source: tests/coroutine/devicedriver.cfa @ d0296db6

//
// Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// devicedriver.cfa --
//
// Author           : Peter A. Buhr
// Created On       : Sat Mar 16 15:30:34 2019
// Last Modified By : Peter A. Buhr
// Last Modified On : Thu Aug 15 18:45:45 2024
// Update Count     : 96
//

#include <fstream.hfa>
#include <coroutine.hfa>

enum Status { CONT, MSG, ESTX, ELNTH, ECRC };

coroutine Driver {
        Status status;
        char * msg, byte;
}; // Driver

void ?{}( Driver & d, char * m ) { d.msg = m; }                 // constructor

Status next( Driver & d, char b ) with( d ) {                   // called by interrupt handler
        byte = b; resume( d ); return status;                           // resume coroutine at last suspend
} // next

void checkCRC( Driver & d, unsigned int sum ) with( d ) {
        suspend;
        unsigned short int crc = byte << 8;                                     // sign extension over written
        suspend;
        // prevent sign extension for signed char
        status = (crc | (unsigned char)byte) == sum ? MSG : ECRC;
} // checkCRC

void main( Driver & d ) with( d ) {
        enum { STX = '\002', ESC = '\033', ETX = '\003', MaxMsg = 64 };
  msg: for () {                                                                                 // parse message
                status = CONT;
                unsigned int lnth = 0, sum = 0;
                while ( byte != STX ) suspend;
          emsg: for () {
                        suspend;
                        choose ( byte ) {                                                       // process byte
                          case STX:
                                status = ESTX; suspend; continue msg;
                          case ETX:
                                break emsg;
                          case ESC:
                                suspend;
                        } // choose
                        if ( lnth >= MaxMsg ) {                                         // buffer full ?
                                status = ELNTH; suspend; continue msg;
                        } // if
                        msg[lnth++] = byte;
                        sum += byte;
                } // for
                msg[lnth] = '\0';                                                               // terminate string
                checkCRC( d, sum );                                                             // refactor CRC check
                suspend;
        } // for
} // main

int main() {
        char msg[65], byte;
        Driver driver = { msg };

        sin | nlOn;                                                                                     // read newline (all) characters
        try {
                for () {                                                                                // read until end of file
                        sin | byte;                                                                     // read one character
                        choose( next( driver, byte ) ) {                        // analyse character
                          case CONT: ;
                          case MSG: sout | "msg:" | msg;
                          case ESTX: sout | "STX in message";
                          case ELNTH: sout | "message too long";
                          case ECRC: sout | "CRC failure";
                        } // choose
                } // for
        } catch( end_of_file * ) {
        } // try
} // main

// Local Variables: //
// compile-command: "cfa -g -Wall -Wextra devicedriver.cfa" //
// End: //