scintilla/SVector.h

   1 // Scintilla source code edit control
   2 /** @file SVector.h
   3  ** A simple expandable vector.
   4  **/
   5 // Copyright 1998-2001 by Neil Hodgson <neilh@hare.net.au>
   6 // The License.txt file describes the conditions under which this software may be distributed.
   7
   8 #ifndef SVECTOR_H
   9 #define SVECTOR_H
  10
  11 /**
  12  * A simple expandable integer vector.
  13  * Storage not allocated for elements until an element is used.
  14  * This makes it very lightweight unless used so is a good match for optional features.
  15  */
  16 class SVector {
  17         enum { allocSize = 4000 };
  18
  19         int *v;                         ///< The vector
  20         unsigned int size;      ///< Number of elements allocated
  21         unsigned int len;       ///< Number of elements used in vector
  22         bool allocFailure;      ///< A memory allocation call has failed
  23
  24         /** Internally allocate more elements than the user wants
  25          * to avoid thrashing the memory allocator. */
  26         void SizeTo(int newSize) {
  27                 if (newSize < allocSize)
  28                         newSize += allocSize;
  29                 else
  30                         newSize = (newSize * 3) / 2;
  31                 int* newv = new int[newSize];
  32                 if (!newv) {
  33                         allocFailure = true;
  34                         return;
  35                 }
  36                 size = newSize;
  37                 unsigned int i=0;
  38                 for (; i<len; i++) {
  39                         newv[i] = v[i];
  40                 }
  41                 for (; i<size; i++) {
  42                         newv[i] = 0;
  43                 }
  44                 delete []v;
  45                 v = newv;
  46         }
  47
  48 public:
  49         SVector() {
  50                 allocFailure = false;
  51                 v = 0;
  52                 len = 0;
  53                 size = 0;
  54         }
  55         ~SVector() {
  56                 Free();
  57         }
  58         /// Constructor from another vector.
  59         SVector(const SVector &other) {
  60                 allocFailure = false;
  61                 v = 0;
  62                 len = 0;
  63                 size = 0;
  64                 if (other.Length() > 0) {
  65                         SizeTo(other.Length());
  66                         if (!allocFailure) {
  67                                 for (int i=0;i<other.Length();i++)
  68                                         v[i] = other.v[i];
  69                                 len = other.Length();
  70                         }
  71                 }
  72         }
  73         /// Copy constructor.
  74         SVector &operator=(const SVector &other) {
  75                 if (this != &other) {
  76                         delete []v;
  77                         allocFailure = false;
  78                         v = 0;
  79                         len = 0;
  80                         size = 0;
  81                         if (other.Length() > 0) {
  82                                 SizeTo(other.Length());
  83                                 if (!allocFailure) {
  84                                         for (int i=0;i<other.Length();i++)
  85                                                 v[i] = other.v[i];
  86                                 }
  87                                 len = other.Length();
  88                         }
  89                 }
  90                 return *this;
  91         }
  92         /** @brief Accessor.
  93          * Allows to access values from the list, and grows it if accessing
  94          * outside the current bounds. The returned value in this case is 0. */
  95         int &operator[](unsigned int i) {
  96                 if (i >= len) {
  97                         if (i >= size) {
  98                                 SizeTo(i);
  99                         }
 100                         len = i+1;
 101                 }
 102                 return v[i];
 103         }
 104         /// Reset vector.
 105         void Free() {
 106                 delete []v;
 107                 v = 0;
 108                 size = 0;
 109                 len = 0;
 110         }
 111         /** @brief Grow vector size.
 112          * Doesn't allow a vector to be shrinked. */
 113         void SetLength(unsigned int newLength) {
 114                 if (newLength > len) {
 115                         if (newLength >= size) {
 116                                 SizeTo(newLength);
 117                         }
 118                 }
 119                 len = newLength;
 120         }
 121         /// Get the current length (number of used elements) of the vector.
 122         int Length() const {
 123                 return len;
 124         }
 125 };
 126
 127 #endif