Mega Code Archive
TGUID String
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Title: TGUID String
Question: Using a GUID filled in by the user
Answer:
It is not possible to fill a variabele of the type TGUID with a string, unless this is a constant e.g.
const appguid: tguid = '{238C0E8D-5465-40C3-9FF1-8EC358AE6BDB}';
In order to convert a GUID(CLSID) to a string, I am using the functions listed below. To use these functions, call function stringtoguid(GUID) where GUID is a valid GUID. (syntax: '{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}'). The return value is the GUID as a TGUID.
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function expnumber(number, exponent: integer): integer;
var counter: integer;
begin
result:=1;
if exponent=0 then exit;
for counter:=1 to exponent do
begin
result:=result*number;
end;
end;
function hextodec(hex: string): integer;
var counter: integer;
value: integer;
begin
result:=0;
for counter:=0 to length(hex)-1 do
begin
case hex[length(hex)-counter] of
'A': value:=10;
'B': value:=11;
'C': value:=12;
'D': value:=13;
'E': value:=14;
'F': value:=15;
else value:=strtoint(hex[length(hex)-counter]);
end;
result:=result+value*expnumber(16, counter);
end;
end;
function stringtoguid(GUID: string): TGUID;
var counter: integer;
newword: string;
begin
//Expect GUID '{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}' as string if not, exit
//result: '{D1 - D2 - D3 - D4a[0..1] - D4b[2..7]}'
if (guid[1] '{') or (guid[10] '-') or (guid[15] '-') or
(guid[20] '-') or (guid[25] '-') or (guid[38] '}') then exit;
//Do D1
newword:='';
for counter:=2 to 9 do
newword:=newword+guid[counter];
Result.d1:=hextodec(newword);
//Do D2
newword:='';
for counter:=11 to 14 do
newword:=newword+guid[counter];
Result.d2:=hextodec(newword);
//Do D3
newword:='';
for counter:=16 to 19 do
newword:=newword+guid[counter];
Result.d3:=hextodec(newword);
//Do D4a
Result.D4[0]:=hextodec(guid[21]+guid[22]);
Result.D4[1]:=hextodec(guid[23]+guid[24]);
//Do D4b
Result.D4[2]:=hextodec(guid[26]+guid[27]);
Result.D4[3]:=hextodec(guid[28]+guid[29]);
Result.D4[4]:=hextodec(guid[30]+guid[31]);
Result.D4[5]:=hextodec(guid[32]+guid[33]);
Result.D4[6]:=hextodec(guid[34]+guid[35]);
Result.D4[7]:=hextodec(guid[36]+guid[37]);
end;
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This can also be the other way around, GUID to string. For this the following functions. Use guidtostr(GUID) function with a valid TGUID variabele, and the retrun value will be the GUID in a string.
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function dectohex(decValue: integer): string;
var counter, counter2, times: integer;
value: integer;
begin
value:=decvalue;
result:='';
counter:=0;
repeat
counter2:=value-expnumber(16, counter);
inc(counter);
until (value-expnumber(16, counter) counter2);
counter:=counter-1;
times:=value div expnumber(16, counter);
value:=value-times*expnumber(16, counter);
case times of
10: result:='A';
11: result:='B';
12: result:='C';
13: result:='D';
14: result:='E';
15: result:='F';
else result:=inttostr(times);
end;
for counter2:=1 to counter do
begin
times:=value div expnumber(16, counter-counter2);
value:=value-times*expnumber(16, counter-counter2);
case times of
10: result:=result+'A';
11: result:=result+'B';
12: result:=result+'C';
13: result:=result+'D';
14: result:=result+'E';
15: result:=result+'F';
else result:=result+inttostr(times);
end;
end;
end;
function guidtostring(GUID: TGUID): string;
var counter: integer;
begin
//Input GUID '{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}' as TGUID
//result: '{D1 - D2 - D3 - D4a[0..1] - D4b[2..7]}'
result:='{'+dectohex(GUID.D1)+'-'+dectohex(GUID.D2)+'-'+dectohex(GUID.D3)+'-'+dectohex(GUID.D4[0])+dectohex(GUID.D4[1])+'-';
for counter:=2 to 7 do
result:=result+dectohex(GUID.D4[counter]);
result:=result+'}';
end;
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