libc/src/string/strspn.cpp

   1 //===-- Implementation of strspn ------------------------------------------===//
   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/strspn.h"
  10
  11 #include "src/__support/CPP/bitset.h"
  12 #include "src/__support/common.h"
  13 #include <stddef.h>
  14
  15 namespace LIBC_NAMESPACE {
  16
  17 LLVM_LIBC_FUNCTION(size_t, strspn, (const char *src, const char *segment)) {
  18   const char *initial = src;
  19   cpp::bitset<256> bitset;
  20
  21   for (; *segment; ++segment)
  22     bitset.set(*reinterpret_cast<const unsigned char *>(segment));
  23   for (; *src && bitset.test(*reinterpret_cast<const unsigned char *>(src));
  24        ++src)
  25     ;
  26   return src - initial;
  27 }
  28
  29 } // namespace LIBC_NAMESPACE