xref: /llvm-project/libc/src/string/memccpy.cpp (revision 5ff3ff33ff930e4ec49da7910612d8a41eb068cb)
1db8a88feSMichael Jones //===-- Implementation of memccpy ----------------------------------------===//
2db8a88feSMichael Jones //
3db8a88feSMichael Jones // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4db8a88feSMichael Jones // See https://llvm.org/LICENSE.txt for license information.
5db8a88feSMichael Jones // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6db8a88feSMichael Jones //
7db8a88feSMichael Jones //===----------------------------------------------------------------------===//
8db8a88feSMichael Jones 
9db8a88feSMichael Jones #include "src/string/memccpy.h"
10db8a88feSMichael Jones 
11db8a88feSMichael Jones #include "src/__support/common.h"
12*5ff3ff33SPetr Hosek #include "src/__support/macros/config.h"
13db8a88feSMichael Jones #include <stddef.h> // For size_t.
14db8a88feSMichael Jones 
15*5ff3ff33SPetr Hosek namespace LIBC_NAMESPACE_DECL {
16db8a88feSMichael Jones 
17db8a88feSMichael Jones LLVM_LIBC_FUNCTION(void *, memccpy,
18db8a88feSMichael Jones                    (void *__restrict dest, const void *__restrict src, int c,
19db8a88feSMichael Jones                     size_t count)) {
20db8a88feSMichael Jones   unsigned char end = static_cast<unsigned char>(c);
211c92911eSMichael Jones   const unsigned char *uc_src = static_cast<const unsigned char *>(src);
221c92911eSMichael Jones   unsigned char *uc_dest = static_cast<unsigned char *>(dest);
23db8a88feSMichael Jones   size_t i = 0;
24db8a88feSMichael Jones   // Copy up until end is found.
251c92911eSMichael Jones   for (; i < count && uc_src[i] != end; ++i)
261c92911eSMichael Jones     uc_dest[i] = uc_src[i];
27db8a88feSMichael Jones   // if i < count, then end must have been found, so copy end into dest and
28db8a88feSMichael Jones   // return the byte after.
29db8a88feSMichael Jones   if (i < count) {
301c92911eSMichael Jones     uc_dest[i] = uc_src[i];
311c92911eSMichael Jones     return uc_dest + i + 1;
32db8a88feSMichael Jones   }
33db8a88feSMichael Jones   return nullptr;
34db8a88feSMichael Jones }
35db8a88feSMichael Jones 
36*5ff3ff33SPetr Hosek } // namespace LIBC_NAMESPACE_DECL
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