• Skip to content
• Skip to link menu

KDE 3.5 API Reference

• KDE API Reference
• API Reference

• Sitemap
• Contact Us

 

kviewshell

DataPool.cpp

Go to the documentation of this file.

//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: DataPool.cpp,v 1.11 2004/08/06 15:11:29 leonb Exp $
// $Name: release_3_5_15 $

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#if NEED_GNUG_PRAGMAS
# pragma implementation
#endif

#include "DataPool.h"
#include "IFFByteStream.h"
#include "GString.h"
#include "GOS.h"
#include "GURL.h"
#include "debug.h"

#ifndef macintosh
# include <sys/types.h>
#endif

#ifdef HAVE_NAMESPACES
namespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode
}
#endif
#endif

const char * DataPool::Stop = ERR_MSG("STOP");

static void
// call_callback(void (* callback)(GP<GPEnabled> &), GP<GPEnabled> cl_data)
call_callback(void (* callback)(void *), void *cl_data)
{
   G_TRY
   {
      if (callback)
        callback(cl_data);
   } G_CATCH_ALL {} G_ENDCATCH;
}


//****************************************************************************
//****************************** OpenFiles ***********************************
//****************************************************************************

#define MAX_OPEN_FILES  15

class DataPool::OpenFiles_File : public GPEnabled
{
public:
  GURL          url;
  GP<ByteStream>            stream;     // Stream connected to 'url'
  GCriticalSection      stream_lock;
  GPList<DataPool>      pools_list; // List of pools using this stream
  GCriticalSection      pools_lock;
  unsigned long     open_time;  // Time when stream was open
  
  int   add_pool(GP<DataPool> &pool);
  int   del_pool(GP<DataPool> &pool);
  
  OpenFiles_File(const GURL &url, GP<DataPool> &pool);
  virtual ~OpenFiles_File(void);
  void clear_stream(void);
};

class DataPool::OpenFiles : public GPEnabled
{
private:
   static OpenFiles * global_ptr;

   GPList<DataPool::OpenFiles_File>     files_list;
   GCriticalSection files_lock;
public:
   static OpenFiles * get(void);

      // Opend the specified file if necessary (or finds an already open one)
      // and returns it. The caller (pool) is stored in the list associated
      // with the stream. Whenever OpenFiles decides, that this stream
      // had better be closed, it will order every pool from the list to
      // ZERO their references to it
   GP<DataPool::OpenFiles_File> request_stream(const GURL &url, GP<DataPool> pool);
      // If there are more than MAX_STREAM_FILES open, close the oldest.
   void     prune(void);
      // Removes the pool from the list associated with the stream.
      // If there is nobody else using this stream, the stream will
      // be closed too.
   void     stream_released(GP<ByteStream> &stream, GP<DataPool> pool);

   void     close_all(void);
};

DataPool::OpenFiles * DataPool::OpenFiles::global_ptr;

DataPool::OpenFiles_File::OpenFiles_File(const GURL &xurl, GP<DataPool> &pool) : url(xurl)
{
   DEBUG_MSG("DataPool::OpenFiles_File::OpenFiles_File(): Opening file '" << url << "'\n");
   DEBUG_MAKE_INDENT(3);
   
   open_time=GOS::ticks();
   stream=ByteStream::create(url,"rb");
   add_pool(pool);
}

DataPool::OpenFiles_File::~OpenFiles_File(void)
{
   DEBUG_MSG("DataPool::OpenFiles_File::~OpenFiles_File(): Closing file '" << url << "'\n");
   DEBUG_MAKE_INDENT(3);
   clear_stream();
}

void
DataPool::OpenFiles_File::clear_stream(void)
{
  GCriticalSectionLock lock(&pools_lock);
  for(GPosition pos=pools_list;pos;++pos)
    if(pools_list[pos])
      pools_list[pos]->clear_stream(false);
  pools_list.empty();
}

int
DataPool::OpenFiles_File::add_pool(GP<DataPool> &pool)
{
   DEBUG_MSG("DataPool::OpenFiles_File::add_pool: pool=" << (void *) pool << "\n");
   DEBUG_MAKE_INDENT(3);
   GCriticalSectionLock lock(&pools_lock);
   if (!pools_list.contains(pool))
     pools_list.append(pool);
   return pools_list.size();
}

int
DataPool::OpenFiles_File::del_pool(GP<DataPool> &pool)
{
   DEBUG_MSG("DataPool::OpenFiles_File::del_pool: pool=" << (void *) pool << "\n");
   DEBUG_MAKE_INDENT(3);
   GCriticalSectionLock lock(&pools_lock);
   GPosition pos;
   if (pools_list.search(pool, pos))
     pools_list.del(pos);
   return pools_list.size();
}

inline DataPool::OpenFiles *
DataPool::OpenFiles::get(void)
{
   DEBUG_MSG("DataPool::OpenFiles::get()\n");
   DEBUG_MAKE_INDENT(3);
   if (!global_ptr)
     global_ptr=new OpenFiles();
   return global_ptr;
}

void
DataPool::OpenFiles::prune(void)
{
  DEBUG_MSG("DataPool::OpenFiles::prune(void): "<<files_list.size()<< "\n");
  DEBUG_MAKE_INDENT(3);
  while(files_list.size()>MAX_OPEN_FILES)
    {
      // Too many open files (streams). Get rid of the oldest one.
      unsigned long oldest_time=GOS::ticks();
      GPosition oldest_pos=files_list;
      for(GPosition pos=files_list;pos;++pos)
        {
          if (files_list[pos]->open_time<oldest_time)
            {
              oldest_time=files_list[pos]->open_time;
              oldest_pos=pos;
            }
        }
      files_list[oldest_pos]->clear_stream();
      files_list.del(oldest_pos);
    }
}

//            GP<ByteStream> & stream,
//            GCriticalSection ** stream_lock)
GP<DataPool::OpenFiles_File>
DataPool::OpenFiles::request_stream(const GURL &url, GP<DataPool> pool)
{
   DEBUG_MSG("DataPool::OpenFiles::request_stream(): url='" << url << "'\n");
   DEBUG_MAKE_INDENT(3);

   GP<DataPool::OpenFiles_File> file;

      // Check: maybe the stream has already been open by request of
      // another DataPool
   GCriticalSectionLock lock(&files_lock);
   for(GPosition pos=files_list;pos;++pos)
   {
      if (files_list[pos]->url==url)
      {
     DEBUG_MSG("found existing stream\n");
     file=files_list[pos];
     break;
      }
   }

      // No? Open the stream, but check, that there are not
      // too many streams open
   if (!file)
   {
      file=new DataPool::OpenFiles_File(url, pool);
      files_list.append(file);
      prune();
   }
   
   file->add_pool(pool);
   return file;
}

void
DataPool::OpenFiles::stream_released(GP<ByteStream> &stream, GP<DataPool> pool)
{
   DEBUG_MSG("DataPool::OpenFiles::stream_release: stream=" 
             << (void *)stream << " pool=" << (void *)pool << "\n");
   DEBUG_MAKE_INDENT(3);
   GCriticalSectionLock lock(&files_lock);
   for(GPosition pos=files_list;pos;)
   {
     GPosition dpos = pos;
     ++pos;
     GP<DataPool::OpenFiles_File> f=files_list[dpos];
     if ((ByteStream *)(f->stream) == (ByteStream *)stream)
       if (f->del_pool(pool)==0)
         files_list.del(dpos);
   }
}

// This isn't really an accurate url.  The files are not really
// closed.  Instead they are dereferenced from the data pool.  If
// a there is another reference to the respective bytestream, it
// will remain open until dereferenced.
void
DataPool::OpenFiles::close_all(void)
{
  DEBUG_MSG("DataPool::OpenFiles::close_all\n");
  DEBUG_MAKE_INDENT(3);
  GCriticalSectionLock lock(&files_lock);
  files_list.empty();
}

//****************************************************************************
//******************************** FCPools ***********************************
//****************************************************************************

class FCPools
{
private:
   GMap<GURL, GPList<DataPool> >    map;    // GMap<GUTF8String, GPList<DataPool>> in fact
   GCriticalSection     map_lock;

   static FCPools   * global_ptr;
public:
   static FCPools * get(void);
      // Adds the <furl, pool> pair into the list
   void     add_pool(const GURL &furl, GP<DataPool> pool);
      // Removes the <furl, pool> pair from the list
   void     del_pool(const GURL &furl, GP<DataPool> pool);
      // Looks for the list of DataPools connected to 'furl' and makes
      // each of them load the contents of the file into memory
   void     load_file(const GURL &url);
      // Retrieve a local URL, if available.
   GP<DataPool> get_pool(const GURL &url, int start, int length);
   void clean(void);
};

void
FCPools::clean(void)
{
  GCriticalSectionLock lock(&map_lock);
  static int count=0;
  if(! count++)
  {
    bool restart = true;
    while (restart)
      {
        restart = false;
        for (GPosition posmap = map; posmap; ++posmap)
          {
            GPList<DataPool> *lst;
            lst = & map[posmap];
            if (lst->isempty())
              {
                map.del(posmap);
                restart = true;
                break;
              }
            for (GPosition poslst = *lst; poslst; ++poslst)
              if ((*lst)[poslst]->get_count() < 2) 
                {
                  lst->del(poslst);
                  restart = true;
                  break;
                }
            if (restart)
              break;
          }
      }
  }
  --count;
}

void
FCPools::add_pool(const GURL &url, GP<DataPool> pool)
{
  DEBUG_MSG("FCPools::add_pool: url='" << url << "' pool=" << (void *)pool << "\n");
  DEBUG_MAKE_INDENT(3);
  GCriticalSectionLock lock(&map_lock);

   if (url.is_local_file_url())
   {
      GPList<DataPool> list;
      GPosition pos(map.contains(url));
      if (! pos)
      {
        map[url]=list;
        pos=map.contains(url);
      }
      GPList<DataPool> &plist=map[pos];
      if (!plist.contains(pool))
        plist.append(pool);
   }
  clean();
}

GP<DataPool>
FCPools::get_pool(const GURL &url, int start, int length)
{
  DEBUG_MSG("FCPools::get_pool: url='" << url << "\n");
  DEBUG_MAKE_INDENT(3);
  GP<DataPool> retval;
  if (url.is_local_file_url())
  {
    GCriticalSectionLock lock(&map_lock);
    GPosition pos(map.contains(url));
    if (pos)
    {
      GPList<DataPool> &plist=map[pos];
      for(pos=plist;pos;++pos)
      {
        DataPool &pool=*plist[pos];
        if(start == pool.start && (length < 0 || (length == pool.length)))
        {
          retval=plist[pos];
          break;
        }
      }
    }
    clean();
  }
  return retval;
}

void
FCPools::del_pool(const GURL &url, GP<DataPool> pool)
{
  DEBUG_MSG("FCPools::del_pool: url='" << url << "' pool=" << (void *)pool << "\n");
  DEBUG_MAKE_INDENT(3);
  GCriticalSectionLock lock(&map_lock);

  clean();
   if (url.is_local_file_url())
   {
      GPosition pos;
      if (map.contains(url, pos))
      {
     GPList<DataPool> &list=map[pos];
     GPosition list_pos;
     while(list.search(pool, list_pos))
        list.del(list_pos);
     if (list.isempty())
     {
        map.del(pos);
     }
      }
   }
}

void
FCPools::load_file(const GURL &url)
{
  DEBUG_MSG("FCPools::load_file: url='" << url << "'\n");
  DEBUG_MAKE_INDENT(3);
  GCriticalSectionLock lock(&map_lock);
   
  clean();
   if (url.is_local_file_url())
   {
      GPosition pos;
      if (map.contains(url, pos))
      {
        // We make here a copy of the list because DataPool::load_file()
        // will call FCPools::del_pool(), which will modify the list
     GPList<DataPool> list=map[pos];
     for(GPosition list_pos=list;list_pos;++list_pos)
        list[list_pos]->load_file();
      }
   }
}

FCPools * FCPools::global_ptr;

inline FCPools *
FCPools::get(void)
{
   if (!global_ptr)
     global_ptr=new FCPools();
   return global_ptr;
}

//****************************************************************************
//****************************** BlockList ***********************************
//****************************************************************************

// Since data can be added to the DataPool at any offset now, there may
// be white spots, which contain illegal data. This class is to contain
// the list of valid and invalid regions.
// The class is basically a list of integers. Abs(integer)=size of the
// block. If the integer is positive, data for the block is known.
// Otherwise it's unkown.

class DataPool::BlockList
{
         // See comments in .cpp file.
private:
   GCriticalSection  lock;
   GList<int>        list;
public:
   BlockList() {};
   void              clear(void);
   void              add_range(int start, int length);
   int               get_bytes(int start, int length) const;
   int               get_range(int start, int length) const;
friend class DataPool;
};

void
DataPool::BlockList::clear(void)
{
  DEBUG_MSG("DataPool::BlockList::clear()\n");
  DEBUG_MAKE_INDENT(3);
   GCriticalSectionLock lk(&lock);
   list.empty();
}

void
DataPool::BlockList::add_range(int start, int length)
      // Adds range of known data.
{
  DEBUG_MSG("DataPool::BlockList::add_range: start=" << start << " length=" << length << "\n");
  DEBUG_MAKE_INDENT(3);
   if (start<0)
     G_THROW( ERR_MSG("DataPool.neg_start") );
   if (length<=0)
     G_THROW( ERR_MSG("DataPool.bad_length") );
   if (length>0)
   {
      GCriticalSectionLock lk(&lock);

     // Look thru existing zones, change their sign and split if
     // necessary.
      GPosition pos=list;
      int block_start=0, block_end=0;
      while(pos && block_start<start+length)
      {
     int size=list[pos];
     block_end=block_start+abs(size);
     if (size<0)
        if (block_start<start)
        {
           if (block_end>start && block_end<=start+length)
           {
          list[pos]=-(start-block_start);
          list.insert_after(pos, block_end-start);
          ++pos;
          block_start=start;
           } else if (block_end>start+length)
           {
          list[pos]=-(start-block_start);
          list.insert_after(pos, length);
          ++pos;
          list.insert_after(pos, -(block_end-(start+length)));
          ++pos;
          block_start=start+length;
           }
        } else if (block_start>=start && block_start<start+length)
        {
           if (block_end<=start+length) list[pos]=abs(size);
           else
           {
          list[pos]=start+length-block_start;
          list.insert_after(pos, -(block_end-(start+length)));
          ++pos;
          block_start=start+length;
           }
        }
     block_start=block_end;
     ++pos;
      }
      if (block_end<start)
      {
     list.append(-(start-block_end));
     list.append(length);
      } else if (block_end<start+length) list.append(start+length-block_end);

     // Now merge adjacent areas with the same sign
      pos=list;
      while(pos)
      {
     GPosition pos1=pos; ++pos1;
     while(pos1)
     {
        if (list[pos]<0 && list[pos1]>0 ||
        list[pos]>0 && list[pos1]<0)
           break;
        list[pos]+=list[pos1];
        GPosition this_pos=pos1;
        ++pos1;
        list.del(this_pos);
     }
     pos=pos1;
      }
   } // if (length>0)
}

int
DataPool::BlockList::get_bytes(int start, int length) const
      // Returns the number of bytes of data available in the range
      // [start, start+length[. There may be holes between data chunks
{
  DEBUG_MSG("DataPool::BlockList::get_bytes: start=" << start << " length=" << length << "\n");
  DEBUG_MAKE_INDENT(3);

   if (length<0)
     G_THROW( ERR_MSG("DataPool.bad_length") );

   GCriticalSectionLock lk((GCriticalSection *) &lock);
   int bytes=0;
   int block_start=0, block_end=0;
   for(GPosition pos=list;pos && block_start<start+length;++pos)
   {
      int size=list[pos];
      block_end=block_start+abs(size);
      if (size>0)
     if (block_start<start)
     {
        if (block_end>=start && block_end<start+length)
           bytes+=block_end-start;
            else if (block_end>=start+length)
           bytes+=length;
     } else
     {
        if (block_end<=start+length)
           bytes+=block_end-block_start;
        else bytes+=start+length-block_start;
     }
      block_start=block_end;
   }
   return bytes;
}

int
DataPool::BlockList::get_range(int start, int length) const
      // Finds a range covering offset=start and returns the length
      // of intersection of this range with [start, start+length[
      // 0 is returned if nothing can be found
{
  DEBUG_MSG("DataPool::BlockList::get_range: start=" << start << " length=" << length << "\n");
  DEBUG_MAKE_INDENT(3);
   if (start<0)
     G_THROW( ERR_MSG("DataPool.neg_start") );
   if (length<=0)
      G_THROW( ERR_MSG("DataPool.bad_length") );

   GCriticalSectionLock lk((GCriticalSection *) &lock);
   int block_start=0, block_end=0;
   for(GPosition pos=list;pos && block_start<start+length;++pos)
   {
      int size=list[pos];
      block_end=block_start+abs(size);
      if (block_start<=start && block_end>start)
     if (size<0) return -1;
         else
        if (block_end>start+length) return length;
            else return block_end-start;
      block_start=block_end;
   }
   return 0;
}

//****************************************************************************
//******************************* DataPool ***********************************
//****************************************************************************

class DataPool::Reader : public GPEnabled
{
public:
   GEvent event;
   bool reenter_flag;
   int  offset;
   int  size;
   Reader() : reenter_flag(false), offset(0), size(-1){};
   Reader(int offset_in, int size_in=-1) :
   reenter_flag(false), offset(offset_in), size(size_in) {};
   virtual ~Reader() {};
};

class DataPool::Trigger : public GPEnabled
{
public:
   GSafeFlags disabled;
   int  start, length;
//   void (* callback)(GP<GPEnabled> &);
   void (* callback)(void *);
//   GP<GPEnabled> cl_data;
   void *cl_data;

   Trigger() : start(0), length(-1), callback(0), cl_data(0) {};
   Trigger(int xstart, int xlength,
//   void (* xcallback)(GP<GPEnabled> &), GP<GPEnabled> xcl_data) :
   void (* xcallback)(void *), void *xcl_data) :
      start(xstart), length(xlength), callback(xcallback), cl_data(xcl_data) {};
   virtual ~Trigger() {};
};

class DataPool::Counter
{
private:
   int               counter;
   GCriticalSection  lock;
public:
   Counter() : counter(0) {};
   operator int(void) const;
   void              inc(void);
   void              dec(void);
};

#define DATAPOOL_INIT eof_flag(false),stop_flag(false), \
    stop_blocked_flag(false), \
    add_at(0),start(0),length(-1)

void
DataPool::init(void)
{
  DEBUG_MSG("DataPool::init(): Initializing\n");
  DEBUG_MAKE_INDENT(3);
  start=0; length=-1; add_at=0;
  eof_flag=false;
  stop_flag=false;
  stop_blocked_flag=false;

  active_readers=new Counter;
  block_list=0;
  G_TRY
  {   
    block_list=new BlockList;
    data=ByteStream::create();
  }
  G_CATCH_ALL
  {
    delete block_list;
    block_list=0;
    delete active_readers;
    active_readers=0;
    G_RETHROW;
  }
  G_ENDCATCH;
}

DataPool::DataPool(void) : DATAPOOL_INIT {}

GP<DataPool>
DataPool::create(void)
{
  DEBUG_MSG("DataPool::DataPool()\n");
  DEBUG_MAKE_INDENT(3);
  DataPool *pool=new DataPool();

  GP<DataPool> retval=pool;
  pool->init();

      // If we maintain the data ourselves, we want to interpret its
      // IFF structure to predict its length
  pool->add_trigger(0, 32, static_trigger_cb, pool);
  return retval;
}

GP<DataPool> 
DataPool::create(const GP<ByteStream> &gstr)
{
  DEBUG_MSG("DataPool::create: str="<<(ByteStream *)gstr<<"\n");
  DEBUG_MAKE_INDENT(3);
  DataPool *pool=new DataPool();
  GP<DataPool> retval=pool;
  pool->init();

      // It's nice to have IFF data analyzed in this case too.
  pool->add_trigger(0, 32, static_trigger_cb, pool);

  pool->data=gstr->duplicate();
  pool->added_data(0,pool->data->size());   
//  char buffer[1024];
//  int length;
//  while((length=str.read(buffer, 1024)))
//     pool->add_data(buffer, length);
  pool->set_eof();
  return retval;
}

GP<DataPool>
DataPool::create(const GP<DataPool> & pool, int start, int length)
{
  DEBUG_MSG("DataPool::DataPool: pool=" << (void *)((DataPool *)pool) << " start=" << start << " length= " << length << "\n");
  DEBUG_MAKE_INDENT(3);

  DataPool *xpool=new DataPool();
  GP<DataPool> retval=xpool;
  xpool->init();
  xpool->connect(pool, start, length);
  return retval;
}

GP<DataPool>
DataPool::create(const GURL &furl, int start, int length)
{
  DEBUG_MSG("DataPool::DataPool: furl='" << furl << "' start=" << start << " length= " << length << "\n");
  DEBUG_MAKE_INDENT(3);

  GP<DataPool> retval=FCPools::get()->get_pool(furl,start,length);
  if(! retval)
  {
    DataPool *pool=new DataPool();
    retval=pool;
    pool->init();
    pool->connect(furl, start, length);
  }
  return retval;
}

void
DataPool::clear_stream(const bool release)
{
  DEBUG_MSG("DataPool::clear_stream()\n");
  DEBUG_MAKE_INDENT(3);
  if(fstream)
  {
    GCriticalSectionLock lock1(&class_stream_lock);
    GP<OpenFiles_File> f=fstream;
    if(f)
    {
      GCriticalSectionLock lock2(&(f->stream_lock));
      fstream=0;
      if(release)
        OpenFiles::get()->stream_released(f->stream, this);
    }
  }
}

DataPool::~DataPool(void)
{
  DEBUG_MSG("DataPool::~DataPool()\n");
  DEBUG_MAKE_INDENT(3);

  clear_stream(true);
  if (furl.is_local_file_url())
  {
    FCPools::get()->del_pool(furl, this);
  }
   
  {
     // Wait until the static_trigger_cb() exits
      GCriticalSectionLock lock(&trigger_lock);
      if (pool)
        pool->del_trigger(static_trigger_cb, this);
      del_trigger(static_trigger_cb, this);
  }

  if (pool)
  {
      GCriticalSectionLock lock(&triggers_lock);
      for(GPosition pos=triggers_list;pos;++pos)
      {
     GP<Trigger> trigger=triggers_list[pos];
     pool->del_trigger(trigger->callback, trigger->cl_data);
      }
  }
  delete block_list;
  delete active_readers;
}

void
DataPool::connect(const GP<DataPool> & pool_in, int start_in, int length_in)
{
   DEBUG_MSG("DataPool::connect(): connecting to another DataPool\n");
   DEBUG_MAKE_INDENT(3);
   
   if (pool) G_THROW( ERR_MSG("DataPool.connected1") );
   if (furl.is_local_file_url()) G_THROW( ERR_MSG("DataPool.connected2") );
   if (start_in<0) G_THROW( ERR_MSG("DataPool.neg_start") );

   pool=pool_in;
   start=start_in;
   length=length_in;

      // The following will work for length<0 too
   if (pool->has_data(start, length))
     eof_flag=true;
   else
     pool->add_trigger(start, length, static_trigger_cb, this);

   data=0;

   wake_up_all_readers();
   
      // Pass registered trigger callbacks to the DataPool
   GCriticalSectionLock lock(&triggers_lock);
   for(GPosition pos=triggers_list;pos;++pos)
   {
      GP<Trigger> t=triggers_list[pos];
      int tlength=t->length;
      if (tlength<0 && length>0)
        tlength=length-t->start;
      pool->add_trigger(start+t->start, tlength, t->callback, t->cl_data);
   }
}

void
DataPool::connect(const GURL &furl_in, int start_in, int length_in)
{
   DEBUG_MSG("DataPool::connect(): connecting to a file\n");
   DEBUG_MAKE_INDENT(3);
   
   if (pool)
     G_THROW( ERR_MSG("DataPool.connected1") );
   if (furl.is_local_file_url())
     G_THROW( ERR_MSG("DataPool.connected2") );
   if (start_in<0)
     G_THROW( ERR_MSG("DataPool.neg_start") );


   if (furl_in.name() == "-")
   {
      DEBUG_MSG("This is stdin => just read the data...\n");
      DEBUG_MAKE_INDENT(3);
      char buffer[1024];
      int length;
      GP<ByteStream> gstr=ByteStream::create(furl_in, "rb");
      ByteStream &str=*gstr;
      while((length=str.read(buffer, 1024)))
     add_data(buffer, length);
      set_eof();
   } else if(furl_in.is_local_file_url())
   {
     // Open the stream (just in this function) too see if
     // the file is accessible. In future we will be using 'OpenFiles'
     // to request and release streams
      GP<ByteStream> str=ByteStream::create(furl_in,"rb");
      str->seek(0, SEEK_END);
      int file_size=str->tell();

      furl=furl_in;
      start=start_in;
      length=length_in;
      if (start>=file_size)
        length=0;
      else if (length<0 || start+length>=file_size)
        length=file_size-start;

      eof_flag=true;

      if(str->is_static())
      {
        data=str;
        added_data(0,length);
      }else 
      {
        data=0;
      }

      FCPools::get()->add_pool(furl, this);

      wake_up_all_readers();
   
     // Call every trigger callback
      GCriticalSectionLock lock(&triggers_lock);
      for(GPosition pos=triggers_list;pos;++pos)
      {
     GP<Trigger> t=triggers_list[pos];
     call_callback(t->callback, t->cl_data);
      }
      triggers_list.empty();
   }
}

int
DataPool::get_length(void) const
{
      // Not connected and length has been guessed
      // Or connected to a file
      // Or connected to a pool, but length was preset
   int retval=(-1);
   if (length>=0) 
   {
     retval=length;
   }else if (pool)
   {
      int plength=pool->get_length();
      if (plength>=0)
        retval=plength-start;
   }
   return retval;
}

int
DataPool::get_size(int dstart, int dlength) const
{
   if (dlength<0 && length>0)
   {
      dlength=length-dstart;
      if (dlength<0) return 0;
   }
   
   if (pool) return pool->get_size(start+dstart, dlength);
   else if (furl.is_local_file_url())
   {
      if (start+dstart+dlength>length) return length-(start+dstart);
      else return dlength;
   } else
   {
      if (dlength<0)
      {
     GCriticalSectionLock lock((GCriticalSection *) &data_lock);
     dlength=data->size()-dstart;
      }
      return (dlength<0)?0:(block_list->get_bytes(dstart, dlength));
   }
}

void
DataPool::add_data(const void * buffer, int size)
      // This function adds data sequentially at 'add_at' position
{
   DEBUG_MSG("DataPool::add_data(): adding " << size << " bytes of data...\n");
   DEBUG_MAKE_INDENT(3);

   add_data(buffer, add_at, size);
   add_at+=size;
}

void
DataPool::add_data(const void * buffer, int offset, int size)
{
   DEBUG_MSG("DataPool::add_data(): adding " << size << " bytes at pos=" <<
         offset << "...\n");
   DEBUG_MAKE_INDENT(3);

   if (furl.is_local_file_url() || pool)
      G_THROW( ERR_MSG("DataPool.add_data") );
   
      // Add data to the data storage
   {
      GCriticalSectionLock lock(&data_lock);
      if (offset>data->size())
      {
     char ch=0;
     data->seek(0, SEEK_END);
     for(int i=data->size();i<offset;i++)
        data->write(&ch, 1);
      } else
      {
     data->seek(offset, SEEK_SET);
     data->writall(buffer, size);
      }
   }

   added_data(offset, size);
}

void
DataPool::added_data(const int offset, const int size)
{
     // Modify map of blocks
  block_list->add_range(offset, size);
   
     // Wake up all threads, which may be waiting for this data
  {
    GCriticalSectionLock lock(&readers_lock);
    for(GPosition pos=readers_list;pos;++pos)
    {
      GP<Reader> reader=readers_list[pos];
      if (block_list->get_bytes(reader->offset, 1))
      {
        DEBUG_MSG("waking up reader: offset=" << reader->offset <<
          ", size=" << reader->size << "\n");
        DEBUG_MAKE_INDENT(3);
        reader->event.set();
      }
    }
  }

    // And call triggers
  check_triggers();

      // Do not undo the following two lines. The reason why we need them
      // here is the connected DataPools, which use 'length' (more exactly
      // has_data()) to see if they have all data required. So, right after
      // all data has been added to the master DataPool, but before EOF
      // is set, the master and slave DataPools disagree regarding if
      // all data is there or not. These two lines solve the problem
  GCriticalSectionLock lock(&data_lock);
  if (length>=0 && data->size()>=length)
    set_eof();
}

bool
DataPool::has_data(int dstart, int dlength)
{
   if (dlength<0 && length>0)
     dlength=length-dstart;
   return (pool?(pool->has_data(start+dstart, dlength))
     :((furl.is_local_file_url())?(start+dstart+dlength<=length)
       :((dlength<0)?is_eof()
         :(block_list->get_bytes(dstart, dlength)==dlength))));
}

int
DataPool::get_data(void * buffer, int offset, int sz)
{
   return get_data(buffer, offset, sz, 0);
}

class DataPool::Incrementor
{
private:
   Counter      & counter;
public:
   Incrementor(Counter & xcounter) : counter(xcounter) {counter.inc();}
   ~Incrementor() {counter.dec();}
};

int
DataPool::get_data(void * buffer, int offset, int sz, int level)
{
   DEBUG_MSG("DataPool::get_data()\n");
   DEBUG_MAKE_INDENT(3);
   Incrementor inc(*active_readers);
   
   if (stop_flag)
     G_THROW( DataPool::Stop );
   if (stop_blocked_flag && !is_eof() &&
       !has_data(offset, sz))
     G_THROW( DataPool::Stop );
   
   if (sz < 0)
     G_THROW( ERR_MSG("DataPool.bad_size") );
   
   if (! sz)
     return 0;
   
   if (pool)
     {
       DEBUG_MSG("DataPool::get_data(): from pool\n");
       DEBUG_MAKE_INDENT(3);
       int retval=0;
       if (length>0 && offset+sz>length)
         sz=length-offset;
       if (sz<0)
        sz=0;
       for(;;)
         {
           // Ask the underlying (master) DataPool for data. Note, that
           // master DataPool may throw the "DATA_POOL_REENTER" exception
           // demanding all readers to restart. This happens when
           // a DataPool in the chain of DataPools stops. All readers
           // should return to the most upper level and then reenter the
           // DataPools hierarchy. Some of them will be stopped by
           // DataPool::Stop exception.
           G_TRY
             {
               if(stop_flag||stop_blocked_flag&&!is_eof()&&!has_data(offset, sz))
                 G_THROW( DataPool::Stop );
               retval=pool->get_data(buffer, start+offset, sz, level+1);
             } 
           G_CATCH(exc) 
             {
               pool->clear_stream(true);
               if ((exc.get_cause() != GUTF8String( ERR_MSG("DataPool.reenter") ) ) || level)
                 G_RETHROW;
             } G_ENDCATCH;
           pool->clear_stream(true);
           return retval;
         }
     }
   else if(data && data->is_static() && eof_flag)
     { 
       DEBUG_MSG("DataPool::get_data(): static\n");
       DEBUG_MAKE_INDENT(3);
       // We're not connected to anybody => handle the data
       int size=block_list->get_range(offset, sz);
       if (size>0)
         {
           // Hooray! Some data is there
           GCriticalSectionLock lock(&data_lock);
           data->seek(offset, SEEK_SET);
           return data->readall(buffer, size);
         }
       return 0;
     } 
   else if (furl.is_local_file_url())
     {
       DEBUG_MSG("DataPool::get_data(): from file\n");
       DEBUG_MAKE_INDENT(3);
       if (length>0 && offset+sz>length)
         sz=length-offset;
       if (sz<0)
         sz=0;
       
       GP<OpenFiles_File> f=fstream;
       if (!f)
         {
           GCriticalSectionLock lock(&class_stream_lock);
           f=fstream;
           if(!f)
             {
               fstream=f=OpenFiles::get()->request_stream(furl, this);
             }
         }
       GCriticalSectionLock lock2(&(f->stream_lock));
       f->stream->seek(start+offset, SEEK_SET); 
       return f->stream->readall(buffer, sz);
     } 
   else
     {
       DEBUG_MSG("DataPool::get_data(): direct\n");
       DEBUG_MAKE_INDENT(3);
       // We're not connected to anybody => handle the data
       int size=block_list->get_range(offset, sz);
       if (size>0)
         {
           // Hooray! Some data is there
           GCriticalSectionLock lock(&data_lock);
           data->seek(offset, SEEK_SET);
           return data->readall(buffer, size);
         }
       
       // No data available.
       
       // If there is no data and nothing else is expected, we can do
       // two things: throw ByteStream::EndOfFile exception or return ZERO bytes.
       // The exception is for the cases when the data flow has been
       // terminated in the middle. ZERO bytes is for regular read() beyond
       // the boundaries of legal data. The problem is to distinguish
       // these two cases. We do it here with the help of analysis of the
       // IFF structure of the data (which sets the 'length' variable).
       // If we attempt to read beyond the [0, length[, ZERO bytes will be
       // returned. Otherwise an ByteStream::EndOfFile exception will be thrown.
       if (eof_flag)
         {
           if (length>0 && offset<length) 
             {
               G_THROW( ByteStream::EndOfFile );
             }
           else 
             {
               return 0;
             }
         } 
       // Some data is still expected => add this reader to the
       // list of readers and call virtual wait_for_data()
       DEBUG_MSG("DataPool::get_data(): There is no data in the pool.\n");
       DEBUG_MSG("offset=" << offset << ", size=" << sz <<
                 ", data_size=" << data->size() << "\n");
       GP<Reader> reader=new Reader(offset, sz);
       G_TRY 
         {
           {
             GCriticalSectionLock slock(&readers_lock);
             readers_list.append(reader);
           }
           wait_for_data(reader);
         } 
       G_CATCH_ALL 
         {
           {
             GCriticalSectionLock slock(&readers_lock);
             GPosition pos;
             if (readers_list.search(reader, pos)) readers_list.del(pos);
           }
           G_RETHROW;
         } 
       G_ENDCATCH;
       
       {
         GCriticalSectionLock slock(&readers_lock);
         GPosition pos;
         if (readers_list.search(reader, pos)) readers_list.del(pos);
       }
       
       // This call to get_data() should return immediately as there MUST
       // be data in the buffer after wait_for_data(reader) returns
       // or eof_flag should be TRUE
       return get_data(buffer, reader->offset, reader->size, level);
     }
   return 0;
}

void
DataPool::wait_for_data(const GP<Reader> & reader)
      // This function may NOT return until there is some data for the
      // given reader in the internal buffer
{
   DEBUG_MSG("DataPool::wait_for_data(): waiting for data at offset=" << reader->offset <<
         ", length=" << reader->size << "\n");
   DEBUG_MAKE_INDENT(3);

#if THREADMODEL==NOTHREADS
   G_THROW( ERR_MSG("DataPool.no_threadless") );
#else
   for(;;)
   {
      if (stop_flag)
        G_THROW( DataPool::Stop );
      if (reader->reenter_flag)
        G_THROW( ERR_MSG("DataPool.reenter") );
      if (eof_flag || block_list->get_bytes(reader->offset, 1))
        return;
      if (pool || furl.is_local_file_url())
        return;

      if (stop_blocked_flag)
        G_THROW( DataPool::Stop );

      DEBUG_MSG("calling event.wait()...\n");
      reader->event.wait();
   }
#endif
   
   DEBUG_MSG("Got some data to read\n");
}

void
DataPool::wake_up_all_readers(void)
{
   DEBUG_MSG("DataPool::wake_up_all_readers(): waking up all readers\n");
   DEBUG_MAKE_INDENT(3);

   GCriticalSectionLock lock(&readers_lock);
   for(GPosition pos=readers_list;pos;++pos)
      readers_list[pos]->event.set();
}

void
DataPool::set_eof(void)
      // Has no effect on connected DataPools
{
   if (!furl.is_local_file_url() && !pool)
   {
      eof_flag=true;
      
     // Can we set the length now?
      if (length<0)
      {
     GCriticalSectionLock lock(&data_lock);
     length=data->size();
      }

     // Wake up all readers to let them rescan the flags
      wake_up_all_readers();
   
     // Activate all trigger callbacks with negative threshold
      check_triggers();
   }
}

void
DataPool::stop(bool only_blocked)
{
   DEBUG_MSG("DataPool::stop(): Stopping this and dependent DataPools, only_blocked="
         << only_blocked << "\n");
   DEBUG_MAKE_INDENT(3);

   if (only_blocked) stop_blocked_flag=true;
   else stop_flag=true;
   

   wake_up_all_readers();

      // Now let all readers, which already go thru to the master DataPool,
      // come back and reenter. While reentering some of them will go
      // thru this DataPool again and will be stopped (DataPool::Stop exception)
      // Others (which entered the master DataPool thru other slave DataPools)
      // will simply continue waiting for their data.
   if (pool)
   {
     // This loop is necessary because there may be another thread, which
     // is going down thru the DataPool chain and did not reach the
     // lowest "master" DataPool yet. Since it didn't reach it yet,
     // the "pool->restart_readers()" will not restart it. So we're going
     // to continue issuing this command until we get rid of all
     // "active_readers"
      while(*active_readers)
      {
#if (THREADMODEL==COTHREADS) || (THREADMODEL==MACTHREADS)
     GThread::yield();
#endif
     pool->restart_readers();
      }
   }
}

void
DataPool::restart_readers(void)
{
   DEBUG_MSG("DataPool::restart_readers(): telling all readers to reenter\n");
   DEBUG_MAKE_INDENT(3);
   
   GCriticalSectionLock slock(&readers_lock);
   for(GPosition pos=readers_list;pos;++pos)
   {
      GP<Reader> reader=readers_list[pos];
      reader->reenter_flag=true;
      reader->event.set();
   }
      
   if (pool)
     pool->restart_readers();
}

void
DataPool::load_file(void)
{
   DEBUG_MSG("DataPool::load_file() called\n");
   DEBUG_MAKE_INDENT(3);

   if (pool)
   {
      DEBUG_MSG("passing the request down.\n");
      pool->load_file();
   } else if (furl.is_local_file_url())
   {
      DEBUG_MSG("loading the data from \""<<(const char *)furl<<"\".\n");

      GCriticalSectionLock lock1(&class_stream_lock);
      GP<OpenFiles_File> f=fstream;
      if (!f)
      {
        fstream=f=OpenFiles::get()->request_stream(furl, this);
      }
      {  // Scope to de-allocate lock2 before stream gets released
         GCriticalSectionLock lock2(&(f->stream_lock));

         data=ByteStream::create();
         block_list->clear();
         FCPools::get()->del_pool(furl, this);
         furl=GURL();

         const GP<ByteStream> gbs=f->stream;
         gbs->seek(0, SEEK_SET);
         data=gbs->duplicate();
         added_data(0,data->size());   
         set_eof();
//         char buffer[1024];
//         int length;
//         while((length=f->stream->read(buffer, 1024)))
//           add_data(buffer, length);
          // No need to set EOF. It should already be set.
        OpenFiles::get()->stream_released(f->stream, this);
      }
      fstream=0;
   } else { DEBUG_MSG("Not connected\n"); }
}

void
DataPool::load_file(const GURL &url )
{
   FCPools::get()->load_file(url);
}

void
DataPool::check_triggers(void)
      // This function is for not connected DataPools only
{
  DEBUG_MSG("DataPool::check_triggers(): calling activated trigger callbacks.\n");
  DEBUG_MAKE_INDENT(3);
  
  if (!pool && !furl.is_local_file_url())
    while(true)
    {
      GP<Trigger> trigger;
      
      // First find a candidate (trigger, which needs to be called)
      // Don't remove it from the list yet. del_trigger() should
      // be able to find it if necessary and disable.
      {
        GCriticalSectionLock list_lock(&triggers_lock);
        for(GPosition pos=triggers_list;pos;++pos)
        {
          GP<Trigger> t=triggers_list[pos];
          if (is_eof() || t->length>=0 &&
            block_list->get_bytes(t->start, t->length)==t->length)
          {
            trigger=t;
            break;
          }
        }
      }
      
      if (trigger)
      {
           // Now check that the trigger is not disabled
           // and lock the trigger->disabled lock for the duration
           // of the trigger. This will block the del_trigger() and
           // will postpone client's destruction (usually following
           // the call to del_trigger())
        {
          GMonitorLock lock(&trigger->disabled);
          if (!trigger->disabled)
            call_callback(trigger->callback, trigger->cl_data);
        }
        
           // Finally - remove the trigger from the list.
        GCriticalSectionLock list_lock(&triggers_lock);
        for(GPosition pos=triggers_list;pos;++pos)
          if (triggers_list[pos]==trigger)
          {
            triggers_list.del(pos);
            break;
          }
      } else break;
    }
}

void
// DataPool::add_trigger(int thresh, void (* callback)(GP<GPEnabled> &), GP<GPEnabled> cl_data)
DataPool::add_trigger(int thresh, void (* callback)(void *), void * cl_data)
{
  if (thresh>=0)
    add_trigger(0, thresh+1, callback, cl_data);
  else
    add_trigger(0, -1, callback, cl_data);
}

void
DataPool::add_trigger(int tstart, int tlength,
//            void (* callback)(GP<GPEnabled> &), GP<GPEnabled> cl_data)
              void (* callback)(void *), void * cl_data)
{
   DEBUG_MSG("DataPool::add_trigger(): start=" << tstart <<
         ", length=" << tlength << ", func=" << (void *) callback << "\n");
   DEBUG_MAKE_INDENT(3);
   
   if (callback)
   {
      if (is_eof())
      {
        call_callback(callback, cl_data);
      }else
      {
     if (pool)
     {
           // We're connected to a DataPool
           // Just pass the triggers down remembering it in the list
        if (tlength<0 && length>0) tlength=length-tstart;
        GP<Trigger> trigger=new Trigger(tstart, tlength, callback, cl_data);
        pool->add_trigger(start+tstart, tlength, callback, cl_data);
        GCriticalSectionLock lock(&triggers_lock);
        triggers_list.append(trigger);
     } else if (!furl.is_local_file_url())
     {
           // We're not connected to anything and maintain our own data
        if (tlength>=0 && block_list->get_bytes(tstart, tlength)==tlength)
           call_callback(callback, cl_data);
        else
        {
           GCriticalSectionLock lock(&triggers_lock);
           triggers_list.append(new Trigger(tstart, tlength, callback, cl_data));
        }
     }
      }
   }
}

void
// DataPool::del_trigger(void (* callback)(GP<GPEnabled> &), GP<GPEnabled> cl_data)
DataPool::del_trigger(void (* callback)(void *), void * cl_data)
{
   DEBUG_MSG("DataPool::del_trigger(): func=" << (void *) callback << "\n");
   DEBUG_MAKE_INDENT(3);

   for(;;)
   {
      GP<Trigger> trigger;
      {
     GCriticalSectionLock lock(&triggers_lock);
     for(GPosition pos=triggers_list;pos;)
     {
        GP<Trigger> t=triggers_list[pos];
        if (t->callback==callback && t->cl_data==cl_data)
        {
           trigger=t;
           GPosition this_pos=pos;
           ++pos;
           triggers_list.del(this_pos);
           break;
        } else
              ++pos;
     }
      }

     // Above we removed the trigger from the list and unlocked the list
     // Now we will disable it and will wait if necessary (if the
     // trigger is currently being processed by check_triggers())
     // check_triggers() locks the trigger for the duration of the
     // trigger callback. Thus we will wait for the trigger callback
     // to finish and avoid client's destruction.
      if (trigger)
        trigger->disabled=1;
      else
        break;
   }

   if (pool)
     pool->del_trigger(callback, cl_data);
}

void
// DataPool::static_trigger_cb(GP<GPEnabled> &cl_data)
DataPool::static_trigger_cb(void *cl_data)
{
//  GP<DataPool> d=(DataPool *)(GPEnabled *)cl_data;
  GP<DataPool> d=(DataPool *)cl_data;
  d->trigger_cb();
}

void
DataPool::trigger_cb(void)
      // This function may be triggered by the DataPool, which we're
      // connected to, or by ourselves, if we're connected to nothing
{
      // Don't want to be destroyed while I'm here. Can't use GP<> life saver
      // because it may be called from the constructor
   GCriticalSectionLock lock(&trigger_lock);
   
   DEBUG_MSG("DataPool::trigger_cb() called\n");
   DEBUG_MAKE_INDENT(3);

   if (pool)
   {
      // Connected to a pool
      // We may be here when either EOF is set on the master DataPool
      // Or when it may have learnt its length (from IFF or whatever)
      if (pool->is_eof() || pool->has_data(start, length)) eof_flag=true;
   } else if (!furl.is_local_file_url())
   {
        // Not connected to anything => Try to guess the length
      if (length<0) analyze_iff();
      
        // Failed to analyze? Check, maybe it's EOF already
      if (length<0 && is_eof())
      {
           GCriticalSectionLock lock(&data_lock);
           length=data->size();
      }
   }
}

void
DataPool::analyze_iff(void)
      // In order to display decode progress properly, we need to know
      // the size of the data. It's trivial to figure it out if is_eof()
      // is true. Otherwise we need to make a prediction. Luckily all
      // DjVuFiles have IFF structure, which makes it possible to do it.
      // If due to some reason we fail, the length will remain -1.
{
   DEBUG_MSG("DataPool::analyze_iff(): Trying to decode IFF structure of " << furl << ".\n");
   DEBUG_MSG("in order to predict the DataPool's size\n");
   DEBUG_MAKE_INDENT(3);

   GP<ByteStream> str=get_stream();
   
   GP<IFFByteStream> giff=IFFByteStream::create(str);
   IFFByteStream &iff=*giff;
   GUTF8String chkid;
   int size;
   if ((size=iff.get_chunk(chkid)) && size>=0)
   {
      length=size+iff.tell()-4;
      DEBUG_MSG("Got size=" << size << ", length=" << length << "\n");
   }
}


//****************************************************************************
//****************************** PoolByteStream ******************************
//****************************************************************************

// This is an internal ByteStream receiving data from the associated DataPool.
// It's just a sequential interface, nothing more. All the job for data
// retrieval, waiting and thread synchronization is done by DataPool

class PoolByteStream : public ByteStream
{
public:
   PoolByteStream(GP<DataPool> data_pool);
   virtual ~PoolByteStream() {};

   virtual size_t read(void *buffer, size_t size);
   virtual size_t write(const void *buffer, size_t size);
   virtual long tell(void) const ;
   virtual int seek(long offset, int whence = SEEK_SET, bool nothrow=false);
private:
      // Don't make data_pool GP<>. The problem is that DataPool creates
      // and soon destroys this ByteStream from the constructor. Since
      // there are no other pointers to the DataPool created yet, it becomes
      // destroyed immediately :(
   DataPool     * data_pool;
   GP<DataPool>     data_pool_lock;
   long         position;
   
   char         buffer[512];
   size_t       buffer_size;
   size_t       buffer_pos;

      // Cancel C++ default stuff
   PoolByteStream & operator=(const PoolByteStream &);
};

inline
PoolByteStream::PoolByteStream(GP<DataPool> xdata_pool) :
   data_pool(xdata_pool), position(0), buffer_size(0), buffer_pos(0)
{
   if (!data_pool) 
       G_THROW( ERR_MSG("DataPool.zero_DataPool") );

      // Secure the DataPool if possible. If we're called from DataPool
      // constructor (get_count()==0) there is no need to secure at all.
   if (data_pool->get_count()) data_pool_lock=data_pool;
}

size_t
PoolByteStream::read(void *data, size_t size)
{
  if (buffer_pos >= buffer_size) {
    if (size >= sizeof(buffer)) {
      // Direct read
      size = data_pool->get_data(data, position, size);
      position += size;
      return size;
    } else {
      // Refill buffer
      buffer_size = data_pool->get_data(buffer, position, sizeof(buffer));
      buffer_pos=0;
    }
  }
  if (buffer_pos + size >= buffer_size)
    size = buffer_size - buffer_pos;
  memcpy(data, buffer+buffer_pos, size);
  buffer_pos += size;
  position += size;
  return size;
}

size_t
PoolByteStream::write(const void *buffer, size_t size)
{
   G_THROW( ERR_MSG("not_implemented_n") "\tPoolByteStream::write()");   //  PoolByteStream::write() is not implemented.
   return 0;    // For compiler not to bark
}

long
PoolByteStream::tell(void) const
{
   return position;
}

int
PoolByteStream::seek(long offset, int whence, bool nothrow)
{
  int retval=(-1);
  switch(whence)
  {
    case SEEK_CUR:
      offset+=position;
      // fallthrough;
    case SEEK_SET:
      if(offset<position)
      {
        if((int)(offset+buffer_pos)>=(int)position)
        {
          buffer_pos-=position-offset;
        }else
        {
          buffer_size=0;
        }
        position=offset;
      }else if(offset>position)
      {
        buffer_pos+=(offset-position)-1;
        position=offset-1;
        unsigned char c;
        if(read(&c,1)<1)
        {
          G_THROW( ByteStream::EndOfFile );
        }
      }
      retval=0;
      break;
    case SEEK_END:
      if(! nothrow)
        G_THROW( ERR_MSG("DataPool.seek_backward") );
      break;
   }
   return retval;
}

void
DataPool::close_all(void)
{
  OpenFiles::get()->close_all();
}


GP<ByteStream>
DataPool::get_stream(void)
{
  if(data && data->is_static())
  {
    GCriticalSectionLock lock(&data_lock);
    data->seek(0, SEEK_SET);
    return data->duplicate(length);
  }else
  {
    return new PoolByteStream(this);
  }
}


inline
DataPool::Counter::operator int(void) const
{
   GCriticalSectionLock lk((GCriticalSection *) &lock);
   int cnt=counter;
   return cnt;
}

inline void
DataPool::Counter::inc(void)
{
   GCriticalSectionLock lk(&lock);
   counter++;
}

inline void
DataPool::Counter::dec(void)
{
   GCriticalSectionLock lk(&lock);
   counter--;
}


#ifdef HAVE_NAMESPACES
}
# ifndef NOT_USING_DJVU_NAMESPACE
using namespace DJVU;
# endif
#endif

kviewshell

Skip menu "kviewshell"

• Main Page
• Namespace List
• Class Hierarchy
• Alphabetical List
• Class List
• File List
• Namespace Members
• Class Members

API Reference

Skip menu "API Reference"

• kviewshell

Generated for API Reference by doxygen 1.5.9
This website is maintained by Adriaan de Groot and Allen Winter.
KDE^® and the K Desktop Environment^® logo are registered trademarks of KDE e.V. | Legal