| 1 | #ifndef NUMBERLIKEARRAY_H |
| 2 | #define NUMBERLIKEARRAY_H |
| 3 | |
| 4 | // Make sure we have NULL. |
| 5 | #ifndef NULL |
| 6 | #define NULL 0 |
| 7 | #endif |
| 8 | |
| 9 | /* A NumberlikeArray<Blk> object holds a heap-allocated array of Blk with a |
| 10 | * length and a capacity and provides basic memory management features. |
| 11 | * BigUnsigned and BigUnsignedInABase both subclass it. |
| 12 | * |
| 13 | * NumberlikeArray provides no information hiding. Subclasses should use |
| 14 | * nonpublic inheritance and manually expose members as desired using |
| 15 | * declarations like this: |
| 16 | * |
| 17 | * public: |
| 18 | * NumberlikeArray< the-type-argument >::getLength; |
| 19 | */ |
| 20 | template <class Blk> |
| 21 | class NumberlikeArray { |
| 22 | public: |
| 23 | |
| 24 | // Type for the index of a block in the array |
| 25 | typedef unsigned int Index; |
| 26 | // The number of bits in a block, defined below. |
| 27 | static const unsigned int N; |
| 28 | |
| 29 | // The current allocated capacity of this NumberlikeArray (in blocks) |
| 30 | Index cap; |
| 31 | // The actual length of the value stored in this NumberlikeArray (in blocks) |
| 32 | Index len; |
| 33 | // Heap-allocated array of the blocks (can be NULL if len == 0) |
| 34 | Blk *blk; |
| 35 | |
| 36 | // Constructs a ``zero'' NumberlikeArray with the given capacity. |
| 37 | NumberlikeArray(Index c) : cap(c), len(0) { |
| 38 | blk = (cap > 0) ? (new Blk[cap]) : NULL; |
| 39 | } |
| 40 | |
| 41 | /* Constructs a zero NumberlikeArray without allocating a backing array. |
| 42 | * A subclass that doesn't know the needed capacity at initialization |
| 43 | * time can use this constructor and then overwrite blk without first |
| 44 | * deleting it. */ |
| 45 | NumberlikeArray() : cap(0), len(0) { |
| 46 | blk = NULL; |
| 47 | } |
| 48 | |
| 49 | // Destructor. Note that `delete NULL' is a no-op. |
| 50 | ~NumberlikeArray() { |
| 51 | delete [] blk; |
| 52 | } |
| 53 | |
| 54 | /* Ensures that the array has at least the requested capacity; may |
| 55 | * destroy the contents. */ |
| 56 | void allocate(Index c); |
| 57 | |
| 58 | /* Ensures that the array has at least the requested capacity; does not |
| 59 | * destroy the contents. */ |
| 60 | void allocateAndCopy(Index c); |
| 61 | |
| 62 | // Copy constructor |
| 63 | NumberlikeArray(const NumberlikeArray<Blk> &x); |
| 64 | |
| 65 | // Assignment operator |
| 66 | void operator=(const NumberlikeArray<Blk> &x); |
| 67 | |
| 68 | // Constructor that copies from a given array of blocks |
| 69 | NumberlikeArray(const Blk *b, Index blen); |
| 70 | |
| 71 | // ACCESSORS |
| 72 | Index getCapacity() const { return cap; } |
| 73 | Index getLength() const { return len; } |
| 74 | Blk getBlock(Index i) const { return blk[i]; } |
| 75 | bool isEmpty() const { return len == 0; } |
| 76 | |
| 77 | /* Equality comparison: checks if both objects have the same length and |
| 78 | * equal (==) array elements to that length. Subclasses may wish to |
| 79 | * override. */ |
| 80 | bool operator ==(const NumberlikeArray<Blk> &x) const; |
| 81 | |
| 82 | bool operator !=(const NumberlikeArray<Blk> &x) const { |
| 83 | return !operator ==(x); |
| 84 | } |
| 85 | }; |
| 86 | |
| 87 | /* BEGIN TEMPLATE DEFINITIONS. They are present here so that source files that |
| 88 | * include this header file can generate the necessary real definitions. */ |
| 89 | |
| 90 | template <class Blk> |
| 91 | const unsigned int NumberlikeArray<Blk>::N = 8 * sizeof(Blk); |
| 92 | |
| 93 | template <class Blk> |
| 94 | void NumberlikeArray<Blk>::allocate(Index c) { |
| 95 | // If the requested capacity is more than the current capacity... |
| 96 | if (c > cap) { |
| 97 | // Delete the old number array |
| 98 | delete [] blk; |
| 99 | // Allocate the new array |
| 100 | cap = c; |
| 101 | blk = new Blk[cap]; |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | template <class Blk> |
| 106 | void NumberlikeArray<Blk>::allocateAndCopy(Index c) { |
| 107 | // If the requested capacity is more than the current capacity... |
| 108 | if (c > cap) { |
| 109 | Blk *oldBlk = blk; |
| 110 | // Allocate the new number array |
| 111 | cap = c; |
| 112 | blk = new Blk[cap]; |
| 113 | // Copy number blocks |
| 114 | Index i; |
| 115 | for (i = 0; i < len; i++) |
| 116 | blk[i] = oldBlk[i]; |
| 117 | // Delete the old array |
| 118 | delete [] oldBlk; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | template <class Blk> |
| 123 | NumberlikeArray<Blk>::NumberlikeArray(const NumberlikeArray<Blk> &x) |
| 124 | : len(x.len) { |
| 125 | // Create array |
| 126 | cap = len; |
| 127 | blk = new Blk[cap]; |
| 128 | // Copy blocks |
| 129 | Index i; |
| 130 | for (i = 0; i < len; i++) |
| 131 | blk[i] = x.blk[i]; |
| 132 | } |
| 133 | |
| 134 | template <class Blk> |
| 135 | void NumberlikeArray<Blk>::operator=(const NumberlikeArray<Blk> &x) { |
| 136 | /* Calls like a = a have no effect; catch them before the aliasing |
| 137 | * causes a problem */ |
| 138 | if (this == &x) |
| 139 | return; |
| 140 | // Copy length |
| 141 | len = x.len; |
| 142 | // Expand array if necessary |
| 143 | allocate(len); |
| 144 | // Copy number blocks |
| 145 | Index i; |
| 146 | for (i = 0; i < len; i++) |
| 147 | blk[i] = x.blk[i]; |
| 148 | } |
| 149 | |
| 150 | template <class Blk> |
| 151 | NumberlikeArray<Blk>::NumberlikeArray(const Blk *b, Index blen) |
| 152 | : cap(blen), len(blen) { |
| 153 | // Create array |
| 154 | blk = new Blk[cap]; |
| 155 | // Copy blocks |
| 156 | Index i; |
| 157 | for (i = 0; i < len; i++) |
| 158 | blk[i] = b[i]; |
| 159 | } |
| 160 | |
| 161 | template <class Blk> |
| 162 | bool NumberlikeArray<Blk>::operator ==(const NumberlikeArray<Blk> &x) const { |
| 163 | if (len != x.len) |
| 164 | // Definitely unequal. |
| 165 | return false; |
| 166 | else { |
| 167 | // Compare corresponding blocks one by one. |
| 168 | Index i; |
| 169 | for (i = 0; i < len; i++) |
| 170 | if (blk[i] != x.blk[i]) |
| 171 | return false; |
| 172 | // No blocks differed, so the objects are equal. |
| 173 | return true; |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | #endif |