/* Copyright (C) 1991, 1997 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" char *strncat (char *s1, const char *s2, size_t n) { reg_char c; char *s = s1; /* Find the end of S1. */ do c = *s1++; while (c != '\0'); /* Make S1 point before next character, so we can increment it while memory is read (wins on pipelined cpus). */ s1 -= 2; if (n >= 4) { size_t n4 = n >> 2; do { c = *s2++; *++s1 = c; if (c == '\0') return s; c = *s2++; *++s1 = c; if (c == '\0') return s; c = *s2++; *++s1 = c; if (c == '\0') return s; c = *s2++; *++s1 = c; if (c == '\0') return s; } while (--n4 > 0); n &= 3; } while (n > 0) { c = *s2++; *++s1 = c; if (c == '\0') return s; n--; } if (c != '\0') *++s1 = '\0'; return s; } libc_hidden_def(strncat)