dict.hpp

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#ifndef SHARE_LIBADT_DICT_HPP
#define SHARE_LIBADT_DICT_HPP

// Dictionaries - An Abstract Data Type

#include "memory/allocation.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/thread.hpp"

class Dict;

// These dictionaries define a key-value mapping.  They can be inserted to,
// searched or deleted from.  They grow and shrink as needed.  The key is a
// pointer to something (or anything which can be stored in a pointer).  A
// key comparison routine determines if two keys are equal or not.  A hash
// function can be provided; if it's not provided the key itself is used
// instead.  A nice string hash function is included.
typedef int32_t (*CmpKey)(const void* key1, const void* key2);
typedef int     (*Hash)(const void* key);

class Dict : public ResourceObj { // Dictionary structure
 private:
  class Arena* _arena;          // Where to draw storage from
  class bucket* _bin;           // Hash table is array of buckets
  uint _size;                   // Size (# of slots) in hash table
  uint32_t _cnt;                // Number of key-value pairs in hash table
  const Hash _hash;             // Hashing function
  const CmpKey _cmp;            // Key comparison function
  void doubhash();              // Double hash table size

 public:
  friend class DictI;            // Friendly iterator function

  // cmp is a key comparision routine.  hash is a routine to hash a key.
  Dict(CmpKey cmp, Hash hash);
  Dict(CmpKey cmp, Hash hash, Arena* arena, int size = 16);
  Dict(const Dict &base, Arena* arena); // Deep-copy
  ~Dict();

  // Return # of key-value pairs in dict
  uint32_t Size(void) const { return _cnt; }

  // Insert inserts the given key-value pair into the dictionary.  The prior
  // value of the key is returned; NULL if the key was not previously defined.
  void* Insert(void* key, void* val, bool replace = true); // A new key-value
  void* Delete(void* key);        // Delete & return old

  // Find finds the value of a given key; or NULL if not found.
  // The dictionary is NOT changed.
  void* operator [](const void* key) const;  // Do a lookup

  // Print out the dictionary contents as key-value pairs
  void print();
};

// Hashing functions
int hashstr(const void* s);        // Nice string hash
// Slimey cheap hash function; no guaranteed performance.  Better than the
// default for pointers, especially on MS-DOS machines.
int hashptr(const void* key);
// Slimey cheap hash function; no guaranteed performance.
int hashkey(const void* key);

// Key comparators
int32_t cmpstr(const void* k1, const void* k2);
// Slimey cheap key comparator.
int32_t cmpkey(const void* key1, const void* key2);

//------------------------------Iteration--------------------------------------
// The class of dictionary iterators.  Fails in the presences of modifications
// to the dictionary during iteration (including searches).
// Usage:  for( DictI i(dict); i.test(); ++i ) { body = i.key; body = i.value;}
class DictI {
 private:
  const Dict* _d;               // Dictionary being iterated over
  uint _i;                      // Counter over the bins
  uint _j;                      // Counter inside each bin
 public:
  const void* _key;
  const void* _value;
  DictI(const Dict* d) { reset(d); }; // Create a new iterator
  void reset(const Dict* dict);       // Reset existing iterator
  void operator ++(void);             // Increment iterator
  int test(void) { return _i < _d->_size; } // Test for end of iteration
};

#endif // SHARE_LIBADT_DICT_HPP