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{其实还可以在FastReplace中先对FindStr进行判断，如果
FindStr完全是中文的话，直接可以在FastReplace中用
FastPos，这样可以提高速度。}
unit fStrRep;
interface
Type
TFastPosProc = function(
const aSourceString, aFindString : String;
const aSourceLen, aFindLen, StartPos : integer
) : integer;
function FastReplace(
var aSourceString : String;
const aFindString, aReplaceString : String;
CaseSensitive : Boolean = False) : String;
function FastPos(
const aSourceString, aFindString : String;
const aSourceLen, aFindLen, StartPos : integer
) : integer;
function FastPosNoCase(
const aSourceString, aFindString : String;
const aSourceLen, aFindLen, StartPos : integer
) : integer;
implementation
// This TYPE declaration will become apparent later.
//The first thing to note here is that I’m passing the SourceLength and FindL
//ength. As neither Source nor Find will alter at any point during FastReplace
//, there’s no need to call the LENGTH subroutine each time!
function FastPos(
const aSourceString, aFindString : String;
const aSourceLen, aFindLen, StartPos : integer
) : integer;
var
SourceLen : integer;
begin
// Next, we determine how many bytes we need to
// scan to find the "start" of aFindString.
SourceLen := aSourceLen;
SourceLen := SourceLen - aFindLen;
if (StartPos-1) > SourceLen then begin
Result := 0;
Exit;
end;
SourceLen := SourceLen - StartPos;
SourceLen := SourceLen +2;
// The ASM starts here.
asm
// Delphi uses ESI, EDI, and EBX a lot,
// so we must preserve them.
push ESI
push EDI
push EBX
// Get the address of sourceString[1]
// and Add (StartPos-1).
// We do this for the purpose of finding
// the NEXT occurrence, rather than
// always the first!
mov EDI, aSourceString
add EDI, StartPos
Dec EDI
// Get the address of aFindString.
mov ESI, aFindString
// Note how many bytes we need to
// look through in aSourceString
// to find aFindString.
mov ECX, SourceLen
// Get the first char of aFindString;
// note how it is done outside of the
// main loop, as it never changes!
Mov Al, [ESI]
// Now the FindFirstCharacter loop!
@ScaSB:
// Get the value of the current
// character in aSourceString.
// This is equal to ah := EDI^, that
// is what the [] are around [EDI].
Mov Ah, [EDI]
// Compare this character with aDestString[1].
cmp Ah,Al
// If they''''re not equal we don''''t
// compare the strings.
jne @NextChar
// If they''''re equal, obviously we do!
@CompareStrings:
// Put the length of aFindLen in EBX.
mov EBX, aFindLen
// We DEC EBX to point to the end of
// the string; that is, we don''''t want to
// add 1 if aFindString is 1 in length!
dec EBX
// add by ShengQuanhu
// If EBX is zero, then we''''ve successfully
// compared each character; i.e. it''''s A MATCH!
// It will be happened when aFindLen=1
Jz @EndOfMatch
//add end
//Here’s another optimization tip. People at this point usually PUSH ESI and
//so on and then POP ESI and so forth at the end–instead, I opted not to chan
//ge ESI and so on at all. This saves lots of pushing and popping!
@CompareNext:
// Get aFindString character +
// aFindStringLength (the last char).
mov Al, [ESI+EBX]
// Get aSourceString character (current
// position + aFindStringLength).
mov Ah, [EDI+EBX]
// Compare them.
cmp Al, Ah
Jz @Matches
// If they don''''t match, we put the first char
// of aFindString into Al again to continue
// looking for the first character.
Mov Al, [ESI]
Jmp @NextChar
@Matches:
// If they match, we DEC EBX (point to
// previous character to compare).
Dec EBX
// If EBX <> 0 ("J"ump "N"ot "Z"ero), we
// continue comparing strings.
Jnz @CompareNext
//add by Shengquanhu
@EndOfMatch:
//add end
// If EBX is zero, then we''''ve successfully
// compared each character; i.e. it''''s A MATCH!
// Move the address of the *current*
// character in EDI.
// Note, we haven''''t altered EDI since
// the first char was found.
mov EAX, EDI
// This is an address, so subtract the
// address of aSourceString[1] to get
// an actual character position.
sub EAX, aSourceString
// Inc EAX to make it 1-based,
// rather than 0-based.
inc EAX
// Put it into result.
mov Result, EAX
// Finish this routine!
jmp @TheEnd
@NextChar:
//This is where I jump to when I want to continue searching for the first char
//acter of aFindString in aSearchString:
// Point EDI (aFindString[X]) to
// the next character.
Inc EDI
// Dec ECX tells us that we''''ve checked
// another character, and that we''''re
// fast running out of string to check!
dec ECX
// If EBX <> 0, then continue scanning
// for the first character.
//add by shengquanhu
//if ah is chinese char,jump again
jz @Result0
cmp ah, $80
jb @ScaSB
Inc EDI
Dec ECX
//add by shengquanhu end
jnz @ScaSB
//add by shengquanhu
@Result0:
//add by shengquanhu end
// If EBX = 0, then move 0 into RESULT.
mov Result,0
// Restore EBX, EDI, ESI for Delphi
// to work correctly.
// Note that they''''re POPped in the
// opposite order they were PUSHed.
@TheEnd:
pop EBX
pop EDI
pop ESI
end;
end;
//This routine is an identical copy of FastPOS except where commented! The ide
//a is that when grabbing bytes, it ANDs them with $df, effectively making the
//m lowercase before comparing. Maybe this would be quicker if aFindString was
// made lowercase in one fell swoop at the beginning of the function, saving a
//n AND instruction each time.
function FastPosNoCase(
const aSourceString, aFindString : String;
const aSourceLen, aFindLen, StartPos : integer
) : integer;
var
SourceLen : integer;
begin
SourceLen := aSourceLen;
SourceLen := SourceLen - aFindLen;
if (StartPos-1) > SourceLen then begin
Result := 0;
Exit;
end;
SourceLen := SourceLen - StartPos;
SourceLen := SourceLen +2;
asm
push ESI
push EDI
push EBX
mov EDI, aSourceString
add EDI, StartPos
Dec EDI
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