Aryadev Chavali
206dce7bab
Instead of having each page be an area of memory, where multiple pointers to differing data may lie, we instead have each page being one allocation. This ensures that a deletion algorithm, as provided, would actually work without destroying older pointers which may have been allocated. Great!
94 lines
1.7 KiB
C
94 lines
1.7 KiB
C
/* Copyright (C) 2023 Aryadev Chavali
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* You may distribute and modify this code under the terms of the
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* GPLv2 license. You should have received a copy of the GPLv2
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* license with this file. If not, please write to:
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* aryadev@aryadevchavali.com.
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* Created: 2023-11-01
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* Author: Aryadev Chavali
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* Description: Arena allocator
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*/
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#include "./heap.h"
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page_t *page_create(size_t max, page_t *next)
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{
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page_t *page = calloc(1, sizeof(*page) + max);
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page->available = max;
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page->next = next;
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return page;
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}
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void page_delete(page_t *page)
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{
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free(page);
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}
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void heap_create(heap_t *heap)
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{
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heap->beg = heap->end = NULL;
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heap->pages = 0;
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}
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void heap_free_page(heap_t *heap, page_t *page)
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{
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if (!page || !heap)
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return;
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if (page == heap->beg)
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{
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heap->beg = heap->beg->next;
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page_delete(page);
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--heap->pages;
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return;
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}
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page_t *prev = NULL, *next = NULL, *cur = NULL;
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for (cur = heap->beg; cur; cur = cur->next)
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{
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next = cur->next;
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if (cur == page)
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break;
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prev = cur;
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}
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if (!cur)
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// Couldn't find the page
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return;
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// Page was found
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prev->next = next;
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if (!next)
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// This means page == heap->end
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heap->end = prev;
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page_delete(page);
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--heap->pages;
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}
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page_t *heap_allocate(heap_t *heap, size_t requested)
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{
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page_t *cur = page_create(requested, NULL);
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if (heap->end)
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heap->end->next = cur;
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else
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heap->beg = cur;
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heap->end = cur;
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heap->pages++;
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return cur;
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}
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void heap_stop(heap_t *heap)
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{
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page_t *ptr = heap->beg;
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for (size_t i = 0; i < heap->pages; ++i)
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{
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page_t *cur = ptr;
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page_t *next = ptr->next;
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page_delete(cur);
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ptr = next;
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}
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heap->beg = NULL;
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heap->end = NULL;
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heap->pages = 0;
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}
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