libc/src/search/lfind.cpp

   1 //===-- Implementation of lfind   -------------------------------*- C++ -*-===//
   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/search/lfind.h"
  10 #include "src/__support/CPP/cstddef.h" // cpp::byte
  11 #include "src/__support/common.h"
  12 #include "src/__support/macros/config.h"
  13 #include "src/__support/memory_size.h"
  14
  15 namespace LIBC_NAMESPACE_DECL {
  16 LLVM_LIBC_FUNCTION(void *, lfind,
  17                    (const void *key, const void *base, size_t *nmemb,
  18                     size_t size, int (*compar)(const void *, const void *))) {
  19   if (key == nullptr || base == nullptr || nmemb == nullptr ||
  20       compar == nullptr)
  21     return nullptr;
  22
  23   size_t byte_len = 0;
  24   if (internal::mul_overflow(*nmemb, size, &byte_len))
  25     return nullptr;
  26
  27   const cpp::byte *next = reinterpret_cast<const cpp::byte *>(base);
  28   const cpp::byte *end = next + byte_len;
  29   for (; next < end; next += size)
  30     if (compar(key, next) == 0)
  31       return const_cast<cpp::byte *>(next);
  32   return nullptr;
  33 }
  34
  35 } // namespace LIBC_NAMESPACE_DECL