QGIS/external/untwine/bu/PointAccessor.hpp
2024-10-22 09:04:34 +10:00

84 lines
2.6 KiB
C++

/*****************************************************************************
* Copyright (c) 2020, Hobu, Inc. (info@hobu.co) *
* *
* All rights reserved. *
* *
* 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 3 of the License, or *
* (at your option) any later version. *
* *
****************************************************************************/
#pragma once
#include "../untwine/Common.hpp"
#include "../untwine/Point.hpp"
#include <mapfile.hpp> // untwine/os
#include "FileInfo.hpp"
namespace untwine
{
namespace bu
{
class PointAccessor
{
public:
PointAccessor(const BaseInfo& b) : m_b(b)
{}
~PointAccessor()
{
for (FileInfo *fi : m_fileInfos)
os::unmapFile(fi->context());
}
void read(FileInfo& fi)
{
std::string filename = m_b.opts.tempDir + "/" + fi.filename();
auto ctx = os::mapFile(filename, true, 0, fi.numPoints() * m_b.pointSize);
if (ctx.m_addr == nullptr)
throw FatalError(filename + ": " + ctx.m_error);
fi.setContext(ctx);
fi.setStart(size());
m_fileInfos.push_back(&fi);
}
Point operator[](size_t offset)
{
for (FileInfo *fi : m_fileInfos)
if (offset >= (size_t)fi->start() &&
offset < (size_t)fi->start() + fi->numPoints())
return Point(fi->address() + ((offset - fi->start()) * m_b.pointSize));
return Point();
}
size_t size()
{
// start() returns the number of points in the file infos before the last one.
// adding numPoints() provides the total number of points.
if (m_fileInfos.empty())
return 0;
else
return m_fileInfos.back()->start() + m_fileInfos.back()->numPoints();
}
void dump()
{
std::cerr << "Accessor infos:\n";
for (FileInfo *fi : m_fileInfos)
std::cerr << fi->filename() << "/" << fi->start() << "/" << fi->numPoints() << "!\n";
std::cerr << "\n";
}
private:
const BaseInfo& m_b;
std::vector<FileInfo *> m_fileInfos;
};
} // namespace bu
} // namespace untwine