Detect EOL on-the-fly in strstr, strcasestr and memmem.

ChangeLog

@@ -1,3 +1,15 @@
+2012-08-21  Maxim Kuvyrkov  <maxim@codesourcery.com>
+
+	[BZ #11607]
+	* NEWS: Add an entry.
+	* string/str-two-way.h (AVAILABLE1, AVAILABLE2, RET0_IF_0): New macros,
+	define their defaults.
+	(two_way_short_needle): Detect end-of-string on-the-fly.
+	* string/strcasestr.c, string/strstr.c (AVAILABLE): Update.
+	(AVAILABLE1, AVAILABLE2, RET0_IF_0, AVAILABLE_USES_J): Define.
+	* string/bug-strcasestr1.c: New test.
+	* string/Makefile: Run it.
+
 2012-08-21  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	[BZ #11607]

NEWS

@@ -9,8 +9,8 @@ Version 2.17
 
 * The following bugs are resolved with this release:
 
-  6778, 6808, 9685, 13717, 13939, 14042, 14090, 14166, 14150, 14151, 14154,
+  6778, 6808, 9685, 11607, 13717, 13939, 14042, 14090, 14166, 14150, 14151,
-  14157, 14166, 14173, 14195, 14283, 14298, 14303, 14307, 14328, 14331,
+  14154, 14157, 14166, 14173, 14195, 14283, 14298, 14303, 14307, 14328, 14331,
   14336, 14337, 14347, 14349
 
 * Support for STT_GNU_IFUNC symbols added for s390 and s390x.
@@ -25,6 +25,9 @@ Version 2.17
 * SystemTap static probes have been added into the dynamic linker.
   Implemented by Gary Benson.
 
+* Optimizations of string functions strstr, strcasestr and memmem.
+  Implemented by Maxim Kuvyrkov.
+
 * The minimum Linux kernel version that this version of the GNU C Library
   can be used with is 2.6.16.
 

string/Makefile

@@ -56,7 +56,7 @@ tests		:= tester inl-tester noinl-tester testcopy test-ffs	\
 		   tst-strtok tst-strxfrm bug-strcoll1 tst-strfry	\
 		   bug-strtok1 $(addprefix test-,$(strop-tests))	\
 		   bug-envz1 tst-strxfrm2 tst-endian tst-svc2		\
-		   bug-strstr1 bug-strchr1 tst-strtok_r
+		   bug-strstr1 bug-strcasestr1 bug-strchr1 tst-strtok_r
 
 
 include ../Rules
@@ -74,6 +74,7 @@ CFLAGS-stratcliff.c = -fno-builtin
 CFLAGS-test-ffs.c = -fno-builtin
 CFLAGS-tst-inlcall.c = -fno-builtin
 CFLAGS-bug-strstr1.c = -fno-builtin
+CFLAGS-bug-strcasestr1.c = -fno-builtin
 
 ifeq ($(cross-compiling),no)
 tests: $(objpfx)tst-svc.out

string/bug-strcasestr1.c

@@ -0,0 +1,39 @@
+/* Test for non-submitted strcasestr bug.
+   Copyright (C) 2012 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <string.h>
+
+#define TEST_FUNCTION do_test ()
+static int
+do_test (void)
+{
+  const char haystack[] = "AOKB";
+  const char needle[] = "OK";
+  const char *sub = strcasestr (haystack, needle);
+
+  if (sub == NULL)
+    {
+      fprintf (stderr, "BUG: didn't find \"%s\" in \"%s\"\n", needle, haystack);
+      return 1;
+    }
+
+  return 0;
+}
+
+#include "../test-skeleton.c"

string/str-two-way.h

@@ -75,6 +75,16 @@
 # define CMP_FUNC memcmp
 #endif
 
+#ifndef AVAILABLE1
+# define AVAILABLE1(h, h_l, j, n_l) AVAILABLE (h, h_l, j, n_l)
+#endif
+#ifndef AVAILABLE2
+# define AVAILABLE2(h, h_l, j, n_l) (1)
+#endif
+#ifndef RET0_IF_0
+# define RET0_IF_0(a) /* nothing */
+#endif
+
 /* Perform a critical factorization of NEEDLE, of length NEEDLE_LEN.
    Return the index of the first byte in the right half, and set
    *PERIOD to the global period of the right half.
@@ -266,37 +276,58 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len,
 	 required, and any mismatch results in a maximal shift.  */
       period = MAX (suffix, needle_len - suffix) + 1;
       j = 0;
-      while (AVAILABLE (haystack, haystack_len, j, needle_len))
+      while (AVAILABLE1 (haystack, haystack_len, j, needle_len))
 	{
+	  unsigned char haystack_char;
+
 	  /* TODO: The first-character loop can be sped up by adapting
 	     longword-at-a-time implementation of memchr/strchr.  */
 	  if (needle_suffix
-	      != CANON_ELEMENT (haystack[suffix + j]))
+	      != (haystack_char = CANON_ELEMENT (haystack[suffix + j])))
 	    {
+	      RET0_IF_0 (haystack_char);
 	      ++j;
 	      continue;
 	    }
 
 	  /* Scan for matches in right half.  */
 	  i = suffix + 1;
-	  while (i < needle_len && (CANON_ELEMENT (needle[i])
+	  while (i < needle_len)
-				    == CANON_ELEMENT (haystack[i + j])))
+	    {
+	      if (CANON_ELEMENT (needle[i])
+		  != (haystack_char = CANON_ELEMENT (haystack[i + j])))
+		{
+		  RET0_IF_0 (haystack_char);
+		  break;
+		}
 	      ++i;
+	    }
 	  if (needle_len <= i)
 	    {
 	      /* Scan for matches in left half.  */
 	      i = suffix - 1;
-	      while (i != SIZE_MAX && (CANON_ELEMENT (needle[i])
+	      while (i != SIZE_MAX)
-				       == CANON_ELEMENT (haystack[i + j])))
+		{
+		  if (CANON_ELEMENT (needle[i])
+		      != (haystack_char = CANON_ELEMENT (haystack[i + j])))
+		    {
+		      RET0_IF_0 (haystack_char);
+		      break;
+		    }
 		  --i;
+		}
 	      if (i == SIZE_MAX)
 		return (RETURN_TYPE) (haystack + j);
 	      j += period;
 	    }
 	  else
 	    j += i - suffix + 1;
+
+	  if (!AVAILABLE2 (haystack, haystack_len, j, needle_len))
+	    break;
 	}
     }
+ ret0: __attribute__ ((unused))
   return NULL;
 }
 
@@ -433,6 +464,9 @@ two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
 }
 
 #undef AVAILABLE
+#undef AVAILABLE1
+#undef AVAILABLE2
 #undef CANON_ELEMENT
 #undef CMP_FUNC
+#undef RET0_IF_0
 #undef RETURN_TYPE

string/strcasestr.c

@@ -1,6 +1,5 @@
 /* Return the offset of one string within another.
-   Copyright (C) 1994, 1996-2000, 2004, 2008, 2009, 2010
+   Copyright (C) 1994-2012 Free Software Foundation, Inc.
-   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
@@ -44,6 +43,9 @@
 #define AVAILABLE(h, h_l, j, n_l)			\
   (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l))	\
    && ((h_l) = (j) + (n_l)))
+#define AVAILABLE1(h, h_l, j, n_l) (true)
+#define AVAILABLE2(h, h_l, j, n_l) AVAILABLE (h, h_l, j, n_l)
+#define RET0_IF_0(a) if (!a) goto ret0
 #define CANON_ELEMENT(c) TOLOWER (c)
 #define CMP_FUNC(p1, p2, l)				\
   __strncasecmp ((const char *) (p1), (const char *) (p2), l)

string/strstr.c

@@ -1,6 +1,5 @@
 /* Return the offset of one string within another.
-   Copyright (C) 1994,1996,1997,2000,2001,2003,2008,2009
+   Copyright (C) 1994-2012 Free Software Foundation, Inc.
-   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
@@ -36,6 +35,9 @@
 #define AVAILABLE(h, h_l, j, n_l)			\
   (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l))	\
    && ((h_l) = (j) + (n_l)))
+#define AVAILABLE1(h, h_l, j, n_l) (true)
+#define AVAILABLE2(h, h_l, j, n_l) AVAILABLE (h, h_l, j, n_l)
+#define RET0_IF_0(a) if (!a) goto ret0
 #include "str-two-way.h"
 
 #undef strstr