129 lines
4.1 KiB
C
129 lines
4.1 KiB
C
#include "list_ops.h"
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#include <string.h>
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// constructs a new list
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list_t *new_list(size_t length, list_element_t elements[]) {
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list_t *newList = malloc(sizeof(list_t) + length * sizeof(list_element_t));
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if (newList != NULL) {
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newList->length = length;
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if (length > 0 && elements != NULL) {
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memcpy(newList->elements, elements, length * sizeof(list_element_t));
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}
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}
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return newList;
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}
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// append entries to a list and return the new list
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list_t *append_list(list_t *list1, list_t *list2) {
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if (list1 == NULL && list2 == NULL) {
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return NULL; // Both lists are empty
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} else if (list1 == NULL) {
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return list2; // Only list1 is empty, return list2
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} else if (list2 == NULL) {
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return list1; // Only list2 is empty, return list1
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}
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size_t new_length = list1->length + list2->length;
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list_t *new_list = malloc(sizeof(list_t) + new_length * sizeof(list_element_t));
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if (new_list == NULL) {
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return NULL; // Memory allocation failed
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}
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memcpy(new_list->elements, list1->elements, list1->length * sizeof(list_element_t));
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memcpy(new_list->elements + list1->length, list2->elements, list2->length * sizeof(list_element_t));
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new_list->length = new_length;
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return new_list;
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}
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// filter list returning only values that satisfy the filter function
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list_t *filter_list(list_t *list, bool (*filter)(list_element_t)) {
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if (list == NULL) return NULL;
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size_t filteredLength = 0;
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for (size_t i = 0; i < list->length; ++i) {
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if (filter(list->elements[i])) {
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++filteredLength;
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}
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}
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list_t *filtered = malloc(sizeof(list_t) + filteredLength * sizeof(list_element_t));
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if (filtered != NULL) {
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filtered->length = filteredLength;
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for (size_t i = 0; i < list->length; ++i) {
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if (filter(list->elements[i])) {
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filtered->elements[i] = list->elements[i];
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}
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}
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}
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return filtered;
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}
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// returns the length of the list
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size_t length_list(list_t *list) {
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return (list != NULL) ? list->length : 0;
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}
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// return a list of elements whose values equal the list value transformed by
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// the mapping function
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list_t *map_list(list_t *list, list_element_t (*map)(list_element_t)) {
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if (list == NULL) return NULL;
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list_t *mappedList = new_list(list->length, list->elements);
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if (mappedList != NULL) {
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for (size_t i = 0; i < list->length; ++i) {
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mappedList->elements[i] = map(list->elements[i]);
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}
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}
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return mappedList;
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}
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// folds (reduces) the given list from the left with a function
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list_element_t foldl_list(list_t *list, list_element_t initial,
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list_element_t (*foldl)(list_element_t, list_element_t)) {
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list_element_t accumulator = initial;
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if (list != NULL) {
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for (size_t i = 0; i < list->length; ++i) {
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accumulator = foldl(list->elements[i], accumulator);
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}
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}
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return accumulator;
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}
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// folds (reduces) the given list from the right with a function
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list_element_t foldr_list(list_t *list, list_element_t initial,
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list_element_t (*foldr)(list_element_t, list_element_t)) {
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list_element_t accumulator = initial;
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if (list != NULL) {
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for (size_t i = list->length; i > 0; --i) {
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accumulator = foldr(list->elements[i - 1], accumulator);
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}
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}
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return accumulator;
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}
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// reverse the elements of the list
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list_t *reverse_list(list_t *list) {
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if (list == NULL) return NULL;
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list_t *reversedList = new_list(list->length, list->elements);
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if (reversedList != NULL) {
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for (size_t i = 0; i < list->length / 2; ++i) {
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list_element_t temp = reversedList->elements[i];
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reversedList->elements[i] = reversedList->elements[list->length - i - 1];
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reversedList->elements[list->length - i - 1] = temp;
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}
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}
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return reversedList;
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}
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// destroy the entire list
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// list will be a dangling pointer after calling this method on it
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void delete_list(list_t *list) {
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free(list);
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}
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