[Feature][ZXW-33]merge ZXW 0428 version
Change-Id: I11f167edfea428d9fab198ff00ff1364932d1b0b
diff --git a/ap/libc/glibc/glibc-2.23/string/strlen.c b/ap/libc/glibc/glibc-2.23/string/strlen.c
new file mode 100644
index 0000000..4943ce2
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/strlen.c
@@ -0,0 +1,109 @@
+/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Written by Torbjorn Granlund (tege@sics.se),
+ with help from Dan Sahlin (dan@sics.se);
+ commentary by Jim Blandy (jimb@ai.mit.edu).
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <string.h>
+#include <stdlib.h>
+
+#undef strlen
+
+#ifndef STRLEN
+# define STRLEN strlen
+#endif
+
+/* Return the length of the null-terminated string STR. Scan for
+ the null terminator quickly by testing four bytes at a time. */
+size_t
+STRLEN (const char *str)
+{
+ const char *char_ptr;
+ const unsigned long int *longword_ptr;
+ unsigned long int longword, himagic, lomagic;
+
+ /* Handle the first few characters by reading one character at a time.
+ Do this until CHAR_PTR is aligned on a longword boundary. */
+ for (char_ptr = str; ((unsigned long int) char_ptr
+ & (sizeof (longword) - 1)) != 0;
+ ++char_ptr)
+ if (*char_ptr == '\0')
+ return char_ptr - str;
+
+ /* All these elucidatory comments refer to 4-byte longwords,
+ but the theory applies equally well to 8-byte longwords. */
+
+ longword_ptr = (unsigned long int *) char_ptr;
+
+ /* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
+ the "holes." Note that there is a hole just to the left of
+ each byte, with an extra at the end:
+
+ bits: 01111110 11111110 11111110 11111111
+ bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
+
+ The 1-bits make sure that carries propagate to the next 0-bit.
+ The 0-bits provide holes for carries to fall into. */
+ himagic = 0x80808080L;
+ lomagic = 0x01010101L;
+ if (sizeof (longword) > 4)
+ {
+ /* 64-bit version of the magic. */
+ /* Do the shift in two steps to avoid a warning if long has 32 bits. */
+ himagic = ((himagic << 16) << 16) | himagic;
+ lomagic = ((lomagic << 16) << 16) | lomagic;
+ }
+ if (sizeof (longword) > 8)
+ abort ();
+
+ /* Instead of the traditional loop which tests each character,
+ we will test a longword at a time. The tricky part is testing
+ if *any of the four* bytes in the longword in question are zero. */
+ for (;;)
+ {
+ longword = *longword_ptr++;
+
+ if (((longword - lomagic) & ~longword & himagic) != 0)
+ {
+ /* Which of the bytes was the zero? If none of them were, it was
+ a misfire; continue the search. */
+
+ const char *cp = (const char *) (longword_ptr - 1);
+
+ if (cp[0] == 0)
+ return cp - str;
+ if (cp[1] == 0)
+ return cp - str + 1;
+ if (cp[2] == 0)
+ return cp - str + 2;
+ if (cp[3] == 0)
+ return cp - str + 3;
+ if (sizeof (longword) > 4)
+ {
+ if (cp[4] == 0)
+ return cp - str + 4;
+ if (cp[5] == 0)
+ return cp - str + 5;
+ if (cp[6] == 0)
+ return cp - str + 6;
+ if (cp[7] == 0)
+ return cp - str + 7;
+ }
+ }
+ }
+}
+libc_hidden_builtin_def (strlen)