source: trunk/minix/lib/other/paramvalue.c@ 20

/*      paramvalue() - decode kernel parameter values   Author: Kees J. Bot
 *                                                              7 May 1994
 * The kernel returns the results of parameter queries
 * by the XXQUERYPARAM svrctl calls as an array of hex digits, like this:
 * "75020000,080C0000".  These are the values of two four-byte variables.
 * Paramvalue() decodes such a string.
 */
#define nil 0
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <minix/queryparam.h>

size_t paramvalue(char **value, void *address, size_t size)
/* Decode the string *value storing the result in the object at address with
 * the given size.  *value is left at the next parameter, *address is padded
 * with zeros if needed, and the actual size of the value is returned.
 */
{
        unsigned char *addr= address;
        char *v= *value;
        int nibble;
        size_t n;

        n= 0;

        while (*v != 0 && *v != ',') {
                nibble= *v++ - '0';
                if (nibble > 0x9) nibble= nibble + '0' - 'A' + 0xA;
                if (nibble > 0xF) nibble= nibble + 'A' - 'a';
                if (size > 0) {
                        if (n % 2 == 0) {
                                *addr= nibble << 4;
                        } else {
                                *addr++|= nibble;
                                size--;
                        }
                        n++;
                }
        }
        while (size > 0) { *addr++= 0; size--; }
        while (*v != 0 && *v++ != ',') {}
        *value= v;
        return n / 2;
}


/*
 * $PchId: paramvalue.c,v 1.3 1996/02/22 09:15:56 philip Exp $
 */