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sc_temporary.hh
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20 /*****************************************************************************
21 
22  sc_temporary.h -- Temporary value pool classes.
23 
24  Original Author: Andy Goodrich, Forte Design Systems, Inc.
25 
26  CHANGE LOG AT END OF FILE
27  *****************************************************************************/
28 
29 #ifndef __SYSTEMC_EXT_DT_SC_TEMPORARY_HH__
30 #define __SYSTEMC_EXT_DT_SC_TEMPORARY_HH__
31 
32 #include <cstddef> // std::size_t
33 
34 namespace sc_core
35 {
36 
37 //-----------------------------------------------------------------------------
38 // sc_byte_heap - CLASS MANAGING A TEMPORARY HEAP OF BYTES
39 //
40 // This facility implements a heap of temporary byte allocations. Once an
41 // request has been allocated it is not freed. However the entire heap
42 // wraps and the storage is reused. This means that no allocations should
43 // be assumed as permanent. Allocations are double-word aligned. This is
44 // raw storage, so objects which contain virtual methods cannot be allocated
45 // with this object. See the sc_vpool object for that type of storage
46 // allocation.
47 //
48 // char* allocate( int size )
49 // This method returns a pointer to block of size bytes. The block
50 // returned is the next available one in the heap. If the current heap
51 // cannot fullfil the request it will be rewound and storage allocated from
52 // its start. All allocations start on an 8-byte boundary.
53 // size = number of bytes to be allocated.
54 //
55 // void initialize( int heap_size=0x100000 )
56 // This method allocates the storage to be managed. If there is already
57 // a block of storage under management it is freed. If no argument is
58 // provided for the heap size, a megabyte will be allocated.
59 // heap_size = number of bytes to allocate for the heap.
60 //
61 // unsigned int length()
62 // This method returns the size of this object's heap in bytes.
63 //
64 // sc_byte_heap()
65 // This is the non-initialized object instance constructor. It does not
66 // allocate the heap storage, that is done by the initialize() method.
67 //
68 // sc_byte_heap(int)
69 // This is the initializing object instance constructor. It does allocates
70 // a heap of the specified number of bytes.
71 // heap_size = number of bytes to allocate for the heap.
72 //-----------------------------------------------------------------------------
73 class sc_byte_heap
74 {
75  public:
76  char *m_bgn_p; // Beginning of heap storage.
77  char *m_end_p; // End of heap storage.
78  char *m_next_p; // Next heap location to be allocated.
79 
80  inline char *
81  allocate(std::size_t bytes_n)
82  {
83  char *result_p;
84  bytes_n = (bytes_n + 7) & ((std::size_t)(-8));
85  result_p = m_next_p;
86  m_next_p += bytes_n;
87  if (m_next_p >= m_end_p) {
88  result_p = m_bgn_p;
89  m_next_p = m_bgn_p + bytes_n;
90  }
91  return result_p;
92  }
93 
94  inline void
95  initialize(std::size_t heap_size=0x100000)
96  {
97  delete [] m_bgn_p;
98  m_bgn_p = new char[heap_size];
99  m_end_p = &m_bgn_p[heap_size];
100  m_next_p = m_bgn_p;
101  }
102 
103  inline std::size_t
104  length()
105  {
106  return (std::size_t)(m_end_p - m_bgn_p);
107  }
108 
109  inline sc_byte_heap() : m_bgn_p(0), m_end_p(0), m_next_p(0) {}
110 
111  inline sc_byte_heap(std::size_t heap_size) :
112  m_bgn_p(0), m_end_p(0), m_next_p(0)
113  {
114  initialize(heap_size);
115  }
116 
117  inline ~sc_byte_heap() { delete [] m_bgn_p; }
118 };
119 
120 
121 //-----------------------------------------------------------------------------
122 // sc_vpool<T> - CLASS MANAGING A TEMPORARY VECTOR OF CLASS T INSTANCES
123 //
124 // This class implements a fixed pool of objects contained in a vector. These
125 // objects are allocated via the allocate() method. An index, m_pool_i,
126 // indicates the next object to be allocated. The vector is a power of 2 in
127 // size, and this fact is used to wrap the list when m_pool_i reaches the
128 // end of the vector.
129 //
130 // sc_vpool( int log2, T* pool_p=0 )
131 // This is the object instance constructor for this class. It configures
132 // the object to manage a vector of 2**log2 entries. If a vector is
133 // not supplied one will be allocated.
134 // log2 = the log base two of the size of the vector.
135 // pool_p -> vector of 2**log2 entries to be managed or 0.
136 //
137 // ~sc_vpool()
138 // This is the object instance destructor for this class. It frees the
139 // block of storage which was being managed.
140 //
141 // T* allocate()
142 // This method returns the address of the next entry in the vector, m_pool_p,
143 // pointed to by the index, m_pool_i, and updates that index. The index
144 // update consists of adding 1 to m_pool_i and masking it by m_wrap.
145 //
146 // void reset()
147 // This method resets the allocation index, m_pool_i, to point to the start
148 // of the vector of objects under management. This call is not usually made
149 // since there are a fixed number of entries and the index wraps. However,
150 // for diagnostics tests it is convenient to be able to reset to the start
151 // of the vector.
152 //
153 // int size()
154 // This method returns the number of object instances contained in the
155 // vector being managed by this object instance.
156 //-----------------------------------------------------------------------------
157 template<class T>
158 class sc_vpool
159 {
160  protected:
161  std::size_t m_pool_i; // Index of next entry to m_pool_m to provide.
162  T *m_pool_p; // Vector of temporaries.
163  std::size_t m_wrap; // Mask to wrap vector index.
164 
165  public:
166  inline sc_vpool(int log2, T *pool_p=0);
167  inline ~sc_vpool();
168  inline T *allocate();
169  inline void reset();
170  inline std::size_t size();
171 };
172 
173 template<class T>
174 sc_vpool<T>::sc_vpool(int log2, T *pool_p) : m_pool_i(0),
175  m_pool_p(pool_p ? pool_p : new T[static_cast<std::size_t>(1) << log2]),
176  m_wrap(~(static_cast<std::size_t>(-1) << log2))
177 {
178  // if (log2 > 32) SC_REPORT_ERROR(SC_ID_POOL_SIZE_, "");
179 }
180 
181 template<class T>
183 {
184  // delete [] m_pool_p;
185 }
186 
187 template<class T>
189 {
190  T *result_p; // Entry to return.
191 
192  result_p = &m_pool_p[m_pool_i];
193  m_pool_i = (m_pool_i + 1) & m_wrap;
194  return result_p;
195 }
196 
197 template<class T>
199 {
200  m_pool_i = 0;
201 }
202 
203 template<class T>
204 std::size_t sc_vpool<T>::size() { return m_wrap + 1; }
205 
206 } // namespace sc_core
207 
208 // $Log: sc_temporary.h,v $
209 // Revision 1.4 2011/08/26 20:46:19 acg
210 // Andy Goodrich: moved the modification log to the end of the file to
211 // eliminate source line number skew when check-ins are done.
212 //
213 // Revision 1.3 2011/08/24 22:05:56 acg
214 // Torsten Maehne: initialization changes to remove warnings.
215 //
216 // Revision 1.2 2011/02/18 20:38:44 acg
217 // Andy Goodrich: Updated Copyright notice.
218 //
219 // Revision 1.1.1.1 2006/12/15 20:20:06 acg
220 // SystemC 2.3
221 //
222 // Revision 1.3 2006/01/13 18:53:11 acg
223 // Andy Goodrich: Added $Log command so that CVS comments are reproduced in
224 // the source.
225 //
226 
227 #endif // __SYSTEMC_EXT_DT_SC_TEMPORARY_HH__
sc_core::sc_vpool::sc_vpool
sc_vpool(int log2, T *pool_p=0)
Definition: sc_temporary.hh:198
sc_core::sc_vpool::m_pool_i
std::size_t m_pool_i
Definition: sc_temporary.hh:185
sc_core::sc_vpool::~sc_vpool
~sc_vpool()
Definition: sc_temporary.hh:206
sc_core
Definition: messages.cc:31
sc_core::sc_byte_heap::m_bgn_p
char * m_bgn_p
Definition: sc_temporary.hh:124
sc_core::sc_vpool::size
std::size_t size()
Definition: sc_temporary.hh:228
sc_core::sc_vpool
Definition: sc_temporary.hh:182
sc_core::sc_vpool::m_pool_p
T * m_pool_p
Definition: sc_temporary.hh:186
sc_core::sc_byte_heap::allocate
char * allocate(std::size_t bytes_n)
Definition: sc_temporary.hh:129
sc_core::sc_vpool::m_wrap
std::size_t m_wrap
Definition: sc_temporary.hh:187
sc_core::sc_byte_heap::m_next_p
char * m_next_p
Definition: sc_temporary.hh:126
sc_core::sc_byte_heap::length
std::size_t length()
Definition: sc_temporary.hh:152
sc_core::sc_byte_heap::sc_byte_heap
sc_byte_heap()
Definition: sc_temporary.hh:157
sc_core::sc_vpool::reset
void reset()
Definition: sc_temporary.hh:222
std
Overload hash function for BasicBlockRange type.
Definition: vec_reg.hh:587
sc_core::sc_vpool::allocate
T * allocate()
Definition: sc_temporary.hh:212
sc_core::sc_byte_heap::initialize
void initialize(std::size_t heap_size=0x100000)
Definition: sc_temporary.hh:143
sc_core::sc_byte_heap::m_end_p
char * m_end_p
Definition: sc_temporary.hh:125
sc_core::sc_byte_heap::~sc_byte_heap
~sc_byte_heap()
Definition: sc_temporary.hh:165

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