xref: /llvm-project/libc/src/string/strncpy.cpp (revision a0b65a7bcd6065688189b3d678c42ed6af9603db)
1 //===-- Implementation of strncpy -----------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/string/strncpy.h"
10 
11 #include "src/__support/common.h"
12 #include <stddef.h> // For size_t.
13 
14 namespace __llvm_libc {
15 
16 LLVM_LIBC_FUNCTION(char *, strncpy,
17                    (char *__restrict dest, const char *__restrict src,
18                     size_t n)) {
19   size_t i = 0;
20   // Copy up until \0 is found.
21   for (; i < n && src[i] != '\0'; ++i)
22     dest[i] = src[i];
23   // When n>strlen(src), n-strlen(src) \0 are appended.
24   for (; i < n; ++i)
25     dest[i] = '\0';
26   return dest;
27 }
28 
29 } // namespace __llvm_libc
30