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#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include "malloc_impl.h"
void *aligned_alloc(size_t align, size_t len)
{
unsigned char *mem, *new;
if ((align & -align) != align) {
errno = EINVAL;
return 0;
}
if (len > SIZE_MAX - align ||
(__malloc_replaced && !__aligned_alloc_replaced)) {
errno = ENOMEM;
return 0;
}
if (align <= SIZE_ALIGN)
return malloc(len);
if (!(mem = malloc(len + align-1)))
return 0;
new = (void *)((uintptr_t)mem + align-1 & -align);
if (new == mem) return mem;
struct chunk *c = MEM_TO_CHUNK(mem);
struct chunk *n = MEM_TO_CHUNK(new);
if (IS_MMAPPED(c)) {
/* Apply difference between aligned and original
* address to the "extra" field of mmapped chunk. */
n->psize = c->psize + (new-mem);
n->csize = c->csize - (new-mem);
return new;
}
struct chunk *t = NEXT_CHUNK(c);
/* Split the allocated chunk into two chunks. The aligned part
* that will be used has the size in its footer reduced by the
* difference between the aligned and original addresses, and
* the resulting size copied to its header. A new header and
* footer are written for the split-off part to be freed. */
n->psize = c->csize = C_INUSE | (new-mem);
n->csize = t->psize -= new-mem;
__bin_chunk(c);
return new;
}
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