Mega Code Archive
Speed Up AnsiUpperCase
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Title: Speed-Up AnsiUpperCase
Question: The SysUtils function AnsiUpperCase is rather slow
because it uses a Windows API call (CharUpperBuff).
Answer:
To speed-up this, simply use an array initially
filled with ANSI upper characters and write
your own function ConvertToANSIUpper (it is about
3.5 times faster, tested by converting a 1,000-byte-string
10,000 times):
var ANSIUpper: array [char] of char;
{********************************************************
fill table with ANSI upper characters because
execution of ANSIUppercase is very slow
*********************************************************}
procedure FillANSIUpper;
var ch: char;
begin
for ch := Low (char) to High (char) do
ANSIUpper [ch] := AnsiUpperCase (ch) [1];
end;
{********************************************************
convert string to ANSI uppercase
about 3.5 times faster than
ANSIUppercase function
********************************************************}
function ConvertToANSIUpper (const s: string): string;
var i: integer;
begin
Result := s;
for i := 1 to length (Result) do
Result [i] := ANSIUpper [Result [i]];
end;
initialization
FillANSIUpper;
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