Wed, 21 Feb 2024 18:32:38 +0100
add visit_on_exit to iterator implementation
relates to #371
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "cx/linked_list.h" #include "cx/utils.h" #include "cx/compare.h" #include <string.h> #include <assert.h> // LOW LEVEL LINKED LIST FUNCTIONS #define CX_LL_PTR(cur, off) (*(void**)(((char*)(cur))+(off))) #define ll_prev(node) CX_LL_PTR(node, loc_prev) #define ll_next(node) CX_LL_PTR(node, loc_next) #define ll_advance(node) CX_LL_PTR(node, loc_advance) #define ll_data(node) (((char*)(node))+loc_data) void *cx_linked_list_at( void const *start, size_t start_index, ptrdiff_t loc_advance, size_t index ) { assert(start != NULL); assert(loc_advance >= 0); size_t i = start_index; void const *cur = start; while (i != index && cur != NULL) { cur = ll_advance(cur); i < index ? i++ : i--; } return (void *) cur; } ssize_t cx_linked_list_find( void const *start, ptrdiff_t loc_advance, ptrdiff_t loc_data, cx_compare_func cmp_func, void const *elem ) { void *dummy; return cx_linked_list_find_node( &dummy, start, loc_advance, loc_data, cmp_func, elem ); } ssize_t cx_linked_list_find_node( void **result, void const *start, ptrdiff_t loc_advance, ptrdiff_t loc_data, cx_compare_func cmp_func, void const *elem ) { assert(result != NULL); assert(start != NULL); assert(loc_advance >= 0); assert(loc_data >= 0); assert(cmp_func); void const *node = start; ssize_t index = 0; do { void *current = ll_data(node); if (cmp_func(current, elem) == 0) { *result = (void*) node; return index; } node = ll_advance(node); index++; } while (node != NULL); *result = NULL; return -1; } void *cx_linked_list_first( void const *node, ptrdiff_t loc_prev ) { return cx_linked_list_last(node, loc_prev); } void *cx_linked_list_last( void const *node, ptrdiff_t loc_next ) { assert(node != NULL); assert(loc_next >= 0); void const *cur = node; void const *last; do { last = cur; } while ((cur = ll_next(cur)) != NULL); return (void *) last; } void *cx_linked_list_prev( void const *begin, ptrdiff_t loc_next, void const *node ) { assert(begin != NULL); assert(node != NULL); assert(loc_next >= 0); if (begin == node) return NULL; void const *cur = begin; void const *next; while (1) { next = ll_next(cur); if (next == node) return (void *) cur; cur = next; } } void cx_linked_list_link( void *left, void *right, ptrdiff_t loc_prev, ptrdiff_t loc_next ) { assert(loc_next >= 0); ll_next(left) = right; if (loc_prev >= 0) { ll_prev(right) = left; } } void cx_linked_list_unlink( void *left, void *right, ptrdiff_t loc_prev, ptrdiff_t loc_next ) { assert (loc_next >= 0); assert(ll_next(left) == right); ll_next(left) = NULL; if (loc_prev >= 0) { assert(ll_prev(right) == left); ll_prev(right) = NULL; } } void cx_linked_list_add( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node ) { void *last; if (end == NULL) { assert(begin != NULL); last = *begin == NULL ? NULL : cx_linked_list_last(*begin, loc_next); } else { last = *end; } cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, last, new_node, new_node); } void cx_linked_list_prepend( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node ) { cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, NULL, new_node, new_node); } void cx_linked_list_insert( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node, void *new_node ) { cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, node, new_node, new_node); } void cx_linked_list_insert_chain( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node, void *insert_begin, void *insert_end ) { // find the end of the chain, if not specified if (insert_end == NULL) { insert_end = cx_linked_list_last(insert_begin, loc_next); } // determine the successor void *successor; if (node == NULL) { assert(begin != NULL || (end != NULL && loc_prev >= 0)); if (begin != NULL) { successor = *begin; *begin = insert_begin; } else { successor = *end == NULL ? NULL : cx_linked_list_first(*end, loc_prev); } } else { successor = ll_next(node); cx_linked_list_link(node, insert_begin, loc_prev, loc_next); } if (successor == NULL) { // the list ends with the new chain if (end != NULL) { *end = insert_end; } } else { cx_linked_list_link(insert_end, successor, loc_prev, loc_next); } } void cx_linked_list_remove( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node ) { assert(node != NULL); assert(loc_next >= 0); assert(loc_prev >= 0 || begin != NULL); // find adjacent nodes void *next = ll_next(node); void *prev; if (loc_prev >= 0) { prev = ll_prev(node); } else { prev = cx_linked_list_prev(*begin, loc_next, node); } // update next pointer of prev node, or set begin if (prev == NULL) { if (begin != NULL) { *begin = next; } } else { ll_next(prev) = next; } // update prev pointer of next node, or set end if (next == NULL) { if (end != NULL) { *end = prev; } } else if (loc_prev >= 0) { ll_prev(next) = prev; } } size_t cx_linked_list_size( void const *node, ptrdiff_t loc_next ) { assert(loc_next >= 0); size_t size = 0; while (node != NULL) { node = ll_next(node); size++; } return size; } #ifndef CX_LINKED_LIST_SORT_SBO_SIZE #define CX_LINKED_LIST_SORT_SBO_SIZE 1024 #endif static void cx_linked_list_sort_merge( ptrdiff_t loc_prev, ptrdiff_t loc_next, ptrdiff_t loc_data, size_t length, void *ls, void *le, void *re, cx_compare_func cmp_func, void **begin, void **end ) { void *sbo[CX_LINKED_LIST_SORT_SBO_SIZE]; void **sorted = length >= CX_LINKED_LIST_SORT_SBO_SIZE ? malloc(sizeof(void *) * length) : sbo; if (sorted == NULL) abort(); void *rc, *lc; lc = ls; rc = le; size_t n = 0; while (lc && lc != le && rc != re) { if (cmp_func(ll_data(lc), ll_data(rc)) <= 0) { sorted[n] = lc; lc = ll_next(lc); } else { sorted[n] = rc; rc = ll_next(rc); } n++; } while (lc && lc != le) { sorted[n] = lc; lc = ll_next(lc); n++; } while (rc && rc != re) { sorted[n] = rc; rc = ll_next(rc); n++; } // Update pointer if (loc_prev >= 0) ll_prev(sorted[0]) = NULL; cx_for_n (i, length - 1) { cx_linked_list_link(sorted[i], sorted[i + 1], loc_prev, loc_next); } ll_next(sorted[length - 1]) = NULL; *begin = sorted[0]; *end = sorted[length-1]; if (sorted != sbo) { free(sorted); } } void cx_linked_list_sort( // NOLINT(misc-no-recursion) - purposely recursive function void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, ptrdiff_t loc_data, cx_compare_func cmp_func ) { assert(begin != NULL); assert(loc_next >= 0); assert(loc_data >= 0); assert(cmp_func); void *lc, *ls, *le, *re; // set start node ls = *begin; // early exit when this list is empty if (ls == NULL) return; // check how many elements are already sorted lc = ls; size_t ln = 1; while (ll_next(lc) != NULL && cmp_func(ll_data(ll_next(lc)), ll_data(lc)) > 0) { lc = ll_next(lc); ln++; } le = ll_next(lc); // if first unsorted node is NULL, the list is already completely sorted if (le != NULL) { void *rc; size_t rn = 1; rc = le; // skip already sorted elements while (ll_next(rc) != NULL && cmp_func(ll_data(ll_next(rc)), ll_data(rc)) > 0) { rc = ll_next(rc); rn++; } re = ll_next(rc); // {ls,...,le->prev} and {rs,...,re->prev} are sorted - merge them void *sorted_begin, *sorted_end; cx_linked_list_sort_merge(loc_prev, loc_next, loc_data, ln + rn, ls, le, re, cmp_func, &sorted_begin, &sorted_end); // Something left? Sort it! size_t remainder_length = cx_linked_list_size(re, loc_next); if (remainder_length > 0) { void *remainder = re; cx_linked_list_sort(&remainder, NULL, loc_prev, loc_next, loc_data, cmp_func); // merge sorted list with (also sorted) remainder cx_linked_list_sort_merge(loc_prev, loc_next, loc_data, ln + rn + remainder_length, sorted_begin, remainder, NULL, cmp_func, &sorted_begin, &sorted_end); } *begin = sorted_begin; if (end) *end = sorted_end; } } int cx_linked_list_compare( void const *begin_left, void const *begin_right, ptrdiff_t loc_advance, ptrdiff_t loc_data, cx_compare_func cmp_func ) { void const *left = begin_left, *right = begin_right; while (left != NULL && right != NULL) { void const *left_data = ll_data(left); void const *right_data = ll_data(right); int result = cmp_func(left_data, right_data); if (result != 0) return result; left = ll_advance(left); right = ll_advance(right); } if (left != NULL) { return 1; } else if (right != NULL) { return -1; } else { return 0; } } void cx_linked_list_reverse( void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next ) { assert(begin != NULL); assert(loc_next >= 0); // swap all links void *prev = NULL; void *cur = *begin; while (cur != NULL) { void *next = ll_next(cur); ll_next(cur) = prev; if (loc_prev >= 0) { ll_prev(cur) = next; } prev = cur; cur = next; } // update begin and end if (end != NULL) { *end = *begin; } *begin = prev; } // HIGH LEVEL LINKED LIST IMPLEMENTATION typedef struct cx_linked_list_node cx_linked_list_node; struct cx_linked_list_node { cx_linked_list_node *prev; cx_linked_list_node *next; char payload[]; }; #define CX_LL_LOC_PREV offsetof(cx_linked_list_node, prev) #define CX_LL_LOC_NEXT offsetof(cx_linked_list_node, next) #define CX_LL_LOC_DATA offsetof(cx_linked_list_node, payload) typedef struct { struct cx_list_s base; cx_linked_list_node *begin; cx_linked_list_node *end; } cx_linked_list; static cx_linked_list_node *cx_ll_node_at( cx_linked_list const *list, size_t index ) { if (index >= list->base.size) { return NULL; } else if (index > list->base.size / 2) { return cx_linked_list_at(list->end, list->base.size - 1, CX_LL_LOC_PREV, index); } else { return cx_linked_list_at(list->begin, 0, CX_LL_LOC_NEXT, index); } } static int cx_ll_insert_at( struct cx_list_s *list, cx_linked_list_node *node, void const *elem ) { // create the new new_node cx_linked_list_node *new_node = cxMalloc(list->allocator, sizeof(cx_linked_list_node) + list->item_size); // sortir if failed if (new_node == NULL) return 1; // initialize new new_node new_node->prev = new_node->next = NULL; memcpy(new_node->payload, elem, list->item_size); // insert cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_insert_chain( (void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node, new_node, new_node ); // increase the size and return list->size++; return 0; } static size_t cx_ll_insert_array( struct cx_list_s *list, size_t index, void const *array, size_t n ) { // out-of bounds and corner case check if (index > list->size || n == 0) return 0; // find position efficiently cx_linked_list_node *node = index == 0 ? NULL : cx_ll_node_at((cx_linked_list *) list, index - 1); // perform first insert if (0 != cx_ll_insert_at(list, node, array)) { return 1; } // is there more? if (n == 1) return 1; // we now know exactly where we are node = node == NULL ? ((cx_linked_list *) list)->begin : node->next; // we can add the remaining nodes and immedately advance to the inserted node char const *source = array; for (size_t i = 1; i < n; i++) { source += list->item_size; if (0 != cx_ll_insert_at(list, node, source)) { return i; } node = node->next; } return n; } static int cx_ll_insert_element( struct cx_list_s *list, size_t index, void const *element ) { return 1 != cx_ll_insert_array(list, index, element, 1); } static int cx_ll_remove( struct cx_list_s *list, size_t index ) { cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_node *node = cx_ll_node_at(ll, index); // out-of-bounds check if (node == NULL) return 1; // element destruction cx_invoke_destructor(list, node->payload); // remove cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node); // adjust size list->size--; // free and return cxFree(list->allocator, node); return 0; } static void cx_ll_clear(struct cx_list_s *list) { if (list->size == 0) return; cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_node *node = ll->begin; while (node != NULL) { cx_invoke_destructor(list, node->payload); cx_linked_list_node *next = node->next; cxFree(list->allocator, node); node = next; } ll->begin = ll->end = NULL; list->size = 0; } #ifndef CX_LINKED_LIST_SWAP_SBO_SIZE #define CX_LINKED_LIST_SWAP_SBO_SIZE 128 #endif unsigned cx_linked_list_swap_sbo_size = CX_LINKED_LIST_SWAP_SBO_SIZE; static int cx_ll_swap( struct cx_list_s *list, size_t i, size_t j ) { if (i >= list->size || j >= list->size) return 1; if (i == j) return 0; // perform an optimized search that finds both elements in one run cx_linked_list *ll = (cx_linked_list *) list; size_t mid = list->size / 2; size_t left, right; if (i < j) { left = i; right = j; } else { left = j; right = i; } cx_linked_list_node *nleft, *nright; if (left < mid && right < mid) { // case 1: both items left from mid nleft = cx_ll_node_at(ll, left); assert(nleft != NULL); nright = nleft; for (size_t c = left; c < right; c++) { nright = nright->next; } } else if (left >= mid && right >= mid) { // case 2: both items right from mid nright = cx_ll_node_at(ll, right); assert(nright != NULL); nleft = nright; for (size_t c = right; c > left; c--) { nleft = nleft->prev; } } else { // case 3: one item left, one item right // chose the closest to begin / end size_t closest; size_t other; size_t diff2boundary = list->size - right - 1; if (left <= diff2boundary) { closest = left; other = right; nleft = cx_ll_node_at(ll, left); } else { closest = right; other = left; diff2boundary = left; nright = cx_ll_node_at(ll, right); } // is other element closer to us or closer to boundary? if (right - left <= diff2boundary) { // search other element starting from already found element if (closest == left) { nright = nleft; for (size_t c = left; c < right; c++) { nright = nright->next; } } else { nleft = nright; for (size_t c = right; c > left; c--) { nleft = nleft->prev; } } } else { // search other element starting at the boundary if (closest == left) { nright = cx_ll_node_at(ll, other); } else { nleft = cx_ll_node_at(ll, other); } } } if (list->item_size > CX_LINKED_LIST_SWAP_SBO_SIZE) { cx_linked_list_node *prev = nleft->prev; cx_linked_list_node *next = nright->next; cx_linked_list_node *midstart = nleft->next; cx_linked_list_node *midend = nright->prev; if (prev == NULL) { ll->begin = nright; } else { prev->next = nright; } nright->prev = prev; if (midstart == nright) { // special case: both nodes are adjacent nright->next = nleft; nleft->prev = nright; } else { // likely case: a chain is between the two nodes nright->next = midstart; midstart->prev = nright; midend->next = nleft; nleft->prev = midend; } nleft->next = next; if (next == NULL) { ll->end = nleft; } else { next->prev = nleft; } } else { // swap payloads to avoid relinking char buf[CX_LINKED_LIST_SWAP_SBO_SIZE]; memcpy(buf, nleft->payload, list->item_size); memcpy(nleft->payload, nright->payload, list->item_size); memcpy(nright->payload, buf, list->item_size); } return 0; } static void *cx_ll_at( struct cx_list_s const *list, size_t index ) { cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_node *node = cx_ll_node_at(ll, index); return node == NULL ? NULL : node->payload; } static ssize_t cx_ll_find_remove( struct cx_list_s *list, void const *elem, bool remove ) { if (remove) { cx_linked_list *ll = ((cx_linked_list *) list); cx_linked_list_node *node; ssize_t index = cx_linked_list_find_node( (void **) &node, ll->begin, CX_LL_LOC_NEXT, CX_LL_LOC_DATA, list->cmpfunc, elem ); if (node != NULL) { cx_invoke_destructor(list, node->payload); cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node); list->size--; cxFree(list->allocator, node); } return index; } else { return cx_linked_list_find( ((cx_linked_list *) list)->begin, CX_LL_LOC_NEXT, CX_LL_LOC_DATA, list->cmpfunc, elem ); } } static void cx_ll_sort(struct cx_list_s *list) { cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_sort((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, CX_LL_LOC_DATA, list->cmpfunc); } static void cx_ll_reverse(struct cx_list_s *list) { cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_reverse((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT); } static int cx_ll_compare( struct cx_list_s const *list, struct cx_list_s const *other ) { cx_linked_list *left = (cx_linked_list *) list; cx_linked_list *right = (cx_linked_list *) other; return cx_linked_list_compare(left->begin, right->begin, CX_LL_LOC_NEXT, CX_LL_LOC_DATA, list->cmpfunc); } static bool cx_ll_iter_valid(void const *it) { struct cx_iterator_s const *iter = it; return iter->elem_handle != NULL; } static void cx_ll_iter_next(void *it) { struct cx_iterator_base_s *itbase = it; if (itbase->remove) { itbase->remove = false; struct cx_mut_iterator_s *iter = it; struct cx_list_s *list = iter->src_handle; cx_linked_list *ll = iter->src_handle; cx_linked_list_node *node = iter->elem_handle; iter->elem_handle = node->next; cx_invoke_destructor(list, node->payload); cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node); list->size--; cxFree(list->allocator, node); } else { struct cx_iterator_s *iter = it; iter->index++; cx_linked_list_node *node = iter->elem_handle; iter->elem_handle = node->next; } } static void cx_ll_iter_prev(void *it) { struct cx_iterator_base_s *itbase = it; if (itbase->remove) { itbase->remove = false; struct cx_mut_iterator_s *iter = it; struct cx_list_s *list = iter->src_handle; cx_linked_list *ll = iter->src_handle; cx_linked_list_node *node = iter->elem_handle; iter->elem_handle = node->prev; iter->index--; cx_invoke_destructor(list, node->payload); cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node); list->size--; cxFree(list->allocator, node); } else { struct cx_iterator_s *iter = it; iter->index--; cx_linked_list_node *node = iter->elem_handle; iter->elem_handle = node->prev; } } static void *cx_ll_iter_current(void const *it) { struct cx_iterator_s const *iter = it; cx_linked_list_node *node = iter->elem_handle; return node->payload; } static CxIterator cx_ll_iterator( struct cx_list_s const *list, size_t index, bool backwards ) { CxIterator iter; iter.index = index; iter.src_handle = list; iter.elem_handle = cx_ll_node_at((cx_linked_list const *) list, index); iter.base.valid = cx_ll_iter_valid; iter.base.current = cx_ll_iter_current; iter.base.next = backwards ? cx_ll_iter_prev : cx_ll_iter_next; iter.base.mutating = false; iter.base.remove = false; return iter; } static int cx_ll_insert_iter( CxMutIterator *iter, void const *elem, int prepend ) { struct cx_list_s *list = iter->src_handle; cx_linked_list_node *node = iter->elem_handle; if (node != NULL) { assert(prepend >= 0 && prepend <= 1); cx_linked_list_node *choice[2] = {node, node->prev}; int result = cx_ll_insert_at(list, choice[prepend], elem); iter->index += prepend * (0 == result); return result; } else { int result = cx_ll_insert_element(list, list->size, elem); iter->index = list->size; return result; } } static void cx_ll_destructor(CxList *list) { cx_linked_list *ll = (cx_linked_list *) list; cx_linked_list_node *node = ll->begin; while (node) { cx_invoke_destructor(list, node->payload); void *next = node->next; cxFree(list->allocator, node); node = next; } cxFree(list->allocator, list); } static cx_list_class cx_linked_list_class = { cx_ll_destructor, cx_ll_insert_element, cx_ll_insert_array, cx_ll_insert_iter, cx_ll_remove, cx_ll_clear, cx_ll_swap, cx_ll_at, cx_ll_find_remove, cx_ll_sort, cx_ll_compare, cx_ll_reverse, cx_ll_iterator, }; CxList *cxLinkedListCreate( CxAllocator const *allocator, cx_compare_func comparator, size_t item_size ) { if (allocator == NULL) { allocator = cxDefaultAllocator; } cx_linked_list *list = cxCalloc(allocator, 1, sizeof(cx_linked_list)); if (list == NULL) return NULL; list->base.cl = &cx_linked_list_class; list->base.allocator = allocator; if (item_size > 0) { list->base.item_size = item_size; list->base.cmpfunc = comparator; } else { list->base.cmpfunc = comparator == NULL ? cx_cmp_ptr : comparator; cxListStorePointers((CxList *) list); } return (CxList *) list; }