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irheostream, orheostream - large data streams

rheostream(2rheolef) rheolef-6.7 rheostream(2rheolef)


irheostream, orheostream - large data streams


This class provides a stream interface for large data management. File decompresion is assumed using gzip and a recursive seach 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:
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);
        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.


The following code:
        irheostream is("results", "data");
will recursively look for a ` results[.data[.gz]]' file in the directory mentionned 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 `' nor `' 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 "" will be created.
File loading and storing are mentionned by a message, either:
        ! load "./"
        ! file "./" created.
on the clog stream. By adding the following:
        clog << noverbose;
you turn off these messages
(see iorheo(4)).


class irheostream : public boost::iostreams::filtering_stream<boost::iostreams::input> {
    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();
    std::ifstream _ifs;
static const bool dont_gzip = false;
class orheostream : public boost::iostreams::filtering_stream<boost::iostreams::output> {
    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; }
    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 occurence 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);
// "/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();


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