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rheostream(2rheolef) rheolef-7.0 rheostream(2rheolef)

NAME

irheostream, orheostream - large data streams

ABSTRACT

This class provides a stream interface for large data management. File decompresion is assumed using gzip and a recursive search in a directory list is provided for input.



     orheostream foo("NAME", "suffix");
is like 



     ofstream foo("NAME.suffix").
However, if NAME does not end with `.suffix', then `.suffix' is automatically added. By default, compression is performed on the fly with gzip, adding an additional `.gz' suffix. The flush action is nicely handled in compression mode: 



     foo.flush();
This feature allows intermediate results to be available during long computations. The compression can be deactivated while opening a file by an optional argument: 



     orheostream foo("NAME", "suffix", io::nogz);
An existing compressed file can be reopen in append mode: new results will be appended at the end of an existing file: 



     orheostream foo("NAME", "suffix", io::app);

Conversely,



        irheostream foo("NAME","suffix");
is like 



        ifstream foo("NAME.suffix").
However, we look at a search path environment variable RHEOPATH in order to find NAME while suffix is assumed. Moreover, gzip compressed files, ending with the `.gz' suffix is assumed, and decompression is done.

Finally, a set of useful functions are provided.

DESCRIPTION

The following code:



        irheostream is("results", "data");
will recursively look for a `results[.data[.gz]]' file in the directory mentioned by the RHEOPATH environment variable.

For instance, if you insert in our ".cshrc" something like:



        setenv RHEOPATH ".:/home/dupont:/usr/local/math/demo"
the process will study the current directory `.', then, if neither `square.data.gz' nor `square.data' exits, it scan all subdirectory of the current directory. Then, if file is not founded, it start recusively in `/home/dupond' and then in `/usr/local/math/demo'.

File decompression is performed by using the gzip command, and data are pipe-lined directly in memory.

If the file start with `.' as `./square' or with a `/' as `/home/oscar/square', no search occurs and RHEOPATH environment variable is not used.

Also, if the environment variable RHEOPATH is not set, the default value is the current directory `.'.

For output stream:



        orheostream os("newresults", "data");
file compression is assumed, and "newresults.data.gz" will be created.

File loading and storing are mentioned by a message, either:



        ! load "./results.data.gz"
or: 



        ! file "./newresults.data.gz" created.
on the clog stream. By adding the following: 



        clog << noverbose;
you turn off these messages
(see iorheo(4)).

IMPLEMENTATION

class irheostream : public boost::iostreams::filtering_stream<boost::iostreams::input> {
public:


    irheostream() : boost::iostreams::filtering_stream<boost::iostreams::input>() {}


    irheostream(const std::string& name, const std::string& suffix = std::string());


    virtual ~irheostream();


    void open  (const std::string& name, const std::string& suffix = std::string());


    void close();
protected:


    std::ifstream _ifs;
};
static const bool dont_gzip = false;
class orheostream : public boost::iostreams::filtering_stream<boost::iostreams::output> {
public:


    orheostream() : boost::iostreams::filtering_stream<boost::iostreams::output>() {}


    orheostream(const std::string& name, const std::string& suffix = std::string(),


        io::mode_type mode = io::out);


    virtual ~orheostream();


    void open  (const std::string& name, const std::string& suffix = std::string(),


        io::mode_type mode = io::out);


    void flush();


    void close();


    const std::string& filename() const { return _full_name; }
protected:


    void  _open_internal (io::mode_type mode);


    void _close_internal ();
// data:


    io::mode_type     _mode;


    std::string       _full_name;
};
std::string itos (std::string::size_type i);
std::string ftos (const Float& x);
// catch first occurrence of string in file
bool scatch (std::istream& in, const std::string& ch, bool full_match = true);
// has_suffix("toto.suffix", "suffix") -> true
bool has_suffix (const std::string& name, const std::string& suffix);
// "toto.suffix" --> "toto"
std::string delete_suffix (const std::string& name, const std::string& suffix);
// has_any_suffix("toto.any_suffix") -> true
bool has_any_suffix (const std::string& name);
// delete_any_suffix("toto.any_suffix") --> "toto"
std::string delete_any_suffix (const std::string& name);
// "/usr/local/dir/toto.suffix" --> "toto.suffix"
std::string get_basename (const std::string& name);
// "/usr/local/dir/toto.suffix" --> "/usr/local/dir"
std::string get_dirname (const std::string& name);
// "toto" --> "/usr/local/math/data/toto.suffix"
std::string get_full_name_from_rheo_path (const std::string& rootname, const std::string& suffix);
// "." + "../geodir" --> ".:../geodir"
void append_dir_to_rheo_path (const std::string& dir);
// "../geodir" + "." --> "../geodir:."
void prepend_dir_to_rheo_path (const std::string& dir);
bool file_exists (const std::string& filename);
// string to float
bool is_float (const std::string&);
Float to_float (const std::string&);
// in TMPDIR environment variable or "/tmp" by default
std::string get_tmpdir();

SEE ALSO

iorheo(4)

COPYRIGHT

Copyright (C) 2000-2018 Pierre Saramito <Pierre.Saramito@imag.fr> GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

rheolef-7.0 rheolef-7.0