I am new to the CAN-BUS protocol. So was going through the CAN Bus Specifications and related documents.
I have always used the CAN ID and Frame at the application level.
CANID like 0x1a1 CAN Frame like ff 22 ff 33 co 33 ee 44 (8 bytes).
In the specification, they mentioned that the Frame consists of identifier field.
I doubt what is that.
Is that the CAN ID like 0x1a1 or CAN ID + some other stuff.
No documents mentioned that clearly.
If that is not CAN ID.. Where is CAN-ID in CAN Format.
Can anyone clarify that doubt?
In short, a single CAN message consists of CANID, the CAN data and other stuffs,
https://en.wikipedia.org/wiki/CAN_bus#Data_frame
Related
I am reading an ogg audio file header and am having some difficulty understanding how to compute the location of the next ogg file segment. i was able to use this webpage as an example: https://www.file-recovery.com/ogg-signature-format.htm using this example.ogg file i was able to compute the right locations of the oggs headers.
BUT... in the example link, at offset (dec) 128 + 1 there is FF FF FF FF FF FF FF FF FF FF FF FF B6 and calculating this is simple, 12*255 = 3060, 3060 + 182 (hex B6) = 3242, 3242 + 1 + 13 + 128 = 3384. so from the start of the last read header 0x3A (dec 58), if i seek a total of 3384 bytes, i am exactly at the spot of the next ogg file header.
now, where my problem comes in is this. in a real ogg/opus file, the values to calculate where the next ogg header are slightly confusing me. here is an image hopefully it will make it a little easier to get my problem across.
i am not sure how to proceed here. 0x48 = dec 72. so i would assume that there are 72 records here that are 3 bytes long each? that doesnt make sense. Or would it be 72 records, and the 0x03 at offset 0xAC is just part of the calculation? this is confusing to me, and i am not sure if i am asking the question right. but what i am trying to do is just parse the whole ogg file from top to bottom. im not looking to do any sort of processing at each header (yet) and i just need to fogire out the correct way to calculate these ogg header/segment location. if i need to elaborate on anything please ask and i will do my best. thanks in advance
i was able to figure this out. was just a simple misunderstanding on my part. when you read (as in the example above) 0x48 = dec 72. next add current position in file, then add 72 to that, then add/sum the next 72 characters, whatever they may be. this will give you the offset ((from the beginning of the file) of the next ogg entry
The powerball schema and separators are not consistent which makes it an unusual file to read. (http://www.powerball.com/powerball/winnums-text.txt)
Sample:
Draw Date WB1 WB2 WB3 WB4 WB5 PB PP
09/24/2016 15 07 29 41 20 22 2
09/21/2016 63 67 01 69 28 17 4
09/17/2016 51 19 09 62 55 14 4
Any suggestions?
This looks like a "fixed column width" file rather than an ordinary CSV (meaning that the columns are not separated by any single character, but instead have fixed number of characters, with padding spaces).
There is some early work on supporting this in F# Data in the pull request here. We'd welcome any help getting this tested - but you'd need to get the soruce code and build F# Data from source (which is just a matter of running the build script though!)
Alternatively, you could probably do some simple pre-processing on the file before reading it as an ordinary CSV file. Looking at the sample file, using a regular expression to replace 1 or more spaces with a comma would produce regular CSV that the CSV provider can consume.
With a Postscript driver (Xerox, Canon, HP, all), when I create a PS file, for example when I print the test page in the printer properties, I get :
OK :
The view of the result is correct (with GSview for example)
Not OK :
The file size is to big, more than 4 MB.
When I edit the file, I have one big image (doNimage). I think is the reason of the big size file.
The example file : https://drive.google.com/open?id=0B9bet657DEU5alV6WFZZdDFjMmc
I'm on Windows 10, similar problem with Windows server 2012 r2.
I let the configuration of the driver by default.
Anyone has an idea ?
Thanks a lot.
Regards.
I don't understand your problem, the file you posted a link to contains text. Here's an example:
360 4485 M <202530360E0F1102381030100D100B0824152D30103102020C302A1E19181B1E1730132E28301530132D3B02230B2A2E22081308>[46 16 28 70 18 42 44 44 54 32 28 32 36 32 25 39 65 40 40 28 32 44 44 44 18 28 53 45 20 47 38 45
40 28 34 40 40 28 40 28 34 40 18 44 44 25 53 40 16 39 34 0]xS
M is a moveto and xS uses the xshow operator to draw the glyphs represented by the character codes in the hexstring, using the values in the array to modify the width of each glyph.
If you were expecting to see ASCII character codes you are going to be sadly disappointed, the files uses an incrementally downloaded subset TrueType font, so the character codes are defined as they are encountered, that is the first glyph used will be given character code 1, the second will be character code 2 and so on.
Even without that, using ASCII would limit the languages that could be supported. Back in the 1980s that maybe didn't seem like a problem, but its a long time since that was considered acceptable.
If you were expecting to be able to modify the text by editing it in a text editor, forget it. PostScript is a programming language, and the output of a PostScript printer driver is a machine-generated program. Its a lengthy process for a skilled user of the language to decipher what the program is doing. The program is not amenable to alteration, if there's a fault in the output, correct the original document and recreate the PostScript program from the original.
PostScript is not an editable format.
Thanks all for your response. I see I was not very clear in my question.
Here is the state :
With the PS driver, on a windows server 2008, I get this file :
http://expirebox.com/download/0bb511565377e8b74eead67641fe7f68.html
Inside the file I can see the text "Page de test d\222imprimante"
On a Windows server 2012 R2 :
http://expirebox.com/download/60fa957cba97c82bbcd5c0e975825b52.html
I can't see any text. It's a printer page test too.
I need to see text because I'll print document with code inside. Code for a printer to identify page type. (for example a white page for the tray n° 1, yellow page for tray 2)
KenS : I understand your point. But why the same driver give different file.
I checked if it's really the same. The only difference I see is the OS, one x86, the other x64.
Thanks.
Regards.
I would like to parse files with several sequences of data (same number of column, same content, ...) with Haskell.
My data sequences will be delimited by keywords before and after.
BEGIN
1 882
2 809
3 435
4 197
5 229
6 425
...
END
BEGIN
1 235 623 684
2 871 699 557
3 918 686 49
4 53 564 906
5 246 344 501
6 929 138 474
...
END
My problem is that after several tests with Parsec, I have the impression that Parsec is rather made to parse a file line by line and not the whole file.
Is Parsec the right way to make what I want or should I consider an other tool like Happy or Alex ?
Is there a website (or other ressource) providing examples of parsing complex text files with Parsec ?
Note : The example I give is a very simple one. Things would be more tricky in my files with many more keywords and combinations.
The format as you've described wouldn't be hard at all to handle in parsec.
As for learning how to use it: your first step should be to avoid whatever guide gave you the impression that parsec worked line-by-line. I recommend Chapter 16 of Real World Haskell as a good place to get started, and once you're comfortable with the basics the reference material at http://hackage.haskell.org/package/parsec is actually very clear.
Here is a sample of my CSV
10820 0 0 0 0
10900 2 4 4 4
11000 21 50 54 58
11100 23 54 59 63
11200 25 59 63 68
11300 27 63 68 73
11400 29 68 73 78
11500 31 72 78 83
11600 32 76 82 88
11700 34 81 87 93
I'm looking to create to use xcode to retreive one line of code from this very lengthy CSV based on the first line.
For example:
if the user enters "10900", the second line columns will be returned.
If the user returns 11650, the 11600 line columns will be returned...always taking the lower line when the input value is less then the following line.
Any help would be appreciated. I've seen code to parse an entire CSV file, but I'm thinking this may be a big memory drain, right now my CSV has 2000 lines of values, which are all in ascending order based on the first column.
You have to load a file into memory anyways to find correct value.
With such a big CSV file I would recommend to turn CSV file into binary file (plist file for example) and put it as binary into your application - instead of parsing it each time in RunTime. It has much better performance and it's easier to work with that since you are working directly with NSDictonaries an NSArrays.
If you don't want to do it for some reason, the next solution is to use something like CHCSVParser:
https://github.com/davedelong/CHCSVParser
It provides optimization for loading only part of file at a time - which is the optimization you might be looking for.