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 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:

            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 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 `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 mentionned 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 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();

SEE ALSO

       iorheo(4)