//

// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)

//

// Distributed under the Boost Software License, Version 1.0. (See accompanying

// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

//

// Official repository: https://github.com/boostorg/json

//

#ifndef BOOST_JSON_IMPL_ARRAY_IPP

#define BOOST_JSON_IMPL_ARRAY_IPP

#include <boost/core/detail/static_assert.hpp>

#include <boost/container_hash/hash.hpp>

#include <boost/json/array.hpp>

#include <boost/json/pilfer.hpp>

#include <boost/json/detail/except.hpp>

#include <cstdlib>

#include <limits>

#include <new>

#include <utility>

namespace boost {

namespace json {

//----------------------------------------------------------

constexpr array::table::table() = default;

// empty arrays point here

BOOST_JSON_REQUIRE_CONST_INIT

array::table array::empty_;

auto

array::

table::

allocate(

    std::size_t capacity,

    storage_ptr const& sp) ->

        table*

{

    BOOST_ASSERT(capacity > 0);

    if(capacity > array::max_size())

    {

        BOOST_STATIC_CONSTEXPR source_location loc = BOOST_CURRENT_LOCATION;

        detail::throw_system_error( error::array_too_large, &loc );

    }

    auto p = reinterpret_cast<

        table*>(sp->allocate(

            sizeof(table) +

                capacity * sizeof(value),

            alignof(value)));

    p->capacity = static_cast<

        std::uint32_t>(capacity);

    return p;

}

void

array::

table::

deallocate(

    table* p,

    storage_ptr const& sp)

{

    if(p->capacity == 0)

        return;

    sp->deallocate(p,

        sizeof(table) +

            p->capacity * sizeof(value),

        alignof(value));

}

//----------------------------------------------------------

array::

revert_insert::

revert_insert(

    const_iterator pos,

    std::size_t n,

    array& arr)

    : arr_(&arr)

    , i_(pos - arr_->data())

    , n_(n)

{

    BOOST_ASSERT(

        pos >= arr_->begin() &&

        pos <= arr_->end());

    if( n_ <= arr_->capacity() -

        arr_->size())

    {

        // fast path

        p = arr_->data() + i_;

        if(n_ == 0)

            return;

        relocate(

            p + n_,

            p,

            arr_->size() - i_);

        arr_->t_->size = static_cast<

            std::uint32_t>(

                arr_->t_->size + n_);

        return;

    }

    if(n_ > max_size() - arr_->size())

    {

        BOOST_STATIC_CONSTEXPR source_location loc = BOOST_CURRENT_LOCATION;

        detail::throw_system_error( error::array_too_large, &loc );

    }

    auto t = table::allocate(

        arr_->growth(arr_->size() + n_),

            arr_->sp_);

    t->size = static_cast<std::uint32_t>(

        arr_->size() + n_);

    p = &(*t)[0] + i_;

    relocate(

        &(*t)[0],

        arr_->data(),

        i_);

    relocate(

        &(*t)[i_ + n_],

        arr_->data() + i_,

        arr_->size() - i_);

    t = detail::exchange(arr_->t_, t);

    table::deallocate(t, arr_->sp_);

}

array::

revert_insert::

~revert_insert()

{

    if(! arr_)

        return;

    BOOST_ASSERT(n_ != 0);

    auto const pos =

        arr_->data() + i_;

    arr_->destroy(pos, p);

    arr_->t_->size = static_cast<

        std::uint32_t>(

            arr_->t_->size - n_);

    relocate(

        pos,

        pos + n_,

        arr_->size() - i_);

}

//----------------------------------------------------------

void

array::

destroy(

    value* first, value* last) noexcept

{

    if(sp_.is_not_shared_and_deallocate_is_trivial())

        return;

    while(last-- != first)

        last->~value();

}

void

array::

destroy() noexcept

{

    if(sp_.is_not_shared_and_deallocate_is_trivial())

        return;

    auto last = end();

    auto const first = begin();

    while(last-- != first)

        last->~value();

    table::deallocate(t_, sp_);

}

//----------------------------------------------------------

//

// Special Members

//

//----------------------------------------------------------

array::

array(detail::unchecked_array&& ua)

    : sp_(ua.storage())

{

    BOOST_CORE_STATIC_ASSERT( alignof(table) == alignof(value) );

    if(ua.size() == 0)

    {

        t_ = &empty_;

        return;

    }

    t_= table::allocate(

        ua.size(), sp_);

    t_->size = static_cast<

        std::uint32_t>(ua.size());

    ua.relocate(data());

}

array::

~array() noexcept

{

    destroy();

}

array::

array(

    std::size_t count,

    value const& v,

    storage_ptr sp)

    : sp_(std::move(sp))

{

    if(count == 0)

    {

        t_ = &empty_;

        return;

    }

    t_= table::allocate(

        count, sp_);

    t_->size = 0;

    revert_construct r(*this);

    while(count--)

    {

        ::new(end()) value(v, sp_);

        ++t_->size;

    }

    r.commit();

}

array::

array(

    std::size_t count,

    storage_ptr sp)

    : sp_(std::move(sp))

{

    if(count == 0)

    {

        t_ = &empty_;

        return;

    }

    t_ = table::allocate(

        count, sp_);

    t_->size = static_cast<

        std::uint32_t>(count);

    auto p = data();

    do

    {

        ::new(p++) value(sp_);

    }

    while(--count);

}

array::

array(array const& other)

    : array(other, other.sp_)

{

}

array::

array(

    array const& other,

    storage_ptr sp)

    : sp_(std::move(sp))

{

    if(other.empty())

    {

        t_ = &empty_;

        return;

    }

    t_ = table::allocate(

        other.size(), sp_);

    t_->size = 0;

    revert_construct r(*this);

    auto src = other.data();

    auto dest = data();

    auto const n = other.size();

    do

    {

        ::new(dest++) value(

            *src++, sp_);

        ++t_->size;

    }

    while(t_->size < n);

    r.commit();

}

array::

array(

    array&& other,

    storage_ptr sp)

    : sp_(std::move(sp))

{

    if(*sp_ == *other.sp_)

    {

        // same resource

        t_ = detail::exchange(

            other.t_, &empty_);

        return;

    }

    else if(other.empty())

    {

        t_ = &empty_;

        return;

    }

    // copy

    t_ = table::allocate(

        other.size(), sp_);

    t_->size = 0;

    revert_construct r(*this);

    auto src = other.data();

    auto dest = data();

    auto const n = other.size();

    do

    {

        ::new(dest++) value(

            *src++, sp_);

        ++t_->size;

    }

    while(t_->size < n);

    r.commit();

}

array::

array(

    std::initializer_list<

        value_ref> init,

    storage_ptr sp)

    : sp_(std::move(sp))

{

    if(init.size() == 0)

    {

        t_ = &empty_;

        return;

    }

    t_ = table::allocate(

        init.size(), sp_);

    t_->size = 0;

    revert_construct r(*this);

    value_ref::write_array(

        data(), init, sp_);

    t_->size = static_cast<

        std::uint32_t>(init.size());

    r.commit();

}

//----------------------------------------------------------

array&

array::

operator=(array const& other)

{

    array(other,

        storage()).swap(*this);

    return *this;

}

array&

array::

operator=(array&& other)

{

    array(std::move(other),

        storage()).swap(*this);

    return *this;

}

array&

array::

operator=(

    std::initializer_list<value_ref> init)

{

    array(init,

        storage()).swap(*this);

    return *this;

}

//----------------------------------------------------------

//

// Element access

//

//----------------------------------------------------------

system::result<value&>

array::try_at(std::size_t pos) noexcept

{

    if(pos >= t_->size)

    {

        system::error_code ec;

        BOOST_JSON_FAIL(ec, error::out_of_range);

        return ec;

    }

    return (*t_)[pos];

}

system::result<value const&>

array::try_at(std::size_t pos) const noexcept

{

    if(pos >= t_->size)

    {

        system::error_code ec;

        BOOST_JSON_FAIL(ec, error::out_of_range);

        return ec;

    }

    return (*t_)[pos];

}

value const&

array::

array::at(std::size_t pos, source_location const& loc) const&

{

    return try_at(pos).value(loc);

}

//----------------------------------------------------------

//

// Capacity

//

//----------------------------------------------------------

void

array::

shrink_to_fit() noexcept

{

    if(capacity() <= size())

        return;

    if(size() == 0)

    {

        table::deallocate(t_, sp_);

        t_ = &empty_;

        return;

    }

#ifndef BOOST_NO_EXCEPTIONS

    try

    {

#endif

        auto t = table::allocate(

            size(), sp_);

        relocate(

            &(*t)[0],

            data(),

            size());

        t->size = static_cast<

            std::uint32_t>(size());

        t = detail::exchange(

            t_, t);

        table::deallocate(t, sp_);

#ifndef BOOST_NO_EXCEPTIONS

    }

    catch(...)

    {

        // eat the exception

        return;

    }

#endif

}

//----------------------------------------------------------

//

// Modifiers

//

//----------------------------------------------------------

void

array::

clear() noexcept

{

    if(size() == 0)

        return;

    destroy(

        begin(), end());

    t_->size = 0;

}

auto

array::

insert(

    const_iterator pos,

    value const& v) ->

        iterator

{

    return emplace(pos, v);

}

auto

array::

insert(

    const_iterator pos,

    value&& v) ->

        iterator

{

    return emplace(pos, std::move(v));

}

auto

array::

insert(

    const_iterator pos,

    std::size_t count,

    value const& v) ->

        iterator

{

    // v may refer to an element of this array, whose

    // storage revert_insert can relocate and free, so

    // copy it before inserting

    value const tmp(v, sp_);

    revert_insert r(

        pos, count, *this);

    while(count--)

    {

        ::new(r.p) value(tmp, sp_);

        ++r.p;

    }

    return r.commit();

}

auto

array::

insert(

    const_iterator pos,

    std::initializer_list<

        value_ref> init) ->

    iterator

{

    // the value_refs in init may point into this

    // array, whose storage revert_insert can

    // relocate and free, so buffer them first

    array temp(init, sp_);

    revert_insert r(

        pos, temp.size(), *this);

    relocate(

        r.p,

        temp.data(),

        temp.size());

    temp.t_->size = 0;

    return r.commit();

}

auto

array::

erase(

    const_iterator pos) noexcept ->

    iterator

{

    BOOST_ASSERT(

        pos >= begin() &&

        pos <= end());

    return erase(pos, pos + 1);

}

auto

array::

erase(

    const_iterator first,

    const_iterator last) noexcept ->

        iterator

{

    BOOST_ASSERT(

        first >= begin() &&

        last >= first &&

        last <= end());

    std::size_t const n =

        last - first;

    auto const p = &(*t_)[0] +

        (first - &(*t_)[0]);

    destroy(p, p + n);

    relocate(p, p + n,

        t_->size - (last -

            &(*t_)[0]));

    t_->size = static_cast<

        std::uint32_t>(t_->size - n);

    return p;

}

void

array::

push_back(value const& v)

{

    emplace_back(v);

}

void

array::

push_back(value&& v)

{

    emplace_back(std::move(v));

}

void

array::

pop_back() noexcept

{

    auto const p = &back();

    destroy(p, p + 1);

    --t_->size;

}

void

array::

resize(std::size_t count)

{

    if(count <= t_->size)

    {

        // shrink

        destroy(

            &(*t_)[0] + count,

            &(*t_)[0] + t_->size);

        t_->size = static_cast<

            std::uint32_t>(count);

        return;

    }

    reserve(count);

    auto p = &(*t_)[t_->size];

    auto const end = &(*t_)[count];

    while(p != end)

        ::new(p++) value(sp_);

    t_->size = static_cast<

        std::uint32_t>(count);

}

void

array::

resize(

    std::size_t count,

    value const& v)

{

    if(count <= size())

    {

        // shrink

        destroy(

            data() + count,

            data() + size());

        t_->size = static_cast<

            std::uint32_t>(count);

        return;

    }

    count -= size();

    // v may refer to an element of this array, whose

    // storage revert_insert can relocate and free, so

    // copy it before inserting

    value const tmp(v, sp_);

    revert_insert r(

        end(), count, *this);

    while(count--)

    {

        ::new(r.p) value(tmp, sp_);

        ++r.p;

    }

    r.commit();

}

void

array::

swap(array& other)

{

    if(*sp_ == *other.sp_)

    {

        t_ = detail::exchange(

            other.t_, t_);

        return;

    }

    array temp1(

        std::move(*this),

        other.storage());

    array temp2(

        std::move(other),

        this->storage());

    this->~array();

    ::new(this) array(

        pilfer(temp2));

    other.~array();

    ::new(&other) array(

        pilfer(temp1));

}

//----------------------------------------------------------

//

// Private

//

//----------------------------------------------------------

std::size_t

array::

growth(

    std::size_t new_size) const

{

    if(new_size > max_size())

    {

        BOOST_STATIC_CONSTEXPR source_location loc = BOOST_CURRENT_LOCATION;

        detail::throw_system_error( error::array_too_large, &loc );

    }

    std::size_t const old = capacity();

    if(old > max_size() - old / 2)

        return new_size;

    std::size_t const g =

        old + old / 2; // 1.5x

    if(g < new_size)

        return new_size;

    return g;

}

// precondition: new_capacity > capacity()

void

array::

reserve_impl(

    std::size_t new_capacity)

{

    BOOST_ASSERT(

        new_capacity > t_->capacity);

    auto t = table::allocate(

        growth(new_capacity), sp_);

    relocate(

        &(*t)[0],

        &(*t_)[0],

        t_->size);

    t->size = t_->size;

    t = detail::exchange(t_, t);

    table::deallocate(t, sp_);

}

// precondition: pv is not aliased

value&

array::

push_back(

    pilfered<value> pv)

{

    auto const n = t_->size;

    if(n < t_->capacity)

    {

        // fast path

        auto& v = *::new(

            &(*t_)[n]) value(pv);

        ++t_->size;

        return v;

    }

    auto const t =

        detail::exchange(t_,

            table::allocate(

                growth(n + 1),

                    sp_));

    auto& v = *::new(

        &(*t_)[n]) value(pv);

    relocate(

        &(*t_)[0],

        &(*t)[0],

        n);

    t_->size = n + 1;

    table::deallocate(t, sp_);

    return v;

}

// precondition: pv is not aliased

auto

array::

insert(

    const_iterator pos,

    pilfered<value> pv) ->

        iterator

{

    BOOST_ASSERT(

        pos >= begin() &&

        pos <= end());

    std::size_t const n =

        t_->size;

    std::size_t const i =

        pos - &(*t_)[0];

    if(n < t_->capacity)

    {

        // fast path

        auto const p =

            &(*t_)[i];

        relocate(

            p + 1,

            p,

            n - i);

        ::new(p) value(pv);

        ++t_->size;

        return p;

    }

    auto t =

        table::allocate(

            growth(n + 1), sp_);

    auto const p = &(*t)[i];

    ::new(p) value(pv);

    relocate(

        &(*t)[0],

        &(*t_)[0],

        i);

    relocate(

        p + 1,

        &(*t_)[i],

        n - i);

    t->size = static_cast<

        std::uint32_t>(size() + 1);

    t = detail::exchange(t_, t);

    table::deallocate(t, sp_);

    return p;

}

//----------------------------------------------------------

bool

array::

equal(

    array const& other) const noexcept

{

    if(size() != other.size())

        return false;

    for(std::size_t i = 0; i < size(); ++i)

        if((*this)[i] != other[i])

            return false;

    return true;

}

} // namespace json

} // namespace boost

//----------------------------------------------------------

//

// std::hash specialization

//

//----------------------------------------------------------

std::size_t

std::hash<::boost::json::array>::operator()(

    ::boost::json::array const& ja) const noexcept

{

    return ::boost::hash< ::boost::json::array >()( ja );

}

//----------------------------------------------------------

#endif