42 lines · cpp
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-exception6//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 and33 // 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_DECL42