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wcsmbs: optimize wcsncpy 

This patch rewrites wcsncpy using wcsnlen, wmemset, and wmemcpy.  This is
similar to the optimization done on strncpy by f6482cf29d and 6423d4754c.

Checked on x86_64-linux-gnu.

	* wcsmbs/wcsncpy.c (__wcsncpy): Rewrite using wcsnlen, wmemset, and
	wmemcpy.
This commit is contained in:
Adhemerval Zanella 2019-02-05 18:48:31 -02:00
parent ddf21ec79f
commit 30a7e2081c
2 changed files with 7 additions and 56 deletions
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3
ChangeLog
View File

@ -1,5 +1,8 @@
2019-02-27 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* wcsmbs/wcsncpy.c (__wcsncpy): Rewrite using wcsnlen, wmemset, and
wmemcpy.
* wcsmbs/wcsncat.c (wcsncat): Rewrite using wcslen, wcsnlen, and
wmemcpy.

60
wcsmbs/wcsncpy.c
View File

@ -26,62 +26,10 @@
wchar_t *
__wcsncpy (wchar_t *dest, const wchar_t *src, size_t n)
{
wint_t c;
wchar_t *const s = dest;
--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 = n - (dest - s) - 1;
if (n == 0)
return s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return s;
do
{
c = *src++;
*++dest = c;
if (--n == 0)
return s;
}
while (c != L'\0');
zero_fill:
do
*++dest = L'\0';
while (--n > 0);
return s;
size_t size = __wcsnlen (src, n);
if (size != n)
__wmemset (dest + size, L'\0', n - size);
return __wmemcpy (dest, src, size);
}
#ifndef WCSNCPY
weak_alias (__wcsncpy, wcsncpy)