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)
 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 = m_capacity = 0;
 148     }
 149
 150     void reserve(size_type n)
 151     {
 152         if ( n <= m_capacity )
 153             return;
 154
 155         // increase the size twice, unless we're already too big or unless
 156         // more is requested
 157         //
 158         // NB: casts to size_type are needed to suppress mingw32 warnings about
 159         //     mixing enums and ints in the same expression
 160         const size_type increment = m_size > 0
 161                                      ? wxMin(m_size, (size_type)ALLOC_MAX_SIZE)
 162                                      : (size_type)ALLOC_INITIAL_SIZE;
 163         if ( m_capacity + increment > n )
 164             n = m_capacity + increment;
 165
 166         m_values = Ops::Realloc(m_values, n * sizeof(value_type), m_size);
 167         m_capacity = n;
 168     }
 169
 170     size_type size() const
 171     {
 172         return m_size;
 173     }
 174
 175     size_type capacity() const
 176     {
 177         return m_capacity;
 178     }
 179
 180     bool empty() const
 181     {
 182         return size() == 0;
 183     }
 184
 185     wxVector& operator=(const wxVector& vb)
 186     {
 187         Copy(vb);
 188         return *this;
 189     }
 190
 191     void push_back(const value_type& v)
 192     {
 193         reserve(size() + 1);
 194
 195         // use placement new to initialize new object in preallocated place in
 196         // m_values and store 'v' in it:
 197         void* const place = m_values + m_size;
 198         new(place) value_type(v);
 199
 200         // only increase m_size if the ctor didn't throw an exception; notice
 201         // that if it _did_ throw, everything is OK, because we only increased
 202         // vector's capacity so far and possibly written some data to
 203         // uninitialized memory at the end of m_values
 204         m_size++;
 205     }
 206
 207     void pop_back()
 208     {
 209         erase(end() - 1);
 210     }
 211
 212     const value_type& at(size_type idx) const
 213     {
 214         wxASSERT(idx < m_size);
 215         return m_values[idx];
 216     }
 217
 218     value_type& at(size_type idx)
 219     {
 220         wxASSERT(idx < m_size);
 221         return m_values[idx];
 222     }
 223
 224     const value_type& operator[](size_type idx) const  { return at(idx); }
 225     value_type& operator[](size_type idx) { return at(idx); }
 226     const value_type& front() const { return at(0); }
 227     value_type& front() { return at(0); }
 228     const value_type& back() const { return at(size() - 1); }
 229     value_type& back() { return at(size() - 1); }
 230
 231     const_iterator begin() const { return m_values; }
 232     iterator begin() { return m_values; }
 233     const_iterator end() const { return m_values + size(); }
 234     iterator end() { return m_values + size(); }
 235
 236     iterator insert(iterator it, const value_type& v = value_type())
 237     {
 238         // NB: this must be done before reserve(), because reserve()
 239         //     invalidates iterators!
 240         const size_t idx = it - begin();
 241         const size_t after = end() - it;
 242
 243         reserve(size() + 1);
 244
 245         // unless we're inserting at the end, move following elements out of
 246         // the way:
 247         if ( after > 0 )
 248         {
 249             Ops::MemmoveForward(m_values + idx + 1, m_values + idx, after);
 250         }
 251
 252 #if wxUSE_EXCEPTIONS
 253         try
 254         {
 255 #endif
 256             // use placement new to initialize new object in preallocated place
 257             // in m_values and store 'v' in it:
 258             void* const place = m_values + idx;
 259             new(place) value_type(v);
 260 #if wxUSE_EXCEPTIONS
 261         }
 262         catch ( ... )
 263         {
 264             // if the ctor threw an exception, we need to move all the elements
 265             // back to their original positions in m_values
 266             if ( after > 0 )
 267             {
 268                 Ops::MemmoveBackward(m_values + idx, m_values + idx + 1, after);
 269             }
 270
 271             throw; // rethrow the exception
 272         }
 273 #endif // wxUSE_EXCEPTIONS
 274
 275         // increment m_size only if ctor didn't throw -- if it did, we'll be
 276         // left with m_values larger than necessary, but number of elements will
 277         // be the same
 278         m_size++;
 279
 280         return begin() + idx;
 281     }
 282
 283     iterator erase(iterator it)
 284     {
 285         return erase(it, it + 1);
 286     }
 287
 288     iterator erase(iterator first, iterator last)
 289     {
 290         if ( first == last )
 291             return first;
 292         wxASSERT( first < end() && last <= end() );
 293
 294         const size_type idx = first - begin();
 295         const size_type count = last - first;
 296         const size_type after = end() - last;
 297
 298         // erase elements by calling their destructors:
 299         for ( iterator i = first; i < last; ++i )
 300             i->~T();
 301
 302         // once that's done, move following elements over to the freed space:
 303         if ( after > 0 )
 304         {
 305             Ops::MemmoveBackward(m_values + idx, m_values + idx + count, after);
 306         }
 307
 308         m_size -= count;
 309
 310         return begin() + idx;
 311     }
 312
 313 #if WXWIN_COMPATIBILITY_2_8
 314     wxDEPRECATED( size_type erase(size_type n) );
 315 #endif // WXWIN_COMPATIBILITY_2_8
 316
 317 private:
 318     // VC6 can't compile static const int members
 319     enum { ALLOC_INITIAL_SIZE = 16 };
 320     enum { ALLOC_MAX_SIZE = 4096 };
 321
 322     void Copy(const wxVector& vb)
 323     {
 324         clear();
 325         reserve(vb.size());
 326
 327         for ( const_iterator i = vb.begin(); i != vb.end(); ++i )
 328             push_back(*i);
 329     }
 330
 331 private:
 332     size_type m_size,
 333               m_capacity;
 334     value_type *m_values;
 335 };
 336
 337 #if WXWIN_COMPATIBILITY_2_8
 338 template<typename T>
 339 inline typename wxVector<T>::size_type wxVector<T>::erase(size_type n)
 340 {
 341     erase(begin() + n);
 342     return n;
 343 }
 344 #endif // WXWIN_COMPATIBILITY_2_8
 345
 346 #endif // wxUSE_STL/!wxUSE_STL
 347
 348 #if WXWIN_COMPATIBILITY_2_8
 349     #define WX_DECLARE_VECTORBASE(obj, cls) typedef wxVector<obj> cls
 350     #define _WX_DECLARE_VECTOR(obj, cls, exp) WX_DECLARE_VECTORBASE(obj, cls)
 351     #define WX_DECLARE_VECTOR(obj, cls) WX_DECLARE_VECTORBASE(obj, cls)
 352 #endif // WXWIN_COMPATIBILITY_2_8
 353
 354 #endif // _WX_VECTOR_H_