headers/private/interface/TextViewSupportBuffer.h

   1 /*
   2  * Copyright 2001-2010, Haiku, Inc.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6 #ifndef __TEXT_VIEW_SUPPORT_BUFFER__H__
   7 #define __TEXT_VIEW_SUPPORT_BUFFER__H__
   8
   9 #include <cstdlib>
  10 #include <cstring>
  11
  12 #include <OS.h>
  13 #include <SupportDefs.h>
  14
  15
  16 // _BTextViewSupportBuffer_ class ----------------------------------------------
  17 template <class T>
  18 class _BTextViewSupportBuffer_ {
  19
  20 public:
  21                                 _BTextViewSupportBuffer_(int32 inExtraCount = 0, int32 inCount = 0);
  22 virtual                 ~_BTextViewSupportBuffer_();
  23
  24                 void    InsertItemsAt(int32 inNumItems, int32 inAtIndex, const T* inItem);
  25                 void    RemoveItemsAt(int32 inNumItems, int32 inAtIndex);
  26
  27                 int32   ItemCount() const;
  28
  29 protected:
  30                 int32   fExtraCount;
  31                 int32   fItemCount;
  32                 int32   fBufferCount;
  33                 T*              fBuffer;
  34 };
  35
  36
  37 template <class T>
  38 _BTextViewSupportBuffer_<T>::_BTextViewSupportBuffer_(int32 inExtraCount,
  39                                                                                                           int32 inCount)
  40         :       fExtraCount(inExtraCount),
  41                 fItemCount(inCount),
  42                 fBufferCount(fExtraCount + fItemCount),
  43                 fBuffer(NULL)
  44 {
  45         fBuffer = (T*)calloc(fExtraCount + fItemCount, sizeof(T));
  46 }
  47
  48
  49 template <class T>
  50 _BTextViewSupportBuffer_<T>::~_BTextViewSupportBuffer_()
  51 {
  52         free(fBuffer);
  53 }
  54
  55
  56 template <class T>
  57 void
  58 _BTextViewSupportBuffer_<T>::InsertItemsAt(int32 inNumItems,
  59                                                                                                 int32 inAtIndex,
  60                                                                                                 const T* inItem)
  61 {
  62         if (inNumItems < 1)
  63                 return;
  64
  65         inAtIndex = (inAtIndex > fItemCount) ? fItemCount : inAtIndex;
  66         inAtIndex = (inAtIndex < 0) ? 0 : inAtIndex;
  67
  68         int32 delta = inNumItems * sizeof(T);
  69         int32 logSize = fItemCount * sizeof(T);
  70         if ((logSize + delta) >= fBufferCount) {
  71                 fBufferCount = logSize + delta + (fExtraCount * sizeof(T));
  72                 fBuffer = (T*)realloc(fBuffer, fBufferCount);
  73                 if (fBuffer == NULL)
  74                         debugger("InsertItemsAt(): reallocation failed");
  75         }
  76
  77         T* loc = fBuffer + inAtIndex;
  78         memmove(loc + inNumItems, loc, (fItemCount - inAtIndex) * sizeof(T));
  79         memcpy(loc, inItem, delta);
  80
  81         fItemCount += inNumItems;
  82 }
  83
  84
  85 template <class T>
  86 void
  87 _BTextViewSupportBuffer_<T>::RemoveItemsAt(int32 inNumItems,
  88                                                                                                 int32 inAtIndex)
  89 {
  90         if (inNumItems < 1)
  91                 return;
  92
  93         inAtIndex = (inAtIndex > fItemCount - 1) ? (fItemCount - 1) : inAtIndex;
  94         inAtIndex = (inAtIndex < 0) ? 0 : inAtIndex;
  95
  96         T* loc = fBuffer + inAtIndex;
  97         memmove(loc, loc + inNumItems,
  98                         (fItemCount - (inNumItems + inAtIndex)) * sizeof(T));
  99
 100         int32 delta = inNumItems * sizeof(T);
 101         int32 logSize = fItemCount * sizeof(T);
 102         uint32 extraSize = fBufferCount - (logSize - delta);
 103         if (extraSize > (fExtraCount * sizeof(T))) {
 104                 fBufferCount = (logSize - delta) + (fExtraCount * sizeof(T));
 105                 fBuffer = (T*)realloc(fBuffer, fBufferCount);
 106                 if (fBuffer == NULL)
 107                         debugger("RemoveItemsAt(): reallocation failed");
 108         }
 109
 110         fItemCount -= inNumItems;
 111 }
 112
 113
 114 template<class T>
 115 inline int32
 116 _BTextViewSupportBuffer_<T>::ItemCount() const
 117 {
 118         return fItemCount;
 119 }
 120
 121
 122 #endif // __TEXT_VIEW_SUPPORT_BUFFER__H__