wxWidgets/include/wx/vector.h

///////////////////////////////////////////////////////////////////////////////
// Name:        wx/vector.h
// Purpose:     STL vector clone
// Author:      Lindsay Mathieson
// Modified by: Vaclav Slavik - make it a template
// Created:     30.07.2001
// Copyright:   (c) 2001 Lindsay Mathieson <lindsay@mathieson.org>,
//                  2007 Vaclav Slavik <vslavik@fastmail.fm>
// Licence:     wxWindows licence
///////////////////////////////////////////////////////////////////////////////

#ifndef _WX_VECTOR_H_
#define _WX_VECTOR_H_

#include "wx/defs.h"

#if wxUSE_STL

#include <vector>
#define wxVector std::vector

#else // !wxUSE_STL

#include "wx/utils.h"
#include "wx/meta/movable.h"
#include "wx/meta/if.h"

#include "wx/beforestd.h"
#include <new> // for placement new
#include "wx/afterstd.h"

namespace wxPrivate
{

// These templates encapsulate memory operations for use by wxVector; there are
// two implementations, both in generic way for any C++ types and as an
// optimized version for "movable" types that uses realloc() and memmove().

// version for movable types:
template<typename T>
struct wxVectorMemOpsMovable
{
    static void Free(T* array)
        { free(array); }

    static T* Realloc(T* old, size_t newCapacity, size_t WXUNUSED(occupiedSize))
        { return (T*)realloc(old, newCapacity * sizeof(T)); }

    static void MemmoveBackward(T* dest, T* source, size_t count)
        { memmove(dest, source, count * sizeof(T)); }

    static void MemmoveForward(T* dest, T* source, size_t count)
        { memmove(dest, source, count * sizeof(T)); }
};

// generic version for non-movable types:
template<typename T>
struct wxVectorMemOpsGeneric
{
    static void Free(T* array)
        { ::operator delete(array); }

    static T* Realloc(T* old, size_t newCapacity, size_t occupiedSize)
    {
        T *mem = (T*)::operator new(newCapacity * sizeof(T));
        for ( size_t i = 0; i < occupiedSize; i++ )
        {
            new(mem + i) T(old[i]);
            old[i].~T();
        }
        ::operator delete(old);
        return mem;
    }

    static void MemmoveBackward(T* dest, T* source, size_t count)
    {
        wxASSERT( dest < source );
        T* destptr = dest;
        T* sourceptr = source;
        for ( size_t i = count; i > 0; --i, ++destptr, ++sourceptr )
        {
            new(destptr) T(*sourceptr);
            sourceptr->~T();
        }
    }

    static void MemmoveForward(T* dest, T* source, size_t count)
    {
        wxASSERT( dest > source );
        T* destptr = dest + count - 1;
        T* sourceptr = source + count - 1;
        for ( size_t i = count; i > 0; --i, --destptr, --sourceptr )
        {
            new(destptr) T(*sourceptr);
            sourceptr->~T();
        }
    }
};


} // namespace wxPrivate

template<typename T>
class wxVector
{
private:
    // This cryptic expression means "typedef Ops to wxVectorMemOpsMovable if
    // type T is movable type, otherwise to wxVectorMemOpsGeneric".
    //
    // Note that we use typedef instead of privately deriving from this (which
    // would allowed us to omit "Ops::" prefixes below) to keep VC6 happy,
    // it can't compile code that derives from wxIf<...>::value.
    typedef typename wxIf< wxIsMovable<T>::value,
                           wxPrivate::wxVectorMemOpsMovable<T>,
                           wxPrivate::wxVectorMemOpsGeneric<T> >::value
            Ops;

public:
    typedef size_t size_type;
    typedef T value_type;
    typedef value_type* iterator;
    typedef const value_type* const_iterator;
    typedef value_type& reference;

    wxVector() : m_size(0), m_capacity(0), m_values(NULL) {}

    wxVector(const wxVector& c) : m_size(0), m_capacity(0), m_values(NULL)
    {
        Copy(c);
    }

    ~wxVector()
    {
        clear();
    }

    void clear()
    {
        // call destructors of stored objects:
        for ( size_type i = 0; i < m_size; i++ )
        {
            m_values[i].~T();
        }

        Ops::Free(m_values);
        m_values = NULL;
        m_size =
        m_capacity = 0;
    }

    void reserve(size_type n)
    {
        if ( n <= m_capacity )
            return;

        // increase the size twice, unless we're already too big or unless
        // more is requested
        //
        // NB: casts to size_type are needed to suppress mingw32 warnings about
        //     mixing enums and ints in the same expression
        const size_type increment = m_size > 0
                                     ? wxMin(m_size, (size_type)ALLOC_MAX_SIZE)
                                     : (size_type)ALLOC_INITIAL_SIZE;
        if ( m_capacity + increment > n )
            n = m_capacity + increment;

        m_values = Ops::Realloc(m_values, n * sizeof(value_type), m_size);
        m_capacity = n;
    }

    size_type size() const
    {
        return m_size;
    }

    size_type capacity() const
    {
        return m_capacity;
    }

    bool empty() const
    {
        return size() == 0;
    }

    wxVector& operator=(const wxVector& vb)
    {
        clear();
        Copy(vb);
        return *this;
    }

    void push_back(const value_type& v)
    {
        reserve(size() + 1);

        // use placement new to initialize new object in preallocated place in
        // m_values and store 'v' in it:
        void* const place = m_values + m_size;
        new(place) value_type(v);

        // only increase m_size if the ctor didn't throw an exception; notice
        // that if it _did_ throw, everything is OK, because we only increased
        // vector's capacity so far and possibly written some data to
        // uninitialized memory at the end of m_values
        m_size++;
    }

    void pop_back()
    {
        erase(end() - 1);
    }

    const value_type& at(size_type idx) const
    {
        wxASSERT(idx < m_size);
        return m_values[idx];
    }

    value_type& at(size_type idx)
    {
        wxASSERT(idx < m_size);
        return m_values[idx];
    }

    const value_type& operator[](size_type idx) const  { return at(idx); }
    value_type& operator[](size_type idx) { return at(idx); }
    const value_type& front() const { return at(0); }
    value_type& front() { return at(0); }
    const value_type& back() const { return at(size() - 1); }
    value_type& back() { return at(size() - 1); }

    const_iterator begin() const { return m_values; }
    iterator begin() { return m_values; }
    const_iterator end() const { return m_values + size(); }
    iterator end() { return m_values + size(); }

    iterator insert(iterator it, const value_type& v = value_type())
    {
        // NB: this must be done before reserve(), because reserve()
        //     invalidates iterators!
        const size_t idx = it - begin();
        const size_t after = end() - it;

        reserve(size() + 1);

        // unless we're inserting at the end, move following elements out of
        // the way:
        if ( after > 0 )
        {
            Ops::MemmoveForward(m_values + idx + 1, m_values + idx, after);
        }

#if wxUSE_EXCEPTIONS
        try
        {
#endif
            // use placement new to initialize new object in preallocated place
            // in m_values and store 'v' in it:
            void* const place = m_values + idx;
            new(place) value_type(v);
#if wxUSE_EXCEPTIONS
        }
        catch ( ... )
        {
            // if the ctor threw an exception, we need to move all the elements
            // back to their original positions in m_values
            if ( after > 0 )
            {
                Ops::MemmoveBackward(m_values + idx, m_values + idx + 1, after);
            }

            throw; // rethrow the exception
        }
#endif // wxUSE_EXCEPTIONS

        // increment m_size only if ctor didn't throw -- if it did, we'll be
        // left with m_values larger than necessary, but number of elements will
        // be the same
        m_size++;

        return begin() + idx;
    }

    iterator erase(iterator it)
    {
        return erase(it, it + 1);
    }

    iterator erase(iterator first, iterator last)
    {
        if ( first == last )
            return first;
        wxASSERT( first < end() && last <= end() );

        const size_type idx = first - begin();
        const size_type count = last - first;
        const size_type after = end() - last;

        // erase elements by calling their destructors:
        for ( iterator i = first; i < last; ++i )
            i->~T();

        // once that's done, move following elements over to the freed space:
        if ( after > 0 )
        {
            Ops::MemmoveBackward(m_values + idx, m_values + idx + count, after);
        }

        m_size -= count;

        return begin() + idx;
    }

#if WXWIN_COMPATIBILITY_2_8
    wxDEPRECATED( size_type erase(size_type n) );
#endif // WXWIN_COMPATIBILITY_2_8

private:
    // VC6 can't compile static const int members
    enum { ALLOC_INITIAL_SIZE = 16 };
    enum { ALLOC_MAX_SIZE = 4096 };

    void Copy(const wxVector& vb)
    {
        reserve(vb.size());

        for ( const_iterator i = vb.begin(); i != vb.end(); ++i )
            push_back(*i);
    }

private:
    size_type m_size,
              m_capacity;
    value_type *m_values;
};

#if WXWIN_COMPATIBILITY_2_8
template<typename T>
inline typename wxVector<T>::size_type wxVector<T>::erase(size_type n)
{
    erase(begin() + n);
    return n;
}
#endif // WXWIN_COMPATIBILITY_2_8

#endif // wxUSE_STL/!wxUSE_STL

#if WXWIN_COMPATIBILITY_2_8
    #define WX_DECLARE_VECTORBASE(obj, cls) typedef wxVector<obj> cls
    #define _WX_DECLARE_VECTOR(obj, cls, exp) WX_DECLARE_VECTORBASE(obj, cls)
    #define WX_DECLARE_VECTOR(obj, cls) WX_DECLARE_VECTORBASE(obj, cls)
#endif // WXWIN_COMPATIBILITY_2_8

#endif // _WX_VECTOR_H_