I transformed the address "1D8A1467" into number using "tonumber(address, 16)" what returned "495588455", and then summed +37 to that number to reach 495588492 and now I want to turn that new number into hex again in order to get the result "1D8A148C", is there a "tohex" function?
local hexStr = string.format("%X", 495588492)
Please read the Lua manual!
https://www.lua.org/manual/5.4/manual.html#pdf-string.format
For formatting options refer to
http://www.cplusplus.com/reference/cstdio/printf/
Related
I am writing a custom Wireshark Lua dissector. One field in the dissector is a UTF16 string. I tried to specify this field with
msg_f = ProtoField.string("mydissector.msg", "msg", base.UNICODE)
local getMsg = buffer(13) -- starting on byte 13
subtree:add_le(m.msg_f, getMsg)
However, this only adds the first character rather than the whole string. It also raises an Expert Info warning undecoded trailing/stray characters.
What is the correct way to parse a UTF16 string?
You haven't specified the range of bytes that comprises the string. This is typically determined by either an explicit length field or by a NULL-terminator. The exact method of determining the range is dependent upon the particular protocol and field in question.
An example of each type:
If there's a length field, say of 1 byte in length that precedes the string, then you can use something like:
local str_len = buffer(13, 1):le_uint()
subtree:add_le(m.msg_len_f, buffer(13))
if str_len > 0 then
subtree:add_le(m.msg_f, buffer(14, str_len))
end
And if the string is NULL-terminated, you can use something like:
local str = buffer(13):stringz()
local str_len = str:len()
subtree:add_le(m.msg_f, buffer(13, str_len + 1))
These are just pseudo-examples, so you'll need to apply whatever method, possibly none of these, to fit your data.
Refer to the Wireshark's Lua API Reference Manual for more details, or to the Wireshark LuaAPI wiki pages.
The solution I came up with is simply:
msg_f = ProtoField.string("mydissector.msg", "msg")
local getMsg = buffer(13) -- starting on byte 13
local msg = getMsg:le_ustring()
subtree:add(msg_f, getMsg, msg)
I'm writing a Wireshark dissector in lua and trying to decode a time-based protocol field.
I've two components 1)
local ref_time = os.time{year=2000, month=1, day=1, hour=0, sec=0}
and 2)
local offset_time = tvbuffer(0:5):bytes()
A 5-Byte (larger than uint32 range) ByteArray() containing the number of milliseconds (in network byte order) since ref_time. Now I'm looking for a human readable date. I didn't know this would be so hard, but 1st it seems I cannot simple add an offset to an os.time value and 2nd the offset exceeds Int32 range ...and most function I tested seem to truncate the exceeding input value.
Any ideas on how I get the date from ref_time and offset_time?
Thank you very much!
Since ref_time is in seconds and offset_time is in milliseconds, just try:
os.date("%c",ref_time+offset_time/1000)
I assume that offset_time is a number. If not, just reconstruct it using arithmetic. Keep in mind that Lua uses doubles for numbers and so a 5-byte integer fits just fine.
I have two cards which contains a hex value, I am struggling to find out what kind of algorithm is used ti get the decimal value.
8HEX from chip: 0b98c44a Printed on card: 3491308370
8HEX from chip: 0c96425c Printed on card: 812204602
does any one of you number experts in here find out how it is done, you helped me with this before :)
The relation between the numbers seems to be that the bits of every byte has been reversed.
When you print first pair in binary they are:
11010000 00011001 00100011 01010010 = 3491308370
00001011 10011000 11000100 01001010 = 0x0b98c44a
The second pair is:
00110000 01101001 01000010 00111010 = 812204602
00001100 10010110 01000010 01011100 = 0x0c96425c
If you want to know how to convert one number to the other, you should mention which programming language you are using.
Hi
I want to convert "qrysth.Fields[i].AsFloat" to a string so I use the following code:
FormatFloat('0.###############',qrysth.Fields[i].AsFloat)
but I find the result string is 12.000000000000001 while qrysth.Fields[i].AsFloat is 12.00. I know FormatFloat actually not use 12.00 to do the convert, but use an infinite number of binary to do the convert. (like 0.1 in decimal system is 0.1, but it is an infinite number in binary system 0.00011001100...)
Is there other way I could get 12.00 in the case above? or 12.000000000000000 at least?
If you really get 12.000000000000001, then your field didn't hold exactly 12, so the output is correct. You asked for high precision by putting so many # characters in the format. If you don't want it so precise, then use a less precise format string.
FormatFloat('0.00',qrysth.Fields[i].AsFloat) will give '12.00'.
To be able to get '12.000000000000000' you should do the rounding yourself, as there's no loss of precision.
I want to convert
"qrysth.Fields[i].AsFloat" to a string
Then why not use AsString?
qrysth.Fields[i].AsString
This will give you the best representation, as long as you're not concerned about the exact width. If you are, use FormatFloat with the exact number of digits you need - in other words, if you're looking for 12.00, use FormatFloat('##.##', qrysth.Fields[i].AsFloat), or even better CurrToStrand AsCurrency, as they automatically uses two digits after the decimal point.
function MyFormatFloat(V: Double): String;
const
DesiredMinPrec = '0.000000000000000';
AssumedMaxPrec = '0.#####';
begin
Result := FormatFloat(DesiredMinPrec, StrToFloat(FormatFloat(AssumedMaxPrec, V)));
end;
Could someone please tell me how to write a custom function in Open Office Basic to be used in Open Office Calc and that returns an array of values. An example of one such built-in function is MINVERSE. I need to write a custom function that populates a range of cells in much the same way.
Help would be much appreciated.
Yay, I just figured it out: all you do is return an array from your macro, BUT you also have to press Ctrl+Shift+Enter when typing in the cell formula to call your function (which is also the case when working with other arrays in calc). Here's an example:
Function MakeArray
Dim ret(2,2)
ret(0,0) = 1
ret(1,0) = 2
ret(0,1) = 3
ret(1,1) = 4
MakeArray = ret
End Function
FWIW, damjan's MakeArray function returns a Variant containing an array, I think. (The type returned by MakeArray is unspecified, so it defaults to Variant. A Variant is a container with a descriptive header, apparently cast as needed by the interpreter.)
Almost, but not quite, the same thing as returning an array. According to http://www.cpearson.com/excel/passingandreturningarrays.htm, Microsoft did not introduce the ability to return an array until 2000. His example [ LoadNumbers(Low As Long, High As Long) As Long()] does not compile in OO, flagging a syntax error on the parens following Long. It appears that OO's Basic emulates the pre-2k VBA.