include/wx/vector.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/vector.h
   3 // Purpose:     STL vector clone
   4 // Author:      Lindsay Mathieson
   5 // Modified by: Vaclav Slavik - make it a template
   6 // Created:     30.07.2001
   7 // Copyright:   (c) 2001 Lindsay Mathieson <lindsay@mathieson.org>,
   8 //                  2007 Vaclav Slavik <vslavik@fastmail.fm>
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_VECTOR_H_
  13 #define _WX_VECTOR_H_
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_STL
  18
  19 #include <vector>
  20 #define wxVector std::vector
  21
  22 #else // !wxUSE_STL
  23
  24 #include "wx/utils.h"
  25 #include "wx/scopeguard.h"
  26 #include "wx/meta/movable.h"
  27 #include "wx/meta/if.h"
  28
  29 #include "wx/beforestd.h"
  30 #include <new> // for placement new
  31 #include "wx/afterstd.h"
  32
  33 namespace wxPrivate
  34 {
  35
  36 // These templates encapsulate memory operations for use by wxVector; there are
  37 // two implementations, both in generic way for any C++ types and as an
  38 // optimized version for "movable" types that uses realloc() and memmove().
  39
  40 // version for movable types:
  41 template<typename T>
  42 struct wxVectorMemOpsMovable
  43 {
  44     static void Free(T* array)
  45         { free(array); }
  46
  47     static T* Realloc(T* old, size_t newCapacity, size_t WXUNUSED(occupiedSize))
  48         { return (T*)realloc(old, newCapacity * sizeof(T)); }
  49
  50     static void MemmoveBackward(T* dest, T* source, size_t count)
  51         { memmove(dest, source, count * sizeof(T)); }
  52
  53     static void MemmoveForward(T* dest, T* source, size_t count)
  54         { memmove(dest, source, count * sizeof(T)); }
  55 };
  56
  57 // generic version for non-movable types:
  58 template<typename T>
  59 struct wxVectorMemOpsGeneric
  60 {
  61     static void Free(T* array)
  62         { ::operator delete(array); }
  63
  64     static T* Realloc(T* old, size_t newCapacity, size_t occupiedSize)
  65     {
  66         T *mem = (T*)::operator new(newCapacity * sizeof(T));
  67         for ( size_t i = 0; i < occupiedSize; i++ )
  68         {
  69             ::new(mem + i) T(old[i]);
  70             old[i].~T();
  71         }
  72         ::operator delete(old);
  73         return mem;
  74     }
  75
  76     static void MemmoveBackward(T* dest, T* source, size_t count)
  77     {
  78         wxASSERT( dest < source );
  79         T* destptr = dest;
  80         T* sourceptr = source;
  81         for ( size_t i = count; i > 0; --i, ++destptr, ++sourceptr )
  82         {
  83             ::new(destptr) T(*sourceptr);
  84             sourceptr->~T();
  85         }
  86     }
  87
  88     static void MemmoveForward(T* dest, T* source, size_t count)
  89     {
  90         wxASSERT( dest > source );
  91         T* destptr = dest + count - 1;
  92         T* sourceptr = source + count - 1;
  93         for ( size_t i = count; i > 0; --i, --destptr, --sourceptr )
  94         {
  95             ::new(destptr) T(*sourceptr);
  96             sourceptr->~T();
  97         }
  98     }
  99 };
 100
 101
 102 } // namespace wxPrivate
 103
 104 template<typename T>
 105 class wxVector
 106 {
 107 private:
 108     // This cryptic expression means "typedef Ops to wxVectorMemOpsMovable if
 109     // type T is movable type, otherwise to wxVectorMemOpsGeneric".
 110     //
 111     // Note that we use typedef instead of privately deriving from this (which
 112     // would allowed us to omit "Ops::" prefixes below) to keep VC6 happy,
 113     // it can't compile code that derives from wxIf<...>::value.
 114     typedef typename wxIf< wxIsMovable<T>::value,
 115                            wxPrivate::wxVectorMemOpsMovable<T>,
 116                            wxPrivate::wxVectorMemOpsGeneric<T> >::value
 117             Ops;
 118
 119 public:
 120     typedef size_t size_type;
 121     typedef size_t difference_type;
 122     typedef T value_type;
 123     typedef value_type* pointer;
 124     typedef value_type* iterator;
 125     typedef const value_type* const_iterator;
 126     typedef value_type& reference;
 127
 128     class reverse_iterator
 129     {
 130     public:
 131         reverse_iterator() : m_ptr(NULL) { }
 132         wxEXPLICIT reverse_iterator(iterator it) : m_ptr(it) { }
 133         reverse_iterator(const reverse_iterator& it) : m_ptr(it.m_ptr) { }
 134
 135         reference operator*() const { return *m_ptr; }
 136         pointer operator->() const { return m_ptr; }
 137
 138         iterator base() const { return m_ptr; }
 139
 140         reverse_iterator& operator++()
 141             { --m_ptr; return *this; }
 142         reverse_iterator operator++(int)
 143             { reverse_iterator tmp = *this; --m_ptr; return tmp; }
 144         reverse_iterator& operator--()
 145             { ++m_ptr; return *this; }
 146         reverse_iterator operator--(int)
 147             { reverse_iterator tmp = *this; ++m_ptr; return tmp; }
 148
 149         reverse_iterator operator+(difference_type n) const
 150             { return reverse_iterator(m_ptr - n); }
 151         reverse_iterator& operator+=(difference_type n)
 152             { m_ptr -= n; return *this; }
 153         reverse_iterator operator-(difference_type n) const
 154             { return reverse_iterator(m_ptr + n); }
 155         reverse_iterator& operator-=(difference_type n)
 156             { m_ptr += n; return *this; }
 157
 158         reference operator[](difference_type n) const
 159             { return *(*this + n); }
 160
 161         bool operator ==(const reverse_iterator& it) const
 162             { return m_ptr == it.m_ptr; }
 163         bool operator !=(const reverse_iterator& it) const
 164             { return m_ptr != it.m_ptr; }
 165
 166     private:
 167         value_type *m_ptr;
 168     };
 169
 170     wxVector() : m_size(0), m_capacity(0), m_values(NULL) {}
 171
 172     wxVector(const wxVector& c) : m_size(0), m_capacity(0), m_values(NULL)
 173     {
 174         Copy(c);
 175     }
 176
 177     ~wxVector()
 178     {
 179         clear();
 180     }
 181
 182     void clear()
 183     {
 184         // call destructors of stored objects:
 185         for ( size_type i = 0; i < m_size; i++ )
 186         {
 187             m_values[i].~T();
 188         }
 189
 190         Ops::Free(m_values);
 191         m_values = NULL;
 192         m_size =
 193         m_capacity = 0;
 194     }
 195
 196     void reserve(size_type n)
 197     {
 198         if ( n <= m_capacity )
 199             return;
 200
 201         // increase the size twice, unless we're already too big or unless
 202         // more is requested
 203         //
 204         // NB: casts to size_type are needed to suppress mingw32 warnings about
 205         //     mixing enums and ints in the same expression
 206         const size_type increment = m_size > 0
 207                                      ? wxMin(m_size, (size_type)ALLOC_MAX_SIZE)
 208                                      : (size_type)ALLOC_INITIAL_SIZE;
 209         if ( m_capacity + increment > n )
 210             n = m_capacity + increment;
 211
 212         m_values = Ops::Realloc(m_values, n * sizeof(value_type), m_size);
 213         m_capacity = n;
 214     }
 215
 216     size_type size() const
 217     {
 218         return m_size;
 219     }
 220
 221     size_type capacity() const
 222     {
 223         return m_capacity;
 224     }
 225
 226     bool empty() const
 227     {
 228         return size() == 0;
 229     }
 230
 231     wxVector& operator=(const wxVector& vb)
 232     {
 233         if (this != &vb)
 234         {
 235             clear();
 236             Copy(vb);
 237         }
 238         return *this;
 239     }
 240
 241     void push_back(const value_type& v)
 242     {
 243         reserve(size() + 1);
 244
 245         // use placement new to initialize new object in preallocated place in
 246         // m_values and store 'v' in it:
 247         void* const place = m_values + m_size;
 248         ::new(place) value_type(v);
 249
 250         // only increase m_size if the ctor didn't throw an exception; notice
 251         // that if it _did_ throw, everything is OK, because we only increased
 252         // vector's capacity so far and possibly written some data to
 253         // uninitialized memory at the end of m_values
 254         m_size++;
 255     }
 256
 257     void pop_back()
 258     {
 259         erase(end() - 1);
 260     }
 261
 262     const value_type& at(size_type idx) const
 263     {
 264         wxASSERT(idx < m_size);
 265         return m_values[idx];
 266     }
 267
 268     value_type& at(size_type idx)
 269     {
 270         wxASSERT(idx < m_size);
 271         return m_values[idx];
 272     }
 273
 274     const value_type& operator[](size_type idx) const  { return at(idx); }
 275     value_type& operator[](size_type idx) { return at(idx); }
 276     const value_type& front() const { return at(0); }
 277     value_type& front() { return at(0); }
 278     const value_type& back() const { return at(size() - 1); }
 279     value_type& back() { return at(size() - 1); }
 280
 281     const_iterator begin() const { return m_values; }
 282     iterator begin() { return m_values; }
 283     const_iterator end() const { return m_values + size(); }
 284     iterator end() { return m_values + size(); }
 285
 286     reverse_iterator rbegin() { return reverse_iterator(end() - 1); }
 287     reverse_iterator rend() { return reverse_iterator(begin() - 1); }
 288
 289     iterator insert(iterator it, const value_type& v = value_type())
 290     {
 291         // NB: this must be done before reserve(), because reserve()
 292         //     invalidates iterators!
 293         const size_t idx = it - begin();
 294         const size_t after = end() - it;
 295
 296         reserve(size() + 1);
 297
 298         // the place where the new element is going to be inserted
 299         value_type * const place = m_values + idx;
 300
 301         // unless we're inserting at the end, move following elements out of
 302         // the way:
 303         if ( after > 0 )
 304             Ops::MemmoveForward(place + 1, place, after);
 305
 306         // if the ctor called below throws an exception, we need to move all
 307         // the elements back to their original positions in m_values
 308         wxScopeGuard moveBack = wxMakeGuard(
 309                 Ops::MemmoveBackward, place, place + 1, after);
 310         if ( !after )
 311             moveBack.Dismiss();
 312
 313         // use placement new to initialize new object in preallocated place in
 314         // m_values and store 'v' in it:
 315         ::new(place) value_type(v);
 316
 317         // now that we did successfully add the new element, increment the size
 318         // and disable moving the items back
 319         moveBack.Dismiss();
 320         m_size++;
 321
 322         return begin() + idx;
 323     }
 324
 325     iterator erase(iterator it)
 326     {
 327         return erase(it, it + 1);
 328     }
 329
 330     iterator erase(iterator first, iterator last)
 331     {
 332         if ( first == last )
 333             return first;
 334         wxASSERT( first < end() && last <= end() );
 335
 336         const size_type idx = first - begin();
 337         const size_type count = last - first;
 338         const size_type after = end() - last;
 339
 340         // erase elements by calling their destructors:
 341         for ( iterator i = first; i < last; ++i )
 342             i->~T();
 343
 344         // once that's done, move following elements over to the freed space:
 345         if ( after > 0 )
 346         {
 347             Ops::MemmoveBackward(m_values + idx, m_values + idx + count, after);
 348         }
 349
 350         m_size -= count;
 351
 352         return begin() + idx;
 353     }
 354
 355 #if WXWIN_COMPATIBILITY_2_8
 356     wxDEPRECATED( size_type erase(size_type n) );
 357 #endif // WXWIN_COMPATIBILITY_2_8
 358
 359 private:
 360     // VC6 can't compile static const int members
 361     enum { ALLOC_INITIAL_SIZE = 16 };
 362     enum { ALLOC_MAX_SIZE = 4096 };
 363
 364     void Copy(const wxVector& vb)
 365     {
 366         reserve(vb.size());
 367
 368         for ( const_iterator i = vb.begin(); i != vb.end(); ++i )
 369             push_back(*i);
 370     }
 371
 372 private:
 373     size_type m_size,
 374               m_capacity;
 375     value_type *m_values;
 376 };
 377
 378 #if WXWIN_COMPATIBILITY_2_8
 379 template<typename T>
 380 inline typename wxVector<T>::size_type wxVector<T>::erase(size_type n)
 381 {
 382     erase(begin() + n);
 383     return n;
 384 }
 385 #endif // WXWIN_COMPATIBILITY_2_8
 386
 387 #endif // wxUSE_STL/!wxUSE_STL
 388
 389 #if WXWIN_COMPATIBILITY_2_8
 390     #define WX_DECLARE_VECTORBASE(obj, cls) typedef wxVector<obj> cls
 391     #define _WX_DECLARE_VECTOR(obj, cls, exp) WX_DECLARE_VECTORBASE(obj, cls)
 392     #define WX_DECLARE_VECTOR(obj, cls) WX_DECLARE_VECTORBASE(obj, cls)
 393 #endif // WXWIN_COMPATIBILITY_2_8
 394
 395 #endif // _WX_VECTOR_H_