git.zerfleddert.de Git - micropolis/blob - src/tcl/compat/strtol.c

   1 /*
   2  * strtol.c --
   3  *
   4  *      Source code for the "strtol" library procedure.
   5  *
   6  * Copyright 1988 Regents of the University of California
   7  * Permission to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose and without
   9  * fee is hereby granted, provided that the above copyright
  10  * notice appear in all copies.  The University of California
  11  * makes no representations about the suitability of this
  12  * software for any purpose.  It is provided "as is" without
  13  * express or implied warranty.
  14  */
  15
  16 #ifndef lint
  17 static char rcsid[] = "$Header: /sprite/src/lib/tcl/compat/RCS/strtol.c,v 1.1 91/09/22 15:42:49 ouster Exp $ SPRITE (Berkeley)";
  18 #endif /* not lint */
  19
  20 #include <ctype.h>
  21
  22 \f
  23 /*
  24  *----------------------------------------------------------------------
  25  *
  26  * strtol --
  27  *
  28  *      Convert an ASCII string into an integer.
  29  *
  30  * Results:
  31  *      The return value is the integer equivalent of string.  If endPtr
  32  *      is non-NULL, then *endPtr is filled in with the character
  33  *      after the last one that was part of the integer.  If string
  34  *      doesn't contain a valid integer value, then zero is returned
  35  *      and *endPtr is set to string.
  36  *
  37  * Side effects:
  38  *      None.
  39  *
  40  *----------------------------------------------------------------------
  41  */
  42
  43 long int
  44 strtol(string, endPtr, base)
  45     char *string;               /* String of ASCII digits, possibly
  46                                  * preceded by white space.  For bases
  47                                  * greater than 10, either lower- or
  48                                  * upper-case digits may be used.
  49                                  */
  50     char **endPtr;              /* Where to store address of terminating
  51                                  * character, or NULL. */
  52     int base;                   /* Base for conversion.  Must be less
  53                                  * than 37.  If 0, then the base is chosen
  54                                  * from the leading characters of string:
  55                                  * "0x" means hex, "0" means octal, anything
  56                                  * else means decimal.
  57                                  */
  58 {
  59     register char *p;
  60     int result;
  61
  62     /*
  63      * Skip any leading blanks.
  64      */
  65
  66     p = string;
  67     while (isspace(*p)) {
  68         p += 1;
  69     }
  70
  71     /*
  72      * Check for a sign.
  73      */
  74
  75     if (*p == '-') {
  76         p += 1;
  77         result = -(strtoul(p, endPtr, base));
  78     } else {
  79         if (*p == '+') {
  80             p += 1;
  81         }
  82         result = strtoul(p, endPtr, base);
  83     }
  84     if ((result == 0) && (endPtr != 0) && (*endPtr == p)) {
  85         *endPtr = string;
  86     }
  87     return result;
  88 }