Problem with Read Serial & CHOP$

[alexfish]

Hi Peter

I updated bacon to latest fossil a few days ago

I have a function to read read gps data, this was working but now have a problem

some code from inside the Function , exception been first 3 lines , they work

A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

OPEN "/dev/ttyACM0" FOR DEVICE AS myserial2

SETSERIAL myserial2 SPEED B38400
SETSERIAL myserial2 IMODE ~IGNBRK
SETSERIAL myserial2 CMODE ~CSIZE
SETSERIAL myserial2 CMODE CS8
SETSERIAL myserial2 CMODE ~PARENB
SETSERIAL myserial2 CMODE ~CSTOPB
'SETSERIAL myserial2 LMODE ICANON
'SETSERIAL myserial2 OTHER VMIN = 0
'SETSERIAL myserial2 OTHER VTIME = 5

WHILE 1 DO
data = MEMORY(1024)
GETBYTE data FROM myserial2 CHUNK 1024 SIZE received
A$ = data
PRINT "READ : " ,A$
IF LEN(A$) THEN
FREE data
A$ = CHOP$(A$)& "\r\n"
PRINT "CHOPPED : " , A$
END
END IF

WEND


Results

./chop
$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77

READ : $GPRMC,170948.00,A,5457.94674,N,00134.33117,W,0.166,,140922,,,A*66

CHOPPED : 0948.00,A,5457.94674,N,00134.33117,W,0.166,,140922,,,A*66

BR
Alex

[bigbass]

Hello Alex

checked the read part of your code
without connecting to a real "serial port"
the idea is the same though

'---simulate a serial device reading data
HOME$ = GETENVIRON$("HOME")

'---un zip in home directory for testing
OPEN HOME$ &"/GPS_DATA/output .nmea" FOR READWRITE AS myserial2



generated a test file from here www.nmeagen.org/

unzip the file place the whole folder in home
then compile and run the demo

I don't know why you only get partial output
your code works!
GPS_DATA.tar.gz (747 B)

Joe




$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77

READ : $GPGGA,044351.241,5230.249,N,01326.372,E,1,12,1.0,0.0,M,0.0,M,,*65
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044351.241,A,5230.249,N,01326.372,E,1814.8,110.5,150922,000.0,W*4D
$GPGGA,044352.241,5229.986,N,01327.078,E,1,12,1.0,0.0,M,0.0,M,,*6E
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044352.241,A,5229.986,N,01327.078,E,4627.8,111.4,150922,000.0,W*4D
$GPGGA,044353.241,5229.293,N,01328.855,E,1,12,1.0,0.0,M,0.0,M,,*68
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044353.241,A,5229.293,N,01328.855,E,661.4,085.2,150922,000.0,W*7B
$GPGGA,044354.241,5229.318,N,01329.153,E,1,12,1.0,0.0,M,0.0,M,,*63
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044354.241,A,5229.318,N,01329.153,E,661.4,085.2,150922,000.0,W*70

CHOPPED : 4351.241,5230.249,N,01326.372,E,1,12,1.0,0.0,M,0.0,M,,*65
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044351.241,A,5230.249,N,01326.372,E,1814.8,110.5,150922,000.0,W*4D
$GPGGA,044352.241,5229.986,N,01327.078,E,1,12,1.0,0.0,M,0.0,M,,*6E
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044352.241,A,5229.986,N,01327.078,E,4627.8,111.4,150922,000.0,W*4D
$GPGGA,044353.241,5229.293,N,01328.855,E,1,12,1.0,0.0,M,0.0,M,,*68
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044353.241,A,5229.293,N,01328.855,E,661.4,085.2,150922,000.0,W*7B
$GPGGA,044354.241,5229.318,N,01329.153,E,1,12,1.0,0.0,M,0.0,M,,*63
$GPGSA,A,3,01,02,03,04,05,06,07,08,09,10,11,12,1.0,1.0,1.0*30
$GPRMC,044354.241,A,5229.318,N,01329.153,E,661.4,085.2,150922,000.0,W*70

[Pjot]

Hi Alex,

I could reproduce your problem with the following code, where the file "data.txt" contains the new string:

A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

data = BLOAD("data.txt")
A$ = data
PRINT "READ : " ,A$

IF LEN(A$) THEN
   A$ = CHOP$(A$) & "\r\n"
   PRINT "CHOPPED : " , A$
   'FREE data
   END
END IF


Output:

$ ./debug
$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77

READ : $GPRMC,170948.00,A,5457.94674,N,00134.33117,W,0.166,,140922,,,A*66

CHOPPED : 0948.00,A,5457.94674,N,00134.33117,W,0.166,,140922,,,A*66


The code itself looks pretty harmless, but it shows the same error. The reason for this is the following line:

A$ = data


You cannot just assign a string variable to a memory address. The memory checker Valgrind also complains at exact this line:

==5729== Invalid read of size 1
==5729==    at 0x484ED24: strlen (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5729==    by 0x4A01602: strdup (strdup.c:41)
==5729==    by 0x10A708: __b2c__strdup (debug.bac.functions.h:409)
==5729==    by 0x10C24D: main (debug.bac.c:48)
==5729==  Address 0x4b839a3 is 0 bytes after a block of size 67 alloc'd
==5729==    at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5729==    by 0x10AE59: __b2c__load (debug.bac.functions.h:578)
==5729==    by 0x10C1F8: main (debug.bac.c:45)


If you assign a memory address with a blob of binary data to a string variable, then BaCon will assume it is a string, meaning, the binary data is terminated with a '0' byte. But in your case, the binary data does not end with such a '0' byte, and therefore, we see this error.

The problem comes to light in the latest beta because of the optimized string concatenation, which handles the "&" differently.

So how to transfer the binary data to a string variable correctly? You can use memory streams for this. This will put a proper '0' byte at the end of the binary data. My sample code should look like:

OPTION MEMSTREAM TRUE

A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

data = BLOAD("data.txt")

' Open the binary data as a textual stream
OPEN data FOR MEMORY AS text

' Put the data into the variable A$
GETLINE A$ FROM text

PRINT "READ : " ,A$

IF LEN(A$) THEN

A$ = CHOP$(A$) & "\r\n"
PRINT "CHOPPED : " , A$
END
END IF

CLOSE MEMORY text
FREE data

END


By opening the binary data as a textual memory stream we can safely put the contents into the string variable A$.

So your code should look something like this:

OPTION MEMSTREAM TRUE

A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

OPEN "/dev/ttyACM0" FOR DEVICE AS myserial2

SETSERIAL myserial2 SPEED B38400
SETSERIAL myserial2 IMODE ~IGNBRK
SETSERIAL myserial2 CMODE ~CSIZE
SETSERIAL myserial2 CMODE CS8
SETSERIAL myserial2 CMODE ~PARENB
SETSERIAL myserial2 CMODE ~CSTOPB
'SETSERIAL myserial2 LMODE ICANON
'SETSERIAL myserial2 OTHER VMIN = 0
'SETSERIAL myserial2 OTHER VTIME = 5

WHILE 1 DO
memory_chunk = MEMORY(1024)
GETBYTE memory_chunk FROM myserial2 CHUNK 1024 SIZE received

OPEN memory_chunk FOR MEMORY AS data
GETLINE A$ FROM data

PRINT "READ : " ,A$
IF LEN(A$) THEN
A$ = CHOP$(A$)& "\r\n"
PRINT "CHOPPED : " , A$
END
END IF
CLOSE MEMORY memory_chunk
FREE data
WEND


HTH
Peter

[bigbass]

Hello Alex and Peter


thanks Peter for explaining the why
and offering a bacon solution


I tested live gps data sent from my phone before
which gives the AIS data for testing

today I ported a c code gps reader app
to read the gps data from a localhost on port 2947
here sourceforge.net/p/bacon-qt5/wiki/gps_from_localhost/

now that is baconized it can be modified to anyway that
seems fit

why ? if you don't have all the AIS equipment
it is difficult to test any software
so I simulated the AIS device
and it works on the RPI3



Joe

[alexfish]

Hi Peter

on Compile - get warnings

WARNING: no FREE for the memory address 'memory_chunk' at line 18 in file '/home/pi/maps/chop.bac'!
WARNING: no CLOSE for the OPEN handle 'data' at line 21 in file '/home/pi/maps/chop.bac'!
/home/pi/maps/chop.bac:28:14: warning: assignment to 'long int' from 'void *' makes integer from pointer without a cast [-Wint-conversion]

Execute?

Have tried FREE , but get :
FREE memory_chunk
Runtime error: statement 'FREE' at line 30 in '/home/pi/maps/chop.bac': Trying to access illegal memory: Socket operation on non-socket

FREE data
munmap_chunk(): invalid pointer
ERROR: signal ABORT received - internal error. Try to compile the program with TRAP LOCAL to find the cause

if no frees then CHOP is as it should be

the code in use


A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

OPEN "/dev/ttyACM0" FOR DEVICE AS myserial2

SETSERIAL myserial2 SPEED B38400
SETSERIAL myserial2 IMODE ~IGNBRK
SETSERIAL myserial2 CMODE ~CSIZE
SETSERIAL myserial2 CMODE CS8
SETSERIAL myserial2 CMODE ~PARENB
SETSERIAL myserial2 CMODE ~CSTOPB
'SETSERIAL myserial2 LMODE ICANON
'SETSERIAL myserial2 OTHER VMIN = 0
'SETSERIAL myserial2 OTHER VTIME = 5

WHILE 1 DO
memory_chunk = MEMORY(1024)
GETBYTE memory_chunk FROM myserial2 CHUNK 1024 SIZE received

OPEN memory_chunk FOR MEMORY AS data
GETLINE A$ FROM data

PRINT "READ : " ,A$
IF LEN(A$) THEN
A$ = CHOP$(A$)& "\r\n"
PRINT "CHOPPED : " , A$
CLOSE MEMORY memory_chunk
CLOSE DEVICE myserial2
'FREE memory_chunk
'FREE data
BREAK

END IF

WEND

??

BR
Alex

[Pjot]

Hi Alex,

Sorry, I made a typo during pasting the code, the FREE and CLOSE are swapped. It should be this:

OPTION MEMSTREAM TRUE

A$ = "$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77"  & NL$
A$ = CHOP$(A$) & "\r\n"
PRINT A$

OPEN "/dev/ttyACM0" FOR DEVICE AS myserial2

SETSERIAL myserial2 SPEED B38400
SETSERIAL myserial2 IMODE ~IGNBRK
SETSERIAL myserial2 CMODE ~CSIZE
SETSERIAL myserial2 CMODE CS8
SETSERIAL myserial2 CMODE ~PARENB
SETSERIAL myserial2 CMODE ~CSTOPB
'SETSERIAL myserial2 LMODE ICANON
'SETSERIAL myserial2 OTHER VMIN = 0
'SETSERIAL myserial2 OTHER VTIME = 5

WHILE 1 DO
memory_chunk = MEMORY(1024)
GETBYTE memory_chunk FROM myserial2 CHUNK 1024 SIZE received

OPEN memory_chunk FOR MEMORY AS data
GETLINE A$ FROM data

PRINT "READ : " ,A$
IF LEN(A$) THEN
A$ = CHOP$(A$)& "\r\n"
PRINT "CHOPPED : " , A$
END
END IF
CLOSE MEMORY data  :' <------- swapped variables here
FREE memory_chunk
WEND


HTH
Peter

[alexfish]

Hi Peter

all is good

result from out

./chop
$GPGLL,5457.94624,N,00134.32928,W,165657.00,A,A*77

READ : $GPRMC,080600.00,A,5457.94716,N,00134.33253,W,0.040,,160922,,,A*6A
CHOPPED : $GPRMC,080600.00,A,5457.94716,N,00134.33253,W,0.040,,160922,,,A*6A

Thank again

BR
Alex

[alexfish]

Hi Joe

with reference to the BaCon code libgps & gpsd

a bit of the out

Fix mode: 3D (3) Time: 1663422383.000000000 Lat 54.965761 Lon -1.572177
Fix mode: 3D (3) Time: 1663422383.000000000 Lat 54.965761 Lon -1.572177

just kind of wondering RE QT widgets & maps

have you tried

qt map (plugin) + the libgps has a QT interface
HERE
both clib and qlib can decode ais as well as the gps positions etc

thanks for to your code and noted the link to the experimental coding forum , its been a while
and could not find the link
experimental-coding.freeforums.net/

BR
Alex

[bigbass]

Hello Alex


thanks
I will make a demo code example for a map using Qt5
it will also be my first go at using QML and imports
lets see what happens ...

on the c code side of things I went over the code line by line
and baconized it even more and simplified the reading of the code
using macros so if we need to use it with bacon code
the gps part works nicely to display the real gps data

that is the gps_baconized

hope something could be useful
for your project

thanks


Joe

[bigbass]

hello Alex and Peter


Alex the Qt5 map works
took some time sorting out all the stuff needed
and adjusting the import versions
and working with qml and qrc files
still thinking how to bundle all that and port it to bacon
for a demo

but anyway ...here is some salty water in your part of the world
its working in QT5!

I got the DD COORDINATES here (they work in the qml code)
latitude.to/map/gb/united-kingdom/cities/dover

then had to hard code the COORDINATES into the qml code then compile it
maybe there is a way to do it dynamically still looking





the links were very useful!
thanks
Joe