list, alpm_list_fn_free fn) { alpm_list_t *it = list; while(it) { if(fn && it->data) { fn(it->data); } it = it->next; } } /* Mutators */ /** * @brief Add a new item to the end of the list. * * @param list the list to add to * @param data the new item to be added to the list * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_add(alpm_list_t *list, void *data) { alpm_list_t *ptr, *lp; ptr = calloc(1, sizeof(alpm_list_t)); if(ptr == NULL) { return list; } ptr->data = data; ptr->next = NULL; /* Special case: the input list is empty */ if(list == NULL) { ptr->prev = ptr; return ptr; } lp = alpm_list_last(list); lp->next = ptr; ptr->prev = lp; list->prev = ptr; return list; } /** * @brief Add items to a list in sorted order. * * @param list the list to add to * @param data the new item to be added to the list * @param fn the comparison function to use to determine order * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_add_sorted(alpm_list_t *list, void *data, alpm_list_fn_cmp fn) { if(!fn || !list) { return alpm_list_add(list, data); } else { alpm_list_t *add = NULL, *prev = NULL, *next = list; add = calloc(1, sizeof(alpm_list_t)); if(add == NULL) { return list; } add->data = data; /* Find insertion point. */ while(next) { if(fn(add->data, next->data) <= 0) break; prev = next; next = next->next; } /* Insert the add node to the list */ if(prev == NULL) { /* special case: we insert add as the first element */ add->prev = list->prev; /* list != NULL */ add->next = list; list->prev = add; return add; } else if(next == NULL) { /* another special case: add last element */ add->prev = prev; add->next = NULL; prev->next = add; list->prev = add; return list; } else { add->prev = prev; add->next = next; next->prev = add; prev->next = add; return list; } } } /** * @brief Join two lists. * The two lists must be independent. Do not free the original lists after * calling this function, as this is not a copy operation. The list pointers * passed in should be considered invalid after calling this function. * * @param first the first list * @param second the second list * * @return the resultant joined list */ alpm_list_t SYMEXPORT *alpm_list_join(alpm_list_t *first, alpm_list_t *second) { alpm_list_t *tmp; if(first == NULL) { return second; } if(second == NULL) { return first; } /* tmp is the last element of the first list */ tmp = first->prev; /* link the first list to the second */ tmp->next = second; /* link the second list to the first */ first->prev = second->prev; /* set the back reference to the tail */ second->prev = tmp; return first; } /** * @brief Merge the two sorted sublists into one sorted list. * * @param left the first list * @param right the second list * @param fn comparison function for determining merge order * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_mmerge(alpm_list_t *left, alpm_list_t *right, alpm_list_fn_cmp fn) { alpm_list_t *newlist, *lp; if(left == NULL) return right; if(right == NULL) return left; if(fn(left->data, right->data) <= 0) { newlist = left; left = left->next; } else { newlist = right; right = right->next; } newlist->prev = NULL; newlist->next = NULL; lp = newlist; while((left != NULL) && (right != NULL)) { if(fn(left->data, right->data) <= 0) { lp->next = left; left->prev = lp; left = left->next; } else { lp->next = right; right->prev = lp; right = right->next; } lp = lp->next; lp->next = NULL; } if(left != NULL) { lp->next = left; left->prev = lp; } else if(right != NULL) { lp->next = right; right->prev = lp; } /* Find our tail pointer * TODO maintain this in the algorithm itself */ lp = newlist; while(lp && lp->next) { lp = lp->next; } newlist->prev = lp; return newlist; } /** * @brief Sort a list of size `n` using mergesort algorithm. * * @param list the list to sort * @param n the size of the list * @param fn the comparison function for determining order * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_msort(alpm_list_t *list, size_t n, alpm_list_fn_cmp fn) { if(n > 1) { alpm_list_t *left = list; alpm_list_t *lastleft = alpm_list_nth(list, n/2 - 1); alpm_list_t *right = lastleft->next; /* terminate first list */ lastleft->next = NULL; left = alpm_list_msort(left, n/2, fn); right = alpm_list_msort(right, n - (n/2), fn); list = alpm_list_mmerge(left, right, fn); } return list; } /** * @brief Remove an item from the list. * item is not freed; this is the responsiblity of the caller. * * @param haystack the list to remove the item from * @param item the item to remove from the list * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_remove_item(alpm_list_t *haystack, alpm_list_t *item) { if(haystack == NULL || item == NULL) { return haystack; } if(item == haystack) { /* Special case: removing the head node which has a back reference to * the tail node */ haystack = item->next; if(haystack) { haystack->prev = item->prev; } item->prev = NULL; } else if(item == haystack->prev) { /* Special case: removing the tail node, so we need to fix the back * reference on the head node. We also know tail != head. */ if(item->prev) { /* i->next should always be null */ item->prev->next = item->next; haystack->prev = item->prev; item->prev = NULL; } } else { /* Normal case, non-head and non-tail node */ if(item->next) { item->next->prev = item->prev; } if(item->prev) { item->prev->next = item->next; } } return haystack; } /** * @brief Remove an item from the list. * * @param haystack the list to remove the item from * @param needle the data member of the item we're removing * @param fn the comparison function for searching * @param data output parameter containing data of the removed item * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_remove(alpm_list_t *haystack, const void *needle, alpm_list_fn_cmp fn, void **data) { alpm_list_t *i = haystack; if(data) { *data = NULL; } if(needle == NULL) { return haystack; } while(i) { if(i->data == NULL) { i = i->next; continue; } if(fn(i->data, needle) == 0) { haystack = alpm_list_remove_item(haystack, i); if(data) { *data = i->data; } free(i); break; } else { i = i->next; } } return haystack; } /** * @brief Remove a string from a list. * * @param haystack the list to remove the item from * @param needle the data member of the item we're removing * @param data output parameter containing data of the removed item * * @return the resultant list */ alpm_list_t SYMEXPORT *alpm_list_remove_str(alpm_list_t *haystack, const char *needle, char **data) { return alpm_list_remove(haystack, (const void *)needle, (alpm_list_fn_cmp)strcmp, (void **)data); } /** * @brief Create a new list without any duplicates. * * This does NOT copy data members. * * @param list the list to copy * * @return a new list containing non-duplicate items */ alpm_list_t SYMEXPORT *alpm_list_remove_dupes(const alpm_list_t *list) { const alpm_list_t *lp = list; alpm_list_t *newlist = NULL; while(lp) { if(!alpm_list_find_ptr(newlist, lp->data)) { newlist = alpm_list_add(newlist, lp->data); } lp = lp->next; } return newlist; } /** * @brief Copy a string list, including data. * * @param list the list to copy * * @return a copy of the original list */ alpm_list_t SYMEXPORT *alpm_list_strdup(const alpm_list_t *list) { const alpm_list_t *lp = list; alpm_list_t *newlist = NULL; while(lp) { newlist = alpm_list_add(newlist, strdup(lp->data)); lp = lp->next; } return newlist; } /** * @brief Copy a list, without copying data. * * @param list the list to copy * * @return a copy of the original list */ alpm_list_t SYMEXPORT *alpm_list_copy(const alpm_list_t *list) { const alpm_list_t *lp = list; alpm_list_t *newlist = NULL; while(lp) { newlist = alpm_list_add(newlist, lp->data); lp = lp->next; } return newlist; } /** * @brief Copy a list and copy the data. * Note that the data elements to be copied should not contain pointers * and should also be of constant size. * * @param list the list to copy * @param size the size of each data element * * @return a copy of the original list, data copied as well */ alpm_list_t SYMEXPORT *alpm_list_copy_data(const alpm_list_t *list, size_t size) { const alpm_list_t *lp = list; alpm_list_t *newlist = NULL; while(lp) { void *newdata = calloc(1, size); if(newdata) { memcpy(newdata, lp->data, size); newlist = alpm_list_add(newlist, newdata); lp = lp->next; } } return newlist; } /** * @brief Create a new list in reverse order. * * @param list the list to copy * * @return a new list in reverse order */ alpm_list_t SYMEXPORT *alpm_list_reverse(alpm_list_t *list) { const alpm_list_t *lp; alpm_list_t *newlist = NULL, *backup; if(list == NULL) { return NULL; } lp = alpm_list_last(list); /* break our reverse circular list */ backup = list->prev; list->prev = NULL; while(lp) { newlist = alpm_list_add(newlist, lp->data); lp = lp->prev; } list->prev = backup; /* restore tail pointer */ return newlist; } /* Accessors */ /** * @brief Get the first element of a list. * * @param list the list * * @return the first element in the list */ inline alpm_list_t SYMEXPORT *alpm_list_first(const alpm_list_t *list) { if(list) { return (alpm_list_t *)list; } else { return NULL; } } /** * @brief Return nth element from list (starting from 0). * * @param list the list * @param n the index of the item to find (n < alpm_list_count(list) IS needed) * * @return an alpm_list_t node for index `n` */ alpm_list_t SYMEXPORT *alpm_list_nth(const alpm_list_t *list, size_t n) { const alpm_list_t *i = list; while(n--) { i = i->next; } return (alpm_list_t *)i; } /** * @brief Get the next element of a list. * * @param node the list node * * @return the next element, or NULL when no more elements exist */ inline alpm_list_t SYMEXPORT *alpm_list_next(const alpm_list_t *node) { if(node) { return node->next; } else { return NULL; } } /** * @brief Get the last item in the list. * * @param list the list * * @return the last element in the list */ alpm_list_t SYMEXPORT *alpm_list_last(const alpm_list_t *list) { if(list) { return list->prev; } else { return NULL; } } /** * @brief Get the data member of a list node. * * @param node the list node * * @return the contained data, or NULL if none */ void SYMEXPORT *alpm_list_getdata(const alpm_list_t *node) { if(node == NULL) return NULL; return node->data; } /* Misc */ /** * @brief Get the number of items in a list. * * @param list the list * * @return the number of list items */ size_t SYMEXPORT alpm_list_count(const alpm_list_t *list) { size_t i = 0; const alpm_list_t *lp = list; while(lp) { ++i; lp = lp->next; } return i; } /** * @brief Find an item in a list. * * @param needle the item to search * @param haystack the list * @param fn the comparison function for searching (!= NULL) * * @return `needle` if found, NULL otherwise */ void SYMEXPORT *alpm_list_find(const alpm_list_t *haystack, const void *needle, alpm_list_fn_cmp fn) { const alpm_list_t *lp = haystack; while(lp) { if(lp->data && fn(lp->data, needle) == 0) { return lp->data; } lp = lp->next; } return NULL; } /* trivial helper function for alpm_list_find_ptr */ static int ptr_cmp(const void *p, const void *q) { return (p != q); } /** * @brief Find an item in a list. * * Search for the item whose data matches that of the `needle`. * * @param needle the data to search for (== comparison) * @param haystack the list * * @return `needle` if found, NULL otherwise */ void SYMEXPORT *alpm_list_find_ptr(const alpm_list_t *haystack, const void *needle) { return alpm_list_find(haystack, needle, ptr_cmp); } /** * @brief Find a string in a list. * * @param needle the string to search for * @param haystack the list * * @return `needle` if found, NULL otherwise */ char SYMEXPORT *alpm_list_find_str(const alpm_list_t *haystack, const char *needle) { return (char *)alpm_list_find(haystack, (const void *)needle, (alpm_list_fn_cmp)strcmp); } /** * @brief Find the differences between list `left` and list `right` * * The two lists must be sorted. Items only in list `left` are added to the * `onlyleft` list. Items only in list `right` are added to the `onlyright` * list. * * @param left the first list * @param right the second list * @param fn the comparison function * @param onlyleft pointer to the first result list * @param onlyright pointer to the second result list * */ void SYMEXPORT alpm_list_diff_sorted(const alpm_list_t *left, const alpm_list_t *right, alpm_list_fn_cmp fn, alpm_list_t **onlyleft, alpm_list_t **onlyright) { const alpm_list_t *l = left; const alpm_list_t *r = right; if(!onlyleft && !onlyright) { return; } while(l != NULL && r != NULL) { int cmp = fn(l->data, r->data); if(cmp < 0) { if(onlyleft) { *onlyleft = alpm_list_add(*onlyleft, l->data); } l = l->next; } else if(cmp > 0) { if(onlyright) { *onlyright = alpm_list_add(*onlyright, r->data); } r = r->next; } else { l = l->next; r = r->next; } } while(l != NULL) { if(onlyleft) { *onlyleft = alpm_list_add(*onlyleft, l->data); } l = l->next; } while(r != NULL) { if(onlyright) { *onlyright = alpm_list_add(*onlyright, r->data); } r = r->next; } } /** * @brief Find the items in list `lhs` that are not present in list `rhs`. * * @param lhs the first list * @param rhs the second list * @param fn the comparison function * * @return a list containing all items in `lhs` not present in `rhs` */ alpm_list_t SYMEXPORT *alpm_list_diff(const alpm_list_t *lhs, const alpm_list_t *rhs, alpm_list_fn_cmp fn) { alpm_list_t *left, *right; alpm_list_t *ret = NULL; left = alpm_list_copy(lhs); left = alpm_list_msort(left, alpm_list_count(left), fn); right = alpm_list_copy(rhs); right = alpm_list_msort(right, alpm_list_count(right), fn); alpm_list_diff_sorted(left, right, fn, &ret, NULL); alpm_list_free(left); alpm_list_free(right); return ret; } /** @} */ /* vim: set ts=2 sw=2 noet: */