Variable to XML marshaling / unmarshaling.
davidgev
Posts: 9
Hi guys,
I have the following structure, that I want to serialize to XML and save to the file, which then can be deserialized and used as a simple variable. Here is the code:
I am using the following methods for serialization / deserialization of the variable into XML:
Please note that I have checked the return codes, and in all cases return value is [highlight]0 - OK[/highlight].
Note, that I have also tried with the encoding options, namely [highlight]XML_ENCODE_TYPES, XML_ENCODE_CHAR_AS_LIST, XML_ENCODE_LE[/highlight].
The encoded string is something like:
which doesn't contain the actual data.
Can you please help me on how to serialize / deserialize the above mentioned structured, [highlight]together with it's data[/highlight].
BTW: VARIABLE_TO_STRING didn't work either.
Sincerely,
David Gevorkyan
http://www.david-gevorkyan.com/
I have the following structure, that I want to serialize to XML and save to the file, which then can be deserialized and used as a simple variable. Here is the code:
DEFINE_TYPE
// Contains information for the specific year.
STRUCTURE _YearStruct
{
DOUBLE MONTHS[12]
}
DEFINE_VARIABLE
_YearStruct CURRENT_YEAR
// Some test data is filled.
// Year
CURRENT_YEAR.MONTHS[1] = 31.5
CURRENT_YEAR.MONTHS[2] = 18.7
CURRENT_YEAR.MONTHS[3] = 23.2
CURRENT_YEAR.MONTHS[4] = 21.2
CURRENT_YEAR.MONTHS[5] = 27.5
CURRENT_YEAR.MONTHS[6] = 13.5
CURRENT_YEAR.MONTHS[7] = 19.5
CURRENT_YEAR.MONTHS[8] = 14.1
CURRENT_YEAR.MONTHS[9] = 26.5
CURRENT_YEAR.MONTHS[10] = 23.5
CURRENT_YEAR.MONTHS[11] = 11.5
CURRENT_YEAR.MONTHS[12] = 18.5
I am using the following methods for serialization / deserialization of the variable into XML:
slReturn = VARIABLE_TO_XML(CURRENT_YEAR, dataToWrite, lPos, 0) slReturn = XML_TO_VARIABLE(CURRENT_YEAR, dataRead, lPos, 0)
Please note that I have checked the return codes, and in all cases return value is [highlight]0 - OK[/highlight].
Note, that I have also tried with the encoding options, namely [highlight]XML_ENCODE_TYPES, XML_ENCODE_CHAR_AS_LIST, XML_ENCODE_LE[/highlight].
The encoded string is something like:
<struct><array><name>MONTHS</name><curLength>0</curLength><encoded><style>be</style><size>8</size><data>0000000000803F ...
which doesn't contain the actual data.
Can you please help me on how to serialize / deserialize the above mentioned structured, [highlight]together with it's data[/highlight].
BTW: VARIABLE_TO_STRING didn't work either.
Sincerely,
David Gevorkyan
http://www.david-gevorkyan.com/
0
Comments
V2S works fine also; I use it all the time. There?s a pretty decent example in the help file.
If there is a DEV in a STRUCT I think one or more of the encoding/decoding methods has issues. I forget the exact details.
That's the XML_TO_VARIABLE to function which didn't work with structures/devices. Here's the thread: http://www.amxforums.com/showthread.php?t=4545.
From what it looks like to me, the length of the MONTHS[ ] array is 0. Might be an issue with the way the array is being filled. Might need to do a SET_LENGTH_ARRAY and REBUILD_EVENT() after it's filled.
--John
I assumed that the data posted:
0000000000803F ...
was the beginning of the values of MONTHS[] described in hex (which it might be), however, I can?t seem to decode it, even if I use SET_LENGTH_ARRAY.
Let?s change the DOUBLE to an INTEGER and use the following code:
DEFINE_DEVICE dvTP = 10001:1:0 DEFINE_TYPE STRUCTURE _YearStruct { INTEGER MONTHS[12] } DEFINE_VARIABLE _YearStruct CURRENT_YEAR _YearStruct ANOTHER_YEAR CHAR dataToWrite[500] DEFINE_START // Some test data is filled. // Year CURRENT_YEAR.MONTHS[1] = 31 CURRENT_YEAR.MONTHS[2] = 18 CURRENT_YEAR.MONTHS[3] = 23 CURRENT_YEAR.MONTHS[4] = 21 CURRENT_YEAR.MONTHS[5] = 27 CURRENT_YEAR.MONTHS[6] = 13 CURRENT_YEAR.MONTHS[7] = 19 CURRENT_YEAR.MONTHS[8] = 14 CURRENT_YEAR.MONTHS[9] = 26 CURRENT_YEAR.MONTHS[10] = 23 CURRENT_YEAR.MONTHS[11] = 11 CURRENT_YEAR.MONTHS[12] = 18 DEFINE_EVENT BUTTON_EVENT[dvTP,1] { PUSH: { VARIABLE_TO_XML(CURRENT_YEAR, dataToWrite, 1, 0) XML_TO_VARIABLE(ANOTHER_YEAR,dataToWrite, 1, 0) } }If you put CURRENT_YEAR, ANOTHER_YEAR, and dataToWrite into the debugger and then press button 1 you will see that ANOTHER_YEAR gets populated with the same data decoded from CURRENT_YEAR.
You will also see that dataToWrite =:
If you break the data into pieces you?ll see that:
$001F = 31 for month[1]
$0012 = 18 for month[2]
etc.
REBUILD_EVENT() doesn?t come into play at all since nothing has been done to the event table to warrant it.
SET_LENGTH_ARRAY is certainly something to keep in mind but I don?t ?think? it?s needed here (at least from an encode/decode standpoint.)
I?m more of a V2S/S2V kind of guy and I know I needed to use SET_LENGTH_ARRAY() in certain situations but I?d have to dig up so code to see where and why it was required.
I guess VARIABLE_TO_XML/XML_TO_VARIABLE has some additional flaws.
DEFINE_DEVICE dvTP = 10001:1:0 DEFINE_TYPE STRUCTURE _YearStruct { DOUBLE MONTHS[12] } DEFINE_VARIABLE _YearStruct CURRENT_YEAR _YearStruct ANOTHER_YEAR CHAR dataToWrite[500] DEFINE_START // Some test data is filled. // Year CURRENT_YEAR.MONTHS[1] = 31.5 CURRENT_YEAR.MONTHS[2] = 18.7 CURRENT_YEAR.MONTHS[3] = 23.2 CURRENT_YEAR.MONTHS[4] = 21.2 CURRENT_YEAR.MONTHS[5] = 27.5 CURRENT_YEAR.MONTHS[6] = 13.5 CURRENT_YEAR.MONTHS[7] = 19.5 CURRENT_YEAR.MONTHS[8] = 14.1 CURRENT_YEAR.MONTHS[9] = 26.5 CURRENT_YEAR.MONTHS[10] = 23.5 CURRENT_YEAR.MONTHS[11] = 11.5 CURRENT_YEAR.MONTHS[12] = 18.5 [b]SET_LENGTH_ARRAY(CURRENT_YEAR.MONTHS,12)[/b] DEFINE_EVENT BUTTON_EVENT[dvTP,1] { PUSH: { [b]VARIABLE_TO_STRING[/b](CURRENT_YEAR, dataToWrite, 1) [b]STRING_TO_VARIABLE[/b](ANOTHER_YEAR,dataToWrite, 1) } }After pressing button 1, ANOTHER_YEAR gets populated with the same data decoded from CURRENT_YEAR.
You will need to do a SET_LENGTH_ARRAY() as John noted earlier if you use VARIABLE_TO_STRING.
If you are using VARIABLE_TO_XML so that you can write it to file and then read/edit it be aware that:
A) You will not get a true XML file. The data is just one big-a*s string formatted with tags.
The following code will give you the look I think you want for you XML output:
DEFINE_DEVICE dvTP = 10001:1:0 DEFINE_TYPE STRUCTURE _YearStruct { CHAR MONTHS[12][4] } DEFINE_VARIABLE _YearStruct CURRENT_YEAR _YearStruct ANOTHER_YEAR CHAR dataToWrite[1500] DEFINE_START // Some test data is filled. // Year CURRENT_YEAR.MONTHS[1] = '31.5' CURRENT_YEAR.MONTHS[2] = '18.7' CURRENT_YEAR.MONTHS[3] = '23.2' CURRENT_YEAR.MONTHS[4] = '21.2' CURRENT_YEAR.MONTHS[5] = '27.5' CURRENT_YEAR.MONTHS[6] = '13.5' CURRENT_YEAR.MONTHS[7] = '19.5' CURRENT_YEAR.MONTHS[8] = '14.1' CURRENT_YEAR.MONTHS[9] = '26.5' CURRENT_YEAR.MONTHS[10] = '23.5' CURRENT_YEAR.MONTHS[11] = '11.5' CURRENT_YEAR.MONTHS[12] = '18.5' DEFINE_EVENT BUTTON_EVENT[dvTP,1] { PUSH: { VARIABLE_TO_XML(CURRENT_YEAR, dataToWrite, 1,0) XML_TO_VARIABLE(ANOTHER_YEAR,dataToWrite, 1,0) } }After pressing button 1 you will also see that dataToWrite =:
Hope some of this helps.
This may seem a like a waste of time, but the time I spent doing this is nowhere near the time I wasted tracking down the flaws in the built-in methods and the troubleshooting I went through figuring out the the problem was with an internal function, not my code.
Jeff
That said though, I?d be lost without V2S/S2V. I use it extensively for passing structures into and out of modules. If you can deal with the additional memory overhead involved V2S and S2V are awesome.
Wierd, I must not have hit the post button correctly yesterday... one of my posts is missing. The reason I was thinking the month array was 0 was because the Netlinx marshalling protocol for arrays is supposed to include all of those index tags which were missing from the original xml file the OP posted. You got them to appear in your last iteration.
In the thread I linked earlier, rgelling mentioned that firmware 3.41.422 fixed some of the issues with xml_to_variable. Were you or davidgev using the latest firmware? Having those guys watching the forums give me more confidence that those issues can get taken care of quickly. I'm with you guys on this though, xml_to_variable makes me nervous given it's history. V2S and S2V seems to work better.
--John
Hi guys,
Thanks a lot for your help and sorry for the late reply (was busy with demo preparation).
John, my controller is also using v3.41.414 firmware.
I have actually made the code work, and basically the following changes were done:
I have added [highlight]SET_LENGTH_ARRAY[/highlight] calls.
Also have changed the array type from [highlight]DOUBLE[/highlight] to [highlight]FLOAT[/highlight].
Please note, that I am still using the [highlight]VARIABLE_TO_XML / XML_TO_VARIABLE[/highlight] serialization / deserialization methods.
Again, thanks for the help.
Sincerely,
David Gevorkyan
http://www.david-gevorkyan.com/
Thanks for letting us know.