Update.

1999-10-04  Ulrich Drepper  <drepper@cygnus.com>

	* include/string.h: Add __memrchr declaration.

	* string/string.h: Moce __memrchr declaration to include/string.h.

1999-10-03  Ulrich Drepper  <drepper@cygnus.com>

	* string/Makefile (routines): Add memrchr.

	* sysdeps/generic/memrchr.c: Don't undef memchr, undef memrchr.
	Correct order of tests for matching bytes.

	* string/tester.c: Add tests for memrchr.

	* sysdeps/i386/i486/bits/string.h (__memrchr): Correct implementation.
	Start from the last character and take decrement not increment
	into account for correction in return line.  Add memrchr alias.
	* sysdeps/i386/bits/string.h: Likewise.

7 files changed, 105 insertions, 27 deletions

diff --git a/ChangeLog b/ChangeLog
index a1a27fbf56..bd320a2fb9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+1999-10-04  Ulrich Drepper  <drepper@cygnus.com>
+
+	* include/string.h: Add __memrchr declaration.
+
+	* string/string.h: Moce __memrchr declaration to include/string.h.
+
+1999-10-03  Ulrich Drepper  <drepper@cygnus.com>
+
+	* string/Makefile (routines): Add memrchr.
+
+	* sysdeps/generic/memrchr.c: Don't undef memchr, undef memrchr.
+	Correct order of tests for matching bytes.
+
+	* string/tester.c: Add tests for memrchr.
+
+	* sysdeps/i386/i486/bits/string.h (__memrchr): Correct implementation.
+	Start from the last character and take decrement not increment
+	into account for correction in return line.  Add memrchr alias.
+	* sysdeps/i386/bits/string.h: Likewise.
+
 1999-10-04  Roland McGrath  <roland@baalperazim.frob.com>
 
 	* stdlib/stdlib.h [__USE_BSD]: Declare getloadavg.
diff --git a/include/string.h b/include/string.h
index 4d610bab62..4cd64fb226 100644
--- a/include/string.h
+++ b/include/string.h
@@ -20,4 +20,6 @@ extern __ptr_t __rawmemchr __P ((__const __ptr_t __s, int __c));
 
 extern char *__strchrnul __P ((__const char *__s, int __c));
 
+extern __ptr_t __memrchr __P ((__const __ptr_t __s, int __c, size_t __n));
+
 #endif
diff --git a/string/string.h b/string/string.h
index 03cf103ad6..a09d42a207 100644
--- a/string/string.h
+++ b/string/string.h
@@ -66,7 +66,6 @@ extern __ptr_t memchr __P ((__const __ptr_t __s, int __c, size_t __n));
 extern __ptr_t rawmemchr __P ((__const __ptr_t __s, int __c));
 
 /* Search N bytes of S for the final occurrence of C.  */
-extern __ptr_t __memrchr __P ((__const __ptr_t __s, int __c, size_t __n));
 extern __ptr_t memrchr __P ((__const __ptr_t __s, int __c, size_t __n));
 #endif
 
diff --git a/string/tester.c b/string/tester.c
index 5105e4eea4..4fed10e4b4 100644
--- a/string/tester.c
+++ b/string/tester.c
@@ -564,6 +564,52 @@ test_strrchr (void)
 }
 
 void
+test_memrchr (void)
+{
+  size_t l;
+  it = "memrchr";
+  check (memrchr ("abcd", 'z', 5) == NULL, 1);	/* Not found. */
+  (void) strcpy (one, "abcd");
+  l = strlen (one) + 1;
+  check (memrchr (one, 'c', l) == one+2, 2);	/* Basic test. */
+  check (memrchr (one, 'd', l) == one+3, 3);	/* End of string. */
+  check (memrchr (one, 'a', l) == one, 4);		/* Beginning. */
+  check (memrchr (one, '\0', l) == one+4, 5);	/* Finding NUL. */
+  (void) strcpy (one, "ababa");
+  l = strlen (one) + 1;
+  check (memrchr (one, 'b', l) == one+3, 6);	/* Finding last. */
+  (void) strcpy (one, "");
+  l = strlen (one) + 1;
+  check (memrchr (one, 'b', l) == NULL, 7);	/* Empty string. */
+  check (memrchr (one, '\0', l) == one, 8);	/* NUL in empty string. */
+
+  /* now test all possible alignment and length combinations to catch
+     bugs due to unrolled loops (assuming unrolling is limited to no
+     more than 128 byte chunks: */
+  {
+    char buf[128 + sizeof(long)];
+    long align, len, i, pos;
+
+    for (align = 0; align < (long) sizeof(long); ++align) {
+      for (len = 0; len < (long) (sizeof(buf) - align); ++len) {
+	for (i = 0; i < len; ++i)
+	  buf[align + i] = 'x';		/* don't depend on memset... */
+
+	for (pos = len - 1; pos >= 0; --pos) {
+#if 0
+	  printf("align %d, len %d, pos %d\n", align, len, pos);
+#endif
+	  check(memrchr(buf + align, 'x', len) == buf + align + pos, 9);
+	  check(memrchr(buf + align + pos + 1, 'x', len - (pos + 1)) == NULL,
+		10);
+	  buf[align + pos] = '-';
+	}
+      }
+    }
+  }
+}
+
+void
 test_rindex (void)
 {
   it = "rindex";
@@ -1183,6 +1229,9 @@ main (void)
   /* strrchr.  */
   test_strrchr ();
 
+  /* memrchr.  */
+  test_memrchr ();
+
   /* rindex - just like strrchr.  */
   test_rindex ();
 
diff --git a/sysdeps/generic/memrchr.c b/sysdeps/generic/memrchr.c
index c86625755b..874caf1072 100644
--- a/sysdeps/generic/memrchr.c
+++ b/sysdeps/generic/memrchr.c
@@ -51,6 +51,8 @@
 
 #include <sys/types.h>
 
+#undef memrchr
+
 
 /* Search no more than N bytes of S for C.  */
 __ptr_t
@@ -163,24 +165,24 @@ __memrchr (s, c_in, n)
 
 	  const unsigned char *cp = (const unsigned char *) longword_ptr;
 
-	  if (cp[0] == c)
-	    return (__ptr_t) cp;
-	  if (cp[1] == c)
-	    return (__ptr_t) &cp[1];
-	  if (cp[2] == c)
-	    return (__ptr_t) &cp[2];
-	  if (cp[3] == c)
-	    return (__ptr_t) &cp[3];
 #if LONG_MAX > 2147483647
-	  if (cp[4] == c)
-	    return (__ptr_t) &cp[4];
-	  if (cp[5] == c)
-	    return (__ptr_t) &cp[5];
-	  if (cp[6] == c)
-	    return (__ptr_t) &cp[6];
 	  if (cp[7] == c)
 	    return (__ptr_t) &cp[7];
+	  if (cp[6] == c)
+	    return (__ptr_t) &cp[6];
+	  if (cp[5] == c)
+	    return (__ptr_t) &cp[5];
+	  if (cp[4] == c)
+	    return (__ptr_t) &cp[4];
 #endif
+	  if (cp[3] == c)
+	    return (__ptr_t) &cp[3];
+	  if (cp[2] == c)
+	    return (__ptr_t) &cp[2];
+	  if (cp[1] == c)
+	    return (__ptr_t) &cp[1];
+	  if (cp[0] == c)
+	    return (__ptr_t) cp;
 	}
 
       n -= sizeof (longword);
diff --git a/sysdeps/i386/bits/string.h b/sysdeps/i386/bits/string.h
index 01c17db68d..b727e2bc17 100644
--- a/sysdeps/i386/bits/string.h
+++ b/sysdeps/i386/bits/string.h
@@ -319,13 +319,16 @@ __memrchr (__const void *__s, int __c, size_t __n)
     ("std\n\t"
      "repne; scasb\n\t"
      "je 1f\n\t"
-     "movl $1,%0\n"
+     "orl $-1,%0\n"
      "1:\tcld"
      : "=D" (__res), "=&c" (__d0)
-     : "a" (__c), "0" (__s), "1" (__n)
+     : "a" (__c), "0" (__s + __n - 1), "1" (__n)
      : "cc");
-  return __res - 1;
+  return __res + 1;
 }
+# ifdef __USE_GNU
+#  define memrchr(s, c, n) __memrchr (s, c, n)
+# endif
 #endif
 
 /* Return the length of S.  */
diff --git a/sysdeps/i386/i486/bits/string.h b/sysdeps/i386/i486/bits/string.h
index 9b37f5898e..54e5ac4620 100644
--- a/sysdeps/i386/i486/bits/string.h
+++ b/sysdeps/i386/i486/bits/string.h
@@ -452,34 +452,37 @@ __STRING_INLINE void *
 __memrchr (__const void *__s, int __c, size_t __n)
 {
   register unsigned long int __d0;
-#ifdef __i686__
+# ifdef __i686__
   register unsigned long int __d1;
-#endif
+# endif
   register void *__res;
   if (__n == 0)
     return NULL;
-#ifdef __i686__
+# ifdef __i686__
   __asm__ __volatile__
     ("std\n\t"
      "repne; scasb\n\t"
      "cmovne %2,%0\n\t"
      "cld"
      : "=D" (__res), "=&c" (__d0), "=&r" (__d1)
-     : "a" (__c), "0" (__s), "1" (__n), "2" (1)
+     : "a" (__c), "0" (__s + __n - 1), "1" (__n), "2" (-1)
      : "cc");
-#else
+# else
   __asm__ __volatile__
     ("std\n\t"
      "repne; scasb\n\t"
      "je 1f\n\t"
-     "movl $1,%0\n"
+     "orl $-1,%0\n"
      "1:\tcld"
      : "=D" (__res), "=&c" (__d0)
-     : "a" (__c), "0" (__s), "1" (__n)
+     : "a" (__c), "0" (__s + __n - 1), "1" (__n)
      : "cc");
-#endif
-  return __res - 1;
+# endif
+  return __res + 1;
 }
+# ifdef __USE_GNU
+#  define memrchr(s, c, n) __memrchr (s, c, n)
+# endif
 #endif
 
 /* Return pointer to C in S.  */