2.5-18.1

string/strcasestr.c

@@ -0,0 +1,142 @@
+/* Return the offset of one string within another.
+   Copyright (C) 1994, 1996-2000, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/*
+ * My personal strstr() implementation that beats most other algorithms.
+ * Until someone tells me otherwise, I assume that this is the
+ * fastest implementation of strstr() in C.
+ * I deliberately chose not to comment it.  You should have at least
+ * as much fun trying to understand it, as I had to write it :-).
+ *
+ * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de	*/
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <ctype.h>
+
+#if defined _LIBC || defined HAVE_STRING_H
+# include <string.h>
+#endif
+
+#ifdef _LIBC
+# include <locale/localeinfo.h>
+# define TOLOWER(c) __tolower_l ((unsigned char) c, loc)
+#else
+# define TOLOWER(c) _tolower (c)
+#endif
+
+typedef unsigned chartype;
+
+#undef strcasestr
+#undef __strcasestr
+
+char *
+__strcasestr (phaystack, pneedle)
+     const char *phaystack;
+     const char *pneedle;
+{
+  register const unsigned char *haystack, *needle;
+  register chartype b, c;
+#ifdef _LIBC
+  __locale_t loc = _NL_CURRENT_LOCALE;
+#endif
+
+  haystack = (const unsigned char *) phaystack;
+  needle = (const unsigned char *) pneedle;
+
+  b = TOLOWER (*needle);
+  if (b != '\0')
+    {
+      haystack--;				/* possible ANSI violation */
+      do
+	{
+	  c = *++haystack;
+	  if (c == '\0')
+	    goto ret0;
+	}
+      while (TOLOWER (c) != (int) b);
+
+      c = TOLOWER (*++needle);
+      if (c == '\0')
+	goto foundneedle;
+      ++needle;
+      goto jin;
+
+      for (;;)
+        {
+          register chartype a;
+	  register const unsigned char *rhaystack, *rneedle;
+
+	  do
+	    {
+	      a = *++haystack;
+	      if (a == '\0')
+		goto ret0;
+	      if (TOLOWER (a) == (int) b)
+		break;
+	      a = *++haystack;
+	      if (a == '\0')
+		goto ret0;
+shloop:
+	      ;
+	    }
+          while (TOLOWER (a) != (int) b);
+
+jin:	  a = *++haystack;
+	  if (a == '\0')
+	    goto ret0;
+
+	  if (TOLOWER (a) != (int) c)
+	    goto shloop;
+
+	  rhaystack = haystack-- + 1;
+	  rneedle = needle;
+	  a = TOLOWER (*rneedle);
+
+	  if (TOLOWER (*rhaystack) == (int) a)
+	    do
+	      {
+		if (a == '\0')
+		  goto foundneedle;
+		++rhaystack;
+		a = TOLOWER (*++needle);
+		if (TOLOWER (*rhaystack) != (int) a)
+		  break;
+		if (a == '\0')
+		  goto foundneedle;
+		++rhaystack;
+		a = TOLOWER (*++needle);
+	      }
+	    while (TOLOWER (*rhaystack) == (int) a);
+
+	  needle = rneedle;		/* took the register-poor approach */
+
+	  if (a == '\0')
+	    break;
+        }
+    }
+foundneedle:
+  return (char*) haystack;
+ret0:
+  return 0;
+}
+
+weak_alias (__strcasestr, strcasestr)