X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/f5851311d3cafff78097f8441d3dc5bf1fc1e6b0..2036bdd30368d117918b565ae990a89841281f33:/include/wx/vector.h diff --git a/include/wx/vector.h b/include/wx/vector.h index 6fc0be174a..85d9257943 100644 --- a/include/wx/vector.h +++ b/include/wx/vector.h @@ -22,10 +22,99 @@ #else // !wxUSE_STL #include "wx/utils.h" +#include "wx/meta/movable.h" +#include "wx/meta/if.h" + +#include "wx/beforestd.h" +#include // 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 +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 +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 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::value, + wxPrivate::wxVectorMemOpsMovable, + wxPrivate::wxVectorMemOpsGeneric >::value + Ops; + public: typedef size_t size_type; typedef T value_type; @@ -47,7 +136,13 @@ public: void clear() { - delete[] m_values; + // 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; } @@ -60,7 +155,7 @@ public: // increase the size twice, unless we're already too big or unless // more is requested // - // NB: casts to size_t are needed to suppress mingw32 warnings about + // 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) @@ -68,16 +163,7 @@ public: if ( m_capacity + increment > n ) n = m_capacity + increment; - value_type *mem = new value_type[n]; - - if ( m_values ) - { - for ( size_type i = 0; i < m_size; ++i ) - mem[i] = m_values[i]; - delete[] m_values; - } - - m_values = mem; + m_values = Ops::Realloc(m_values, n * sizeof(value_type), m_size); m_capacity = n; } @@ -105,7 +191,17 @@ public: void push_back(const value_type& v) { reserve(size() + 1); - m_values[m_size++] = v; + + // 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() @@ -139,16 +235,46 @@ public: iterator insert(iterator it, const value_type& v = value_type()) { - size_t idx = it - begin(); + // 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 values out of + // unless we're inserting at the end, move following elements out of // the way: - for ( size_t n = m_size; n != idx; --n ) - m_values[n] = m_values[n-1]; + if ( after > 0 ) + { + Ops::MemmoveForward(m_values + idx + 1, m_values + idx, after); + } - m_values[idx] = v; +#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; @@ -165,20 +291,23 @@ public: return first; wxASSERT( first < end() && last <= end() ); - size_type index = first - begin(); - size_type count = last - first; + const size_type idx = first - begin(); + const size_type count = last - first; + const size_type after = end() - last; - // move the remaining values over to the freed space: - for ( iterator i = last; i < end(); ++i ) - *(i - count) = *i; + // erase elements by calling their destructors: + for ( iterator i = first; i < last; ++i ) + i->~T(); - // erase items behind the new end of m_values: - for ( iterator j = end() - count; j < end(); ++j ) - *j = value_type(); + // 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() + index; + return begin() + idx; } #if WXWIN_COMPATIBILITY_2_8 @@ -207,7 +336,7 @@ private: #if WXWIN_COMPATIBILITY_2_8 template -typename wxVector::size_type wxVector::erase(size_type n) +inline typename wxVector::size_type wxVector::erase(size_type n) { erase(begin() + n); return n;