/* Copyright (C) 1991-2013 Free Software Foundation, Inc. This file is part of the GNU C Library. 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 <memcopy.h> #undef strncpy #ifndef STRNCPY #define STRNCPY strncpy #endif char * STRNCPY (char *s1, const char *s2, size_t n) { char c; char *s = s1; --s1; if (n >= 4) { size_t n4 = n >> 2; for (;;) { c = *s2++; *++s1 = c; if (c == '\0') break; c = *s2++; *++s1 = c; if (c == '\0') break; c = *s2++; *++s1 = c; if (c == '\0') break; c = *s2++; *++s1 = c; if (c == '\0') break; if (--n4 == 0) goto last_chars; } n = n - (s1 - s) - 1; if (n == 0) return s; goto zero_fill; } last_chars: n &= 3; if (n == 0) return s; do { c = *s2++; *++s1 = c; if (--n == 0) return s; } while (c != '\0'); zero_fill: do *++s1 = '\0'; while (--n > 0); return s; } libc_hidden_builtin_def (strncpy)