[PATCH v4] string: Adds tests for test-strncasecmp and test-strncpy

[Raphael Moreira Zinsly]

A couple more changes based on Adhemerval's review, thanks.

Changes since v3:
	- Using a cache line size of 64 if the system doesn't have meaningful
	information on _SC_LEVEL1_DCACHE_LINESIZE.
	- Using buf2 instead of a buf1 copy for s2 at
	string/test-strncasecmp.c.

--- >8 ---

Adds tests to check if strings placed at page bondaries are
handled correctly by strncasecmp and strncpy similar to tests
for strncmp and strnlen.
---
 string/test-strncasecmp.c | 43 +++++++++++++++++++++++++++++++++++++++
 string/test-strncpy.c     | 41 +++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)

diff --git a/string/test-strncasecmp.c b/string/test-strncasecmp.c
index 6a9c27beae..63f6d59ef2 100644
--- a/string/test-strncasecmp.c
+++ b/string/test-strncasecmp.c
@@ -137,6 +137,48 @@ do_test (size_t align1, size_t align2, size_t n, size_t len, int max_char,
     do_one_test (impl, s1, s2, n, exp_result);
 }
 
+static void
+do_page_tests (void)
+{
+  size_t i, offset, cacheline_size;
+  char *s1, *s2;
+  int exp_result;
+
+  offset = page_size - 1;
+  s1 = (char *) buf1;
+  s2 = (char *) buf2;
+  memset (s1, '\1', offset);
+  memset (s2, '\1', offset);
+  s1[offset] = '\0';
+  s2[offset] = '\0';
+
+  /* s2 has a fixed offset, half page long.
+     page_size is actually 2 * getpagesize.  */
+  offset = page_size / 4;
+  s2 += offset;
+  /* Start offset for s1 at half of the second page.  */
+  offset = 3 * page_size / 4;
+  s1 += offset;
+
+  /* Try to cross the page boundary at every offset of a cache line.  */
+  cacheline_size = sysconf (_SC_LEVEL1_DCACHE_LINESIZE);
+  /* Use 64 as default.  */
+  if(cacheline_size == 0)
+    cacheline_size = 64;
+  for (i = 0; i < cacheline_size; ++i)
+    {
+      exp_result = *s1;
+
+      FOR_EACH_IMPL (impl, 0)
+	{
+	  check_result (impl, s1, s2, page_size, -exp_result);
+	  check_result (impl, s2, s1, page_size, exp_result);
+	}
+
+      s1++;
+    }
+}
+
 static void
 do_random_tests (void)
 {
@@ -334,6 +376,7 @@ test_locale (const char *locale)
     }
 
   do_random_tests ();
+  do_page_tests ();
 }
 
 int
diff --git a/string/test-strncpy.c b/string/test-strncpy.c
index c978753ad8..051257f200 100644
--- a/string/test-strncpy.c
+++ b/string/test-strncpy.c
@@ -155,6 +155,46 @@ do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char)
     do_one_test (impl, s2, s1, len, n);
 }
 
+static void
+do_page_tests (void)
+{
+  size_t i, small_len, big_len, short_offset, long_offset, cacheline_size;
+  CHAR *s1, *s2;
+  /* Calculate the null character offset.  */
+  size_t last_offset = (page_size / sizeof (CHAR)) - 1;
+
+  s2 = (CHAR *) buf1;
+  s1 = (CHAR *) buf2;
+  MEMSET (s1, '\1', last_offset);
+  s1[last_offset] = '\0';
+
+  long_offset = (last_offset + 1) / 2;
+  short_offset = last_offset;
+
+  /* Try to cross the page boundary at every offset of a cache line.  */
+  cacheline_size = sysconf (_SC_LEVEL1_DCACHE_LINESIZE);
+  /* Use 64 as default.  */
+  if(cacheline_size == 0)
+    cacheline_size = 64;
+  for (i = 0; i < cacheline_size; i++)
+    {
+      /* Place long strings ending at page boundary.  */
+      long_offset++;
+      big_len = last_offset - long_offset;
+      /* Place short strings ending at page boundary.  */
+      short_offset--;
+      small_len = last_offset - short_offset;
+
+      FOR_EACH_IMPL (impl, 0)
+        {
+	  do_one_test (impl, s2, (CHAR *) (s1 + short_offset), small_len,
+	               small_len);
+	  do_one_test (impl, s2, (CHAR *) (s1 + long_offset), page_size,
+	               big_len);
+	}
+    }
+}
+
 static void
 do_random_tests (void)
 {
@@ -317,6 +357,7 @@ test_main (void)
     }
 
   do_random_tests ();
+  do_page_tests ();
   return ret;
 }
 
-- 
2.26.2