source: trunk/minix/commands/aal/long2str.c@ 15

/* $Header: /cvsup/minix/src/commands/aal/long2str.c,v 1.1.1.1 2005/04/21 14:53:57 beng Exp $ */
/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* Integer to String translator
        -> base is a value from [-16,-2] V [2,16]
        -> base < 0: see 'val' as unsigned value
        -> no checks for buffer overflow and illegal parameters
        (1985, EHB)
*/

#define MAXWIDTH 32

char *
long2str(val, base)
        register long val;
        register base;
{
        static char numbuf[MAXWIDTH];
        static char vec[] = "0123456789ABCDEF";
        register char *p = &numbuf[MAXWIDTH];
        int sign = (base > 0);

        *--p = '\0';            /* null-terminate string        */
        if (val) {
                if (base > 0) {
                        if (val < 0L) {
                                long v1 = -val;
                                if (v1 == val)
                                        goto overflow;
                                val = v1;
                        }
                        else
                                sign = 0;
                }
                else
                if (base < 0) {                 /* unsigned */
                        base = -base;
                        if (val < 0L) { /* taken from Amoeba src */
                                register mod, i;
                        overflow:
                                mod = 0;
                                for (i = 0; i < 8 * sizeof val; i++) {
                                        mod <<= 1;
                                        if (val < 0)
                                                mod++;
                                        val <<= 1;
                                        if (mod >= base) {
                                                mod -= base;
                                                val++;
                                        }
                                }
                                *--p = vec[mod];
                        }
                }
                do {
                        *--p = vec[(int) (val % base)];
                        val /= base;
                } while (val != 0L);
                if (sign)
                        *--p = '-';     /* don't forget it !!   */
        }
        else
                *--p = '0';             /* just a simple 0      */
        return p;
}