femtolisp/llt/memalign.c

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#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <alloca.h>
#include "dtypes.h"
#include "utils.h"
#define ALIGNED_TO_ACTUAL(p) (((char*)p) - ((long*)p)[-1])
static void *aligned_ptr(char *ptr, size_t align_size)
{
char *ptr2, *aligned_ptr;
ptr2 = ptr + sizeof(long);
aligned_ptr = (char*)ALIGN(((uptrint_t)ptr2), align_size);
((long*)aligned_ptr)[-1] = (long)(aligned_ptr - ptr);
return aligned_ptr;
}
/* align_size has to be a power of two */
void *malloc_aligned(size_t size, size_t align_size)
{
char *ptr;
ptr = (char*)malloc(size + align_size-1 + sizeof(long));
if (ptr == NULL)
return NULL;
return aligned_ptr(ptr, align_size);
}
void free_aligned(void *ptr)
{
free(ALIGNED_TO_ACTUAL(ptr));
}
void *realloc_aligned(void *ptr, size_t size, size_t align_size)
{
char *pnew;
if (ptr != NULL)
ptr = ALIGNED_TO_ACTUAL(ptr);
pnew = realloc(ptr, size + align_size-1 + sizeof(long));
if (pnew == NULL)
return NULL;
return aligned_ptr(pnew, align_size);
}