wcsmbs: optimize wcpncpy

This patch rewrites wcpncpy using wcslen, wmemcpy, and wmemset.  This is
similar to the optimization done on stpncpy by 48497aba8e.

Checked on x86_64-linux-gnu.

        * wcsmbs/wcpncpy.c (__wcpcpy): Rewrite using wcslen, wmemcpy, and
	wmemset.

diff --git a/ChangeLog b/ChangeLog
index 2e0b69d20df337ed3c5d438c04462b5fea3f2b0d..5ff8f8af438dbae2d6c51f914c8c823a3073c1f3 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2019-02-27  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+       * wcsmbs/wcpncpy.c (__wcpcpy): Rewrite using wcslen, wmemcpy, and
+       wmemset.
+
        * sysdeps/m68k/wcpcpy.c: Remove file.
        * wcsmbs/wcpcpy.c (__wcpcpy): Rewrite using wcslen and wmemcpy.
 

diff --git a/wcsmbs/wcpncpy.c b/wcsmbs/wcpncpy.c
index 7568f3b11c4ab2e6b0e50c8129b85656924accb5..74f22c277cdcd296b9011a90ddd3c5d8af2c29d5 100644 (file)
--- a/wcsmbs/wcpncpy.c
+++ b/wcsmbs/wcpncpy.c
@@ -27,59 +27,12 @@
 wchar_t *
 __wcpncpy (wchar_t *dest, const wchar_t *src, size_t n)
 {
-  wint_t c;
-  wchar_t *const s = dest;
-
-  if (n >= 4)
-    {
-      size_t n4 = n >> 2;
-
-      for (;;)
-       {
-         c = *src++;
-         *dest++ = c;
-         if (c == L'\0')
-           break;
-         c = *src++;
-         *dest++ = c;
-         if (c == L'\0')
-           break;
-         c = *src++;
-         *dest++ = c;
-         if (c == L'\0')
-           break;
-         c = *src++;
-         *dest++ = c;
-         if (c == L'\0')
-           break;
-         if (--n4 == 0)
-           goto last_chars;
-       }
-      n -= dest - s;
-      goto zero_fill;
-    }
-
- last_chars:
-  n &= 3;
-  if (n == 0)
+  size_t size = __wcsnlen (src, n);
+  __wmemcpy (dest, src, size);
+  dest += size;
+  if (size == n)
     return dest;
-
-  for (;;)
-    {
-      c = *src++;
-      --n;
-      *dest++ = c;
-      if (c == L'\0')
-       break;
-      if (n == 0)
-       return dest;
-    }
-
- zero_fill:
-  while (n-- > 0)
-    dest[n] = L'\0';
-
-  return dest - 1;
+  return wmemset (dest, L'\0', (n - size));
 }
 
 #ifndef WCPNCPY