cached_container.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright 2013-2017 CERN
 * Copyright (C) 2020-2021 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * @author Maciej Suminski <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include <gal/opengl/cached_container.h>
#include <gal/opengl/vertex_manager.h>
#include <gal/opengl/vertex_item.h>
#include <gal/opengl/utils.h>
 
#include <list>
#include <algorithm>
#include <cassert>
 
#ifdef __WIN32__
#include <excpt.h>
#endif
 
#ifdef KICAD_GAL_PROFILE
#include <wx/log.h>
#include <profile.h>
#endif /* KICAD_GAL_PROFILE */
 
using namespace KIGFX;
 
CACHED_CONTAINER::CACHED_CONTAINER( unsigned int aSize ) :
 VERTEX_CONTAINER( aSize ),
 m_item( nullptr ),
 m_chunkSize( 0 ),
 m_chunkOffset( 0 ),
 m_maxIndex( 0 )
{
 // In the beginning there is only free space
 m_freeChunks.insert( std::make_pair( aSize, 0 ) );
}
 
 
void CACHED_CONTAINER::SetItem( VERTEX_ITEM* aItem )
{
 assert( aItem != nullptr );
 
 unsigned int itemSize = aItem->GetSize();
 m_item = aItem;
 m_chunkSize = itemSize;
 
 // Get the previously set offset if the item was stored previously
 m_chunkOffset = itemSize > 0 ? aItem->GetOffset() : -1;
}
 
 
void CACHED_CONTAINER::FinishItem()
{
 assert( m_item != nullptr );
 
 unsigned int itemSize = m_item->GetSize();
 
 // Finishing the previously edited item
 if( itemSize < m_chunkSize )
 {
 // There is some not used but reserved memory left, so we should return it to the pool
 int itemOffset = m_item->GetOffset();
 
 // Add the not used memory back to the pool
 addFreeChunk( itemOffset + itemSize, m_chunkSize - itemSize );
 // mergeFreeChunks(); // veery slow and buggy
 
 m_maxIndex = std::max( itemOffset + itemSize, m_maxIndex );
 }
 
 if( itemSize > 0 )
 m_items.insert( m_item );
 
 m_item = nullptr;
 m_chunkSize = 0;
 m_chunkOffset = 0;
 
#if CACHED_CONTAINER_TEST > 1
 test();
#endif
}
 
 
VERTEX* CACHED_CONTAINER::Allocate( unsigned int aSize )
{
 assert( m_item != nullptr );
 assert( IsMapped() );
 
 if( m_failed )
 return nullptr;
 
 unsigned int itemSize = m_item->GetSize();
 unsigned int newSize = itemSize + aSize;
 
 if( newSize > m_chunkSize )
 {
 // There is not enough space in the currently reserved chunk, so we have to resize it
 if( !reallocate( newSize ) )
 {
 m_failed = true;
 return nullptr;
 }
 }
 
 VERTEX* reserved = &m_vertices[m_chunkOffset + itemSize];
 
 // Now the item officially possesses the memory chunk
 m_item->setSize( newSize );
 
 // The content has to be updated
 m_dirty = true;
 
#if CACHED_CONTAINER_TEST > 0
 test();
#endif
#if CACHED_CONTAINER_TEST > 2
 showFreeChunks();
 showUsedChunks();
#endif
 
 return reserved;
}
 
 
void CACHED_CONTAINER::Delete( VERTEX_ITEM* aItem )
{
 assert( aItem != nullptr );
 assert( m_items.find( aItem ) != m_items.end() || aItem->GetSize() == 0 );
 
 int size = aItem->GetSize();
 
 if( size == 0 )
 return; // Item is not stored here
 
 int offset = aItem->GetOffset();
 
 // Insert a free memory chunk entry in the place where item was stored
 addFreeChunk( offset, size );
 
 // Indicate that the item is not stored in the container anymore
 aItem->setSize( 0 );
 
 m_items.erase( aItem );
 
#if CACHED_CONTAINER_TEST > 0
 test();
#endif
 
 // This dynamic memory freeing optimize memory usage, but in fact can create
 // out of memory issues because freeing and reallocation large chunks of memory
 // can create memory fragmentation and no room to reallocate large chunks
 // after many free/reallocate cycles during a session using the same complex board
 // So it can be disable.
 // Currently: it is disable to avoid "out of memory" issues
#if 0
 // Dynamic memory freeing, there is no point in holding
 // a large amount of memory when there is no use for it
 if( m_freeSpace > ( 0.75 * m_currentSize ) && m_currentSize > m_initialSize )
 {
 defragmentResize( 0.5 * m_currentSize );
 }
#endif
}
 
 
void CACHED_CONTAINER::Clear()
{
 m_freeSpace = m_currentSize;
 m_maxIndex = 0;
 m_failed = false;
 
 // Set the size of all the stored VERTEX_ITEMs to 0, so it is clear that they are not held
 // in the container anymore
 for( ITEMS::iterator it = m_items.begin(); it != m_items.end(); ++it )
 ( *it )->setSize( 0 );
 
 m_items.clear();
 
 // Now there is only free space left
 m_freeChunks.clear();
 m_freeChunks.insert( std::make_pair( m_freeSpace, 0 ) );
}
 
 
bool CACHED_CONTAINER::reallocate( unsigned int aSize )
{
 assert( aSize > 0 );
 assert( IsMapped() );
 
 unsigned int itemSize = m_item->GetSize();
 
 // Find a free space chunk >= aSize
 FREE_CHUNK_MAP::iterator newChunk = m_freeChunks.lower_bound( aSize );
 
 // Is there enough space to store vertices?
 if( newChunk == m_freeChunks.end() )
 {
 bool result;
 
 // Would it be enough to double the current space?
 if( aSize < m_freeSpace + m_currentSize )
 {
 // Yes: exponential growing
 result = defragmentResize( m_currentSize * 2 );
 }
  else
 {
 // No: grow to the nearest greater power of 2
 result = defragmentResize( pow( 2, ceil( log2( m_currentSize * 2 + aSize ) ) ) );
 }
 
 if( !result )
 return false;
 
 newChunk = m_freeChunks.lower_bound( aSize );
 assert( newChunk != m_freeChunks.end() );
 }
 
 // Parameters of the allocated chunk
 unsigned int newChunkSize = getChunkSize( *newChunk );
 unsigned int newChunkOffset = getChunkOffset( *newChunk );
 
 assert( newChunkSize >= aSize );
 assert( newChunkOffset < m_currentSize );
 
 // Check if the item was previously stored in the container
 if( itemSize > 0 )
 {
 // The item was reallocated, so we have to copy all the old data to the new place
 memcpy( &m_vertices[newChunkOffset], &m_vertices[m_chunkOffset], itemSize * VERTEX_SIZE );
 
 // Free the space used by the previous chunk
 addFreeChunk( m_chunkOffset, m_chunkSize );
 }
 
 // Remove the new allocated chunk from the free space pool
 m_freeChunks.erase( newChunk );
 m_freeSpace -= newChunkSize;
 
 m_chunkSize = newChunkSize;
 m_chunkOffset = newChunkOffset;
 
 m_item->setOffset( m_chunkOffset );
 
 return true;
}
 
 
void CACHED_CONTAINER::defragment( VERTEX* aTarget )
{
 // Defragmentation
 ITEMS::iterator it, it_end;
 int newOffset = 0;
 
 [&]()
 {
#ifdef __WIN32__
 #ifdef __MINGW32__
 // currently, because SEH (Structured Exception Handling) is not documented on msys
 // (for intance __try or __try1 exists without doc) or is not supported, do nothing
 #else
 __try
 #endif
#endif
 {
 for( VERTEX_ITEM* item : m_items )
 {
 int itemOffset = item->GetOffset();
 int itemSize = item->GetSize();
 
 // Move an item to the new container
 memcpy( &aTarget[newOffset], &m_vertices[itemOffset], itemSize * VERTEX_SIZE );
 
 // Update new offset
 item->setOffset( newOffset );
 
 // Move to the next free space
 newOffset += itemSize;
 }
 
 // Move the current item and place it at the end
 if( m_item->GetSize() > 0 )
 {
 memcpy( &aTarget[newOffset], &m_vertices[m_item->GetOffset()],
 m_item->GetSize() * VERTEX_SIZE );
 m_item->setOffset( newOffset );
 m_chunkOffset = newOffset;
 }
 }
#ifdef __WIN32__
 #ifdef __MINGW32__
 // currently, because SEH (Structured Exception Handling) is not documented on msys
 // (for intance __except1 exists without doc) or is not supported, do nothing
 #else
 __except( GetExceptionCode() == STATUS_ACCESS_VIOLATION ? EXCEPTION_EXECUTE_HANDLER
 : EXCEPTION_CONTINUE_SEARCH )
 {
 throw std::runtime_error(
 "Access violation in defragment. This is usually an indicator of "
 "system or GPU memory running low." );
 };
 #endif
#endif
 }();
 
 m_maxIndex = usedSpace();
}
 
 
void CACHED_CONTAINER::mergeFreeChunks()
{
 if( m_freeChunks.size() <= 1 ) // There are no chunks that can be merged
 return;
 
#ifdef KICAD_GAL_PROFILE
 PROF_TIMER totalTime;
#endif /* KICAD_GAL_PROFILE */
 
 // Reversed free chunks map - this one stores chunk size with its offset as the key
 std::list<CHUNK> freeChunks;
 
 FREE_CHUNK_MAP::const_iterator it, it_end;
 
 for( it = m_freeChunks.begin(), it_end = m_freeChunks.end(); it != it_end; ++it )
 {
 freeChunks.emplace_back( it->second, it->first );
 }
 
 m_freeChunks.clear();
 freeChunks.sort();
 
 std::list<CHUNK>::const_iterator itf, itf_end;
 unsigned int offset = freeChunks.front().first;
 unsigned int size = freeChunks.front().second;
 freeChunks.pop_front();
 
 for( itf = freeChunks.begin(), itf_end = freeChunks.end(); itf != itf_end; ++itf )
 {
 if( itf->first == offset + size )
 {
 // These chunks can be merged, so just increase the current chunk size and go on
 size += itf->second;
 }
 else
 {
 // These chunks cannot be merged
 // So store the previous one
 m_freeChunks.insert( std::make_pair( size, offset ) );
 // and let's check the next chunk
 offset = itf->first;
 size = itf->second;
 }
 }
 
 // Add the last one
 m_freeChunks.insert( std::make_pair( size, offset ) );
 
#if CACHED_CONTAINER_TEST > 0
 test();
#endif
}
 
 
void CACHED_CONTAINER::addFreeChunk( unsigned int aOffset, unsigned int aSize )
{
 assert( aOffset + aSize <= m_currentSize );
 assert( aSize > 0 );
 
 m_freeChunks.insert( std::make_pair( aSize, aOffset ) );
 m_freeSpace += aSize;
}
 
 
void CACHED_CONTAINER::showFreeChunks()
{
}
 
 
void CACHED_CONTAINER::showUsedChunks()
{
}
 
 
void CACHED_CONTAINER::test()
{
#ifdef KICAD_GAL_PROFILE
 // Free space check
 unsigned int freeSpace = 0;
 FREE_CHUNK_MAP::iterator itf;
 
 for( itf = m_freeChunks.begin(); itf != m_freeChunks.end(); ++itf )
 freeSpace += getChunkSize( *itf );
 
 assert( freeSpace == m_freeSpace );
 
 // Used space check
 unsigned int used_space = 0;
 ITEMS::iterator itr;
 
 for( itr = m_items.begin(); itr != m_items.end(); ++itr )
 used_space += ( *itr )->GetSize();
 
 // If we have a chunk assigned, then there must be an item edited
 assert( m_chunkSize == 0 || m_item );
 
 // Currently reserved chunk is also counted as used
 used_space += m_chunkSize;
 
 assert( ( m_freeSpace + used_space ) == m_currentSize );
 
 // Overlapping check TODO
#endif /* KICAD_GAL_PROFILE */
}