node/src/util-inl.h

#ifndef SRC_UTIL_INL_H_
#define SRC_UTIL_INL_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include "util.h"
#include <cstring>

#if defined(_MSC_VER)
#include <intrin.h>
#define BSWAP_2(x) _byteswap_ushort(x)
#define BSWAP_4(x) _byteswap_ulong(x)
#define BSWAP_8(x) _byteswap_uint64(x)
#else
#define BSWAP_2(x) ((x) << 8) | ((x) >> 8)
#define BSWAP_4(x)                                                            \
  (((x) & 0xFF) << 24) |                                                      \
  (((x) & 0xFF00) << 8) |                                                     \
  (((x) >> 8) & 0xFF00) |                                                     \
  (((x) >> 24) & 0xFF)
#define BSWAP_8(x)                                                            \
  (((x) & 0xFF00000000000000ull) >> 56) |                                     \
  (((x) & 0x00FF000000000000ull) >> 40) |                                     \
  (((x) & 0x0000FF0000000000ull) >> 24) |                                     \
  (((x) & 0x000000FF00000000ull) >> 8) |                                      \
  (((x) & 0x00000000FF000000ull) << 8) |                                      \
  (((x) & 0x0000000000FF0000ull) << 24) |                                     \
  (((x) & 0x000000000000FF00ull) << 40) |                                     \
  (((x) & 0x00000000000000FFull) << 56)
#endif

namespace node {

template <typename T>
ListNode<T>::ListNode() : prev_(this), next_(this) {}

template <typename T>
ListNode<T>::~ListNode() {
  Remove();
}

template <typename T>
void ListNode<T>::Remove() {
  prev_->next_ = next_;
  next_->prev_ = prev_;
  prev_ = this;
  next_ = this;
}

template <typename T>
bool ListNode<T>::IsEmpty() const {
  return prev_ == this;
}

template <typename T, ListNode<T> (T::*M)>
ListHead<T, M>::Iterator::Iterator(ListNode<T>* node) : node_(node) {}

template <typename T, ListNode<T> (T::*M)>
T* ListHead<T, M>::Iterator::operator*() const {
  return ContainerOf(M, node_);
}

template <typename T, ListNode<T> (T::*M)>
const typename ListHead<T, M>::Iterator&
ListHead<T, M>::Iterator::operator++() {
  node_ = node_->next_;
  return *this;
}

template <typename T, ListNode<T> (T::*M)>
bool ListHead<T, M>::Iterator::operator!=(const Iterator& that) const {
  return node_ != that.node_;
}

template <typename T, ListNode<T> (T::*M)>
ListHead<T, M>::~ListHead() {
  while (IsEmpty() == false)
    head_.next_->Remove();
}

template <typename T, ListNode<T> (T::*M)>
void ListHead<T, M>::MoveBack(ListHead* that) {
  if (IsEmpty())
    return;
  ListNode<T>* to = &that->head_;
  head_.next_->prev_ = to->prev_;
  to->prev_->next_ = head_.next_;
  head_.prev_->next_ = to;
  to->prev_ = head_.prev_;
  head_.prev_ = &head_;
  head_.next_ = &head_;
}

template <typename T, ListNode<T> (T::*M)>
void ListHead<T, M>::PushBack(T* element) {
  ListNode<T>* that = &(element->*M);
  head_.prev_->next_ = that;
  that->prev_ = head_.prev_;
  that->next_ = &head_;
  head_.prev_ = that;
}

template <typename T, ListNode<T> (T::*M)>
void ListHead<T, M>::PushFront(T* element) {
  ListNode<T>* that = &(element->*M);
  head_.next_->prev_ = that;
  that->prev_ = &head_;
  that->next_ = head_.next_;
  head_.next_ = that;
}

template <typename T, ListNode<T> (T::*M)>
bool ListHead<T, M>::IsEmpty() const {
  return head_.IsEmpty();
}

template <typename T, ListNode<T> (T::*M)>
T* ListHead<T, M>::PopFront() {
  if (IsEmpty())
    return nullptr;
  ListNode<T>* node = head_.next_;
  node->Remove();
  return ContainerOf(M, node);
}

template <typename T, ListNode<T> (T::*M)>
typename ListHead<T, M>::Iterator ListHead<T, M>::begin() const {
  return Iterator(head_.next_);
}

template <typename T, ListNode<T> (T::*M)>
typename ListHead<T, M>::Iterator ListHead<T, M>::end() const {
  return Iterator(const_cast<ListNode<T>*>(&head_));
}

template <typename Inner, typename Outer>
ContainerOfHelper<Inner, Outer>::ContainerOfHelper(Inner Outer::*field,
                                                   Inner* pointer)
    : pointer_(reinterpret_cast<Outer*>(
          reinterpret_cast<uintptr_t>(pointer) -
          reinterpret_cast<uintptr_t>(&(static_cast<Outer*>(0)->*field)))) {
}

template <typename Inner, typename Outer>
template <typename TypeName>
ContainerOfHelper<Inner, Outer>::operator TypeName*() const {
  return static_cast<TypeName*>(pointer_);
}

template <typename Inner, typename Outer>
inline ContainerOfHelper<Inner, Outer> ContainerOf(Inner Outer::*field,
                                                   Inner* pointer) {
  return ContainerOfHelper<Inner, Outer>(field, pointer);
}

template <class TypeName>
inline v8::Local<TypeName> PersistentToLocal(
    v8::Isolate* isolate,
    const v8::Persistent<TypeName>& persistent) {
  if (persistent.IsWeak()) {
    return WeakPersistentToLocal(isolate, persistent);
  } else {
    return StrongPersistentToLocal(persistent);
  }
}

template <class TypeName>
inline v8::Local<TypeName> StrongPersistentToLocal(
    const v8::Persistent<TypeName>& persistent) {
  return *reinterpret_cast<v8::Local<TypeName>*>(
      const_cast<v8::Persistent<TypeName>*>(&persistent));
}

template <class TypeName>
inline v8::Local<TypeName> WeakPersistentToLocal(
    v8::Isolate* isolate,
    const v8::Persistent<TypeName>& persistent) {
  return v8::Local<TypeName>::New(isolate, persistent);
}

inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
                                           const char* data,
                                           int length) {
  return v8::String::NewFromOneByte(isolate,
                                    reinterpret_cast<const uint8_t*>(data),
                                    v8::NewStringType::kNormal,
                                    length).ToLocalChecked();
}

inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
                                           const signed char* data,
                                           int length) {
  return v8::String::NewFromOneByte(isolate,
                                    reinterpret_cast<const uint8_t*>(data),
                                    v8::NewStringType::kNormal,
                                    length).ToLocalChecked();
}

inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
                                           const unsigned char* data,
                                           int length) {
  return v8::String::NewFromOneByte(isolate,
                                    reinterpret_cast<const uint8_t*>(data),
                                    v8::NewStringType::kNormal,
                                    length).ToLocalChecked();
}

template <typename TypeName>
void Wrap(v8::Local<v8::Object> object, TypeName* pointer) {
  CHECK_EQ(false, object.IsEmpty());
  CHECK_GT(object->InternalFieldCount(), 0);
  object->SetAlignedPointerInInternalField(0, pointer);
}

void ClearWrap(v8::Local<v8::Object> object) {
  Wrap<void>(object, nullptr);
}

template <typename TypeName>
TypeName* Unwrap(v8::Local<v8::Object> object) {
  CHECK_EQ(false, object.IsEmpty());
  CHECK_GT(object->InternalFieldCount(), 0);
  void* pointer = object->GetAlignedPointerFromInternalField(0);
  return static_cast<TypeName*>(pointer);
}

void SwapBytes16(char* data, size_t nbytes) {
  CHECK_EQ(nbytes % 2, 0);

#if defined(_MSC_VER)
  int align = reinterpret_cast<uintptr_t>(data) % sizeof(uint16_t);
  if (align == 0) {
    // MSVC has no strict aliasing, and is able to highly optimize this case.
    uint16_t* data16 = reinterpret_cast<uint16_t*>(data);
    size_t len16 = nbytes / sizeof(*data16);
    for (size_t i = 0; i < len16; i++) {
      data16[i] = BSWAP_2(data16[i]);
    }
    return;
  }
#endif

  uint16_t temp;
  for (size_t i = 0; i < nbytes; i += sizeof(temp)) {
    memcpy(&temp, &data[i], sizeof(temp));
    temp = BSWAP_2(temp);
    memcpy(&data[i], &temp, sizeof(temp));
  }
}

void SwapBytes32(char* data, size_t nbytes) {
  CHECK_EQ(nbytes % 4, 0);

#if defined(_MSC_VER)
  int align = reinterpret_cast<uintptr_t>(data) % sizeof(uint32_t);
  // MSVC has no strict aliasing, and is able to highly optimize this case.
  if (align == 0) {
    uint32_t* data32 = reinterpret_cast<uint32_t*>(data);
    size_t len32 = nbytes / sizeof(*data32);
    for (size_t i = 0; i < len32; i++) {
      data32[i] = BSWAP_4(data32[i]);
    }
    return;
  }
#endif

  uint32_t temp;
  for (size_t i = 0; i < nbytes; i += sizeof(temp)) {
    memcpy(&temp, &data[i], sizeof(temp));
    temp = BSWAP_4(temp);
    memcpy(&data[i], &temp, sizeof(temp));
  }
}

void SwapBytes64(char* data, size_t nbytes) {
  CHECK_EQ(nbytes % 8, 0);

#if defined(_MSC_VER)
  int align = reinterpret_cast<uintptr_t>(data) % sizeof(uint64_t);
  if (align == 0) {
    // MSVC has no strict aliasing, and is able to highly optimize this case.
    uint64_t* data64 = reinterpret_cast<uint64_t*>(data);
    size_t len64 = nbytes / sizeof(*data64);
    for (size_t i = 0; i < len64; i++) {
      data64[i] = BSWAP_8(data64[i]);
    }
    return;
  }
#endif

  uint64_t temp;
  for (size_t i = 0; i < nbytes; i += sizeof(temp)) {
    memcpy(&temp, &data[i], sizeof(temp));
    temp = BSWAP_8(temp);
    memcpy(&data[i], &temp, sizeof(temp));
  }
}

char ToLower(char c) {
  return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c;
}

bool StringEqualNoCase(const char* a, const char* b) {
  do {
    if (*a == '\0')
      return *b == '\0';
    if (*b == '\0')
      return *a == '\0';
  } while (ToLower(*a++) == ToLower(*b++));
  return false;
}

bool StringEqualNoCaseN(const char* a, const char* b, size_t length) {
  for (size_t i = 0; i < length; i++) {
    if (ToLower(a[i]) != ToLower(b[i]))
      return false;
    if (a[i] == '\0')
      return true;
  }
  return true;
}

inline size_t MultiplyWithOverflowCheck(size_t a, size_t b) {
  size_t ret = a * b;
  if (a != 0)
    CHECK_EQ(b, ret / a);

  return ret;
}

// These should be used in our code as opposed to the native
// versions as they abstract out some platform and or
// compiler version specific functionality.
// malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
// that the standard allows them to either return a unique pointer or a
// nullptr for zero-sized allocation requests.  Normalize by always using
// a nullptr.
template <typename T>
T* UncheckedRealloc(T* pointer, size_t n) {
  size_t full_size = MultiplyWithOverflowCheck(sizeof(T), n);

  if (full_size == 0) {
    free(pointer);
    return nullptr;
  }

  void* allocated = realloc(pointer, full_size);

  if (UNLIKELY(allocated == nullptr)) {
    // Tell V8 that memory is low and retry.
    LowMemoryNotification();
    allocated = realloc(pointer, full_size);
  }

  return static_cast<T*>(allocated);
}

// As per spec realloc behaves like malloc if passed nullptr.
template <typename T>
inline T* UncheckedMalloc(size_t n) {
  if (n == 0) n = 1;
  return UncheckedRealloc<T>(nullptr, n);
}

template <typename T>
inline T* UncheckedCalloc(size_t n) {
  if (n == 0) n = 1;
  MultiplyWithOverflowCheck(sizeof(T), n);
  return static_cast<T*>(calloc(n, sizeof(T)));
}

template <typename T>
inline T* Realloc(T* pointer, size_t n) {
  T* ret = UncheckedRealloc(pointer, n);
  if (n > 0) CHECK_NE(ret, nullptr);
  return ret;
}

template <typename T>
inline T* Malloc(size_t n) {
  T* ret = UncheckedMalloc<T>(n);
  if (n > 0) CHECK_NE(ret, nullptr);
  return ret;
}

template <typename T>
inline T* Calloc(size_t n) {
  T* ret = UncheckedCalloc<T>(n);
  if (n > 0) CHECK_NE(ret, nullptr);
  return ret;
}

// Shortcuts for char*.
inline char* Malloc(size_t n) { return Malloc<char>(n); }
inline char* Calloc(size_t n) { return Calloc<char>(n); }
inline char* UncheckedMalloc(size_t n) { return UncheckedMalloc<char>(n); }
inline char* UncheckedCalloc(size_t n) { return UncheckedCalloc<char>(n); }

}  // namespace node

#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#endif  // SRC_UTIL_INL_H_