Mega Code Archive
String Pattern Matching
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Title: String Pattern Matching
Question: Use it when you want to compare strings using '*' or '?' operator
Answer:
String Pattern Matching
The islike function take 2 strings and compare them using simple pattern matching. Only '*' and '?' are implemented, range syntaxe '[]' are not implemented.
Exemple : islike('abcdxabcdxabcdefg', '*abcd?abcdefg*') = true,
islike('abc*defg', 'abc*efg') = true ,
islike('abaababcac', '*abaabcac*') = false , etc...
Maybe this is faster than the MatchesMask function and the another recursive function which is translated from MatchPattern() of common.c in MSDN Samples\VC98\sdk\sdktools\tlist .
.
Function IsLike(const ABC, AX:string) :boolean;
Var
axNext,nextval:array of integer;
AbcLen,AxLen,AbcI,AxI,AxWWW,AxStar:integer;
Begin//aaa
Result:= true;
abclen:=length(abc);
axlen:=length(ax) ;
setlength(axnext,axlen+1);
setlength(nextval,axlen+1);
abci:=1;
axi:=1;
axstar:=0;
axwww:=0;
axnext[1]:=0;
nextval[1]:=0;
while ((abcibegin while(axi begin//eeeeeeee
if ax[axi]='*' then
begin
nextval[axi+1]:=axi;axnext[axi+1]:=axi;axwww:=axi;break;
end;
if (ax[axwww]='*')or(ax[axi]=ax[axwww])or(ax[axwww]='?')or(axwww=0)then
begin
axwww:=axwww+1;axnext[axi+1]:=axwww;
if ax[axi+1]ax[axwww] then
nextval[axi+1]:=axwww
else
nextval[axi+1]:=nextval[axwww];
break;
end
else
begin
axwww:=nextval[axwww];
end;
end;//eeeeeeee
if(ax[axi]='*') then begin //xxx
axstar:=axi;axi:=axi+1;continue;
end;//xxx
if(ax[axi]= '?') then begin
abci:=abci+1; axi:=axi+1;continue;
end;
if(ax[axi]=abc[abci])then
begin
inc(abci);inc(axi);continue;
end;
if(ax[axi]abc[abci])then begin//ccc
axi:=axnext[axi];
if axi=0 then axwww:=0
else axwww:= axnext[axi];
if (axi=axstar) and (axstar=1) then
begin
inc(abci); continue;
end;
if (axi=axstar) and (axstar=0) then
begin
result:=false; break;
end;
end;//ccc
end;//main
if (result=true)and (abciabclen) and(axiif (result=true)and (abciaxlen) and (ax[axlen]'*') then result:=false;
end;//aaa
author: JunYu . Li ,a chinese , email: e271828@163.net,msSQLserver2000@163.com
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