1//===-- Implementation of memccpy ----------------------------------------===//
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/memccpy.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(void *, memccpy,
19 (void *__restrict dest, const void *__restrict src, int c,
20 size_t count)) {
21 if (count) {
22 LIBC_CRASH_ON_NULLPTR(dest);
23 LIBC_CRASH_ON_NULLPTR(src);
24 }
25 unsigned char end = static_cast<unsigned char>(c);
26 const unsigned char *uc_src = static_cast<const unsigned char *>(src);
27 unsigned char *uc_dest = static_cast<unsigned char *>(dest);
28 size_t i = 0;
29 // Copy up until end is found.
30 for (; i < count && uc_src[i] != end; ++i)
31 uc_dest[i] = uc_src[i];
32 // if i < count, then end must have been found, so copy end into dest and
33 // return the byte after.
34 if (i < count) {
35 uc_dest[i] = uc_src[i];
36 return uc_dest + i + 1;
37 }
38 return nullptr;
39}
40
41} // namespace LIBC_NAMESPACE_DECL
42

source code of libc/src/string/memccpy.cpp