include/AD/contain/vararray.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are free to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome any suggestions
  19 // and help from the users.
  20 //
  21 // Allen Leung
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef variable_sized_array_h
  26 #define variable_sized_array_h
  27
  28 ///////////////////////////////////////////////////////////////////////////
  29 //  Class VarArray<T> provides an abstraction for
  30 //  an dense mapping from integers to type T.
  31 //  The array will grow in size when necessary.
  32 //  Both positive and negative indices are allowed.
  33 //  The indices should be centered around 0.
  34 ///////////////////////////////////////////////////////////////////////////
  35
  36 #include <new.h>
  37 #include <string.h>
  38 #include <AD/generic/generic.h>   // Generic definitions
  39
  40 template<class T>
  41    class VarArray {
  42       T * array;       // array of elements; displaced by offset
  43       int low, high;   // upper and lower bound on array
  44       int growthRate;  // minimal number of elements for expansion
  45
  46       void grow(int i);
  47
  48    public:
  49
  50       //////////////////////////////////////////////////////////////////
  51       // Constructor and destructors
  52       //////////////////////////////////////////////////////////////////
  53       VarArray(int lowerBound = 0,
  54                int upperBound = 9, int growthFactor = 32);
  55       VarArray(const VarArray& A) : array(0), low(0) { *this = A; }
  56       VarArray(size_t size, const T []);
  57      ~VarArray();
  58
  59       ////////////////////////////////////////////////////////////////////
  60       // Assignment
  61       ////////////////////////////////////////////////////////////////////
  62       VarArray& operator = (const VarArray&);
  63
  64       ////////////////////////////////////////////////////////////////////
  65       // Conversion
  66       ////////////////////////////////////////////////////////////////////
  67       inline operator const T * () const { return array; }
  68       inline operator T * ()             { return array; }
  69
  70       ////////////////////////////////////////////////////////////////////
  71       // Selectors
  72       ////////////////////////////////////////////////////////////////////
  73       inline int hi() const             { return high; }
  74       inline int lo() const             { return low; }
  75       inline int size() const           { return high - low + 1; }
  76       inline int capacity() const       { return size(); }
  77       inline Bool hasKey(int i) const   { return i >= low && i <= high; }
  78       inline const T& operator [] (int i) const { return array[i]; }
  79       inline T& operator [] (int i)
  80          { if (! hasKey(i)) grow(i); return array[i]; }
  81
  82       ////////////////////////////////////////////////////////////////////
  83       // Iteration
  84       ////////////////////////////////////////////////////////////////////
  85       inline Ix first()    const { return low > high ? 0 : (Ix)&array[lo()]; }
  86       inline Ix last()     const { return low > high ? 0 : (Ix)&array[hi()]; }
  87       inline Ix next(Ix i) const { return i >= (Ix)(array + hi()) ? 0 : (((T*)i)+1); }
  88       inline Ix prev(Ix i) const { return i <= (Ix)(array + lo()) ? 0 : (((T*)i)-1); }
  89       inline const T& operator() (Ix i) const { return *(T*)i; }
  90       inline T& operator() (Ix i) { return *(T*)i; }
  91    };
  92
  93 ////////////////////////////////////////////////////////////////////
  94 // Implementation comes here
  95 ////////////////////////////////////////////////////////////////////
  96 template<class T>
  97    VarArray<T>::VarArray(int lowerBound, int upperBound, int growthFactor)
  98    {  long size = lowerBound <= upperBound ? upperBound - lowerBound + 1 : 0;
  99       high = upperBound; low = lowerBound;
 100       T * mem = size > 0 ? new T [size] : (T*)0;
 101       array = mem - low;
 102       growthRate = growthFactor;
 103    }
 104
 105 template<class T>
 106    VarArray<T>::VarArray(size_t size, const T A[])
 107    {  array = new T [size];
 108       low = 0; high = size - 1;
 109       growthRate = 32;
 110       for (register int i = high; i >= 0; i--) array[i] = A[i];
 111    }
 112
 113 template<class T>
 114    VarArray<T>::~VarArray()
 115      { delete [] (array + low); }
 116
 117 template<class T>
 118    VarArray<T>& VarArray<T>::operator = (const VarArray<T>& A)
 119    {  if (this != &A) {
 120          delete [] (array + low);
 121          high = A.high; low = A.low;
 122          array = new T [high - low + 1] - A.low;
 123          for (int i = low; i <= high; i++) array[i] = A.array[i];
 124       }
 125       return *this;
 126    }
 127
 128 template<class T>
 129    void VarArray<T>::grow(int i)
 130    {  int newHigh, newLow;
 131       int growth = growthRate <= 0 ? (size() * 3 / 2 + 32) : growthRate;
 132       if (i > high)
 133          if (i < high + growth) newHigh = high + growth;
 134          else newHigh = i;
 135       else newHigh = high;
 136       if (i < low)
 137          if (i > low - growth) newLow = low - growth;
 138          else newLow = i;
 139       else newLow = low;
 140       register T * newArray = new T [newHigh - newLow + 1] - newLow;
 141       for (register int j = low; j <= high; j++) newArray[j] = array[j];
 142       delete [] (array + low);
 143       array = newArray;
 144       low = newLow; high = newHigh;
 145    }
 146
 147 #endif