minix/lib/libminlib/paramvalue.c

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2005-11-08 14:59:27 +01:00
/* 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 $
*/