libcxx/src/typeinfo.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <typeinfo>

#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_ABI_VCRUNTIME)

#  include <string.h>

int std::type_info::__compare(const type_info& __rhs) const noexcept {
  if (&__data == &__rhs.__data)
    return 0;
  return strcmp(&__data.__decorated_name[1], &__rhs.__data.__decorated_name[1]);
}

const char* std::type_info::name() const noexcept {
  // TODO(compnerd) cache demangled &__data.__decorated_name[1]
  return &__data.__decorated_name[1];
}

size_t std::type_info::hash_code() const noexcept {
#  if defined(_WIN64)
  constexpr size_t fnv_offset_basis = 14695981039346656037ull;
  constexpr size_t fnv_prime        = 10995116282110ull;
#  else
  constexpr size_t fnv_offset_basis = 2166136261ull;
  constexpr size_t fnv_prime        = 16777619ull;
#  endif

  size_t value = fnv_offset_basis;
  for (const char* c = &__data.__decorated_name[1]; *c; ++c) {
    value ^= static_cast<size_t>(static_cast<unsigned char>(*c));
    value *= fnv_prime;
  }

#  if defined(_WIN64)
  value ^= value >> 32;
#  endif

  return value;
}
#endif // _LIBCPP_ABI_MICROSOFT

// FIXME: Remove the _LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY configuration.
#if (!defined(LIBCXX_BUILDING_LIBCXXABI) && !defined(LIBCXXRT) && !defined(__GLIBCXX__) &&                             \
     !defined(_LIBCPP_ABI_VCRUNTIME)) ||                                                                               \
    defined(_LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY)
std::type_info::~type_info() {}
#endif