1 files changed, 125 insertions, 0 deletions
diff --git a/lib/sh/strstr.c b/lib/sh/strstr.c
new file mode 100644
index 0000000..c43b05e
--- /dev/null
+++ b/lib/sh/strstr.c
@@ -0,0 +1,125 @@
+/* strstr - find a substring within a string */
+
+/* Copyright (C) 1994, 1999 Free Software Foundation, Inc.
+
+   This file is part of GNU Bash, the Bourne Again SHell.
+
+   Bash is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   Bash 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ * 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
+
+#if defined _LIBC || defined HAVE_STRING_H
+# include <string.h>
+#endif
+#include <sys/types.h>
+
+typedef unsigned chartype;
+
+#undef strstr
+
+char *
+strstr (const char *phaystack, const char *pneedle)
+{
+  register const unsigned char *haystack, *needle;
+  register chartype b, c;
+
+  haystack = (const unsigned char *) phaystack;
+  needle = (const unsigned char *) pneedle;
+
+  b = *needle;
+  if (b != '\0')
+    {
+      haystack--;				/* possible ANSI violation */
+      do
+	{
+	  c = *++haystack;
+	  if (c == '\0')
+	    goto ret0;
+	}
+      while (c != b);
+
+      c = *++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 (a == b)
+		break;
+	      a = *++haystack;
+	      if (a == '\0')
+		goto ret0;
+shloop:;    }
+          while (a != b);
+
+jin:	  a = *++haystack;
+	  if (a == '\0')
+	    goto ret0;
+
+	  if (a != c)
+	    goto shloop;
+
+	  rhaystack = haystack-- + 1;
+	  rneedle = needle;
+	  a = *rneedle;
+
+	  if (*rhaystack == a)
+	    do
+	      {
+		if (a == '\0')
+		  goto foundneedle;
+		++rhaystack;
+		a = *++needle;
+		if (*rhaystack != a)
+		  break;
+		if (a == '\0')
+		  goto foundneedle;
+		++rhaystack;
+		a = *++needle;
+	      }
+	    while (*rhaystack == a);
+
+	  needle = rneedle;		   /* took the register-poor approach */
+
+	  if (a == '\0')
+	    break;
+        }
+    }
+foundneedle:
+  return (char*) haystack;
+ret0:
+  return 0;
+}