usr/src/lib/libast/common/comp/strstr.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 #if defined(__STDPP__directive) && defined(__STDPP__hide)
  25 __STDPP__directive pragma pp:hide strstr
  26 #else
  27 #define strstr          ______strstr
  28 #endif
  29
  30 #include <ast.h>
  31
  32 #if defined(__STDPP__directive) && defined(__STDPP__hide)
  33 __STDPP__directive pragma pp:nohide strstr
  34 #else
  35 #undef  strstr
  36 #endif
  37
  38 #if _lib_strstr
  39
  40 NoN(strstr)
  41
  42 #else
  43
  44 #if defined(__EXPORT__)
  45 #define extern  __EXPORT__
  46 #endif
  47
  48 extern char*
  49 strstr(register const char* s1, register const char* s2)
  50 {
  51         register int            c1;
  52         register int            c2;
  53         register const char*    t1;
  54         register const char*    t2;
  55
  56         if (s2)
  57         {
  58                 if (!*s2)
  59                         return (char*)s1;
  60                 c2 = *s2++;
  61                 while (c1 = *s1++)
  62                         if (c1 == c2)
  63                         {
  64                                 t1 = s1;
  65                                 t2 = s2;
  66                                 do
  67                                 {
  68                                         if (!*t2)
  69                                                 return (char*)s1 - 1;
  70                                 } while (*t1++ == *t2++);
  71                         }
  72         }
  73         return 0;
  74 }
  75
  76 #endif