little endian 和 big endian 转换



/* Routines to handle endianness */

#include <stdio.h>
#include <stdlib.h>

/* the following routine is taken from plikernel.c where it is static */
/* It swaps nitems of length size pointed to by ptr */

void sm_swap(void *ptr, size_t size, size_t nitems) {

        int i;
        char tmp, *lptr, *uptr;

        /* check for quick return */

        if ((size < 2) || (nitems < 1)) return;

        /* loop over all items */

        for (i = 0; i < nitems; i++) {
                lptr = ptr; lptr = lptr + i * size;
                uptr = lptr + size - 1;
                while (lptr < uptr) {
                        tmp = *lptr; *lptr = *uptr; *uptr = tmp;
                        lptr++; uptr--;
                }
        }

        /* normal return */

        return;

}