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