buffer.cc

一个非常好的GIS开源新版本

// Spatial Index Library
//
// Copyright (C) 2002 Navel Ltd.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//  Email:
//    [e-mail]

#include "../spatialindex/SpatialIndexImpl.h"

#include "Buffer.h"

using namespace SpatialIndex::StorageManager;
using std::map;

Buffer::Buffer(IStorageManager& sm, Tools::PropertySet& ps) :
	m_capacity(10),
	m_bWriteThrough(false),
	m_pStorageManager(&sm),
	m_hits(0)
{
	Tools::Variant var = ps.getProperty("Capacity");
	if (var.m_varType != Tools::VT_EMPTY)
	{
		if (var.m_varType != Tools::VT_ULONG) throw Tools::IllegalArgumentException("Property Capacity must be Tools::VT_ULONG");
		m_capacity = var.m_val.ulVal;
	}

	var = ps.getProperty("WriteThrough");
	if (var.m_varType != Tools::VT_EMPTY)
	{
		if (var.m_varType != Tools::VT_BOOL) throw Tools::IllegalArgumentException("Property WriteThrough must be Tools::VT_BOOL");
		m_bWriteThrough = var.m_val.blVal;
	}
}

Buffer::~Buffer()
{
	for (map<long, Entry*>::iterator it = m_buffer.begin(); it != m_buffer.end(); it++)
	{
		Entry* e = (*it).second;
		long id = (*it).first;
		if (e->m_bDirty) m_pStorageManager->storeByteArray(id, e->m_length, e->m_pData);
		delete e;
	}
}

void Buffer::loadByteArray(const long id, unsigned long& len, byte** data)
{
	map<long, Entry*>::iterator it = m_buffer.find(id);

	if (it != m_buffer.end())
	{
		m_hits++;
		Entry* e = (*it).second;
		len = e->m_length;
		*data = new byte[len];
		memcpy(*data, e->m_pData, len);
	}
	else
	{
		m_pStorageManager->loadByteArray(id, len, data);
		Entry* e = new Entry(len, (const byte *) *data);
		addEntry(id, e);
	}
}

void Buffer::storeByteArray(long& id, const unsigned long len, const byte* const data)
{
	if (id == NewPage)
	{
		m_pStorageManager->storeByteArray(id, len, data);
		assert(m_buffer.find(id) == m_buffer.end());
		Entry* e = new Entry(len, data);
		addEntry(id, e);
	}
	else
	{
		if (m_bWriteThrough)
		{
			m_pStorageManager->storeByteArray(id, len, data);
		}

		Entry* e = new Entry(len, data);
		if (m_bWriteThrough == false) e->m_bDirty = true;

		map<long, Entry*>::iterator it = m_buffer.find(id);
		if (it != m_buffer.end())
		{
			delete (*it).second;
			(*it).second = e;
			if (m_bWriteThrough == false) m_hits++;
		}
		else
		{
			addEntry(id, e);
		}
	}
}

void Buffer::deleteByteArray(const long id)
{
	map<long, Entry*>::iterator it = m_buffer.find(id);
	if (it != m_buffer.end())
	{
		delete (*it).second;
		m_buffer.erase(it);
	}

	m_pStorageManager->deleteByteArray(id);
}

void Buffer::clear()
{
	for (map<long, Entry*>::iterator it = m_buffer.begin(); it != m_buffer.end(); it++)
	{
		if ((*it).second->m_bDirty)
		{
			long id = (*it).first;
			m_pStorageManager->storeByteArray(id, ((*it).second)->m_length, (const byte *) ((*it).second)->m_pData);
		}

		delete (*it).second;
	}

	m_buffer.clear();
	m_hits = 0;
}

unsigned long Buffer::getHits()
{
	return m_hits;
}