1 #include <stdlib.h> 2 #include <assert.h> 3 #include <inttypes.h> 4 5 #include "memalign.h" 6 7 #define PTR_ALIGN(ptr, mask) \ 8 (char *)((uintptr_t)((ptr) + (mask)) & ~(mask)) 9 10 struct align_footer { 11 unsigned int offset; 12 }; 13 14 void *fio_memalign(size_t alignment, size_t size) 15 { 16 struct align_footer *f; 17 void *ptr, *ret = NULL; 18 19 assert(!(alignment & (alignment - 1))); 20 21 ptr = malloc(size + alignment + size + sizeof(*f) - 1); 22 if (ptr) { 23 ret = PTR_ALIGN(ptr, alignment - 1); 24 f = ret + size; 25 f->offset = (uintptr_t) ret - (uintptr_t) ptr; 26 } 27 28 return ret; 29 } 30 31 void fio_memfree(void *ptr, size_t size) 32 { 33 struct align_footer *f = ptr + size; 34 35 free(ptr - f->offset); 36 } 37
