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authorRoland McGrath <roland@gnu.org>2002-11-08 22:10:01 +0000
committerRoland McGrath <roland@gnu.org>2002-11-08 22:10:01 +0000
commite8c1660f7ba480c5a17103b557941fc6db7a5146 (patch)
tree71673df7864e35860bd8c7e8d2f3424fdb1dffc9
parente0bc9a8d13290de5328ae49311493246f406e0bd (diff)
downloadglibc-e8c1660f7ba480c5a17103b557941fc6db7a5146.tar.gz
glibc-e8c1660f7ba480c5a17103b557941fc6db7a5146.tar.xz
glibc-e8c1660f7ba480c5a17103b557941fc6db7a5146.zip
* string/test-strchr.c (stupid_strchr): New function.
	(do_random_tests): Make sure the string is zero terminated.
	* string/test-strpbrk.c (stupid_strpbrk): New function.
	(do_random_tests): Make sure the string is zero terminated.
	* string/test-strcmp.c (stupid_strcmp): New function.
	(do_random_tests): Make sure the strings are zero terminated.
	* string/test-strspn.c (stupid_strspn): New function.
	(simple_strspn): Rename rej argument to acc.
	(do_random_tests): Make sure the string is zero terminated.
	* string/test-strcspn.c (stupid_strcspn): New function.
	* string/test-strncpy.c (stupid_strncpy): New function.
	* string/test-stpncpy.c (stupid_stpncpy): New function.
	* string/test-strncmp.c (stupid_strncmp): New function.
	(do_random_tests): Make sure the strings are zero terminated.
	* string/test-string.h (impl_t): Change test into long.
	(IMPL): Add __attribute__((aligned (sizeof (void *)))).
-rw-r--r--ChangeLog22
-rw-r--r--string/test-stpncpy.c15
-rw-r--r--string/test-strchr.c24
-rw-r--r--string/test-strcmp.c57
-rw-r--r--string/test-strcspn.c17
-rw-r--r--string/test-string.h6
-rw-r--r--string/test-strncmp.c56
-rw-r--r--string/test-strncpy.c15
-rw-r--r--string/test-strpbrk.c44
-rw-r--r--string/test-strspn.c63
10 files changed, 233 insertions, 86 deletions
diff --git a/ChangeLog b/ChangeLog
index 2bde52c348..d9a987ac58 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,22 @@
+2002-11-08  Jakub Jelinek  <jakub@redhat.com>
+
+	* string/test-strchr.c (stupid_strchr): New function.
+	(do_random_tests): Make sure the string is zero terminated.
+	* string/test-strpbrk.c (stupid_strpbrk): New function.
+	(do_random_tests): Make sure the string is zero terminated.
+	* string/test-strcmp.c (stupid_strcmp): New function.
+	(do_random_tests): Make sure the strings are zero terminated.
+	* string/test-strspn.c (stupid_strspn): New function.
+	(simple_strspn): Rename rej argument to acc.
+	(do_random_tests): Make sure the string is zero terminated.
+	* string/test-strcspn.c (stupid_strcspn): New function.
+	* string/test-strncpy.c (stupid_strncpy): New function.
+	* string/test-stpncpy.c (stupid_stpncpy): New function.
+	* string/test-strncmp.c (stupid_strncmp): New function.
+	(do_random_tests): Make sure the strings are zero terminated.
+	* string/test-string.h (impl_t): Change test into long.
+	(IMPL): Add __attribute__((aligned (sizeof (void *)))).
+
 2002-11-08  Roland McGrath  <roland@redhat.com>
 
 	* sysdeps/ia64/elf/configure.in: Add TLS check.
@@ -11,9 +30,6 @@
 	[_LIBC] (_IO_do_write): Define as macro for _IO_new_do_write and
 	#undef before versioned_symbol use.
 
-	* string/test-string.h (test_init): Fill BUF1 and BUF2 with nonzero
-	characters.
-
 2002-11-07  Richard Henderson  <rth@redhat.com>
 
 	* configure.in (ASM_ALPHA_NG_SYMBOL_PREFIX): Remove test.
diff --git a/string/test-stpncpy.c b/string/test-stpncpy.c
index 5892c68dc1..5bcb1ddef4 100644
--- a/string/test-stpncpy.c
+++ b/string/test-stpncpy.c
@@ -23,7 +23,9 @@
 #include "test-string.h"
 
 char *simple_stpncpy (char *, const char *, size_t);
+char *stupid_stpncpy (char *, const char *, size_t);
 
+IMPL (stupid_stpncpy, 0)
 IMPL (simple_stpncpy, 0)
 IMPL (stpncpy, 1)
 
@@ -42,4 +44,17 @@ simple_stpncpy (char *dst, const char *src, size_t n)
   return dst;
 }
 
+char *
+stupid_stpncpy (char *dst, const char *src, size_t n)
+{
+  size_t ns = strlen (src);
+  size_t i, nc = n < ns ? n : ns;
+
+  for (i = 0; i < nc; ++i)
+    dst[i] = src[i];
+  for (; i < n; ++i)
+    dst[i] = '\0';
+  return dst + nc;
+}
+
 #include "test-strncpy.c"
diff --git a/string/test-strchr.c b/string/test-strchr.c
index 72f7ec9557..9483e719c0 100644
--- a/string/test-strchr.c
+++ b/string/test-strchr.c
@@ -23,7 +23,9 @@
 
 typedef char *(*proto_t) (const char *, int);
 char *simple_strchr (const char *, int);
+char *stupid_strchr (const char *, int);
 
+IMPL (stupid_strchr, 0)
 IMPL (simple_strchr, 0)
 IMPL (strchr, 1)
 
@@ -36,6 +38,17 @@ simple_strchr (const char *s, int c)
   return (char *) s;
 }
 
+char *
+stupid_strchr (const char *s, int c)
+{
+  size_t n = strlen (s) + 1;
+
+  while (n--)
+    if (*s++ == (char) c)
+      return (char *) s - 1;
+  return NULL;
+}
+
 static void
 do_one_test (impl_t *impl, const char *s, int c, char *exp_res)
 {
@@ -115,15 +128,18 @@ do_random_tests (void)
     {
       align = random () & 15;
       pos = random () & 511;
+      seek_char = random () & 255;
       if (pos + align >= 511)
 	pos = 510 - align - (random () & 7);
       len = random () & 511;
-      if (pos >= len)
-	len = pos + (random () & 7);
+      if ((pos == len && seek_char)
+	  || (pos > len && (random () & 1)))
+	len = pos + 1 + (random () & 7);
       if (len + align >= 512)
         len = 511 - align - (random () & 7);
-      seek_char = random () & 255;
-      j = len + align + 64;
+      if (pos == len && seek_char)
+	len = pos + 1;
+      j = (pos > len ? pos : len) + align + 64;
       if (j > 512)
         j = 512;
 
diff --git a/string/test-strcmp.c b/string/test-strcmp.c
index bfc147b701..dbbe3a4ff6 100644
--- a/string/test-strcmp.c
+++ b/string/test-strcmp.c
@@ -23,7 +23,9 @@
 
 typedef int (*proto_t) (const char *, const char *);
 int simple_strcmp (const char *, const char *);
+int stupid_strcmp (const char *, const char *);
 
+IMPL (stupid_strcmp, 0)
 IMPL (simple_strcmp, 0)
 IMPL (strcmp, 1)
 
@@ -37,6 +39,19 @@ simple_strcmp (const char *s1, const char *s2)
   return ret;
 }
 
+int
+stupid_strcmp (const char *s1, const char *s2)
+{
+  size_t ns1 = strlen (s1) + 1, ns2 = strlen (s2) + 1;
+  size_t n = ns1 < ns2 ? ns1 : ns2;
+  int ret = 0;
+
+  while (n--)
+    if ((ret = *(unsigned char *) s1++ - *(unsigned char *) s2++) != 0)
+      break;
+  return ret;
+}
+
 static void
 do_one_test (impl_t *impl, const char *s1, const char *s2, int exp_result)
 {
@@ -110,7 +125,7 @@ do_test (size_t align1, size_t align2, size_t len, int max_char,
 static void
 do_random_tests (void)
 {
-  size_t i, j, n, align1, align2, pos, len;
+  size_t i, j, n, align1, align2, pos, len1, len2;
   int result, r;
   unsigned char *p1 = buf1 + page_size - 512;
   unsigned char *p2 = buf2 + page_size - 512;
@@ -123,22 +138,25 @@ do_random_tests (void)
       else
 	align2 = align1 + (random () & 24);
       pos = random () & 511;
-      j = align1;
-      if (align2 > j)
-	j = align2;
+      j = align1 > align2 ? align1 : align2;
       if (pos + j >= 511)
 	pos = 510 - j - (random () & 7);
-      len = random () & 511;
-      if (pos >= len)
-        len = pos + (random () & 7);
-      if (len + j >= 512)
-        len = 511 - j - (random () & 7);
-      j = len + align1 + 64;
-      if (j > 512) j = 512;
+      len1 = random () & 511;
+      if (pos >= len1 && (random () & 1))
+        len1 = pos + (random () & 7);
+      if (len1 + j >= 512)
+        len1 = 511 - j - (random () & 7);
+      if (pos >= len1)
+	len2 = len1;
+      else
+	len2 = len1 + (len1 != 511 - j ? random () % (511 - j - len1) : 0);
+      j = (pos > len2 ? pos : len2) + align1 + 64;
+      if (j > 512)
+	j = 512;
       for (i = 0; i < j; ++i)
 	{
 	  p1[i] = random () & 255;
-	  if (i < len + align1 && !p1[i])
+	  if (i < len1 + align1 && !p1[i])
 	    {
 	      p1[i] = random () & 255;
 	      if (!p1[i])
@@ -148,7 +166,7 @@ do_random_tests (void)
       for (i = 0; i < j; ++i)
 	{
 	  p2[i] = random () & 255;
-	  if (i < len + align2 && !p2[i])
+	  if (i < len2 + align2 && !p2[i])
 	    {
 	      p2[i] = random () & 255;
 	      if (!p2[i])
@@ -158,12 +176,7 @@ do_random_tests (void)
 
       result = 0;
       memcpy (p2 + align2, p1 + align1, pos);
-      if (pos >= len)
-	{
-	  p1[len + align1] = 0;
-	  p2[len + align2] = 0;
-	}
-      else
+      if (pos < len1)
 	{
 	  if (p2[align2 + pos] == p1[align1 + pos])
 	    {
@@ -177,6 +190,8 @@ do_random_tests (void)
 	  else
 	    result = 1;
 	}
+      p1[len1 + align1] = 0;
+      p2[len2 + align2] = 0;
 
       FOR_EACH_IMPL (impl, 1)
 	{
@@ -185,8 +200,8 @@ do_random_tests (void)
 	      || (r < 0 && result >= 0)
 	      || (r > 0 && result <= 0))
 	    {
-	      error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %zd, %zd, %zd) %d != %d, p1 %p p2 %p",
-		     n, impl->name, align1, align2, len, pos, r, result, p1, p2);
+	      error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %zd, %zd, %zd, %zd) %d != %d, p1 %p p2 %p",
+		     n, impl->name, align1, align2, len1, len2, pos, r, result, p1, p2);
 	      ret = 1;
 	    }
 	}
diff --git a/string/test-strcspn.c b/string/test-strcspn.c
index 0fd65cd988..b5631790b6 100644
--- a/string/test-strcspn.c
+++ b/string/test-strcspn.c
@@ -25,7 +25,9 @@
 
 typedef size_t (*proto_t) (const char *, const char *);
 size_t simple_strcspn (const char *, const char *);
+size_t stupid_strcspn (const char *, const char *);
 
+IMPL (stupid_strcspn, 0)
 IMPL (simple_strcspn, 0)
 IMPL (strcspn, 1)
 
@@ -34,7 +36,7 @@ simple_strcspn (const char *s, const char *rej)
 {
   const char *r, *str = s;
   char c;
-    
+
   while ((c = *s++) != '\0')
     for (r = rej; *r != '\0'; ++r)
       if (*r == c)
@@ -42,4 +44,17 @@ simple_strcspn (const char *s, const char *rej)
   return s - str - 1;
 }
 
+size_t
+stupid_strcspn (const char *s, const char *rej)
+{
+  size_t ns = strlen (s), nrej = strlen (rej);
+  size_t i, j;
+
+  for (i = 0; i < ns; ++i)
+    for (j = 0; j < nrej; ++j)
+      if (s[i] == rej[j])
+	return i;
+  return i;
+}
+
 #include "test-strpbrk.c"
diff --git a/string/test-string.h b/string/test-string.h
index 896b713e17..ae7fc3440a 100644
--- a/string/test-string.h
+++ b/string/test-string.h
@@ -22,13 +22,13 @@ typedef struct
 {
   const char *name;
   void (*fn) (void);
-  int test;
+  long test;
 } impl_t;
 extern impl_t __start_impls[], __stop_impls[];
 
 #define IMPL(name, test) \
-  impl_t tst_ ## name				\
-  __attribute__ ((section ("impls"))) 		\
+  impl_t tst_ ## name							\
+  __attribute__ ((section ("impls"), aligned (sizeof (void *))))	\
     = { #name, (void (*) (void))name, test };
 
 #ifdef TEST_MAIN
diff --git a/string/test-strncmp.c b/string/test-strncmp.c
index b02b98775f..8881909646 100644
--- a/string/test-strncmp.c
+++ b/string/test-strncmp.c
@@ -23,7 +23,9 @@
 
 typedef int (*proto_t) (const char *, const char *, size_t);
 int simple_strncmp (const char *, const char *, size_t);
+int stupid_strncmp (const char *, const char *, size_t);
 
+IMPL (stupid_strncmp, 0)
 IMPL (simple_strncmp, 0)
 IMPL (strncmp, 1)
 
@@ -37,6 +39,18 @@ simple_strncmp (const char *s1, const char *s2, size_t n)
   return ret;
 }
 
+int
+stupid_strncmp (const char *s1, const char *s2, size_t n)
+{
+  size_t ns1 = strlen (s1) + 1, ns2 = strlen (s2) + 1;
+  int ret = 0;
+
+  n = ns1 < n ? ns1 : n;
+  n = ns2 < n ? ns2 : n;
+  while (n-- && (ret = *(unsigned char *) s1++ - * (unsigned char *) s2++) == 0);
+  return ret;
+}
+
 static void
 do_one_test (impl_t *impl, const char *s1, const char *s2, size_t n,
 	     int exp_result)
@@ -117,7 +131,7 @@ do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char,
 static void
 do_random_tests (void)
 {
-  size_t i, j, n, align1, align2, pos, len, size;
+  size_t i, j, n, align1, align2, pos, len1, len2, size;
   int result, r;
   unsigned char *p1 = buf1 + page_size - 512;
   unsigned char *p2 = buf2 + page_size - 512;
@@ -131,22 +145,25 @@ do_random_tests (void)
 	align2 = align1 + (random () & 24);
       pos = random () & 511;
       size = random () & 511;
-      j = align1;
-      if (align2 > j)
-	j = align2;
+      j = align1 > align2 ? align1 : align2;
       if (pos + j >= 511)
 	pos = 510 - j - (random () & 7);
-      len = random () & 511;
-      if (pos >= len)
-        len = pos + (random () & 7);
-      if (len + j >= 512)
-        len = 511 - j - (random () & 7);
-      j = len + align1 + 64;
-      if (j > 512) j = 512;
+      len1 = random () & 511;
+      if (pos >= len1 && (random () & 1))
+	len1 = pos + (random () & 7);
+      if (len1 + j >= 512)
+	len1 = 511 - j - (random () & 7);
+      if (pos >= len1)
+	len2 = len1;
+      else
+	len2 = len1 + (len1 != 511 - j ? random () % (511 - j - len1) : 0);
+      j = (pos > len2 ? pos : len2) + align1 + 64;
+      if (j > 512)
+	j = 512;
       for (i = 0; i < j; ++i)
 	{
 	  p1[i] = random () & 255;
-	  if (i < len + align1 && !p1[i])
+	  if (i < len1 + align1 && !p1[i])
 	    {
 	      p1[i] = random () & 255;
 	      if (!p1[i])
@@ -156,7 +173,7 @@ do_random_tests (void)
       for (i = 0; i < j; ++i)
 	{
 	  p2[i] = random () & 255;
-	  if (i < len + align2 && !p2[i])
+	  if (i < len2 + align2 && !p2[i])
 	    {
 	      p2[i] = random () & 255;
 	      if (!p2[i])
@@ -166,12 +183,7 @@ do_random_tests (void)
 
       result = 0;
       memcpy (p2 + align2, p1 + align1, pos);
-      if (pos >= len)
-	{
-	  p1[len + align1] = 0;
-	  p2[len + align2] = 0;
-	}
-      else
+      if (pos < len1)
 	{
 	  if (p2[align2 + pos] == p1[align1 + pos])
 	    {
@@ -188,6 +200,8 @@ do_random_tests (void)
 		result = 1;
 	    }
 	}
+      p1[len1 + align1] = 0;
+      p2[len2 + align2] = 0;
 
       FOR_EACH_IMPL (impl, 1)
 	{
@@ -196,8 +210,8 @@ do_random_tests (void)
 	      || (r < 0 && result >= 0)
 	      || (r > 0 && result <= 0))
 	    {
-	      error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %zd, %zd, %zd, %zd) %d != %d, p1 %p p2 %p",
-		     n, impl->name, align1, align2, len, pos, size, r, result, p1, p2);
+	      error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %zd, %zd, %zd, %zd, %zd) %d != %d, p1 %p p2 %p",
+		     n, impl->name, align1, align2, len1, len2, pos, size, r, result, p1, p2);
 	      ret = 1;
 	    }
 	}
diff --git a/string/test-strncpy.c b/string/test-strncpy.c
index 5aa51692bb..11ff30eebf 100644
--- a/string/test-strncpy.c
+++ b/string/test-strncpy.c
@@ -24,7 +24,9 @@
 # include "test-string.h"
 
 char *simple_strncpy (char *, const char *, size_t);
+char *stupid_strncpy (char *, const char *, size_t);
 
+IMPL (stupid_strncpy, 0)
 IMPL (simple_strncpy, 0)
 IMPL (strncpy, 1)
 
@@ -41,6 +43,19 @@ simple_strncpy (char *dst, const char *src, size_t n)
       }
   return ret;
 }
+
+char *
+stupid_strncpy (char *dst, const char *src, size_t n)
+{
+  size_t ns = strlen (src);
+  size_t i, nc = n < ns ? n : ns;
+
+  for (i = 0; i < nc; ++i)
+    dst[i] = src[i];
+  for (; i < n; ++i)
+    dst[i] = '\0';
+  return dst;
+}
 #endif
 
 typedef char *(*proto_t) (char *, const char *, size_t);
diff --git a/string/test-strpbrk.c b/string/test-strpbrk.c
index 06832556b6..77cf56dd16 100644
--- a/string/test-strpbrk.c
+++ b/string/test-strpbrk.c
@@ -26,7 +26,9 @@
 
 typedef char *(*proto_t) (const char *, const char *);
 char *simple_strpbrk (const char *, const char *);
+char *stupid_strpbrk (const char *, const char *);
 
+IMPL (stupid_strpbrk, 0)
 IMPL (simple_strpbrk, 0)
 IMPL (strpbrk, 1)
 
@@ -42,6 +44,19 @@ simple_strpbrk (const char *s, const char *rej)
 	return (char *) s - 1;
   return NULL;
 }
+
+char *
+stupid_strpbrk (const char *s, const char *rej)
+{
+  size_t ns = strlen (s), nrej = strlen (rej);
+  size_t i, j;
+
+  for (i = 0; i < ns; ++i)
+    for (j = 0; j < nrej; ++j)
+      if (s[i] == rej[j])
+	return (char *) s + i;
+  return NULL;
+}
 #endif
 
 static void
@@ -127,7 +142,7 @@ do_test (size_t align, size_t pos, size_t len)
 static void
 do_random_tests (void)
 {
-  size_t i, j, n, align, pos, len;
+  size_t i, j, n, align, pos, len, rlen;
   RES_TYPE result;
   int c;
   unsigned char *p = buf1 + page_size - 512;
@@ -139,12 +154,17 @@ do_random_tests (void)
       pos = random () & 511;
       if (pos + align >= 511)
 	pos = 510 - align - (random () & 7);
+      len = random () & 511;
+      if (pos >= len && (random () & 1))
+	len = pos + 1 + (random () & 7);
+      if (len + align >= 512)
+	len = 511 - align - (random () & 7);
       if (random () & 1)
-	len = random () & 63;
+	rlen = random () & 63;
       else
-	len = random () & 15;
-      rej = buf2 + page_size - len - 1 - (random () & 7);
-      for (i = 0; i < len; ++i)
+	rlen = random () & 15;
+      rej = buf2 + page_size - rlen - 1 - (random () & 7);
+      for (i = 0; i < rlen; ++i)
 	{
 	  rej[i] = random () & 255;
 	  if (!rej[i])
@@ -156,14 +176,16 @@ do_random_tests (void)
       for (c = 1; c <= 255; ++c)
 	if (strchr (rej, c) == NULL)
 	  break;
-      j = pos + align + 64;
+      j = (pos > len ? pos : len) + align + 64;
       if (j > 512)
 	j = 512;
 
       for (i = 0; i < j; i++)
 	{
-	  if (i == pos + align)
-	    p[i] = rej[random () % (len + 1)];
+	  if (i == len + align)
+	    p[i] = '\0';
+	  else if (i == pos + align)
+	    p[i] = rej[random () % (rlen + 1)];
 	  else if (i < align || i > pos + align)
 	    p[i] = random () & 255;
 	  else
@@ -178,13 +200,13 @@ do_random_tests (void)
 	    }
 	}
 
-      result = STRPBRK_RESULT (p + align, pos);
+      result = STRPBRK_RESULT (p + align, pos < len ? pos : len);
 
       FOR_EACH_IMPL (impl, 1)
 	if (CALL (impl, p + align, rej) != result)
 	  {
-	    error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %p, %zd, %zd) %p != %p",
-		   n, impl->name, align, rej, len, pos,
+	    error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %p, %zd, %zd, %zd) %p != %p",
+		   n, impl->name, align, rej, rlen, pos, len,
 		   (void *) CALL (impl, p + align, rej), (void *) result);
 	    ret = 1;
 	  }
diff --git a/string/test-strspn.c b/string/test-strspn.c
index 00e30b4657..4a6475295e 100644
--- a/string/test-strspn.c
+++ b/string/test-strspn.c
@@ -23,19 +23,21 @@
 
 typedef size_t (*proto_t) (const char *, const char *);
 size_t simple_strspn (const char *, const char *);
+size_t stupid_strspn (const char *, const char *);
 
+IMPL (stupid_strspn, 0)
 IMPL (simple_strspn, 0)
 IMPL (strspn, 1)
 
 size_t
-simple_strspn (const char *s, const char *rej)
+simple_strspn (const char *s, const char *acc)
 {
   const char *r, *str = s;
   char c;
 
   while ((c = *s++) != '\0')
     {
-      for (r = rej; *r != '\0'; ++r)
+      for (r = acc; *r != '\0'; ++r)
 	if (*r == c)
 	  break;
       if (*r == '\0')
@@ -44,6 +46,23 @@ simple_strspn (const char *s, const char *rej)
   return s - str - 1;
 }
 
+size_t
+stupid_strspn (const char *s, const char *acc)
+{
+  size_t ns = strlen (s), nacc = strlen (acc);
+  size_t i, j;
+
+  for (i = 0; i < ns; ++i)
+    {
+      for (j = 0; j < nacc; ++j)
+	if (s[i] == acc[j])
+	  break;
+      if (j == nacc)
+	return i;
+    }
+  return i;
+}
+
 static void
 do_one_test (impl_t *impl, const char *s, const char *acc, size_t exp_res)
 {
@@ -115,7 +134,7 @@ do_test (size_t align, size_t pos, size_t len)
 static void
 do_random_tests (void)
 {
-  size_t i, j, n, align, pos, len;
+  size_t i, j, n, align, pos, alen, len;
   unsigned char *p = buf1 + page_size - 512;
   unsigned char *acc;
 
@@ -123,17 +142,20 @@ do_random_tests (void)
     {
       align = random () & 15;
       if (random () & 1)
-	len = random () & 63;
+	alen = random () & 63;
       else
-	len = random () & 15;
-      if (!len)
+	alen = random () & 15;
+      if (!alen)
 	pos = 0;
       else
 	pos = random () & 511;
       if (pos + align >= 511)
 	pos = 510 - align - (random () & 7);
-      acc = buf2 + page_size - len - 1 - (random () & 7);
-      for (i = 0; i < len; ++i)
+      len = random () & 511;
+      if (len + align >= 512)
+	len = 511 - align - (random () & 7);
+      acc = buf2 + page_size - alen - 1 - (random () & 7);
+      for (i = 0; i < alen; ++i)
 	{
 	  acc[i] = random () & 255;
 	  if (!acc[i])
@@ -142,35 +164,32 @@ do_random_tests (void)
 	    acc[i] = 1 + (random () & 127);
 	}
       acc[i] = '\0';
-      j = pos + align + 64;
+      j = (pos > len ? pos : len) + align + 64;
       if (j > 512)
 	j = 512;
 
       for (i = 0; i < j; i++)
 	{
-	  if (i == pos + align)
+	  if (i == len + align)
+	    p[i] = '\0';
+	  else if (i == pos + align)
 	    {
-	      if ((random () & 7) == 0)
+	      p[i] = random () & 255;
+	      if (strchr (acc, p[i]))
 		p[i] = '\0';
-	      else
-		{
-		  p[i] = random () & 255;
-		  if (strchr (acc, p[i]))
-		    p[i] = '\0';
-		}
 	    }
 	  else if (i < align || i > pos + align)
 	    p[i] = random () & 255;
 	  else
-	    p[i] = acc [random () % len];
+	    p[i] = acc [random () % alen];
 	}
 
       FOR_EACH_IMPL (impl, 1)
-	if (CALL (impl, p + align, acc) != pos)
+	if (CALL (impl, p + align, acc) != (pos < len ? pos : len))
 	  {
-	    error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %p, %zd) %zd != %zd",
-		   n, impl->name, align, acc, len,
-		   CALL (impl, p + align, acc), pos);
+	    error (0, 0, "Iteration %zd - wrong result in function %s (%zd, %p, %zd, %zd, %zd) %zd != %zd",
+		   n, impl->name, align, acc, alen, pos, len,
+		   CALL (impl, p + align, acc), (pos < len ? pos : len));
 	    ret = 1;
 	  }
     }