Inserting NULLs into a message....

Erel

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• Mar 15, 2012

• #2

Byte cannot be null. It is a number. You should probably put 0.

 

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P

PaulR

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• Mar 15, 2012

• #3

Yes, that makes sense. What would be the syntax for appending values into a Byte? I am doing this...

B4X:

Dim data() As Byte
data = "/foo".0.0.0.0.GetBytes("UTF8")

... but getting a syntax error (works without the zeros).

 

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J

Jost aus Soest

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• Mar 15, 2012

• #4

GetBytes works only on strings and results in an byte array.

For example you could do something like this:

B4X:

Dim data() As Byte
data = "/foo....".GetBytes("UTF8")  '<-- "." as placeholder
data(4) = 0
data(5) = 0
data(6) = 0
data(7) = 0

Or you use the chr-function, e. g.:

B4X:

s = "/foo....".Replace(".", Chr(0))

or

B4X:

s = "/foo" & Chr(0) & Chr(0) & Chr(0) & Chr(0)

 

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P

PaulR

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• Mar 15, 2012

• #5

Thank you very much, the Replace method is perfect.

 

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J

Jost aus Soest

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• Mar 15, 2012

• #6

You're welcome!

Jost

 

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PaulR

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• Mar 15, 2012

• #7

Sorry, but how would I go around putting appending a Big Endian 32 bit twos compliment integer or a 32 bit floating point into a string?

 

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J

Jost aus Soest

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• Mar 15, 2012

• #8

For such special cases you should use the ByteConverter library:
Basic4android - ByteConverter

 

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PaulR

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• Mar 15, 2012

• #9

Thanks again! I've downloaded that and will have a play around with it. :sign0188:

 

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rbsoft

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• Mar 16, 2012

• #10

@Jost

Nice picture. Is that inspired by the "Jäger von Soest", Simplicius Simplicissimus?

Rolf

 

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J

Jost aus Soest

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• Mar 16, 2012

• #11

OT: Dat Jägerken von Soest

@rbsoft: Yes, you're right!

It's the symbol figure of Soest:
[Soest-Blog] Soester Weblog - Das Jägerken von Soest

I had the honor to represent the Jägerken last year!

 

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rbsoft

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• Mar 16, 2012

• #12

Schickes Outfit!

Rolf

 

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PaulR

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• Mar 16, 2012

• #13

Hi, sorry to derail the thread.

I have two messages, one is....


blah = "^^^1".Replace("^", Chr(0)).Replace("1",Chr(1))

blah = "~~~~".Replace("^", Chr(0)).Replace("~",Chr(255))

The first one when I.....

data = blah.GetBytes("UTF8")

... sends okay (a 1 value), but the second one sends -1010842689 instead of -1 (which is what 0xFFFFFFFF should be).

Any ideas as to what is happening, all I want to do is send FFFFFFFF....

:sign0013:

 

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P

PaulR

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• Mar 16, 2012

• #14

Well it turns out that any value above 127 is sent in multiple bytes with UTF-8. 255 is an invalid value.

On a wing I tried GetBytes("ASCII") but it too doesn't send any value about 127, changing any value above that to 63.

I tried GetBytes(""), but it crashes the app.

So my revised question is how do I send byte values greater than 127 via UDP in Basic4Android?

edit: I have also been using the ByteConverter library StringToBytes function that requires stating what encoding will be used. The issue is that I don't want any encoding.

edit2: So my final question is... how do I send raw data via UDP? (I can send raw data, on a byte by byte basis, but want to store the information in a string, for conversion to ASCII values).

 

Last edited: Mar 17, 2012

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