modules/src/string/long2str.c

   1 /* $Id: long2str.c,v 1.6 1994/06/24 11:22:36 ceriel Exp $ */
   2 /*
   3  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
   4  * See the copyright notice in the ACK home directory, in the file "Copyright".
   5  */
   6 /* Integer to String translator
   7         -> base is a value from [-16,-2] V [2,16]
   8         -> base < 0: see 'val' as unsigned value
   9         -> no checks for buffer overflow and illegal parameters
  10         (1985, EHB)
  11 */
  12
  13 #include "ack_string.h"
  14
  15 #define MAXWIDTH 32
  16
  17 char *
  18 long2str(val, base)
  19         register long val;
  20         register base;
  21 {
  22         static char numbuf[MAXWIDTH];
  23         static char vec[] = "0123456789ABCDEF";
  24         register char *p = &numbuf[MAXWIDTH];
  25         int sign = (base > 0);
  26
  27         *--p = '\0';            /* null-terminate string        */
  28         if (val) {
  29                 if (base > 0) {
  30                         if (val < 0L) {
  31                                 long v1 = -val;
  32                                 if (v1 == val)
  33                                         goto overflow;
  34                                 val = v1;
  35                         }
  36                         else
  37                                 sign = 0;
  38                 }
  39                 else
  40                 if (base < 0) {                 /* unsigned */
  41                         base = -base;
  42                         if (val < 0L) { /* taken from Amoeba src */
  43                                 register mod, i;
  44                         overflow:
  45                                 mod = 0;
  46                                 for (i = 0; i < 8 * sizeof val; i++) {
  47                                         mod <<= 1;
  48                                         if (val < 0)
  49                                                 mod++;
  50                                         val <<= 1;
  51                                         if (mod >= base) {
  52                                                 mod -= base;
  53                                                 val++;
  54                                         }
  55                                 }
  56                                 *--p = vec[mod];
  57                         }
  58                 }
  59                 do {
  60                         *--p = vec[(int) (val % base)];
  61                         val /= base;
  62                 } while (val != 0L);
  63                 if (sign)
  64                         *--p = '-';     /* don't forget it !!   */
  65         }
  66         else
  67                 *--p = '0';             /* just a simple 0      */
  68         return p;
  69 }