// SPDX-License-Identifier: MIT OR MPL-2.0 OR LGPL-2.1-or-later OR GPL-2.0-or-later
// Copyright 2010, SIL International, All rights reserved.


// designed to have a limited subset of the std::vector api
#pragma once

#include <cstddef>
#include <cassert>
#include <cstring>
#include <cstdlib>
#include <new>

#include "Main.h"

namespace graphite2 {

template <typename T>
inline
ptrdiff_t distance(T* first, T* last) { return last-first; }


template <typename T>
class Vector
{
    T * m_first, *m_last, *m_end;
public:
    typedef       T &   reference;
    typedef const T &   const_reference;
    typedef       T *   iterator;
    typedef const T *   const_iterator;

    Vector() : m_first(0), m_last(0), m_end(0) {}
    Vector(size_t n, const T& value = T())      : m_first(0), m_last(0), m_end(0) { insert(begin(), n, value); }
    Vector(const Vector<T> &rhs)                : m_first(0), m_last(0), m_end(0) { insert(begin(), rhs.begin(), rhs.end()); }
    template <typename I>
    Vector(I first, const I last)               : m_first(0), m_last(0), m_end(0) { insert(begin(), first, last); }
    ~Vector() { clear(); free(m_first); }

    iterator            begin()         { return m_first; }
    const_iterator      begin() const   { return m_first; }

    iterator            end()           { return m_last; }
    const_iterator      end() const     { return m_last; }

    bool                empty() const   { return m_first == m_last; }
    size_t              size() const    { return m_last - m_first; }
    size_t              capacity() const{ return m_end - m_first; }

    void                reserve(size_t n);
    void                resize(size_t n, const T & v = T());

    reference           front()         { assert(size() > 0); return *begin(); }
    const_reference     front() const   { assert(size() > 0); return *begin(); }
    reference           back()          { assert(size() > 0); return *(end()-1); }
    const_reference     back() const    { assert(size() > 0); return *(end()-1); }

    Vector<T>         & operator = (const Vector<T> & rhs) { assign(rhs.begin(), rhs.end()); return *this; }
    reference           operator [] (size_t n)          { assert(size() > n); return m_first[n]; }
    const_reference     operator [] (size_t n) const    { assert(size() > n); return m_first[n]; }

    void                assign(size_t n, const T& u)    { clear(); insert(begin(), n, u); }
    void                assign(const_iterator first, const_iterator last)      { clear(); insert(begin(), first, last); }
    iterator            insert(iterator p, const T & x) { p = _insert_default(p, 1); new (p) T(x); return p; }
    void                insert(iterator p, size_t n, const T & x);
    void                insert(iterator p, const_iterator first, const_iterator last);
    void                pop_back()              { assert(size() > 0); --m_last; }
    void                push_back(const T &v)   { if (m_last == m_end) reserve(size()+1); new (m_last++) T(v); }

    void                clear()                 { erase(begin(), end()); }
    iterator            erase(iterator p)       { return erase(p, p+1); }
    iterator            erase(iterator first, iterator last);

private:
    iterator            _insert_default(iterator p, size_t n);
};

template <typename T>
inline
void Vector<T>::reserve(size_t n)
{
    if (n > capacity())
    {
        const ptrdiff_t sz = size();
        size_t requested;
        if (checked_mul(n,sizeof(T), requested))  std::abort();
        m_first = static_cast<T*>(realloc(m_first, requested));
        if (!m_first)   std::abort();
        m_last  = m_first + sz;
        m_end   = m_first + n;
    }
}

template <typename T>
inline
void Vector<T>::resize(size_t n, const T & v) {
    const ptrdiff_t d = n-size();
    if (d < 0)      erase(end()+d, end());
    else if (d > 0) insert(end(), d, v);
}

template<typename T>
inline
typename Vector<T>::iterator Vector<T>::_insert_default(iterator p, size_t n)
{
    assert(begin() <= p && p <= end());
    const ptrdiff_t i = p - begin();
    reserve(((size() + n + 7) >> 3) << 3);
    p = begin() + i;
    // Move tail if there is one
    if (p != end()) memmove(p + n, p, distance(p,end())*sizeof(T));
    m_last += n;
    return p;
}

template<typename T>
inline
void Vector<T>::insert(iterator p, size_t n, const T & x)
{
    p = _insert_default(p, n);
    // Copy in elements
    for (; n; --n, ++p) { new (p) T(x); }
}

template<typename T>
inline
void Vector<T>::insert(iterator p, const_iterator first, const_iterator last)
{
    p = _insert_default(p, distance(first, last));
    // Copy in elements
    for (;first != last; ++first, ++p) { new (p) T(*first); }
}

template<typename T>
inline
typename Vector<T>::iterator Vector<T>::erase(iterator first, iterator last)
{
    for (iterator e = first; e != last; ++e) e->~T();
    const size_t sz = distance(first, last);
    if (m_last != last) memmove(first, last, distance(last,end())*sizeof(T));
    m_last -= sz;
    return first;
}

} // namespace graphite2