// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_UTIL_INL_H_
#define SRC_UTIL_INL_H_

#ifndef NODE_UTIL_H_INCLUDE
    #error "util-inl.h could only be included in util.h"
#endif

#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_
