]> git.saurik.com Git - wxWidgets.git/blobdiff - include/wx/hash.h
1. added support for bitmaps with alpha channel
[wxWidgets.git] / include / wx / hash.h
index 4634f96313b6f3d25a5d81d575619295655f81e8..337eb80371d4daf8dbeaf3f24fc49bff1284ada8 100644 (file)
@@ -1,23 +1,43 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        hash.h
+// Name:        wx/hash.h
 // Purpose:     wxHashTable class
 // Author:      Julian Smart
-// Modified by:
+// Modified by: VZ at 25.02.00: type safe hashes with WX_DECLARE_HASH()
 // Created:     01/02/97
 // RCS-ID:      $Id$
 // Copyright:   (c)
-// Licence:    wxWindows licence
+// Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
-#ifndef _WX_WXHASHH__
-#define _WX_WXHASHH__
+#ifndef _WX_HASH_H__
+#define _WX_HASH_H__
 
-#ifdef __GNUG__
+#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
 #pragma interface "hash.h"
 #endif
 
-#include "wx/object.h"
-#include "wx/list.h"
+#include "wx/defs.h"
+
+#if !wxUSE_STL && WXWIN_COMPATIBILITY_2_4
+    #define wxUSE_OLD_HASH_TABLE 1
+#else
+    #define wxUSE_OLD_HASH_TABLE 0
+#endif
+
+#if !wxUSE_STL
+    #include "wx/object.h"
+#else
+    class WXDLLIMPEXP_BASE wxObject;
+#endif
+#if wxUSE_OLD_HASH_TABLE
+    #include "wx/list.h"
+#endif
+#if WXWIN_COMPATIBILITY_2_4
+    #include "wx/dynarray.h"
+#endif
+
+// the default size of the hash
+#define wxHASH_SIZE_DEFAULT     (1000)
 
 /*
  * A hash table is an array of user-definable size with lists
  * the list to find the desired item.
 */
 
-class WXDLLEXPORT wxHashTable: public wxObject
+// ----------------------------------------------------------------------------
+// this is the base class for object hashes: hash tables which contain
+// pointers to objects
+// ----------------------------------------------------------------------------
+
+#if wxUSE_OLD_HASH_TABLE
+
+class WXDLLIMPEXP_BASE wxHashTableBase : public wxObject
+{
+public:
+    wxHashTableBase();
+
+    void Create(wxKeyType keyType = wxKEY_INTEGER,
+                size_t size = wxHASH_SIZE_DEFAULT);
+    void Destroy();
+
+    size_t GetSize() const { return m_hashSize; }
+    size_t GetCount() const { return m_count; }
+
+    void DeleteContents(bool flag);
+
+protected:
+    // find the node for (key, value)
+    wxNodeBase *GetNode(long key, long value) const;
+
+    // the array of lists in which we store the values for given key hash
+    wxListBase **m_hashTable;
+
+    // the size of m_lists array
+    size_t m_hashSize;
+
+    // the type of indexing we use
+    wxKeyType m_keyType;
+
+    // the total number of elements in the hash
+    size_t m_count;
+
+    // should we delete our data?
+    bool m_deleteContents;
+
+private:
+    // no copy ctor/assignment operator (yet)
+    DECLARE_NO_COPY_CLASS(wxHashTableBase)
+};
+
+#else // if !wxUSE_OLD_HASH_TABLE
+
+#if !defined(wxENUM_KEY_TYPE_DEFINED)
+#define wxENUM_KEY_TYPE_DEFINED
+
+enum wxKeyType
+{
+    wxKEY_NONE,
+    wxKEY_INTEGER,
+    wxKEY_STRING
+};
+
+#endif
+
+union wxHashKeyValue
+{
+    long integer;
+    wxChar *string;
+};
+
+class WXDLLIMPEXP_BASE wxHashTableBase_Node
+{
+    friend class WXDLLIMPEXP_BASE wxHashTableBase;
+    typedef class WXDLLIMPEXP_BASE wxHashTableBase_Node _Node;
+public:
+    wxHashTableBase_Node( long key, void* value,
+                          wxHashTableBase* table );
+    wxHashTableBase_Node( const wxChar* key, void* value,
+                          wxHashTableBase* table );
+    ~wxHashTableBase_Node();
+
+    long GetKeyInteger() const { return m_key.integer; }
+    const wxChar* GetKeyString() const { return m_key.string; }
+
+    void* GetData() const { return m_value; }
+    void SetData( void* data ) { m_value = data; }
+
+protected:
+    _Node* GetNext() const { return m_next; }
+
+protected:
+    // next node in the chain
+    wxHashTableBase_Node* m_next;
+
+    // key
+    wxHashKeyValue m_key;
+
+    // value
+    void* m_value;
+
+    // pointer to the hash containing the node, used to remove the
+    // node from the hash when the user deletes the node iterating
+    // through it
+    // TODO: move it to wxHashTable_Node (only wxHashTable supports
+    //       iteration)
+    wxHashTableBase* m_hashPtr;
+};
+
+class WXDLLIMPEXP_BASE wxHashTableBase
+#if !wxUSE_STL
+    : public wxObject
+#endif
+{
+    friend class WXDLLIMPEXP_BASE wxHashTableBase_Node;
+public:
+    typedef wxHashTableBase_Node Node;
+
+    wxHashTableBase();
+    virtual ~wxHashTableBase() { };
+
+    void Create( wxKeyType keyType = wxKEY_INTEGER,
+                 size_t size = wxHASH_SIZE_DEFAULT );
+    void Clear();
+    void Destroy();
+
+    size_t GetSize() const { return m_size; }
+    size_t GetCount() const { return m_count; }
+
+    void DeleteContents( bool flag ) { m_deleteContents = flag; }
+
+    static long MakeKey(const wxChar *string);
+
+protected:
+    void DoPut( long key, long hash, void* data );
+    void DoPut( const wxChar* key, long hash, void* data );
+    void* DoGet( long key, long hash ) const;
+    void* DoGet( const wxChar* key, long hash ) const;
+    void* DoDelete( long key, long hash );
+    void* DoDelete( const wxChar* key, long hash );
+
+private:
+    // Remove the node from the hash, *only called from
+    // ~wxHashTable*_Node destructor
+    void DoRemoveNode( wxHashTableBase_Node* node );
+
+    // destroys data contained in the node if appropriate:
+    // deletes the key if it is a string and destrys
+    // the value if m_deleteContents is true
+    void DoDestroyNode( wxHashTableBase_Node* node );
+
+    // inserts a node in the table (at the end of the chain)
+    void DoInsertNode( size_t bucket, wxHashTableBase_Node* node );
+
+    // removes a node from the table (fiven a pointer to the previous
+    // but does not delete it (only deletes its contents)
+    void DoUnlinkNode( size_t bucket, wxHashTableBase_Node* node,
+                       wxHashTableBase_Node* prev );
+
+    // unconditionally deletes node value (invoking the
+    // correct destructor)
+    virtual void DoDeleteContents( wxHashTableBase_Node* node ) = 0;
+
+protected:
+    // number of buckets
+    size_t m_size;
+
+    // number of nodes (key/value pairs)
+    size_t m_count;
+
+    // table
+    Node** m_table;
+
+    // key typ (INTEGER/STRING)
+    wxKeyType m_keyType;
+
+    // delete contents when hash is cleared
+    bool m_deleteContents;
+
+private:
+    DECLARE_NO_COPY_CLASS(wxHashTableBase)
+};
+
+#endif // wxUSE_OLD_HASH_TABLE
+
+#if !wxUSE_STL
+
+#if WXWIN_COMPATIBILITY_2_4
+
+// ----------------------------------------------------------------------------
+// a hash table which stores longs
+// ----------------------------------------------------------------------------
+
+class WXDLLIMPEXP_BASE wxHashTableLong : public wxObject
+{
+public:
+    wxHashTableLong(size_t size = wxHASH_SIZE_DEFAULT)
+        { Init(size); }
+    virtual ~wxHashTableLong();
+
+    void Create(size_t size = wxHASH_SIZE_DEFAULT);
+    void Destroy();
+
+    size_t GetSize() const { return m_hashSize; }
+    size_t GetCount() const { return m_count; }
+
+    void Put(long key, long value);
+    long Get(long key) const;
+    long Delete(long key);
+
+protected:
+    void Init(size_t size);
+
+private:
+    wxArrayLong **m_values,
+                **m_keys;
+
+    // the size of array above
+    size_t m_hashSize;
+
+    // the total number of elements in the hash
+    size_t m_count;
+
+    // not implemented yet
+    DECLARE_NO_COPY_CLASS(wxHashTableLong)
+};
+
+// ----------------------------------------------------------------------------
+// wxStringHashTable: a hash table which indexes strings with longs
+// ----------------------------------------------------------------------------
+
+class WXDLLIMPEXP_BASE wxStringHashTable : public wxObject
+{
+public:
+    wxStringHashTable(size_t sizeTable = wxHASH_SIZE_DEFAULT);
+    virtual ~wxStringHashTable();
+
+    // add a string associated with this key to the table
+    void Put(long key, const wxString& value);
+
+    // get the string from the key: if not found, an empty string is returned
+    // and the wasFound is set to FALSE if not NULL
+    wxString Get(long key, bool *wasFound = NULL) const;
+
+    // remove the item, returning TRUE if the item was found and deleted
+    bool Delete(long key) const;
+
+    // clean up
+    void Destroy();
+
+private:
+    wxArrayLong **m_keys;
+    wxArrayString **m_values;
+
+    // the size of array above
+    size_t m_hashSize;
+
+    DECLARE_NO_COPY_CLASS(wxStringHashTable)
+};
+
+#endif // WXWIN_COMPATIBILITY_2_4
+
+#endif // !wxUSE_STL
+
+// ----------------------------------------------------------------------------
+// for compatibility only
+// ----------------------------------------------------------------------------
+
+#if !wxUSE_OLD_HASH_TABLE
+
+class WXDLLIMPEXP_BASE wxHashTable_Node : public wxHashTableBase_Node
+{
+    friend class WXDLLIMPEXP_BASE wxHashTable;
+public:
+    wxHashTable_Node( long key, void* value,
+                      wxHashTableBase* table )
+        : wxHashTableBase_Node( key, value, table ) { }
+    wxHashTable_Node( const wxChar* key, void* value,
+                      wxHashTableBase* table )
+        : wxHashTableBase_Node( key, value, table ) { }
+
+    wxObject* GetData() const
+        { return (wxObject*)wxHashTableBase_Node::GetData(); }
+    void SetData( wxObject* data )
+        { wxHashTableBase_Node::SetData( data ); }
+
+    wxHashTable_Node* GetNext() const
+        { return (wxHashTable_Node*)wxHashTableBase_Node::GetNext(); }
+};
+
+// should inherit protectedly, but it is public for compatibility in
+// order to publicly inherit from wxObject
+class WXDLLIMPEXP_BASE wxHashTable : public wxHashTableBase
+{
+    typedef wxHashTableBase hash;
+public:
+    typedef wxHashTable_Node Node;
+    typedef wxHashTable_Node* compatibility_iterator;
+public:
+    wxHashTable( wxKeyType keyType = wxKEY_INTEGER,
+                 size_t size = wxHASH_SIZE_DEFAULT )
+        : wxHashTableBase() { Create( keyType, size ); BeginFind(); }
+    wxHashTable( const wxHashTable& table );
+
+    virtual ~wxHashTable() { Destroy(); }
+
+    const wxHashTable& operator=( const wxHashTable& );
+
+    // key and value are the same
+    void Put(long value, wxObject *object)
+        { DoPut( value, value, object ); }
+    void Put(long hash, long value, wxObject *object)
+        { DoPut( value, hash, object ); }
+    void Put(const wxChar *value, wxObject *object)
+        { DoPut( value, MakeKey( value ), object ); }
+    void Put(long hash, const wxChar *value, wxObject *object)
+        { DoPut( value, hash, object ); }
+
+    // key and value are the same
+    wxObject *Get(long value) const
+        { return (wxObject*)DoGet( value, value ); }
+    wxObject *Get(long hash, long value) const
+        { return (wxObject*)DoGet( value, hash ); }
+    wxObject *Get(const wxChar *value) const
+        { return (wxObject*)DoGet( value, MakeKey( value ) ); }
+    wxObject *Get(long hash, const wxChar *value) const
+        { return (wxObject*)DoGet( value, hash ); }
+
+    // Deletes entry and returns data if found
+    wxObject *Delete(long key)
+        { return (wxObject*)DoDelete( key, key ); }
+    wxObject *Delete(long hash, long key)
+        { return (wxObject*)DoDelete( key, hash ); }
+    wxObject *Delete(const wxChar *key)
+        { return (wxObject*)DoDelete( key, MakeKey( key ) ); }
+    wxObject *Delete(long hash, const wxChar *key)
+        { return (wxObject*)DoDelete( key, hash ); }
+
+    // Construct your own integer key from a string, e.g. in case
+    // you need to combine it with something
+    long MakeKey(const wxChar *string) const
+        { return wxHashTableBase::MakeKey(string); }
+
+    // Way of iterating through whole hash table (e.g. to delete everything)
+    // Not necessary, of course, if you're only storing pointers to
+    // objects maintained separately
+    void BeginFind() { m_curr = NULL; m_currBucket = 0; }
+    Node* Next();
+
+    void Clear() { wxHashTableBase::Clear(); }
+
+    size_t GetCount() const { return wxHashTableBase::GetCount(); }
+protected:
+    virtual void DoDeleteContents( wxHashTableBase_Node* node );
+
+    // copy helper
+    void DoCopy( const wxHashTable& copy );
+
+    // searches the next node starting from bucket bucketStart and sets
+    // m_curr to it and m_currBucket to its bucket
+    void GetNextNode( size_t bucketStart );
+private:
+    // current node
+    Node* m_curr;
+
+    // bucket the current node belongs to
+    size_t m_currBucket;
+};
+
+#else // if wxUSE_OLD_HASH_TABLE
+
+class WXDLLIMPEXP_BASE wxHashTable : public wxObject
 {
-  DECLARE_DYNAMIC_CLASS(wxHashTable)
-
- public:
-  int n;
-  int current_position;
-  wxNode *current_node;
-
-  unsigned int key_type;
-  wxList **hash_table;
-
-  wxHashTable(int the_key_type = wxKEY_INTEGER, int size = 1000);
-  ~wxHashTable(void);
-  
-  // copy ctor and assignment operator
-  wxHashTable(const wxHashTable& table) { DoCopy(table); }
-  wxHashTable& operator=(const wxHashTable& table) { Clear(); DoCopy(table); return *this; }
-  void DoCopy(const wxHashTable& table);
-  
-  void Destroy(void);  // Robert Roebling
-
-  bool Create(int the_key_type = wxKEY_INTEGER, int size = 1000);
-
-  // Note that there are 2 forms of Put, Get.
-  // With a key and a value, the *value* will be checked
-  // when a collision is detected. Otherwise, if there are
-  // 2 items with a different value but the same key,
-  // we'll retrieve the WRONG ONE. So where possible,
-  // supply the required value along with the key.
-  // In fact, the value-only versions make a key, and still store
-  // the value. The use of an explicit key might be required
-  // e.g. when combining several values into one key.
-  // When doing that, it's highly likely we'll get a collision,
-  // e.g. 1 + 2 = 3, 2 + 1 = 3.
-
-  // key and value are NOT necessarily the same
-  void Put(long key, long value, wxObject *object);
-  void Put(long key, const wxChar *value, wxObject *object);
-
-  // key and value are the same
-  void Put(long value, wxObject *object);
-  void Put(const wxChar *value, wxObject *object);
-
-  // key and value not the same
-  wxObject *Get(long key, long value) const;
-  wxObject *Get(long key, const wxChar *value) const;
-
-  // key and value are the same
-  wxObject *Get(long value) const;
-  wxObject *Get(const wxChar *value) const;
-
-  // Deletes entry and returns data if found
-  wxObject *Delete(long key);
-  wxObject *Delete(const wxChar *key);
-
-  wxObject *Delete(long key, int value);
-  wxObject *Delete(long key, const wxChar *value);
-
-  // Construct your own integer key from a string, e.g. in case
-  // you need to combine it with something
-  long MakeKey(const wxChar *string) const;
-
-  // Way of iterating through whole hash table (e.g. to delete everything)
-  // Not necessary, of course, if you're only storing pointers to
-  // objects maintained separately
-
-  void BeginFind(void);
-  wxNode *Next(void);
-
-  void DeleteContents(bool flag);
-  void Clear(void);
+public:
+    typedef wxNode Node;
+    typedef wxNode* compatibility_iterator;
+
+    int n;
+    int current_position;
+    wxNode *current_node;
+
+    unsigned int key_type;
+    wxList **hash_table;
+
+    wxHashTable(int the_key_type = wxKEY_INTEGER,
+                int size = wxHASH_SIZE_DEFAULT);
+    ~wxHashTable();
+
+    // copy ctor and assignment operator
+    wxHashTable(const wxHashTable& table) : wxObject()
+        { DoCopy(table); }
+    wxHashTable& operator=(const wxHashTable& table)
+        { Clear(); DoCopy(table); return *this; }
+
+    void DoCopy(const wxHashTable& table);
+
+    void Destroy();
+
+    bool Create(int the_key_type = wxKEY_INTEGER,
+                int size = wxHASH_SIZE_DEFAULT);
+
+    // Note that there are 2 forms of Put, Get.
+    // With a key and a value, the *value* will be checked
+    // when a collision is detected. Otherwise, if there are
+    // 2 items with a different value but the same key,
+    // we'll retrieve the WRONG ONE. So where possible,
+    // supply the required value along with the key.
+    // In fact, the value-only versions make a key, and still store
+    // the value. The use of an explicit key might be required
+    // e.g. when combining several values into one key.
+    // When doing that, it's highly likely we'll get a collision,
+    // e.g. 1 + 2 = 3, 2 + 1 = 3.
+
+    // key and value are NOT necessarily the same
+    void Put(long key, long value, wxObject *object);
+    void Put(long key, const wxChar *value, wxObject *object);
+
+    // key and value are the same
+    void Put(long value, wxObject *object);
+    void Put(const wxChar *value, wxObject *object);
+
+    // key and value not the same
+    wxObject *Get(long key, long value) const;
+    wxObject *Get(long key, const wxChar *value) const;
+
+    // key and value are the same
+    wxObject *Get(long value) const;
+    wxObject *Get(const wxChar *value) const;
 
+    // Deletes entry and returns data if found
+    wxObject *Delete(long key);
+    wxObject *Delete(const wxChar *key);
+
+    wxObject *Delete(long key, int value);
+    wxObject *Delete(long key, const wxChar *value);
+
+    // Construct your own integer key from a string, e.g. in case
+    // you need to combine it with something
+    long MakeKey(const wxChar *string) const;
+
+    // Way of iterating through whole hash table (e.g. to delete everything)
+    // Not necessary, of course, if you're only storing pointers to
+    // objects maintained separately
+
+    void BeginFind();
+    Node* Next();
+
+    void DeleteContents(bool flag);
+    void Clear();
+
+    // Returns number of nodes
+    size_t GetCount() const { return m_count; }
+
+private:
+    size_t m_count;             // number of elements in the hashtable
+    bool m_deleteContents;
+
+    DECLARE_DYNAMIC_CLASS(wxHashTable)
 };
 
+#endif // wxUSE_OLD_HASH_TABLE
+
+#if !wxUSE_OLD_HASH_TABLE
+
+// defines a new type safe hash table which stores the elements of type eltype
+// in lists of class listclass
+#define _WX_DECLARE_HASH(eltype, dummy, hashclass, classexp)                  \
+    classexp hashclass : public wxHashTableBase                               \
+    {                                                                         \
+    public:                                                                   \
+        hashclass(wxKeyType keyType = wxKEY_INTEGER,                          \
+                  size_t size = wxHASH_SIZE_DEFAULT)                          \
+            : wxHashTableBase() { Create(keyType, size); }                    \
+                                                                              \
+        virtual ~hashclass() { Destroy(); }                                   \
+                                                                              \
+        void Put(long key, eltype *data) { DoPut(key, key, (void*)data); }    \
+        void Put(long hash, long key, eltype *data)                           \
+            { DoPut(key, hash, (void*)data); }                                \
+        eltype *Get(long key) const { return (eltype*)DoGet(key, key); }      \
+        eltype *Get(long hash, long key) const                                \
+            { return (eltype*)DoGet(key, hash); }                             \
+        eltype *Delete(long key) { return (eltype*)DoDelete(key, key); }      \
+        eltype *Delete(long hash, long key)                                   \
+            { return (eltype*)DoDelete(key, hash); }                          \
+    protected:                                                                \
+        virtual void DoDeleteContents( wxHashTableBase_Node* node )           \
+            { delete (eltype*)node->GetData(); }                              \
+                                                                              \
+        DECLARE_NO_COPY_CLASS(hashclass)                                      \
+    }
+
+#else // if wxUSE_OLD_HASH_TABLE
+
+#define _WX_DECLARE_HASH(eltype, listclass, hashclass, classexp)               \
+    classexp hashclass : public wxHashTableBase                                \
+    {                                                                          \
+    public:                                                                    \
+        hashclass(wxKeyType keyType = wxKEY_INTEGER,                           \
+                  size_t size = wxHASH_SIZE_DEFAULT)                           \
+            { Create(keyType, size); }                                         \
+                                                                               \
+        ~hashclass() { Destroy(); }                                            \
+                                                                               \
+        void Put(long key, long val, eltype *data) { DoPut(key, val, data); }  \
+        void Put(long key, eltype *data) { DoPut(key, key, data); }            \
+                                                                               \
+        eltype *Get(long key, long value) const                                \
+        {                                                                      \
+            wxNodeBase *node = GetNode(key, value);                            \
+            return node ? ((listclass::Node *)node)->GetData() : (eltype *)0;  \
+        }                                                                      \
+        eltype *Get(long key) const { return Get(key, key); }                  \
+                                                                               \
+        eltype *Delete(long key, long value)                                   \
+        {                                                                      \
+            eltype *data;                                                      \
+                                                                               \
+            wxNodeBase *node = GetNode(key, value);                            \
+            if ( node )                                                        \
+            {                                                                  \
+                data = ((listclass::Node *)node)->GetData();                   \
+                                                                               \
+                delete node;                                                   \
+                m_count--;                                                     \
+            }                                                                  \
+            else                                                               \
+            {                                                                  \
+                data = (eltype *)0;                                            \
+            }                                                                  \
+                                                                               \
+            return data;                                                       \
+        }                                                                      \
+        eltype *Delete(long key) { return Delete(key, key); }                  \
+                                                                               \
+    protected:                                                                 \
+        void DoPut(long key, long value, eltype *data)                         \
+        {                                                                      \
+            size_t slot = (size_t)abs((int)(key % (long)m_hashSize));          \
+                                                                               \
+            if ( !m_hashTable[slot] )                                          \
+            {                                                                  \
+                m_hashTable[slot] = new listclass(m_keyType);                  \
+                if ( m_deleteContents )                                        \
+                    m_hashTable[slot]->DeleteContents(TRUE);                   \
+            }                                                                  \
+                                                                               \
+            ((listclass *)m_hashTable[slot])->Append(value, data);             \
+            m_count++;                                                         \
+        }                                                                      \
+                                                                               \
+        DECLARE_NO_COPY_CLASS(hashclass)                                       \
+    }
+
+#endif // wxUSE_OLD_HASH_TABLE
+
+// this macro is to be used in the user code
+#define WX_DECLARE_HASH(el, list, hash) \
+    _WX_DECLARE_HASH(el, list, hash, class)
+
+// and this one does exactly the same thing but should be used inside the
+// library
+#define WX_DECLARE_EXPORTED_HASH(el, list, hash)  \
+    _WX_DECLARE_HASH(el, list, hash, class WXDLLEXPORT)
+
+#define WX_DECLARE_USER_EXPORTED_HASH(el, list, hash, usergoo)  \
+    _WX_DECLARE_HASH(el, list, hash, class usergoo)
+
+// delete all hash elements
+//
+// NB: the class declaration of the hash elements must be visible from the
+//     place where you use this macro, otherwise the proper destructor may not
+//     be called (a decent compiler should give a warning about it, but don't
+//     count on it)!
+#define WX_CLEAR_HASH_TABLE(hash)                                            \
+    {                                                                        \
+        (hash).BeginFind();                                                  \
+        wxHashTable::compatibility_iterator it = (hash).Next();              \
+        while( it )                                                          \
+        {                                                                    \
+            delete it->GetData();                                            \
+            it = (hash).Next();                                              \
+        }                                                                    \
+        (hash).Clear();                                                      \
+    }
+
 #endif
-    // _WX_WXHASHH__
+    // _WX_HASH_H__