149 lines
3.2 KiB
C
149 lines
3.2 KiB
C
#ifndef LINKED_LIST_C
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#define LINKED_LIST_C
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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typedef struct page_tag {
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size_t size;
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struct page_tag *prev;
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struct page_tag *next;
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} page_tag;
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page_tag *start;
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page_tag *__searchPage(void *data) {
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page_tag *curr_page = start;
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while (curr_page + (sizeof(page_tag)) != data) {
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curr_page = curr_page->next;
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}
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return curr_page;
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}
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///**
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// * @param alignment
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// * @param size
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// * @return A block aligned with the alignment parameter.
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// */
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//void* aligned_alloc(int alignment, int size){
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// // TODO
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// return NULL;
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//}
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void *__alloc(size_t size) {
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page_tag *curr_page = start;
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while (curr_page->next != NULL) {
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page_tag *new_page = ((void *) curr_page) + sizeof(page_tag) + curr_page->size;
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if ((void *) new_page + sizeof(page_tag) + size <= curr_page->next) {
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new_page->size = size;
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curr_page->next->prev = new_page;
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new_page->next = curr_page->next;
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curr_page->next = new_page;
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new_page->prev = curr_page;
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return new_page + 1;
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}
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curr_page = curr_page->next;
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}
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page_tag *new_page = ((void *) curr_page) + sizeof(page_tag) + curr_page->size;
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new_page->size = size;
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curr_page->next = new_page;
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new_page->prev = curr_page;
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return new_page + 1;
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}
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void __free(void *data) {
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page_tag *data_tag = data - sizeof(page_tag);
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printf("found tag at %p\n", data_tag);
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data_tag->prev->next = data_tag->next;
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data_tag->next->prev = data_tag->prev;
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}
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void print() {
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printf("==== MEM DUMP ====\n");
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page_tag *curr_page = start;
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int i = 0;
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while (curr_page != NULL) {
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printf("%d: [%p (%zu)] [%p (%zu)]\n",
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i,
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curr_page, sizeof(page_tag),
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curr_page + 1, curr_page->size);
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void *empty_start = (void *) curr_page + sizeof(page_tag) + curr_page->size;
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if (empty_start + sizeof(page_tag) < (void *) curr_page->next) {
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printf("empty_page (%ld, %ld)\n",
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sizeof(page_tag),
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(void *) curr_page->next -
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(empty_start + sizeof(page_tag)));
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} else if (empty_start < (void *) curr_page->next) {
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printf("not enough room (%ld)\n",
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(void *) curr_page->next - empty_start);
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}
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curr_page = curr_page->next;
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i++;
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}
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printf("-------------------\n\n");
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}
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void test_allocs() {
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void *ptr0 = __alloc(64);
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void *ptr1 = __alloc(64);
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void *ptr4 = __alloc(64);
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print();
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printf("Free nr 2 -> %p\n", ptr1);
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__free(ptr1);
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print();
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printf("Alloc 32 bytes\n");
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void *ptr2 = __alloc(32);
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print();
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printf("Alloc 32 bytes\n");
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__alloc(32);
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print();
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printf("Alloc 8 bytes\n");
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void *ptr3 = __alloc(8);
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print();
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__free(ptr2);
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print();
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__free(ptr4);
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print();
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__free(ptr3);
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print();
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__free(ptr0);
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print();
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printf("#########\nTry almost fill\n");
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__alloc(160);
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print();
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__alloc(50);
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print();
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}
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int main() {
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start = malloc(sizeof(size_t) * 1000);
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start->next = NULL;
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start->prev = NULL;
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test_allocs();
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}
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#endif // LINKED_LIST_C
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