DBCacheBenchmarking/SequentialScan.cpp at master · adamanthil/DBCacheBenchmarking · GitHub

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#include <new>
#include <stdio.h>
#include <iostream>

#include "SequentialScan.h"
#include "FileManager.h"
#include "BufferManager.h"

SequentialScan::SequentialScan(const Table * table, const std::string & alias,
			       const Columns & columns)
  : m_clause(NULL), m_rid(0), m_page(NULL)
{
  m_fd = FileManager::getInstance()->open(table->path());
  m_buffer = BufferManager::getInstance()->allocate();

  m_schema = new Schema();
  for (int i = 0; i < columns.count(); i++)
    {
      const Column * c = columns[i];
      const Attribute * a = (*table->schema())[c->m_name];
      Attribute attribute(a->id(), 0, a->name(),
			  alias, a->size(), a->type());
      m_schema->add(&attribute);
    }
  m_data = new byte[m_schema->rsize()];

  m_tuple.m_data = NULL;
  m_tuple.schema(NULL);

  m_tsw = new TupleStreamWriter(*m_buffer, m_schema->rsize());
}

SequentialScan::~SequentialScan()
{
  delete [] m_data;
  delete m_schema;
  delete m_clause;

  delete m_tuple.m_data;
  delete m_tuple.schema();

  delete m_tsw;
  BufferManager::getInstance()->deallocate(m_buffer);
  FileManager::getInstance()->close(m_fd);
}

void SequentialScan::layout(const MaterializationLayout * layout)
{
  m_tsw->layout(layout);
}

void SequentialScan::filter(BooleanExpression * expression, const std::vector<std::string> & filterColumns)
{
  m_clause = new WhereClause(expression);

  Schema * schema = new Schema();
  for (int i = 0; i < filterColumns.size(); i++)
    {
      std::string s = filterColumns[i];
      const Attribute * a = (*m_schema)[s];

      schema->add(a);
    }

  m_tuple.m_data = new byte[schema->rsize()];
  m_tuple.schema(schema);
}

const Schema * SequentialScan::schema() const
{
  return m_schema;
}

bool SequentialScan::moveNext()
{
  size_t rsize = m_schema->rsize();

  // TODO: create global for this.
  Tuple t;
  t.m_data = m_data;
  t.schema(m_schema);

  m_tsw->discard();

  while (!m_tsw->isStreamFull()) // available >= rsize)
    {
      // determine if we consumed all the data on current page
      if (m_page == NULL || m_rid >= m_page->size())
	{
	  m_page = !m_fd->eof() ? BufferManager::getInstance()->read(m_fd) : NULL;
	  m_rid = 0;

	  if (m_page == NULL)
	      break;
	}

      for (; m_rid < m_page->size() && !m_tsw->isStreamFull(); /* available >= rsize */m_rid++)
	{
	  /* extract data to update variable expressions. */
	  if (m_clause != NULL)
	    {
	      m_page->get(m_rid, m_tuple.schema(), m_tuple.m_data, m_tuple.schema()->rsize());
	    }

	  if (m_clause == NULL || m_clause->evaluate(m_tuple))
	    {
	      memset(m_data, 0, rsize);
	      m_page->get(m_rid, m_schema, m_data, rsize);
	      m_tsw->write(t);
	    }
	}
    }

  return m_buffer->getSize() > 0;
}

void SequentialScan::next(MemoryBlock & block)
{
  block.copy(*m_buffer);
}

void SequentialScan::reset()
{
  m_rid = 0;
  m_page = NULL;
  m_fd->reset();
  m_tsw->discard();
}