77 lines
2.4 KiB
C
77 lines
2.4 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include <sys/ksys.h>
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#include "_mem.h"
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// realloc mem. using if other ways not working
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static void* fail_realloc(void* ptr, size_t newsize)
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{
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// Allocate a new block of memory with the new size.
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void* new_ptr = malloc(newsize);
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// If both the old pointer and the new pointer are not NULL:
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if (ptr != NULL && new_ptr != NULL) {
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// Copy the data from the old block to the new block.
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memcpy(new_ptr, ptr, min(newsize, GET_MEM_NODE_USED_MEM(GET_MEM_NODE_HEADER(ptr))));
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}
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if (ptr) {
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free(ptr); // Free the old block.
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}
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return new_ptr;
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}
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void* realloc(void* ptr, size_t newsize)
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{
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void* new_ptr = NULL;
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struct mem_node* node = NULL;
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if (ptr && newsize) {
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// Get a pointer to the mem_node header from the user data pointer.
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node = GET_MEM_NODE_HEADER(ptr);
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newsize = __mem_default_align(newsize);
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if (node->size >= newsize) { // current node have enough mem
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// it work always if newsize is smaller
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// Update the free space in the current node.
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node->free = node->size - newsize;
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// Return the original pointer.
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new_ptr = ptr;
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} else if (node->last && MEM_NODE_IS_FREE(node->last) && node->size + node->last->size >= newsize) {
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// So what happens here is that the node merges with the last node if their volume is sufficient.
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// And a reallock is called in the hopes that the first condition will be met.
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// if merge failed realloc anyway return pointer, but it will got from `fail_realloc`
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struct mem_node* l = node->last;
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l = __mem_MERGE_MEM_NODES(l, node);
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if (l) {
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memmove(GET_MEM_NODE_PTR(l), ptr, GET_MEM_NODE_USED_MEM(node));
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new_ptr = realloc(GET_MEM_NODE_PTR(l), newsize);
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}
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}
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}
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if (new_ptr == NULL) {
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// Allocate a new block of memory with the new size.
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new_ptr = malloc(newsize);
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// If both the old pointer and the new pointer are not NULL:
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if (ptr != NULL && new_ptr != NULL) {
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// Copy the data from the old block to the new block.
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memcpy(new_ptr, ptr, min(newsize, GET_MEM_NODE_USED_MEM(GET_MEM_NODE_HEADER(ptr))));
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}
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if (ptr) {
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free(ptr); // Free the old block.
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}
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}
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// Return the new pointer.
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return new_ptr;
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}
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