File content as of revision 13:ffeff9b5e513:

#include "mbed.h"
#include "IothubSerial.h"
#include "crt_abstractions.h"

const char* nametemp = "temp";
const char* namevolt = "volt";
const char* namedeg = "rot";
const char* nameload = "load";

IothubSerial::IothubSerial()
{
    _hasPending = false;
}

// try to serialize the measurements into the buffer
// return bytes used or -1 if buffer too small or other error
// current serialization is a json array with ',' at end
//  eg: temp: [22.0, 23.1, 22.3],
int IothubSerial::MeasureGroupToString(MeasureGroup& mg, char* buf, int bufsize)
{
    const char* name;
    int slen;
    int startlen = bufsize;
    
    switch (mg.MeasId)
    {
        case NM_Temperature:
            name = nametemp;
            break;
            
        case NM_Voltage:
            name = namevolt;
            break;
            
        case NM_Degrees:
            name = namedeg;
            break;
            
        case NM_Load:
            name = nameload;
            break;
            
        default:
            return -1;
    }
    
    slen = sprintf_s(buf, bufsize, "\"%s\": [", name);
    if (slen > 0)
    {
        bufsize -= slen;
        buf += slen;
    }
    else
        return -1;
       
    for (int i = 0; i < mg.NumVals; i++)
    {
        if (i < mg.NumVals - 1)
            slen = sprintf_s(buf, bufsize, "%.2f, ", mg.MeasVals[i]);
        else
            slen = sprintf_s(buf, bufsize, "%.2f ", mg.MeasVals[i]);
        if (slen > 0)
        {
            bufsize -= slen;
            buf += slen;
        }
        else
            return -1;
    }
    
    slen = sprintf_s(buf, bufsize, "],");
    if (slen > 0)
    {
        bufsize -= slen;
        buf += slen;
    }
    else
        return -1;
    
    return startlen - bufsize;
}

int AddTime(time_t seconds, char* buf, int bufsize)
{
    if (bufsize > 32)
    {
        int slen = strftime(buf, 32, "\"time\": \"%FT%T\",", localtime(&seconds));
        if (slen > 0)
        {
            return slen;
        }
        else
            return -1;
    }        
    else
        return -1;
}

// try to serialize one or more measurements into the buffer
// return bytes used / -1 if buffer too small / 0 if no data
// current serialization is a json array of objects with time and array per measure
// eg: [{ "time": "2016-01-23T14:55:02", "temp": [1, 2], "volt": [12.1, 12.2] }]
int IothubSerial::MeasureBufToString(char* buf, int bufsize)
{
    int slen;
    bool hasdata = false;
    bool copydata = false;
    char* startbuf = buf;
    bool settime = false;
    char* lastcomma = NULL;
    
    time_t secs = 0;
    // reserve 1 space for end
    bufsize--;
    
    slen = sprintf_s(buf, bufsize, "[{");
    if (slen > 0)
    {
        bufsize -= slen;
        buf += slen;
    }
    else
        return -1;
 
    if (_hasPending)
    {
        hasdata = true;
        secs = _pending.Created;
        slen = AddTime(secs, buf, bufsize);
        if (slen > 0)
        {
            bufsize -= slen;
            buf += slen;
            settime = true;
        }
        else
            return -1;          // no room for pending record

        slen = MeasureGroupToString(_pending, buf, bufsize);
        if (slen > 0)
        {
            bufsize -= slen;
            buf += slen;
            lastcomma = buf;
            _hasPending = false;
            copydata = true;
        }
        else
            return -1;          // no room for pending record
    }
    
    while (!MeasureBuf.empty())
    {
        if (!MeasureBuf.pop(_pending))
        {
            break;
        }
        hasdata = true;
        _hasPending = true;
        
        if (secs != _pending.Created)
        {
            if (settime && lastcomma != NULL)
            {
                *(lastcomma - 1) = '}';
                if (bufsize > 2)
                {
                    strcpy(buf, ",{");
                    buf += 2;
                    bufsize -= 2;
                }
            }
            secs = _pending.Created;
            slen = AddTime(secs, buf, bufsize);
            if (slen > 0)
            {
                bufsize -= slen;
                buf += slen;
                settime = true;
            }
            else
                break;
        }
        
        slen = MeasureGroupToString(_pending, buf, bufsize);
        if (slen > 0)
        {
            bufsize -= slen;
            buf += slen;
            lastcomma = buf;
            _hasPending = false;
            copydata = true;
        }
        else
            break;              // no room to serialize, leave pending for next message
    }
    
    if (!hasdata)
        return 0;               // no data
        
    if (!copydata)
        return -1;              // have data but buffer too small

    // replace final ',' with '}'
    *(lastcomma - 1) = '}';
    // this is the extra space we reserved at the start.
    *(lastcomma) = ']';
    lastcomma++;
    
    return lastcomma - startbuf;
}


// try to serialize one or more alerts into the buffer
// return bytes used or -1 if buffer too small or other error. 0 if no data
// Serialize to a json object with time, measurename, value, message, and index of joint
// eg: { "alerttype": "Temperature", "message": "too hot", "measurename", "temp", "index": 2, "value": 79.3, "time": "2016-01-23T14:55:02" }
int IothubSerial::AlertBufToString(char* buf, int bufsize)
{
    int slen;
    bool hasdata = false;
    bool copydata = false;
    int startlen = bufsize;
 
    if (AlertBuf.pop(_pendAlert))
    {
        char tbuf[32];
        (void)strftime(tbuf, 32, "%FT%T", localtime(&_pendAlert.Created));
        hasdata = true;
        slen = sprintf_s(buf, bufsize, "{ \"alerttype\": \"%s\", \"message\": \"%s\", \"measurename\": \"%s\",  \"index\": %d ,  \"value\": %f, \"time\": \"%s\" }", 
                                            _pendAlert.AlertType, _pendAlert.Msg, _pendAlert.MeasureName, _pendAlert.Index, _pendAlert.Value, tbuf);
        if (slen > 0)
        {
            bufsize -= slen;
            buf += slen;
            copydata = true;
        }
    }
    
    if (!hasdata)
        return 0;               // no data
        
    if (!copydata)
        return -1;              // have data but buffer too small


    return startlen - bufsize;
}

bool IothubSerial::HasMeasureGroup()
{
    return _hasPending;
}