| 1 | //
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
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| 3 | //
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| 4 | // The contents of this file are covered under the licence agreement in the
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| 5 | // file "LICENCE" distributed with Cforall.
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| 6 | //
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| 7 | // devicedriver.cfa --
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| 8 | //
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| 9 | // Author : Peter A. Buhr
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| 10 | // Created On : Sat Mar 16 15:30:34 2019
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| 11 | // Last Modified By : Peter A. Buhr
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| 12 | // Last Modified On : Tue Mar 19 15:59:06 2019
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| 13 | // Update Count : 87
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| 14 | //
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| 15 |
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| 16 | #include <fstream.hfa>
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| 17 | #include <coroutine.hfa>
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| 18 |
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| 19 | enum Status { CONT, MSG, ESTX, ELNTH, ECRC };
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| 20 | coroutine Driver {
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| 21 | Status status;
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| 22 | char * msg, byte;
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| 23 | }; // Driver
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| 24 |
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| 25 | void ?{}( Driver & d, char * m ) { d.msg = m; }
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| 26 | Status next( Driver & d, char b ) with( d ) {
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| 27 | byte = b; resume( d ); return status;
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| 28 | } // next
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| 29 |
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| 30 | void checkCRC( Driver & d, unsigned int sum ) with( d ) {
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| 31 | suspend();
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| 32 | unsigned short int crc = byte << 8; // sign extension over written
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| 33 | suspend();
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| 34 | // prevent sign extension for signed char
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| 35 | status = (crc | (unsigned char)byte) == sum ? MSG : ECRC;
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| 36 | } // checkCRC
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| 37 |
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| 38 | void main( Driver & d ) with( d ) {
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| 39 | enum { STX = '\002', ESC = '\033', ETX = '\003', MaxMsg = 64 };
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| 40 | msg: for () { // parse message
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| 41 | status = CONT;
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| 42 | unsigned int lnth = 0, sum = 0;
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| 43 | while ( byte != STX ) suspend();
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| 44 | emsg: for () {
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| 45 | suspend();
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| 46 | choose ( byte ) { // process byte
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| 47 | case STX:
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| 48 | status = ESTX; suspend(); continue msg;
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| 49 | case ETX:
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| 50 | break emsg;
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| 51 | case ESC:
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| 52 | suspend();
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| 53 | } // choose
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| 54 | if ( lnth >= MaxMsg ) { // buffer full ?
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| 55 | status = ELNTH; suspend(); continue msg;
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| 56 | } // if
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| 57 | msg[lnth++] = byte;
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| 58 | sum += byte;
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| 59 | } // for
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| 60 | msg[lnth] = '\0'; // terminate string
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| 61 | checkCRC( d, sum ); // refactor CRC check
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| 62 | suspend();
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| 63 | } // for
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| 64 | } // main
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| 65 |
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| 66 | int main() {
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| 67 | char msg[65], byte;
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| 68 | Driver driver = { msg };
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| 69 | eof: for () { // read until end of file
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| 70 | sin | byte; // read one character
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| 71 | if ( eof( sin ) ) break eof; // eof ?
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| 72 | choose( next( driver, byte ) ) { // analyse character
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| 73 | case MSG:
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| 74 | sout | "msg:" | msg;
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| 75 | case ESTX:
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| 76 | sout | "STX in message";
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| 77 | case ELNTH:
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| 78 | sout | "message too long";
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| 79 | case ECRC:
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| 80 | sout | "CRC failure";
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| 81 | default: ;
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| 82 | } // choose
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| 83 | } // for
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| 84 | } // main
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| 85 |
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| 86 | // Local Variables: //
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| 87 | // tab-width: 4 //
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| 88 | // compile-command: "cfa -g -Wall -Wextra devicedriver.cfa" //
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| 89 | // End: //
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