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Diffstat (limited to 'kviewshell/plugins/djvu/libdjvu/GSmartPointer.h')
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diff --git a/kviewshell/plugins/djvu/libdjvu/GSmartPointer.h b/kviewshell/plugins/djvu/libdjvu/GSmartPointer.h new file mode 100644 index 00000000..04b79ecf --- /dev/null +++ b/kviewshell/plugins/djvu/libdjvu/GSmartPointer.h @@ -0,0 +1,489 @@ +//C- -*- C++ -*- +//C- ------------------------------------------------------------------- +//C- DjVuLibre-3.5 +//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun. +//C- Copyright (c) 2001 AT&T +//C- +//C- This software is subject to, and may be distributed under, the +//C- GNU General Public License, Version 2. The license should have +//C- accompanied the software or you may obtain a copy of the license +//C- from the Free Software Foundation at http://www.fsf.org . +//C- +//C- This program is distributed in the hope that it will be useful, +//C- but WITHOUT ANY WARRANTY; without even the implied warranty of +//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +//C- GNU General Public License for more details. +//C- +//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library +//C- distributed by Lizardtech Software. On July 19th 2002, Lizardtech +//C- Software authorized us to replace the original DjVu(r) Reference +//C- Library notice by the following text (see doc/lizard2002.djvu): +//C- +//C- ------------------------------------------------------------------ +//C- | DjVu (r) Reference Library (v. 3.5) +//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved. +//C- | The DjVu Reference Library is protected by U.S. Pat. No. +//C- | 6,058,214 and patents pending. +//C- | +//C- | This software is subject to, and may be distributed under, the +//C- | GNU General Public License, Version 2. The license should have +//C- | accompanied the software or you may obtain a copy of the license +//C- | from the Free Software Foundation at http://www.fsf.org . +//C- | +//C- | The computer code originally released by LizardTech under this +//C- | license and unmodified by other parties is deemed "the LIZARDTECH +//C- | ORIGINAL CODE." Subject to any third party intellectual property +//C- | claims, LizardTech grants recipient a worldwide, royalty-free, +//C- | non-exclusive license to make, use, sell, or otherwise dispose of +//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the +//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU +//C- | General Public License. This grant only confers the right to +//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to +//C- | the extent such infringement is reasonably necessary to enable +//C- | recipient to make, have made, practice, sell, or otherwise dispose +//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to +//C- | any greater extent that may be necessary to utilize further +//C- | modifications or combinations. +//C- | +//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY +//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED +//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF +//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. +//C- +------------------------------------------------------------------ +// +// $Id: GSmartPointer.h,v 1.11 2003/11/07 22:08:21 leonb Exp $ +// $Name: release_3_5_15 $ + +#ifndef _GSMARTPOINTER_H_ +#define _GSMARTPOINTER_H_ +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#if NEED_GNUG_PRAGMAS +# pragma interface +#endif + +/** @name GSmartPointer.h + + Files #"GSmartPointer.h"# and #"GSmartPointer.cpp"# define a smart-pointer + class which automatically performs thread-safe reference counting. Class + \Ref{GP} implements smart-pointers by overloading the usual pointer + assignment and dereferencing operators. The overloaded operators maintain + the reference counters and destroy the pointed objects as soon as their + reference counter reaches zero. Transparent type conversions are provided + between smart-pointers and regular pointers. Objects referenced by + smart-pointers must be derived from class \Ref{GPEnabled}. + + @memo + Thread-Safe reference counting smart-pointers. + @author + L\'eon Bottou <leonb@research.att.com> -- initial implementation\\ + Andrei Erofeev <eaf@geocities.com> -- bug fix. + +// From: Leon Bottou, 1/31/2002 +// Class GPBuffer has been added (but not documented) by Lizardtech. +// Our original implementation consisted of multiple classes. +// <http://prdownloads.sourceforge.net/djvu/DjVu2_2b-src.tgz>. + + @version + #$Id: GSmartPointer.h,v 1.11 2003/11/07 22:08:21 leonb Exp $# + @args +*/ +//@{ + +#if defined(_MSC_VER) +// Language lawyer say MSVC6 is wrong on that one. +// Cf section 5.4.7 in november 1997 draft. +#pragma warning( disable : 4243 ) +#endif + +#include "DjVuGlobal.h" + +#ifdef HAVE_NAMESPACES +namespace DJVU { +# ifdef NOT_DEFINED // Just to fool emacs c++ mode +} +#endif +#endif + + + +/* What is this innovation ? + What does it do that a GArray does not do ? */ + +class GPBufferBase +{ +public: + GPBufferBase(void *&,const size_t n,const size_t t); + void swap(GPBufferBase &p); + void resize(const size_t n,const size_t t); + void replace(void *nptr,const size_t n); + void set(const size_t t,const char c); + ~GPBufferBase(); + operator int(void) const { return ptr ? num : 0; } +private: + void *&ptr; + size_t num; +}; + +template<class TYPE> +class GPBuffer : public GPBufferBase +{ +public: + GPBuffer(TYPE *&xptr,const size_t n=0) : GPBufferBase((void *&)xptr,n,sizeof(TYPE)) {} + inline void resize(const size_t n) {GPBufferBase::resize(n,sizeof(TYPE));} + inline void clear(void) {GPBufferBase::set(sizeof(TYPE),0);} + inline void set(const char c) {GPBufferBase::set(sizeof(TYPE),c);} + inline operator int(void) const {return GPBufferBase::operator int();} +}; + +/** Base class for reference counted objects. + This is the base class for all reference counted objects. + Any instance of a subclass of #GPEnabled# can be used with + smart-pointers (see \Ref{GP}). + */ +class GPEnabled +{ +public: + /// Null constructor. + GPEnabled(); + /// Copy construcotr + GPEnabled(const GPEnabled & obj); + /// Virtual destructor. + virtual ~GPEnabled(); + /// Copy operator + GPEnabled & operator=(const GPEnabled & obj); + /** Returns the number of references to this object. This should be only + used for debugging purposes. Other uses are not thread-safe. */ + int get_count(void) const; +protected: + /// The reference counter + volatile int count; +private: + friend class GPBase; + void unref(); + void ref(); + void destroy(); +}; + + + +/** Base class for all smart-pointers. + This class implements common mechanisms for all + smart-pointers (see \Ref{GP}). There should be no need + to use this class directly. Its sole purpose consists + in reducing the template expansion overhead. +*/ + +class GPBase +{ +public: + /** Null Constructor. */ + GPBase(); + /** Copy Constructor. + Increments the reference count. + @param sptr reference to a #GPBase# object. */ + GPBase(const GPBase &sptr); + /** Construct a GPBase from a pointer. + Increments the reference count. + @param nptr pointer to a #GPEnabled# object. */ + GPBase(GPEnabled *nptr); + /** Destructor. Decrements the reference count. */ + ~GPBase(); + /** Accesses the actual pointer. */ + GPEnabled* get() const; + /** Assignment from smartpointer. + Increments the counter of the new value of the pointer. + Decrements the counter of the previous value of the pointer. */ + GPBase& assign(const GPBase &sptr); + /** Assignment from pointer. + Checks that the object is not being destroyed. + Increments the counter of the new value of the pointer. + Decrements the counter of the previous value of the pointer. */ + GPBase& assign(GPEnabled *nptr); + /** Assignment operator. */ + GPBase & operator=(const GPBase & obj); + /** Comparison operator. */ + int operator==(const GPBase & g2) const; +protected: + /** Actual pointer */ + GPEnabled *ptr; +}; + + +/** Reference counting pointer. + Class #GP<TYPE># represents a smart-pointer to an object of type #TYPE#. + Type #TYPE# must be a subclass of #GPEnabled#. This class overloads the + usual pointer assignment and dereferencing operators. The overloaded + operators maintain the reference counters and destroy the pointed object + as soon as their reference counter reaches zero. Transparent type + conversions are provided between smart-pointers and regular pointers. + + Using a smart-pointer is a convenience and not an obligation. There is no + need to use a smart-pointer to access a #GPEnabled# object. As long as + you never use a smart-pointer to access a #GPEnabled# object, its + reference counter remains zero. Since the reference counter is never + decremented from one to zero, the object is never destroyed by the + reference counting code. You can therefore choose to only use regular + pointers to access objects allocated on the stack (automatic variables) or + objects allocated dynamically. In the latter case you must explicitly + destroy the dynamically allocated object with operator #delete#. + + The first time you use a smart-pointer to access #GPEnabled# object, the + reference counter is incremented to one. Object destruction will then + happen automatically when the reference counter is decremented back to + zero (i.e. when the last smart-pointer referencing this object stops doing so). + This will happen regardless of how many regular pointers reference this object. + In other words, if you start using smart-pointers with a #GPEnabled# + object, you engage automatic mode for this object. You should only do + this with objects dynamically allocated with operator #new#. You should + never destroy the object yourself, but let the smart-pointers control the + life of the object. + + {\bf Performance considerations} --- Thread safe reference counting incurs + a significant overhead. Smart-pointer are best used with sizeable objects + for which the cost of maintaining the counters represent a small fraction + of the processing time. It is always possible to cache a smart-pointer + into a regular pointer. The cached pointer will remain valid until the + smart-pointer object is destroyed or the smart-pointer value is changed. + + {\bf Safety considerations} --- As explained above, a #GPEnabled# object + switches to automatic mode as soon as it becomes referenced by a + smart-pointer. There is no way to switch the object back to manual mode. + Suppose that you have decided to only use regular pointers with a + particular #GPEnabled# object. You therefore plan to destroy the object + explicitly when you no longer need it. When you pass a regular pointer to + this object as argument to a function, you really need to be certain that + the function implementation will not assign this pointer to a + smart-pointer. Doing so would indeed destroy the object as soon as the + function returns. The bad news is that the fact that a function assigns a + pointer argument to a smart-pointer does not necessarily appear in the + function prototype. Such a behavior must be {\em documented} with the + function public interface. As a convention, we usually write such + functions with smart-pointer arguments instead of a regular pointer + arguments. This is not enough to catch the error at compile time, but + this is a simple way to document such a behavior. We still believe that + this is a small problem in regard to the benefits of the smart-pointer. + But one has to be aware of its existence. */ + +template <class TYPE> +class GP : protected GPBase +{ +public: + /** Constructs a null smart-pointer. */ + GP(); + /** Constructs a copy of a smart-pointer. + @param sptr smart-pointer to copy. */ + GP(const GP<TYPE> &sptr); + /** Constructs a smart-pointer from a regular pointer. + The pointed object must be dynamically allocated (with operator #new#). + You should no longer explicitly destroy the object referenced by #sptr# + since the object life is now controlled by smart-pointers. + @param nptr regular pointer to a {\em dynamically allocated object}. */ + GP(TYPE *nptr); + /** Converts a smart-pointer into a regular pointer. + This is useful for caching the value of a smart-pointer for performances + purposes. The cached pointer will remain valid until the smart-pointer + is destroyed or until the smart-pointer value is changed. */ + operator TYPE* () const; + /** Assigns a regular pointer to a smart-pointer lvalue. + The pointed object must be dynamically allocated (with operator #new#). + You should no longer explicitly destroy the object referenced by #sptr# + since the object life is now controlled by smart-pointers. + @param nptr regular pointer to a {\em dynamically allocated object}. */ + GP<TYPE>& operator= (TYPE *nptr); + /** Assigns a smart-pointer to a smart-pointer lvalue. + @param sptr smart-pointer copied into this smart-pointer. */ + GP<TYPE>& operator= (const GP<TYPE> &sptr); + /** Indirection operator. + This operator provides a convenient access to the members + of a smart-pointed object. Operator #-># works with smart-pointers + exactly as with regular pointers. */ + TYPE* operator->() const; + /** Dereferencement operator. + This operator provides a convenient access to the smart-pointed object. + Operator #*# works with smart-pointers exactly as with regular pointers. */ + TYPE& operator*() const; + /** Comparison operator. + Returns true if both this smart-pointer and pointer #nptr# point to the + same object. The automatic conversion from smart-pointers to regular + pointers allows you to compare two smart-pointers as well. + @param nptr pointer to compare with. */ + int operator== (TYPE *nptr) const; + /** Comparison operator. + Returns true if this smart-pointer and pointer #nptr# point to different + objects. The automatic conversion from smart-pointers to regular + pointers allows you to compare two smart-pointers as well. + @param nptr pointer to compare with. */ + int operator!= (TYPE *nptr) const; + /** Test operator. + Returns true if the smart-pointer is null. The automatic conversion + from smart-pointers to regular pointers allows you to test whether + a smart-pointer is non-null. You can use both following constructs: + \begin{verbatim} + if (gp) { ... } + while (! gp) { ... } + \end{verbatim} */ + int operator! () const; +}; + +//@} + +// INLINE FOR GPENABLED + +inline +GPEnabled::GPEnabled() + : count(0) +{ +} + +inline +GPEnabled::GPEnabled(const GPEnabled & obj) + : count(0) +{ + +} + +inline int +GPEnabled::get_count(void) const +{ + return count; +} + +inline GPEnabled & +GPEnabled::operator=(const GPEnabled & obj) +{ + /* The copy operator should do nothing because the count should not be + changed. Subclasses of GPEnabled will call this version of the copy + operator as part of the default 'memberwise copy' strategy. */ + return *this; +} + +// INLINE FOR GPBASE + +inline +GPBase::GPBase() + : ptr(0) +{ +} + +inline +GPBase::GPBase(GPEnabled *nptr) + : ptr(0) +{ + assign(nptr); +} + +inline +GPBase::GPBase(const GPBase &sptr) +{ + if (sptr.ptr) + sptr.ptr->ref(); + ptr = sptr.ptr; +} + +inline +GPBase::~GPBase() +{ + GPEnabled *old = ptr; + ptr = 0; + if (old) + old->unref(); +} + +inline GPEnabled* +GPBase::get() const +{ + return ptr; +} + +inline GPBase & +GPBase::operator=(const GPBase & obj) +{ + return assign(obj); +} + +inline int +GPBase::operator==(const GPBase & g2) const +{ + return ptr == g2.ptr; +} + + + + +// INLINE FOR GP<TYPE> + +template <class TYPE> inline +GP<TYPE>::GP() +{ +} + +template <class TYPE> inline +GP<TYPE>::GP(TYPE *nptr) +: GPBase((GPEnabled*)nptr) +{ +} + +template <class TYPE> inline +GP<TYPE>::GP(const GP<TYPE> &sptr) +: GPBase((const GPBase&) sptr) +{ +} + +template <class TYPE> inline +GP<TYPE>::operator TYPE* () const +{ + return (TYPE*) ptr; +} + +template <class TYPE> inline TYPE* +GP<TYPE>::operator->() const +{ + return (TYPE*) ptr; +} + +template <class TYPE> inline TYPE& +GP<TYPE>::operator*() const +{ + return *(TYPE*) ptr; +} + +template <class TYPE> inline GP<TYPE>& +GP<TYPE>::operator= (TYPE *nptr) +{ + return (GP<TYPE>&)( assign(nptr) ); +} + +template <class TYPE> inline GP<TYPE>& +GP<TYPE>::operator= (const GP<TYPE> &sptr) +{ + return (GP<TYPE>&)( assign((const GPBase&)sptr) ); +} + +template <class TYPE> inline int +GP<TYPE>::operator== (TYPE *nptr) const +{ + return ( (TYPE*)ptr == nptr ); +} + +template <class TYPE> inline int +GP<TYPE>::operator!= (TYPE *nptr) const +{ + return ( (TYPE*)ptr != nptr ); +} + +template <class TYPE> inline int +GP<TYPE>::operator! () const +{ + return !ptr; +} + + +#ifdef HAVE_NAMESPACES +} +# ifndef NOT_USING_DJVU_NAMESPACE +using namespace DJVU; +# endif +#endif +#endif |