Mega Code Archive
String Pattern Matching. updt []
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Title: String Pattern Matching. updt '[]'
Question: Use it when you want to compare strings using '*' or '?' operator.
Answer:
The MatchPattern function take 2 strings and compare them using simple pattern matching. Only '*' and '?' are implemented, range syntaxe '[]' are implemented.
Exemple : MatchPattern('autoexec.bat', '*.bat') = true, etc...
MatchPattern('johnny', 'j[aeiou]hnny') = true
MatchPattern('Yooha!', 'Y[a-z]oh[0-9]!') = false
Notes :
14/11/00 the '15 1*5' bug is corrected. Thank to Paramjeet.
A more complete version is available at
http://www.delphi3000.com/article.asp?ID=1561
function MatchPattern(s : PCHAR; pattern : PCHAR) : boolean;
{* simple pattern matching
* metachar are :'*', '?', '[x-y]' (range), '[wxyz]'
* translated from MatchPattern() of common.c in MSDN Samples\VC98\sdk\sdktools\tlist
*}
var
c : char;
p : char;
l : char;
begin
while (true) do
begin
p := Pattern^;
inc(Pattern);
case p of
#0 : begin // End of pattern
result := s^ = #0; // if end of string TRUE
exit;
end;
'*': begin
while(bool(s^)) do
begin // Match zero or more char
if(MatchPattern(s, pattern)) then
begin
result := true;
exit;
inc(s); // Thanks to Paramjeet
end;
end;
result := MatchPattern(s, pattern);
exit;
end;
'?': begin
if (s^ = #0) then
begin // match any one char
result := false; // not end of string
exit;
end;
inc(s);
end;
'[' : begin
c := s^; // c = *s++
inc(s); // match char set [0123] or [0-3]
if (c = #0) then
begin
result := false;
exit;
end;
l := #0;
p := pattern^;
inc(pattern);
while (bool(p)) do
begin
if (p = ']') then
begin // if end of char set, then no match found
result := false;
exit;
end;
if (p = '-') then
begin // check a ronge of char ?
p := pattern^;
if (p = #0) or (p = ']') then
begin // Get high limit of range
result := false;
exit;
end;
if (c = l) and (c begin
break; // if in range, move on (redo while)
end;
end;
l := p;
if (c = p) then
break; // if char matches this element, move on (redo while)
p := pattern^;
inc(pattern);
end;
while (bool(p) and (p ']')) do
begin // got a match in char set
p := pattern^;
inc(pattern); // skip to end of set
end;
end;
else
begin
c := s^;
inc(s);
if (c p) then
begin // check for exact char
result := false;
exit;
end;
end;
end;
end;
end;
Note : this is 50% faster than the Eva Hummer function, using D3.
http://www.delphi3000.com/article.asp?id=639
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