mk4.h

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// mk4.h --
// $Id: mk4.h,v 1.40 2004/01/28 21:33:39 jcw Exp $
// This is part of Metakit, see https://www.equi4.com/metakit/

#ifndef __MK4_H__
#define __MK4_H__

//---------------------------------------------------------------------------
//
//  TITLE
//                                
//      The Metakit Library, by Coen Siegerink, Equi4 Software, NL.
//      
//  DESCRIPTION
//                                
//      Structured data storage with commit / rollback and on-demand loading.
//  
//  ACKNOWLEDGEMENTS
//                                                                        
//      To Liesbeth and Myra, for making this possible.
//
//---------------------------------------------------------------------------
//
//  NAMING CONVENTIONS        PREFIX    REMARKS
//                              
//      Compile time options    q4_     Always defined as 1 or 0, capitalized
//      Preprocessor defines    d4_     Use with "#ifdef" or "#if defined()"
//      Classes                 c4_     Classes, listed at start of headers
//      Typedefs                t4_     Type definitions, if outside classes
//      Global functions        f4_     Internal, these are rarely defined
//
//      Member functions                Start in uppercase
//      Instance variables      _       And start in lowercase
//      Static members          _       And start in uppercase
//
//      Local variable names            Start in lowercase
//      Formal parameter names          Start lowercase, end with underscore
//
//---------------------------------------------------------------------------

#define d4_MetakitLibraryVersion 249    // 2.4.9.4 release, Jun 10, 2005
#define d4_MetaKitLibraryVersion d4_MetakitLibraryVersion // compat, yuck

//---------------------------------------------------------------------------
// Declarations in this file

    class c4_View;                      // a view on underlying data
    class c4_Cursor;                    // an index into a view
    class c4_RowRef;                    // a reference to a row
        class c4_Row;                   // one row in a view
    class c4_Bytes;                     // used to pass around generic data
    class c4_Storage;                   // manages view persistence
    class c4_CustomViewer;              // used for customizable views
    class c4_Stream;                    // abstract stream class
    class c4_Strategy;                  // system and file interface

    class c4_Property;                  // for access inside rows
        class c4_IntProp;
        class c4_LongProp;
        class c4_FloatProp;
        class c4_DoubleProp;
        class c4_StringProp;
        class c4_BytesProp;
        class c4_ViewProp;

    // Everything below is part of the implementation, not for public use

    class c4_Sequence;                  // a collection of rows

    class c4_Reference;                 // refers to the actual data values
        class c4_IntRef;
        class c4_LongRef;
        class c4_FloatRef;
        class c4_DoubleRef;
        class c4_BytesRef;
        class c4_StringRef;
        class c4_ViewRef;

    class c4_Dependencies;              // not defined here
    class c4_Handler;                   // not defined here
    class c4_Notifier;                  // not defined here
    class c4_Persist;                   // not defined here

//---------------------------------------------------------------------------

    // determine whether we need to include "mk4dll.h" to link as DLL
#if defined (MKDLL_EXPORTS) && !defined (q4_KITDLL)
#define q4_KITDLL 1
#endif

    // omit floats and doubles in small model 16-bit Intel builds
#if defined (_DOS) && defined (_M_I86SM) && !defined (q4_TINY)
#define q4_TINY 1
#endif

    // and here's the other end of the scale...
#if !defined (_WIN32) && !defined (q4_LONG64)
#if defined (_PA_RISC2_0) || defined (__powerpc64__) || defined(__sparcv9) || \
    defined (__x86_64__) || defined (__s390x__) || defined (__alpha) || \
    (defined (__ia64) && (!defined (__HP_aCC) || defined(__LP64__)))
#define q4_LONG64 1
#endif
#endif

    // default to inlining for maximum performance
#if !defined (q4_INLINE)
#define q4_INLINE 1
#endif

//---------------------------------------------------------------------------

    // Borland C++ and C++ Builder
#if defined (__BORLANDC__)
    // by default, if runtime is linked as a DLL, then so is Metakit
#if defined (_RTLDLL) && !defined (q4_KITDLL)
#define q4_KITDLL 1
#endif

    // Borland 5.0 supports the bool datatype
#if __BORLANDC__ >= 0x500
#define q4_BOOL 1
#endif
#endif // __BORLANDC__

    // IRIX supports the bool datatype
    // define before gcc to cover both the gcc and MipsPRO compiler
#if defined (sgi)
#define q4_BOOL 1
#undef bool
#undef true
#undef false
#endif

    // GNU gcc/egcs
#if defined (__GNUC__)
#ifndef q4_BOOL
#define q4_BOOL 1
#endif
#ifndef HAVE_LONG_LONG
#define HAVE_LONG_LONG 1
#endif
#endif

    // HP aCC
#if defined (__HP_aCC)
#ifndef HAVE_LONG_LONG
#define HAVE_LONG_LONG 1
#endif
#endif

    // Metrowerks CodeWarrior
#if defined (__MWERKS__)
#if __option(bool)
#define q4_BOOL 1       // bool datatype is optionally supported
    // undef, these conflict with c4_Storage::c4_Storage overloading
#undef bool
#undef true
#undef false
#endif
#endif

    // Microsoft Visual C++
#if defined (_MSC_VER)
    // MSVC 5.0 supports the bool datatype, MSVC 4.x has no namespaces
#if _MSC_VER >= 1100
#define q4_BOOL 1
#define LONG_LONG __int64
#else
#define q4_NO_NS 1
#endif

    // a kludge to avoid having to use ugly DLL exprt defs in this header
#pragma warning(disable: 4273) // inconsistent dll linkage
#endif // _MSC_VER

//---------------------------------------------------------------------------
// Other definitions needed by the public Metakit library header files

#if !q4_BOOL && !q4_STD         // define a bool datatype
#define false 0
#define true 1
#define bool int
#endif

#if q4_KITDLL                   // add declaration specifiers
#include "mk4dll.h"
#endif

#if q4_INLINE                   // enable inline expansion
#define d4_inline inline
#else
#define d4_inline
#endif

typedef unsigned char t4_byte;  // create typedefs for t4_byte, etc.

#if q4_LONG64
typedef int t4_i32;             // if longs are 64b, then int must be 32b
#else
typedef long t4_i32;            // if longs aren't 64b, then they are 32b
#endif

#if q4_LONG64           // choose a way to represent 64b integers
typedef long t4_i64;
#elif defined (LONG_LONG)
typedef LONG_LONG t4_i64;
#elif HAVE_LONG_LONG
typedef long long t4_i64;
#else
struct t4_i64 { long l1; long l2; };
bool operator== (const t4_i64 a_, const t4_i64 b_);
bool operator< (const t4_i64 a_, const t4_i64 b_);
#endif

//---------------------------------------------------------------------------

class c4_View
{
protected:
  c4_Sequence* _seq;

public:
/* Construction / destruction / assignment */
  c4_View (c4_Sequence* =0);
  c4_View (c4_CustomViewer*);
  c4_View (c4_Stream*);
  c4_View (const c4_Property& property_);
  c4_View (const c4_View&);
  ~c4_View ();
  
  c4_View& operator= (const c4_View&);
  c4_Persist* Persist() const; // added 16-11-2000 to simplify c4_Storage

/* Getting / setting the number of rows */
  int GetSize() const;    
  void SetSize(int, int =-1); 

  void RemoveAll();

/*: Getting / setting individual elements */
  c4_RowRef GetAt(int) const;
  c4_RowRef operator[] (int) const;
  
  void SetAt(int, const c4_RowRef&);
  c4_RowRef ElementAt(int);

  bool GetItem(int, int, c4_Bytes&) const;
  void SetItem(int, int, const c4_Bytes&) const;

/* These can increase the number of rows */
  void SetAtGrow(int, const c4_RowRef&);   
  int Add(const c4_RowRef&);

/* Insertion / deletion of rows */
  void InsertAt(int, const c4_RowRef&, int =1);
  void RemoveAt(int, int =1);
  void InsertAt(int, const c4_View&);

  bool IsCompatibleWith(const c4_View&) const;
  void RelocateRows(int, int, c4_View&, int);

/* Dealing with the properties of this view */
  int NumProperties() const; 
  const c4_Property& NthProperty(int) const;
  int FindProperty(int);
  int FindPropIndexByName(const char*) const;
  c4_View Duplicate() const;
  c4_View Clone() const;
  int AddProperty(const c4_Property&);
  c4_View operator, (const c4_Property&) const;

  const char* Description() const;
  
/* Derived views */
  c4_View Sort() const;
  c4_View SortOn(const c4_View&) const;
  c4_View SortOnReverse(const c4_View&, const c4_View&) const;

  c4_View Select(const c4_RowRef&) const;
  c4_View SelectRange(const c4_RowRef&, const c4_RowRef&) const;

  c4_View Project(const c4_View&) const;
  c4_View ProjectWithout(const c4_View&) const;

  int GetIndexOf(const c4_RowRef&) const;
  int RestrictSearch(const c4_RowRef&, int&, int&);

/* Custom views */
  c4_View Slice(int, int =-1, int =1) const;
  c4_View Product(const c4_View&) const;
  c4_View RemapWith(const c4_View&) const;
  c4_View Pair(const c4_View&) const;
  c4_View Concat(const c4_View&) const;
  c4_View Rename(const c4_Property&, const c4_Property&) const;

  c4_View GroupBy(const c4_View&, const c4_ViewProp&) const;
  c4_View Counts(const c4_View&, const c4_IntProp&) const;
  c4_View Unique() const;

  c4_View Union(const c4_View&) const;
  c4_View Intersect(const c4_View&) const;
  c4_View Different(const c4_View&) const;
  c4_View Minus(const c4_View&) const;

  c4_View JoinProp(const c4_ViewProp&, bool =false) const;
  c4_View Join(const c4_View&, const c4_View&, bool =false) const;

  c4_View ReadOnly() const;
  c4_View Hash(const c4_View&, int =1) const;
  c4_View Blocked() const;
  c4_View Ordered(int =1) const;
  c4_View Indexed(const c4_View&, const c4_View&, bool =false) const;

/* Searching */
  int Find(const c4_RowRef&, int =0) const;
  int Search(const c4_RowRef&) const;
  int Locate(const c4_RowRef&, int* =0) const;
  
/* Comparing view contents */
  int Compare(const c4_View&) const;

  friend bool operator== (const c4_View&, const c4_View&);
  friend bool operator!= (const c4_View&, const c4_View&);
  friend bool operator< (const c4_View&, const c4_View&);
  friend bool operator> (const c4_View&, const c4_View&);
  friend bool operator<= (const c4_View&, const c4_View&);
  friend bool operator>= (const c4_View&, const c4_View&);
  
protected:
  void _IncSeqRef();
  void _DecSeqRef();

  friend class c4_ViewRef;

  // DROPPED: Structure() const;
  // DROPPED: Description(const c4_View& view_);
};

//---------------------------------------------------------------------------

#if defined(os_aix) && defined(compiler_ibmcxx) && (compiler_ibmcxx > 500)
  bool operator== (const c4_RowRef& a_, const c4_RowRef& b_);
  bool operator!= (const c4_RowRef& a_, const c4_RowRef& b_);
  bool operator<= (const c4_RowRef& a_, const c4_RowRef& b_);
  bool operator>= (const c4_RowRef& a_, const c4_RowRef& b_);
  bool operator> (const c4_RowRef& a_, const c4_RowRef& b_);
  bool operator< (const c4_RowRef& a_, const c4_RowRef& b_);
#endif

class c4_Cursor
{
public: 
  c4_Sequence* _seq;
  int _index;

/* Construction / destruction / dereferencing */
  c4_Cursor (c4_Sequence&, int);
  
  c4_RowRef operator* () const;
  
  c4_RowRef operator[] (int) const;

/* Stepping the iterator forwards / backwards */
  c4_Cursor& operator++ ();
  c4_Cursor operator++ (int);
  c4_Cursor& operator-- ();
  c4_Cursor operator-- (int);

  c4_Cursor& operator+= (int);
  c4_Cursor& operator-= (int);

  c4_Cursor operator- (int) const;
  int operator- (c4_Cursor) const;
  
  friend c4_Cursor operator+ (c4_Cursor, int);
  friend c4_Cursor operator+ (int, c4_Cursor);

/* Comparing row positions */
  friend bool operator== (c4_Cursor, c4_Cursor);
  friend bool operator!= (c4_Cursor, c4_Cursor);
  friend bool operator< (c4_Cursor, c4_Cursor);
  friend bool operator> (c4_Cursor, c4_Cursor);
  friend bool operator<= (c4_Cursor, c4_Cursor);
  friend bool operator>= (c4_Cursor, c4_Cursor);

/* Comparing row contents */
  friend bool operator== (const c4_RowRef&, const c4_RowRef&);
  friend bool operator!= (const c4_RowRef&, const c4_RowRef&);
  friend bool operator< (const c4_RowRef&, const c4_RowRef&);
  friend bool operator> (const c4_RowRef&, const c4_RowRef&);
  friend bool operator<= (const c4_RowRef&, const c4_RowRef&);
  friend bool operator>= (const c4_RowRef&, const c4_RowRef&);
};

//---------------------------------------------------------------------------

class c4_RowRef
{
  c4_Cursor _cursor;

public: 
/* General operations */
  c4_RowRef operator= (const c4_RowRef&);
  c4_Cursor operator& () const;
  c4_View Container() const;

protected:
  c4_RowRef (c4_Cursor);

  friend class c4_Cursor;
  friend class c4_Row;
};

//---------------------------------------------------------------------------
//
//  Rows can exist by themselves and as contents of views.  Row assignment
//  implies that a copy of the contents of the originating row is made.
//
//  A row is implemented as an unattached view with exactly one element.

class c4_Row : public c4_RowRef 
{
public:
  c4_Row ();
  c4_Row (const c4_Row&);
  c4_Row (const c4_RowRef&);
  ~c4_Row ();
  
  c4_Row& operator= (const c4_Row&);
  c4_Row& operator= (const c4_RowRef&);
  
  void ConcatRow(const c4_RowRef&);
  friend c4_Row operator+ (const c4_RowRef&, const c4_RowRef&);
  
private:
  static c4_Cursor Allocate();
  static void Release(c4_Cursor);
};

//---------------------------------------------------------------------------

class c4_Bytes
{
  union {
    t4_byte _buffer [16];
    double _aligner; // on a Sparc, the int below wasn't enough...
  };

  t4_byte* _contents;
  int _size;
  bool _copy;

public:
  c4_Bytes ();
  c4_Bytes (const void*, int);
  c4_Bytes (const void*, int, bool);
  c4_Bytes (const c4_Bytes&);
  ~c4_Bytes ();
  
  c4_Bytes& operator= (const c4_Bytes&);
  void Swap(c4_Bytes&);
  
  int Size() const;
  const t4_byte* Contents() const;
  
  t4_byte* SetBuffer(int);
  t4_byte* SetBufferClear(int);

  friend bool operator== (const c4_Bytes&, const c4_Bytes&);
  friend bool operator!= (const c4_Bytes&, const c4_Bytes&);

private:
  void _MakeCopy();
  void _LoseCopy();
};

//---------------------------------------------------------------------------

class c4_Storage : public c4_View
{
public:
  c4_Storage (); 
  c4_Storage (c4_Strategy&, bool =false, int =1); 
  c4_Storage (const char*, int);
  c4_Storage (const c4_View&);
  ~c4_Storage ();
  
  void SetStructure(const char*);
  bool AutoCommit(bool =true);
  c4_Strategy& Strategy() const;
  const char* Description(const char* =0);
  
  bool SetAside(c4_Storage&);
  c4_Storage* GetAside() const;

  bool Commit(bool =false);
  bool Rollback(bool =false);
  
  c4_ViewRef View(const char*);
  c4_View GetAs(const char*);

  bool LoadFrom(c4_Stream&);
  void SaveTo(c4_Stream&);

  t4_i32 FreeSpace(t4_i32* bytes_ =0);

  //DROPPED: c4_Storage (const char* filename_, const char* description_);
  //DROPPED: c4_View Store(const char* name_, const c4_View& view_);
  //DROPPED: c4_HandlerSeq& RootTable() const;
  //DROPPED: c4_RowRef xContents() const;

private:
  void Initialize(c4_Strategy&, bool, int);
};

//---------------------------------------------------------------------------

class c4_Property
{
  short _id;
  char _type;

public:
  c4_Property (char, int);
  c4_Property (char, const char*);
  ~c4_Property ();
  
  c4_Property (const c4_Property&);
  void operator= (const c4_Property&);

  const char* Name() const;
  char Type() const;

  int GetId() const;

  c4_Reference operator() (const c4_RowRef&) const;

  void Refs(int) const;

  c4_View operator, (const c4_Property&) const;

  static void CleanupInternalData();
};

class c4_IntProp : public c4_Property 
{
public:
  c4_IntProp (const char*);
  ~c4_IntProp ();
  
  c4_IntRef operator() (const c4_RowRef&) const;
  t4_i32 Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, t4_i32) const;

  c4_Row operator[] (t4_i32) const;
  c4_Row AsRow(t4_i32) const;
};

#if !q4_TINY

class c4_LongProp : public c4_Property 
{
public:
  c4_LongProp (const char*);
  ~c4_LongProp ();
  
  c4_LongRef operator() (const c4_RowRef&) const;
  t4_i64 Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, t4_i64) const;

  c4_Row operator[] (t4_i64) const;
  c4_Row AsRow(t4_i64) const;
};

class c4_FloatProp : public c4_Property 
{
public:
  c4_FloatProp (const char*);
  ~c4_FloatProp ();
  
  c4_FloatRef operator() (const c4_RowRef&) const;
  double Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, double) const;

  c4_Row operator[] (double) const;
  c4_Row AsRow(double) const;
};

class c4_DoubleProp : public c4_Property 
{
public:
  c4_DoubleProp (const char*);
  ~c4_DoubleProp ();
  
  c4_DoubleRef operator() (const c4_RowRef&) const;
  double Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, double) const;

  c4_Row operator[] (double) const;
  c4_Row AsRow(double) const;
};
#endif // !q4_TINY

class c4_StringProp : public c4_Property
{
public:
  c4_StringProp (const char*);
  ~c4_StringProp ();
  
  c4_StringRef operator() (const c4_RowRef&) const;
  const char* Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, const char*) const;

  c4_Row operator[] (const char*) const;
  c4_Row AsRow(const char*) const;
};

class c4_BytesProp : public c4_Property
{
public:
  c4_BytesProp (const char*);
  ~c4_BytesProp ();
  
  c4_BytesRef operator() (const c4_RowRef&) const;
  c4_Bytes Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, const c4_Bytes&) const;

  c4_Row operator[] (const c4_Bytes&) const;
  c4_Row AsRow(const c4_Bytes&) const;
};

class c4_ViewProp : public c4_Property
{
public:
  c4_ViewProp (const char*);
  ~c4_ViewProp ();
  
  c4_ViewRef operator() (const c4_RowRef&) const;
  c4_View Get(const c4_RowRef&) const;
  void Set(const c4_RowRef&, const c4_View&) const;

  c4_Row operator[] (const c4_View&) const;
  c4_Row AsRow(const c4_View&) const;
};

//---------------------------------------------------------------------------

class c4_CustomViewer
{
protected: 
  c4_CustomViewer ();
public: 
  virtual ~c4_CustomViewer ();
  
  virtual c4_View GetTemplate() = 0;
  virtual int GetSize() = 0;
  int Lookup(const c4_RowRef&, int&);
  virtual int Lookup(c4_Cursor, int&);
  virtual bool GetItem(int, int, c4_Bytes&) = 0;
  virtual bool SetItem(int, int, const c4_Bytes&);
  bool InsertRows(int, const c4_RowRef&, int =1);
  virtual bool InsertRows(int, c4_Cursor, int =1);
  virtual bool RemoveRows(int, int =1);
};

//---------------------------------------------------------------------------

class c4_Stream
{
public:
  virtual ~c4_Stream ();

  virtual int Read(void*, int) = 0;
  virtual bool Write(const void*, int) = 0;
};

//---------------------------------------------------------------------------

class c4_Strategy
{
public:
  c4_Strategy ();
  virtual ~c4_Strategy ();

  virtual bool IsValid() const;
  virtual int  DataRead(t4_i32, void*, int);
  virtual void DataWrite(t4_i32, const void*, int);
  virtual void DataCommit(t4_i32);
  virtual void ResetFileMapping();
  virtual t4_i32 FileSize();
  virtual t4_i32 FreshGeneration();

  void SetBase(t4_i32);
  t4_i32 EndOfData(t4_i32 =-1);

  bool _bytesFlipped;
  int _failure;
  const t4_byte* _mapStart;
  t4_i32 _dataSize;
  t4_i32 _baseOffset;
  t4_i32 _rootPos;
  t4_i32 _rootLen;
};

//---------------------------------------------------------------------------
//
//  Sequences represent arrays of rows (or indexed collections / tables).
//  Insertion and removal of entries is allowed, but could take linear time.
//  A reference count is maintained to decide when the object should go away.

class c4_Sequence
{
  int _refCount;
  c4_Dependencies* _dependencies;

protected:
  int _propertyLimit;
  short* _propertyMap; // see c4_HandlerSeq::Reset()
  c4_Bytes* _tempBuf;

public: 
/* General */
  c4_Sequence ();
  
  virtual int Compare(int, c4_Cursor) const;
  virtual bool RestrictSearch(c4_Cursor, int&, int&);
  void SetAt(int, c4_Cursor);
  virtual int RemapIndex(int, const c4_Sequence*) const;
  
/* Reference counting */
  void IncRef();
  void DecRef();
  int NumRefs() const;

/* Adding / removing rows */
  virtual int NumRows() const = 0;
  void Resize(int, int =-1);
  
  virtual void InsertAt(int, c4_Cursor, int =1);
  virtual void RemoveAt(int, int =1);
  virtual void Move(int, int);

/* Properties */
  int NthPropId(int) const;
  int PropIndex(int);
  int PropIndex(const c4_Property&);
  
  virtual int NumHandlers() const = 0;
  virtual c4_Handler& NthHandler(int) const = 0;
  virtual const c4_Sequence* HandlerContext(int) const = 0;
  virtual int AddHandler(c4_Handler*) = 0;
  virtual c4_Handler* CreateHandler(const c4_Property&) = 0;

  virtual const char* Description();

/* Element access */
  virtual int ItemSize(int, int);
  virtual bool Get(int, int, c4_Bytes&);
  virtual void Set(int, const c4_Property&, const c4_Bytes&);
  
/* Dependency notification */
  void Attach(c4_Sequence*);
  void Detach(c4_Sequence*);
  c4_Dependencies* GetDependencies() const;

  virtual c4_Notifier* PreChange(c4_Notifier&);
  virtual void PostChange(c4_Notifier&);
  
  const char* UseTempBuffer(const char*);

protected:
  virtual ~c4_Sequence ();

  void ClearCache();

public: 
  virtual void SetNumRows(int) = 0;
  virtual c4_Persist* Persist() const;

  c4_Bytes& Buffer();

private:
  c4_Sequence (const c4_Sequence&);   // not implemented
  void operator= (const c4_Sequence&); // not implemented
};

//---------------------------------------------------------------------------
//
//  Objects of this class are only intended to be used as a temporary handle
//  while getting and setting properties in a row.  They are normally only
//  constructed as result of function overload operators: "property (row)".

class c4_Reference
{
protected:
  c4_Cursor _cursor;
  const c4_Property& _property;

public:
  c4_Reference (const c4_RowRef&, const c4_Property&);

  c4_Reference& operator= (const c4_Reference&);

  int GetSize() const;
  bool GetData(c4_Bytes&) const;
  void SetData(const c4_Bytes&) const;
  
  friend bool operator== (const c4_Reference&, const c4_Reference&);
  friend bool operator!= (const c4_Reference&, const c4_Reference&);

private:
  void operator& () const;            // not implemented
};

//---------------------------------------------------------------------------

class c4_IntRef : public c4_Reference
{
public:
  c4_IntRef (const c4_Reference&);
  operator t4_i32 () const;
  c4_IntRef& operator= (t4_i32);
};

#if !q4_TINY

class c4_LongRef : public c4_Reference
{
public:
  c4_LongRef (const c4_Reference&);
  operator t4_i64 () const;
  c4_LongRef& operator= (t4_i64);
};

class c4_FloatRef : public c4_Reference
{
public:
  c4_FloatRef (const c4_Reference&);
  operator double () const;
  c4_FloatRef& operator= (double);
};

class c4_DoubleRef : public c4_Reference
{
public:
  c4_DoubleRef (const c4_Reference&);
  operator double () const;
  c4_DoubleRef& operator= (double);
};

#endif // !q4_TINY

class c4_BytesRef : public c4_Reference
{
public:
  c4_BytesRef (const c4_Reference&);
  operator c4_Bytes () const;
  c4_BytesRef& operator= (const c4_Bytes&);

  c4_Bytes Access(t4_i32, int =0) const;
  bool Modify(const c4_Bytes&, t4_i32, int =0) const;
};

class c4_StringRef : public c4_Reference
{
public:
  c4_StringRef (const c4_Reference&);
  operator const char* () const;
  c4_StringRef& operator= (const char*);
};

class c4_ViewRef : public c4_Reference
{
public:
  c4_ViewRef (const c4_Reference&);
  operator c4_View () const;
  c4_ViewRef& operator= (const c4_View&);
};

//---------------------------------------------------------------------------
// Debug logging option, can generate log of changes for one/all properties

#if q4_LOGPROPMODS
FILE* f4_LogPropMods(FILE* fp_, int propId_);
#else
#define f4_LogPropMods(a,b) 0
#endif

//---------------------------------------------------------------------------

#if q4_INLINE
#include "mk4.inl"
#endif

//---------------------------------------------------------------------------

#endif // __MK4_H__

---

Metakit C++ API Reference - https://www.equi4.com/metakit.html - extracted with Doxygen