X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2FMoof%2Fstlplus%2Fhash.hpp;fp=src%2FMoof%2Fstlplus%2Fhash.hpp;h=05d3b7dcec718d2e8ffd4ef3da47150e94b943db;hp=0000000000000000000000000000000000000000;hb=72d4af22710317acffab861421c4364b1780b6fe;hpb=493ddb59a8620b49dfa0ff62ce93395ebfd02e86

diff --git a/src/Moof/stlplus/hash.hpp b/src/Moof/stlplus/hash.hpp
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+#ifndef STLPLUS_HASH
+#define STLPLUS_HASH
+////////////////////////////////////////////////////////////////////////////////
+
+//   Author:    Andy Rushton
+//   Copyright: (c) Southampton University 1999-2004
+//              (c) Andy Rushton           2004-2009
+//   License:   BSD License, see ../docs/license.html
+
+//   A chained hash table using STL semantics
+
+////////////////////////////////////////////////////////////////////////////////
+#include "containers_fixes.hpp"
+#include "exceptions.hpp"
+#include "safe_iterator.hpp"
+#include <map>
+
+namespace stlplus
+{
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // internals
+
+  template<typename K, typename T, class H, class E> class hash;
+  template<typename K, typename T, class H, class E> class hash_element;
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // iterator class
+
+  template<typename K, typename T, class H, class E, typename V>
+  class hash_iterator : public safe_iterator<hash<K,T,H,E>,hash_element<K,T,H,E> >
+  {
+  public:
+    friend class hash<K,T,H,E>;
+
+    // local type definitions
+    // an iterator points to a value whilst a const_iterator points to a const value
+    typedef V                                                  value_type;
+    typedef hash_iterator<K,T,H,E,std::pair<const K,T> >       iterator;
+    typedef hash_iterator<K,T,H,E,const std::pair<const K,T> > const_iterator;
+    typedef hash_iterator<K,T,H,E,V>                           this_iterator;
+    typedef V&                                                 reference;
+    typedef V*                                                 pointer;
+
+    // constructor to create a null iterator - you must assign a valid value to this iterator before using it
+    // any attempt to dereference or use a null iterator is an error
+    // the only valid thing you can do is assign an iterator to it
+    hash_iterator(void);
+    ~hash_iterator(void);
+
+    // Type conversion methods allow const_iterator and iterator to be converted
+    // convert an iterator/const_iterator to a const_iterator
+    const_iterator constify(void) const;
+    // convert an iterator/const_iterator to an iterator
+    iterator deconstify(void) const;
+
+    // increment operators used to step through the set of all values in a hash
+    // it is only legal to increment a valid iterator
+    // there's no decrement - I've only implemented this as a unidirectional iterator
+    // pre-increment
+    this_iterator& operator ++ (void)
+      throw(null_dereference,end_dereference);
+    // post-increment
+    this_iterator operator ++ (int)
+      throw(null_dereference,end_dereference);
+
+    // test useful for testing whether iteration has completed
+    bool operator == (const this_iterator& r) const;
+    bool operator != (const this_iterator& r) const;
+    bool operator < (const this_iterator& r) const;
+
+    // access the value - a const_iterator gives you a const value, an iterator a non-const value
+    // it is illegal to dereference an invalid (i.e. null or end) iterator
+    reference operator*(void) const
+      throw(null_dereference,end_dereference);
+    pointer operator->(void) const
+      throw(null_dereference,end_dereference);
+
+  private:
+    friend class hash_element<K,T,H,E>;
+
+    // constructor used by hash to create a non-null iterator
+    // you cannot create a valid iterator except by calling a hash method that returns one
+    explicit hash_iterator(hash_element<K,T,H,E>* element);
+    // constructor used to create an end iterator
+    explicit hash_iterator(const hash<K,T,H,E>* owner);
+    // used to create an alias of an iterator
+    explicit hash_iterator(const safe_iterator<hash<K,T,H,E>, hash_element<K,T,H,E> >& iterator);
+  };
+
+  ////////////////////////////////////////////////////////////////////////////////
+  // Hash class
+  // K = key type
+  // T = value type
+  // H = hash function object with the profile 'unsigned H(const K&)'
+  // E = equal function object with profile 'bool E(const K&, const K&)' defaults to equal_to which in turn calls '=='
+
+  template<typename K, typename T, class H, class E = std::equal_to<K> >
+  class hash
+  {
+  public:
+    typedef unsigned                                size_type;
+    typedef K                                       key_type;
+    typedef T                                       data_type;
+    typedef T                                       mapped_type;
+    typedef std::pair<const K, T>                   value_type;
+    typedef hash_iterator<K,T,H,E,value_type>       iterator;
+    typedef hash_iterator<K,T,H,E,const value_type> const_iterator;
+
+    // construct a hash table with specified number of bins
+    // the default 0 bins means leave it to the table to decide
+    // specifying 0 bins also enables auto-rehashing, otherwise auto-rehashing defaults off
+    hash(unsigned bins = 0);
+    ~hash(void);
+
+    // copy and equality copy the data elements but not the size of the copied table
+    hash(const hash&);
+    hash& operator = (const hash&);
+
+    // test for an empty table and for the size of a table
+    // efficient because the size is stored separately from the table contents
+    bool empty(void) const;
+    unsigned size(void) const;
+
+    // test for equality - two hashes are equal if they contain equal values
+    bool operator == (const hash&) const;
+    bool operator != (const hash&) const;
+
+    // switch auto-rehash on
+    void auto_rehash(void);
+    // switch auto-rehash off
+    void manual_rehash(void);
+    // force a rehash now
+    // default of 0 means implement built-in size calculation for rehashing (recommended - it doubles the number of bins)
+    void rehash(unsigned bins = 0);
+    // test the loading ratio, which is the size divided by the number of bins
+    // use this if you are doing your own rehashing
+    // the recommendation is to double the bins when the loading exceeds 0.5 which is what auto-rehashing does
+    float loading(void) const;
+
+    // test for the presence of a key
+    bool present(const K& key) const;
+    // provide map equivalent key count function (0 or 1, as not a multimap)
+    size_type count(const K& key) const;
+
+    // insert a new key/data pair - replaces any previous value for this key
+    iterator insert(const K& key, const T& data);
+    // insert a copy of the pair into the table (std::map compatible)
+    std::pair<iterator, bool> insert(const value_type& value);
+    // insert a new key and return the iterator so that the data can be filled in
+    iterator insert(const K& key);
+
+    // remove a key/data pair from the hash table
+    bool erase(const K& key);
+    // remove all elements from the hash table
+    void erase(void);
+    // provide the std::map equivalent clear function
+    void clear(void);
+
+    // find a key and return an iterator to it
+    // The iterator is like a pointer to a pair<const K,T>
+    // end() is returned if the find fails
+    const_iterator find(const K& key) const;
+    iterator find(const K& key);
+
+    // returns the data corresponding to the key
+    // const version is used for const hashes and cannot change the hash, so failure causes an exception
+    // non-const version is for non-const hashes and is like map - it creates a new key/data pair if find fails
+    const T& operator[] (const K& key) const throw(std::out_of_range);
+    T& operator[] (const K& key);
+
+    // iterators allow the hash table to be traversed
+    // iterators remain valid unless an item is removed or unless a rehash happens
+    const_iterator begin(void) const;
+    iterator begin(void);
+    const_iterator end(void) const;
+    iterator end(void);
+
+    // internals
+  private:
+    friend class hash_element<K,T,H,E>;
+    friend class hash_iterator<K,T,H,E,std::pair<const K,T> >;
+    friend class hash_iterator<K,T,H,E,const std::pair<const K,T> >;
+
+    unsigned m_rehash;
+    unsigned m_bins;
+    unsigned m_size;
+    hash_element<K,T,H,E>** m_values;
+  };
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+} // end namespace stlplus
+
+#include "hash.tpp"
+#endif