#include <stdlib.h>
#include "csumconv.h"

char *
csumconv_stob(s, b, l)
	const char *s;
	char *b;
	int l;
{
	char c;
	int i;
	
	for (i=0; i<l; ++i) {
		if ('0' <= s[i] && s[i] <= '9')
			c=s[i]-'0';
		else if ('a' <= s[i] && s[i] <= 'f')
			c=s[i]-'a'+10;
		else
			return (NULL);
		if (i%2==0)
			c<<=4;
		b[i/2]|=c;					
	}
	return (b);
}

char *
csumconv_btos(b, s, l)
	char *s;
	const char *b;
	int l;
{
	char c;
	int i;

	for (i=0; i<l; ++i) {
		c=b[i/2];
		if (i%2==0)
			c>>=4;
		c&=0xf;		
		s[i]=(c<=9 ? '0'+c : 'a'+c-10);
	}
	s[l]=0x0;
	return (s);
}