PXDLocalDAQFile Class Reference

A class to manage I/O for a chain of blocked files. More...

#include <PXDLocalDAQFile.h>

Public Member Functions
	PXDLocalDAQFile (const std::string &filename)
	Constructor.
	~PXDLocalDAQFile ()
	Destructor.
	PXDLocalDAQFile (const PXDLocalDAQFile &)=delete
	No copying.
PXDLocalDAQFile &	operator= (const PXDLocalDAQFile &)=delete
	No assignment.
int	status () const
	Returns status after constructor call.
int	read (char *buf, int max)
	Read a record from a file.
int	read_data (char *data, size_t len)
	Read a record from a file.

Private Member Functions
void	openFile (std::string filename)
	actually open the file

Private Attributes
std::string	m_filename
	Name of the opened file.
int	m_fd { -1}
	file descriptor.
bool	m_compressed {false}
	is file bzip2 compressed?
std::unique_ptr< std::ios >	m_stream
	pointer to the filtering input or output stream

Detailed Description

A class to manage I/O for a chain of blocked files.

Definition at line 22 of file PXDLocalDAQFile.h.

Constructor & Destructor Documentation

PXDLocalDAQFile()

PXDLocalDAQFile ( const std::string &  filename )

explicit

Constructor.

Definition at line 25 of file PXDLocalDAQFile.cc.

                                                         :
  m_filename(filename)
{
  if (filename.empty()) {
    B2ERROR("PXDLocalDAQFile: Empty filename given");
    return;
  }
  // is the file already compressed?
  m_compressed = filename.size() > 4 && filename.compare(filename.size() - 4, 4, ".bz2") == 0;
 
  // open the file
  openFile(m_filename);
  if (m_fd < 0 && !m_compressed) {
    B2WARNING("PXDLocalDAQFile: error opening '" << filename << "': " << strerror(errno)
              << ", trying again with '.bz2'");
    m_compressed = true;
    openFile(m_filename);
  }
  // is the file open now?
  if (m_fd < 0) {
    B2ERROR("PXDLocalDAQFile: error opening '" << filename << "': " << strerror(errno));
  } else {
    B2INFO("PXDLocalDAQFile: " << m_filename << " opened (fd=" << m_fd << ")");
  }
 
}

~PXDLocalDAQFile()

~PXDLocalDAQFile

(

)

Destructor.

Definition at line 65 of file PXDLocalDAQFile.cc.

{
  B2INFO("Closing PXDLocalDAQFile ");
  //closed automatically by m_stream.
}

Member Function Documentation

openFile()

void openFile ( std::string  filename )

private

actually open the file

Definition at line 52 of file PXDLocalDAQFile.cc.

{
 
  //open file in read mode and set stream correctly
  m_fd = open(filename.c_str(), O_RDONLY);
  auto* filter = new io::filtering_istream();
  if (m_compressed) filter->push(io::bzip2_decompressor());
  filter->push(io::file_descriptor_source(m_fd, io::close_handle));
  filter->exceptions(ios_base::badbit | ios_base::failbit);
  m_stream.reset(filter);
 
}

read()

int read	(	char *	buf,
		int	max
	)

Read a record from a file.

Returns the data size read.

Definition at line 76 of file PXDLocalDAQFile.cc.

{
  // cast stream object
  auto in = dynamic_cast<std::istream*>(m_stream.get());
  if (!in) {
    B2FATAL("PXDLocalDAQFile::read() cannot get input file");
  }
  //trigger eof if there's nothing left int the file. Could throw an error on decompress failure
  try {
    in->peek();
  } catch (ios_base::failure& e) {
    B2ERROR("PXDLocalDAQFile::read() cannot read file: " << e.what());
    return -1;
  }
  // return -1 if eof
  if (in->eof()) {
    B2DEBUG(29, "PXDLocalDAQFile::read() eof");
    return -1;
  }
 
  // read from file
  try {
    in->read(buf, size);
  } catch (ios_base::failure& e) {
    B2ERROR("PXDLocalDAQFile::read() " << e.what() << ": could only read " << in->gcount() << " bytes, expected " << size);
    return -1;
  }
 
  return in->gcount();
}

read_data()

int read_data	(	char *	data,
		size_t	len
	)

Read a record from a file.

Returns the data size if successfully read, otherwise 0.

Definition at line 107 of file PXDLocalDAQFile.cc.

{
  size_t l = read(data, len);
  if (l != len) return 0;
  return l;
}

status()

int status

(

)

const

Returns status after constructor call.

If success, fd is returned. If not, -1

Definition at line 71 of file PXDLocalDAQFile.cc.

{
  return m_fd;
}

Member Data Documentation

m_compressed

bool m_compressed {false}

private

is file bzip2 compressed?

Definition at line 48 of file PXDLocalDAQFile.h.

m_fd

int m_fd { -1}

private

file descriptor.

Definition at line 47 of file PXDLocalDAQFile.h.

m_filename

std::string m_filename

private

Name of the opened file.

Definition at line 46 of file PXDLocalDAQFile.h.

m_stream

std::unique_ptr<std::ios> m_stream

private

pointer to the filtering input or output stream

Definition at line 49 of file PXDLocalDAQFile.h.

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The documentation for this class was generated from the following files:

• pxd/unpacking/include/PXDLocalDAQFile.h
• pxd/unpacking/src/PXDLocalDAQFile.cc