usr/src/lib/libast/common/string/chrtoi.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * Glenn Fowler
  25  * AT&T Bell Laboratories
  26  *
  27  * convert a 0 terminated character constant string to an int
  28  */
  29
  30 #include <ast.h>
  31
  32 int
  33 chrtoi(register const char* s)
  34 {
  35         register int    c;
  36         register int    n;
  37         register int    x;
  38         char*           p;
  39
  40         c = 0;
  41         for (n = 0; n < sizeof(int) * CHAR_BIT; n += CHAR_BIT)
  42         {
  43                 switch (x = *((unsigned char*)s++))
  44                 {
  45                 case '\\':
  46                         x = chresc(s - 1, &p);
  47                         s = (const char*)p;
  48                         break;
  49                 case 0:
  50                         return(c);
  51                 }
  52                 c = (c << CHAR_BIT) | x;
  53         }
  54         return(c);
  55 }