diff options
Diffstat (limited to 'string/strncat.c')
| -rw-r--r-- | string/strncat.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/string/strncat.c b/string/strncat.c new file mode 100644 index 0000000000..2e2de11508 --- /dev/null +++ b/string/strncat.c @@ -0,0 +1,85 @@ +/* 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <string.h> + +#ifdef _LIBC +# include <memcopy.h> +#else +typedef char reg_char; +#endif + +#undef strncat + +char * +strncat (s1, s2, n) + 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; +} |