36 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9#include "src/string/strncpy.h"10 11#include "src/__support/common.h"12#include "src/__support/macros/config.h"13#include "src/__support/macros/null_check.h"14#include <stddef.h> // For size_t.15 16namespace LIBC_NAMESPACE_DECL {17 18LLVM_LIBC_FUNCTION(char *, strncpy,19 (char *__restrict dest, const char *__restrict src,20 size_t n)) {21 if (n) {22 LIBC_CRASH_ON_NULLPTR(dest);23 LIBC_CRASH_ON_NULLPTR(src);24 }25 size_t i = 0;26 // Copy up until \0 is found.27 for (; i < n && src[i] != '\0'; ++i)28 dest[i] = src[i];29 // When n>strlen(src), n-strlen(src) \0 are appended.30 for (; i < n; ++i)31 dest[i] = '\0';32 return dest;33}34 35} // namespace LIBC_NAMESPACE_DECL36