dict.hpp revision 1472:c18cbe5936b8 
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24
25#ifndef _DICT_
26#define _DICT_
27// Dictionaries - An Abstract Data Type
28//INTERFACE
29class ostream;
30class Dict;
31
32// These dictionaries define a key-value mapping.  They can be inserted to,
33// searched or deleted from.  They grow and shrink as needed.  The key is a
34// pointer to something (or anything which can be stored in a pointer).  A
35// key comparison routine determines if two keys are equal or not.  A hash
36// function can be provided; if it's not provided the key itself is used
37// instead.  A nice string hash function is included.
38typedef int32 (*CmpKey)(const void *key1, const void *key2);
39typedef int  (*Hash)(const void *key);
40typedef void (*FuncDict)(const void *key, const void *val, Dict *d);
41
42class Dict : public ResourceObj { // Dictionary structure
43 private:
44  class Arena *_arena;          // Where to draw storage from
45  class bucket *_bin;           // Hash table is array of buckets
46  uint _size;                   // Size (# of slots) in hash table
47  uint32 _cnt;                  // Number of key-value pairs in hash table
48  const Hash _hash;             // Hashing function
49  const CmpKey _cmp;            // Key comparison function
50  void doubhash( void );        // Double hash table size
51
52 public:
53  friend class DictI;            // Friendly iterator function
54
55  // cmp is a key comparision routine.  hash is a routine to hash a key.
56  Dict( CmpKey cmp, Hash hash );
57  Dict( CmpKey cmp, Hash hash, Arena *arena, int size=16 );
58  ~Dict();
59
60  Dict( const Dict & );         // Deep-copy guts
61  Dict &operator =( const Dict & );
62
63  // Zap to empty; ready for re-use
64  void Clear();
65
66  // Return # of key-value pairs in dict
67  uint32 Size(void) const { return _cnt; }
68
69  // Insert inserts the given key-value pair into the dictionary.  The prior
70  // value of the key is returned; NULL if the key was not previously defined.
71  void *Insert(void *key, void *val, bool replace = true); // A new key-value
72  void *Delete(void *key);        // Delete & return old
73
74  // Find finds the value of a given key; or NULL if not found.
75  // The dictionary is NOT changed.
76  void *operator [](const void *key) const;  // Do a lookup
77
78  // == compares two dictionaries; they must have the same keys (their keys
79  // must match using CmpKey) and they must have the same values (pointer
80  // comparison).  If so 1 is returned, if not 0 is returned.
81  int32 operator ==(const Dict &d) const;   // Compare dictionaries for equal
82
83  // Print out the dictionary contents as key-value pairs
84  void print();
85};
86
87// Hashing functions
88int hashstr(const void *s);        // Nice string hash
89// Slimey cheap hash function; no guaranteed performance.  Better than the
90// default for pointers, especially on MS-DOS machines.
91int hashptr(const void *key);
92// Slimey cheap hash function; no guaranteed performance.
93int hashkey(const void *key);
94
95// Key comparators
96int32 cmpstr(const void *k1, const void *k2);
97// Slimey cheap key comparator.
98int32 cmpkey(const void *key1, const void *key2);
99
100//------------------------------Iteration--------------------------------------
101// The class of dictionary iterators.  Fails in the presences of modifications
102// to the dictionary during iteration (including searches).
103// Usage:  for( DictI i(dict); i.test(); ++i ) { body = i.key; body = i.value;}
104class DictI {
105 private:
106  const Dict *_d;               // Dictionary being iterated over
107  uint _i;                      // Counter over the bins
108  uint _j;                      // Counter inside each bin
109 public:
110  const void *_key, *_value;    // Easy access to the key-value pair
111  DictI( const Dict *d ) {reset(d);}; // Create a new iterator
112  void reset( const Dict *dict );     // Reset existing iterator
113  void operator ++(void);             // Increment iterator
114  int test(void) { return _i<_d->_size;} // Test for end of iteration
115};
116
117#endif // _DICT_
118