small_tel/Daemons/weatherdaemon/term.c

/*
 * This file is part of the weatherdaemon project.
 * Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <ctype.h>  // isspace
#include <stdio.h>
#include <string.h>
#include <strings.h> // strncasecmp
#include <time.h>    // time(NULL)
#include <limits.h>  // INT_MAX, INT_MIN
#include "term.h"
#include "cmdlnopts.h"

#define BUFLEN 1024

TTY_descr *ttydescr = NULL;
extern glob_pars *GP;

static char buf[BUFLEN];
static const char *emultemplate = "<?U> 06:50:36, 20.01.00, TE-2.20, DR1405.50, WU2057.68, RT0.00, WK1.00, WR177.80, WT-2.20, FE0.69, RE0.00, WG7.36, WV260.03, TI0.00, FI0.00,";

/**
 * read strings from terminal (ending with '\n') with timeout
 * @return NULL if nothing was read or pointer to static buffer
 */
static char *read_string(){
    //static int done = 0;
    if(GP->emul){
        //if(done) return NULL;
        strncpy(buf, emultemplate, BUFLEN);
        //done = 1;
        return buf;
    }
    if(!ttydescr) ERRX("Serial device not initialized");
    size_t r = 0, l;
    int LL = BUFLEN - 1;
    char *ptr = buf;
    double d0 = dtime();
    do{
        if((l = read_tty(ttydescr))){
            r += l; LL -= l; ptr += l;
            d0 = dtime();
        }
    }while(dtime() - d0 < WAIT_TMOUT && LL);
    if(r){
        buf[r] = 0;
        return buf;
    }
    return NULL;
}

/**
 * Try to connect to `device` at baudrate speed
 * @return 1 if OK
 */
int try_connect(char *device, int baudrate){
    if(!device) return 0;
    fflush(stdout);
    ttydescr = new_tty(device, baudrate, 1024);
    if(ttydescr) ttydescr = tty_open(ttydescr, 1); // exclusive open
    if(!ttydescr) return 0;
    while(read_tty(ttydescr)); // clear rbuf
    LOGMSG("Connected to %s", device);
    return 1;
}

/**
 * @brief getpar - get parameter value
 * @param string (i) - string where to search
 * @param Val (o)    - value found
 * @param Name       - parameter name
 * @return 0 if found
 */
static int getpar(char *string, double *Val, char *Name){
    char *p = strstr(string, Name);
    if(!p) return 1;
    p += strlen(Name);
    DBG("search %s", Name);
    if(!Val) return 0;
    char *endptr;
    *Val = strtod(p, &endptr);
    DBG("eptr=%s, val=%g", endptr, *Val);
    if(endptr == string){
        WARNX("Double value not found");
        return 2;
    }
    return 0;
}


/**
 * Poll serial port for new dataportion
 * @return: NULL if no data received, pointer to string if valid data received
 */
char *poll_device(){
    static char ans[BUFLEN];
    char *ptr = ans, *r = NULL;
    if(!GP->emul){
        if(write_tty(ttydescr->comfd, "?U\r\n", 4))
            return NULL;
    }
    double t0 = dtime();
    while(dtime() - t0 < T_POLLING_TMOUT){
        if((r = read_string())){ // parse new data
            DBG("got %s", r);
            if(strncmp(r, "<?U>", 4)){
                WARNX("Wrong answer");
                LOGWARN("poll_device() get wrong answer: %s", r);
                return NULL;
            }
            r += 4;
            DBG("R=%s", r);
            while(*r){if(isspace(*r)) ++r; else break;}
            DBG("R=%s", r);
            char *eol = strchr(r, '\n');
            if(eol) *eol = 0;
            double d;
            size_t L = BUFLEN, l;
            if(!getpar(r, &d, "RT")){
                l = snprintf(ptr, L, "Rain=%g\n", d);
                if(l > 0){
                    L -= l;
                    ptr += l;
                }
            }
            if(!getpar(r, &d, "WU")){
                l = snprintf(ptr, L, "Clouds=%g\n", d);
                if(l > 0){
                    L -= l;
                    ptr += l;
                }
            }
            if(!getpar(r, &d, "TE")){
                l = snprintf(ptr, L, "Exttemp=%g\n", d);
                if(l > 0){
                    L -= l;
                    ptr += l;
                }
            }
            if(!getpar(r, &d, "WG")){
                l = snprintf(ptr, L, "Wind=%g\n", d/3.6);
                if(l > 0){
                    L -= l;
                    ptr += l;
                }
            }
            snprintf(ptr, L, "Time=%lld\n", (long long)time(NULL));
            DBG("Buffer: %s", ans);
            return ans;
        }
    }
    return NULL;
}