I am reading UDP packets using the TIdUDPServer.OnUDPRead event. Embedded in each packet is an 8-byte QUint64, which represents a radio frequency. I am trying to read that frequency.
All attempts using BytesToInt64() are resulting in erroneous results. I have verified the data is correct by reading the hex values with Wireshark and using a web-based hex-to-decimal converter.
I know the frequency in the packet data starts at position 23 and is 8 bytes long.
procedure TWSJTxUDPClient.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread;
const AData: TIdBytes; ABinding: TIdSocketHandle);
var
FreqInt: Int64;
begin
FreqInt := BytesToInt64(AData,23);
LabelFreq.Caption := IntToStr(FreqInt);
end;
Here is the data on the wire in hex notation, starting at position 23:
00 00 00 00 00 6b f0 d0
Which represents a freq of 7074000 hz.
My code above is resulting in a freq value of 58811137507983360.
I have also confirmed the hex data by reading each byte with the Ord() function on a string representing the frequency.
FreqStr := BytesToString(Adata,23,8);
Int8 := Ord(FreqStr[8]);
Int8 is now = 208 - the correct value for 0xd0. Did same for bytes 5, 6, & 7. Confirmed.
So I know I am missing something basic.
You are not taking endian into account.
Decimal 7074000 is hex 0x6BF0D0. Decimal 58811137507983360 is hex 0xD0F06B00000000. See the similarity? Their bytes are in opposite order.
The bytes in your packet are in network byte order (big endian) but your machine uses little endian instead. You need to swap the bytes of the Int64. You can use Indy's GStack.NetworkToHost() method for that:
procedure TWSJTxUDPClient.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; const AData: TIdBytes; ABinding: TIdSocketHandle);
var
FreqInt: Int64;
begin
FreqInt := BytesToInt64(AData, 23);
FreqInt := Int64(GStack.NetworkToHost(UInt64(FreqInt)));
LabelFreq.Caption := IntToStr(FreqInt);
end;
Related
I have been using the Lazarus/FPC Blowfish library to encrypt file streams a while, and it works very well for me.
Now I tried to adapt the library to encrypt and decrypt arbitrary memory structures (records, but also strings), and got a problem which I could not resolve in days, so please help.
Problem is that strings having a length beeing an exact multiple of the Blowfish block size (8 Bytes) are encrypted and decrypted properly. If a string does not end at an exact 8 Byte boundary, the characters exceeding the boundary are mangled.
Here is the code (for the complete Lazarus project please follow the link)
Link to Lazarus project zip
Procedure BlowfishEncrypt(var Contents;ContentsLength:Integer;var Key:String);
// chop Contents into 64 bit blocks and encrypt using key
var
arrShadowContent:Array of Byte absolute Contents;
objBlowfish: TBlowFish;
BlowfishBlock: TBFBlock;
ptrBlowfishKey:PBlowFishKey;
p1,count,maxP:integer;
begin
ptrBlowfishKey := addr(Key[1]);
objBlowfish := TBlowFish.Create(ptrBlowfishKey^,Length(Key));
p1 := 0;
maxP := ContentsLength - 1;
count := SizeOf(BlowfishBlock);
while p1 < maxP do
begin
fillChar(BlowfishBlock,SizeOf(BlowfishBlock),0); // only for debugging
if p1 + count > maxP then
count := ContentsLength - p1;
Move(arrShadowContent[p1],BlowfishBlock,count);
objBlowfish.Encrypt(BlowfishBlock);
Move(BlowfishBlock,arrShadowContent[p1],count);
p1 := p1 + count;
end;
FreeAndNil(objBlowfish);
end;
And this is the call ...
procedure TForm1.CryptButtonClick(Sender: TObject);
var
ContentsBuffer,Key:String;
begin
ContentsBuffer := PlainTextEdit.Text;
Key := KeyTextEdit.Text;
BlowFishEncrypt(ContentsBuffer,Length(ContentsBuffer),Key);
CryptOutEdit.Text := ContentsBuffer;
BlowFishDecrypt(ContentsBuffer,Length(ContentsBuffer),Key);
CryptCheckEdit.Text := ContentsBuffer;
end;
And here you see what's happening:
Screenshot of Test GUI
Resolved. The problem is that I am not allowed to truncate a TBFBlock. For Blowfish Decryption to work, ContetLength must be a multiple of TBFBlock size.
I am trying to write a detailed error message to the system log using the ReportEventW function. Unfortunately, I am encountering problems which are apparently related to the limits within the function but I can't find any real documentation of them: there is a documented limit on dwDataSize and another limit on the maximum length of each string. I am not violating any of these limits, but I am still receiving a FALSE and GetLastError reports RPC_S_INVALID_BOUND.
Through testing, I found that for my test case the limit is caused by the number of strings (wNumStrings), with 203 being the most I can put through correctly (additionally, for 204-206 strings the ReportEventW will return a TRUE but will not write to the log!). If I add 1024 dummy characters to the first line, I once again get an error and have to decrease the number of lines, as far as I can tell, by the same number of characters I added earlier, which would indicate that some total character limit on the whole message is coming to play. Unfortunately, I can't match it against any documented limit even if I ignore what the limits should apply to - my value of about 33300 characters is close to the value 31839 characters (max. length of each string), but sufficiently higher than that to make me discard the theory that the limit on a length of individual string also applies to the total length of the whole message. Apparently, if I add extra raw data, the limit goes down again, which suggests a limitation on the size of the whole event log record.
My questions are:
1) Does anyone know the actual limits for writing to the event log?
2) Do these limits change with the different operating systems? All my tests were performed on Win10 x64, but I have a nasty suspicion that with different OSes, I will encounter a different limitation.
3) Is this documented somewhere?
Thanks.
Actual code (added on request)
procedure WriteToEventLog(const Messages: array of string; const RawData: AnsiString);
const
MaxStringCount = High(Word); // je to WORD! Realne se limit zda byt mnohem mensi
MaxRawDataLen = 61440;
EmptyMessage = #0#0#0#0;
type
TPCharArray = array[0..65535] of PChar;
var
Handle: THandle;
Msgs: ^TPCharArray;
MsgCount: integer;
DataPtr: PAnsiChar;
DataLen: integer;
i: Integer;
begin
MsgCount := Length(Messages);
if MsgCount > MaxStringCount then
MsgCount := MaxStringCount;
Msgs := AllocMem(MsgCount * Sizeof(PChar));
try
for i := 0 to Pred(MsgCount) do
begin
if Messages[i] = ''
then Msgs[i] := EmptyMessage
else Msgs[i] := PChar(Messages[i]);
end;
if RawData = '' then
begin
DataPtr := nil;
DataLen := 0;
end
else
begin
DataPtr := #RawData[1];
DataLen := Length(RawData);
if DataLen > MaxRawDataLen then
DataLen := MaxRawDataLen;
end;
Handle := RegisterEventSource(nil, PChar(ParamStr(0)));
if Handle <> 0 then
begin
try
ReportEvent(Handle, EVENTLOG_ERROR_TYPE, 0, 0, nil, MsgCount, DataLen, Msgs, DataPtr);
finally
DeregisterEventSource(Handle);
end;
end;
finally
FreeMem(Msgs);
end;
end;
It is called with Messages array containing rows from an EurekaLog report (one row per message, about 300 rows).
I can't answer your questions comprehensively, but I just ran into a similar issue. I only used the wNumStrings and lpStrings parameters and, contrary to documentation, still received the RPC_S_INVALID_BOUND error code (1734). On a nagging suspicion, I reduced the number of strings to 256 and it worked. Sure enough, it failed with 257. This was true regardless of the size of the individual strings. There are probably upper limits for individual strings and total message size too, but I didn't bother figuring those out.
TL/DR: wNumStrings <= 256
I have delphi application, i need to rewrite it for OS X.
This app writes/reads data to/from HID-device.
I have issues when i'm trying to write string from mac.
Here is the line that i'm writing(from debugger on windows): 'Новый комплекс 1'
and this works good. Meanwhile if copy this from debugger to somewhere it becomes 'Íîâûé êîìïëåêñ 1'. Device shows it as it was written, in cyrillic. And that's OK.
When i'm trying to repeat this steps on OS X, device shows unreadeble symbols. But if i do hardcode 'Íîâûé êîìïëåêñ 1' from windows example it's OK again.
Give some hints.
How it on windows
Some code:
s:= 'Новый комлекс 1'
s:= AnsiToUtf8(ReplaceNull(s));
Here is ReplaceNULL:
function ReplaceNull(const Input: string): string;
var
Index: Integer;
Res: String;
begin
Res:= '';
for Index := 1 to Length(Input) do
begin
if Input[Index] = #0 then
Res:= Res + #$12
else
Res:= Res + Input[Index];
end;
ReplaceNull:= Res;
end;
this string i put to Tstringlist and then save to file:
ProgsList.SaveToFile(Mwork.pathLibs+'stream.ini', TEncoding.UTF8);
Other program read this list and then writes to device:
Progs:= TStringList.Create();
Progs.LoadFromFile(****);
s:= UTF8ToAnsi(stringreplace(Progs.Strings[i], #$12, #0, [rfReplaceAll, rfIgnoreCase]));
And then write it to device.
So the line wich writes seems like this:
"'þ5'#0'ÿ'#$11'Новый комплекс 1'#0'T45/180;55;70;85;90;95;100;T45/180'#0'ÿ'"
On the mac i succesfully get the same string. But device can't show this in cyrillic.
A Delphi string is encoded in UTF-16 on all platforms. There is no need to convert it, unless you are interacting with non-Unicode data outside of your app.
That being said, if you have a byte array that is encoded in a particular charset, you can convert it to another charset using Delphi's TEncoding.Convert() method. You can use the TEncoding.GetEncoding() method to get a TEncoding object for a particular charset (if different than the standard supported charsets - ANSI, ASCII, UTF-7, UTF-8, and UTF-16 - which have their own property getters in TEncoding).
var
SrcEnc, DstEnc: TEncoding;
SrcBytes, ConvertedBytes: TBytes;
begin
SrcBytes := ...; // Cyrillic encoded bytes
SrcEnc := TEncoding.GetEncoding('Cyrillic'); // or whatever the real name is...
try
DstEnc := TEncoding.GetEncoding('Windows-1251');
try
ConvertedBytes := TEncoding.Convert(SrcEnc, DstEnc, SrcBytes);
finally
DstEnc.Free;
end;
finally
SrcEnc.Free;
end;
// use ConvertedBytes as needed...
end;
Update: To encode a Unicode string in a particular charset, simply call the TEncoding.GetBytes() method, eg:
s := 'Новый комлекс 1';
Enc := TEncoding.GetEncoding('Windows-1251');
try
bytes := Enc.GetBytes(s);
finally
Enc.Free;
end;
s := 'Новый комлекс 1';
bytes := TEncoding.UTF8.GetBytes(s);
You can use the TEncoding.GetString() to decode bytes in a particular charset back to a String, eg:
bytes := ...; // Windows-1251 encoded bytes
Enc := TEncoding.GetEncoding('Windows-1251');
try
s := Enc.GetString(bytes);
finally
Enc.Free;
end;
bytes := ...; // UTF-8 encoded bytes
s := TEncoding.UTF8.GetString(bytes);
The answer was next. Delphi Berlin 10.1 uses KOI8-R, and my device - cp1251.
As i'd wanted to write russian symbols(Cyrillic) i've created table of matches for symbols from KOI8-R and cp1251.
So, i take string in KOI8-R make it in cp1251.
Simple code:
Dict:=TDictionary<String,String>.Create;
Dict.Add(#$439,#$E9);//'й'
Dict.Add(#$44E,#$FE);//'ю'
Dict.Add(#$430,#$E0);//'а'
....
function tkoitocp.getCP1251Code(str:string):string;
var i:integer; res,key,val:string; pair:Tpair<String,String>;
begin
res:='';
for i:=1 to length(str) do
begin
if dict.ContainsKey(str[i]) then
begin
pair:= dict.ExtractPair(str[i]);
res:=res+pair.Value;
dict.Add(pair.Key,pair.Value);
end
else
res:=res+str[i];
end;
Result:=res;
end;
I have Japanese string of 'ぱはめ'. I want to convert it into '%82%CF%82%CD%82%DF'. I hope someone will give me a function for this converting.
You need to take the string and encode it in a specific code page. Then take each encoded byte and produce its hex representation. Like this:
function MyEncode(const S: string; const CodePage: Integer): string;
var
Encoding: TEncoding;
Bytes: TBytes;
b: Byte;
sb: TStringBuilder;
begin
Encoding := TEncoding.GetEncoding(932);
try
Bytes := Encoding.GetBytes(S);
finally
Encoding.Free;
end;
sb := TStringBuilder.Create;
try
for b in Bytes do begin
sb.Append('%');
sb.Append(IntToHex(b, 2));
end;
Result := sb.ToString;
finally
sb.Free;
end;
end;
Although you have not stated this, you wish to encode the text as code page 932. So you should pass that value when calling the function.
Writeln(MyEncode('ぱはめ', 932));
I must say that in the modern day, it is somewhat surprising to see this Windows specific multi byte encoding still in use.
How to convert a WideString (or other long string) to byte array in UTF-8?
A function like this will do what you need:
function UTF8Bytes(const s: UTF8String): TBytes;
begin
Assert(StringElementSize(s)=1);
SetLength(Result, Length(s));
if Length(Result)>0 then
Move(s[1], Result[0], Length(s));
end;
You can call it with any type of string and the RTL will convert from the encoding of the string that is passed to UTF-8. So don't be tricked into thinking you must convert to UTF-8 before calling, just pass in any string and let the RTL do the work.
After that it's a fairly standard array copy. Note the assertion that explicitly calls out the assumption on string element size for a UTF-8 encoded string.
If you want to get the zero-terminator you would write it so:
function UTF8Bytes(const s: UTF8String): TBytes;
begin
Assert(StringElementSize(s)=1);
SetLength(Result, Length(s)+1);
if Length(Result)>0 then
Move(s[1], Result[0], Length(s));
Result[high(Result)] := 0;
end;
You can use TEncoding.UTF8.GetBytes in SysUtils.pas
If you're using Delphi 2009 or later (the Unicode versions), converting a WideString to a UTF8String is a simple assignment statement:
var
ws: WideString;
u8s: UTF8String;
u8s := ws;
The compiler will call the right library function to do the conversion because it knows that values of type UTF8String have a "code page" of CP_UTF8.
In Delphi 7 and later, you can use the provided library function Utf8Encode. For even earlier versions, you can get that function from other libraries, such as the JCL.
You can also write your own conversion function using the Windows API:
function CustomUtf8Encode(const ws: WideString): UTF8String;
var
n: Integer;
begin
n := WideCharToMultiByte(cp_UTF8, 0, PWideChar(ws), Length(ws), nil, 0, nil, nil);
Win32Check(n <> 0);
SetLength(Result, n);
n := WideCharToMultiByte(cp_UTF8, 0, PWideChar(ws), Length(ws), PAnsiChar(Result), n, nil, nil);
Win32Check(n = Length(Result));
end;
A lot of the time, you can simply use a UTF8String as an array, but if you really need a byte array, you can use David's and Cosmin's functions. If you're writing your own character-conversion function, you can skip the UTF8String and go directly to a byte array; just change the return type to TBytes or array of Byte. (You may also wish to increase the length by one, if you want the array to be null-terminated. SetLength will do that to the string implicitly, but to an array.)
If you have some other string type that's neither WideString, UnicodeString, nor UTF8String, then the way to convert it to UTF-8 is to first convert it to WideString or UnicodeString, and then convert it back to UTF-8.
var S: UTF8String;
B: TBytes;
begin
S := 'Șase sași în șase saci';
SetLength(B, Length(S)); // Length(s) = 26 for this 22 char string.
CopyMemory(#B[0], #S[1], Length(S));
end.
Depending on what you need the bytes for, you might want to include an NULL terminator.
For production code make sure you test for empty string. Adding the 3-4 LOC required would just make the sample harder to read.
I have the following two routines (source code can be downloaded here - http://www.csinnovations.com/framework_utilities.htm):
function CsiBytesToStr(const pInData: TByteDynArray; pStringEncoding: TECsiStringEncoding; pIncludesBom: Boolean): string;
function CsiStrToBytes(const pInStr: string; pStringEncoding: TECsiStringEncoding;
pIncludeBom: Boolean): TByteDynArray;
widestring -> UTF8:
http://www.freepascal.org/docs-html/rtl/system/utf8decode.html
the opposite:
http://www.freepascal.org/docs-html/rtl/system/utf8encode.html
Note that assigning a widestring to an ansistring in a pre D2009 system (including current Free Pascal) will convert to the local ansi encoding, garbling characters.
For the TBytes part, see the remark of Rob Kennedy above.