src/string_port.cpp

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/******************************************************************************
* MODULE     : string_port.cpp
* DESCRIPTION: Strings as input and output ports
* COPYRIGHT  : (C) 2010  Joris van der Hoeven
*******************************************************************************
* This software falls under the GNU general public license and comes WITHOUT
* ANY WARRANTY WHATSOEVER. See the file $TEXMACS_PATH/LICENSE for more details.
* If you don't have this file, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
******************************************************************************/

#include <basix/port.hpp>
#include <basix/string.hpp>


namespace mmx {

/******************************************************************************
* Output string ports
******************************************************************************/

class output_string_port_rep: public port_rep {
  string& s;

public:
  virtual syntactic expression () const {
    return syn ("output_string_port", syntactic (quote (s))); }
  bool is_output_port () { return true; }
  bool busy () { return true; }
  nat  can_write () { return (nat) (-1); }
  void write (const char* x, nat n) { s << string (x, n); }

public:
  inline output_string_port_rep (string& s2): s (s2) {}
};

port
output_string_port (string& s) {
  return (port_rep*) new output_string_port_rep (s);
}

/******************************************************************************
* Input string ports
******************************************************************************/

class input_string_port_rep: public port_rep {
  string s;
  nat pos;

public:
  virtual syntactic expression () const {
    return syn ("input_string_port", syntactic (quote (s (pos, N(s))))); }
  bool is_input_port () { return true; }
  bool busy () { return pos < N(s); }
  nat  can_read () { return N(s) - pos; }
  void read (char* x, nat n) {
    ASSERT (pos + n <= N(s), "no more input");
    mem_copy (x, inside (s, pos), n);
    pos += n; }

public:
  inline input_string_port_rep (const string& s2): s (s2), pos (0) {}
};

port
input_string_port (const string& s) {
  return (port_rep*) new input_string_port_rep (s);
}

/******************************************************************************
* Input output string ports
******************************************************************************/

class input_output_string_port_rep: public port_rep {
  string& s;
  nat pos;

public:
  virtual syntactic expression () const {
    return syn ("input_output_string_port",
                syntactic (quote (s (pos, N(s))))); }
  bool is_output_port () { return true; }
  bool is_input_port () { return true; }
  bool busy () { return true; }
  nat  can_write () { return (nat) (-1); }
  nat  can_read () { return N(s) - pos; }
  void write (const char* x, nat n) { s << string (x, n); }
  void read (char* x, nat n) {
    ASSERT (pos + n <= N(s), "no more input");
    mem_copy (x, inside (s, pos), n);
    pos += n;
    if (pos > ((N(s) >> 1) + 1024)) {
      s= s (pos, N(s));
      pos= 0;
    }
  }

public:
  inline input_output_string_port_rep (string& s2): s (s2), pos (0) {}
};

port
input_output_string_port (string& s) {
  return (port_rep*) new input_output_string_port_rep (s);
}

} // namespace mmx

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