Op Fri, 25 Jan 2013, schreef Michael Schnell:
On 01/25/2013 11:12 AM, Michael Van Canneyt wrote:
Pchar ?
You seem to miss my point: the n'th printable character in an utf-8 coded
string (may same be stored as a pchar or a string) starts at the m'th byte
(m>=n).
To find m for a given n you need to scan all bytes < m.
Thus a loop such as
for I = 1 to 100000 do begin
n = Integer (random(100000));
c = myString[n];
end;
Is rather fast with ANSI coded Strings.
When myString is coded in utf-8, it obviously provides silly code byte
instead of printable characters, and replacing the term myString[n] by a
straight forward function searching for the n'th printable character will be
very slow.
Yes, it is a known fact that this is a weakness of UTF-8. Consider
transforming the string to UTF-16, UTF-32 or even an internal
datastructure before doing the random access.
Random access inside UTF-8 is an algorithmic time complexity issue. A
language extension can only be a band-aid for that.
Daniël
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