VARIOUS TEXT MANIPULATION ROUTINES INCLUDING STRING COMPARISON ASSIGNMENT
To copy from PChar to PChar, or from PChar to array, use StrCopy...
***************************VARIOUS*********************************
var
userWordPC, dictWordPC: PChar;
dictWord: String
thisWord: String;
thisChunk: array [1..30] of Char;
fileNameArray: array[0..13] of Char;
fileNameString: String;
begin
userWordPC := 'tree';
dictWordPC := PChar(dictWord);
thisWord := String(thisChunk);
{next one copies a Delphi-style PChar string into a character array}
fileNameArray := StrPCopy(CWForm.SaveDialog.Filename);
{and to copy a character array INTO a string, we just use a typecast:}
fileNameString := String(fileNameArray);
{and to copy a normal string (of String type) into a character array we
must explicitly copy characters one at a time, like this:}
var
stringLength, i: Integer;
longFileName: String;
tempArray: array[0..100] of Char;
begin
stringLength := Length(longFileName);
for i := 1 to stringLength do
begin
tempArray[i - 1] := longFilename[i];
end;
end;
*******************************************************************************************
SPLIT STRING BY DELIMITER
Hi
Here is a generic 'SplitStringByDelimiter' routine
which might be useful (if only for filing away)
Richard
procedure TMainForm.FormCreate(Sender: TObject);
var
lines: TStringList;
ballOfString: String;
returnValue: Integer;
tempString: String;
begin
lines := TStringList.Create;
ballOfString := 'this is a ball of string, useful for finding your way, in a dark cave, if you had the foresight to trail it, behind you on the way in';
returnValue := SplitStringByDelimiter(ballOfString, lines, ',');
if (returnValue = -1) then
begin
tempString := 'Problems were encountered when trying to split long strings';
Application.MessageBox(PChar(tempString), ' String Handling Error', mb_OK);
end;
lines.Free;
end;
//////////////////////////////////////////////////////////////////////////////////////////
function TMainForm.SplitStringByDelimiter(longString: String; var subStrings: TStringList;
delimiter: Char): Integer;
const
MaxStrLength = 4096;
var
subStrStart: Integer;
idx: Integer;
lenStr: Integer;
tempArray: array[0..MaxStrLength] of Char;
tempString: String;
begin
lenStr := Length(longString);
if (lenStr >= MaxStrLength) then
begin
Result := -1;
exit;
end;
for idx := 1 to lenStr do
begin
tempArray[idx - 1] := longString[idx];
end;
tempArray[idx] := #0;
subStrStart := 0;
for idx := 0 to lenStr do
begin
if (tempArray[idx] = delimiter) then
begin
tempString := Copy(tempArray, subStrStart, (idx - subStrStart));
subStrings.Add(tempString);
end;
end;
end;
////////////////////////////////////////////////
--------------------------------------------
*************************************************************************************
COMPARISON
{WHERE compResult is an Integer, and userWordPC and dictWordPC are PChars}
compResult := StrComp(userWordPC,dictWordPC);
if (compResult = 0) then
procedure TForm1.TempFindMatch(dictWord: String);
{check dictionary word against user word and see if they match
string comparison routines can be a little unpredictable in
Delphi -you SHOULD be able to say if StrOne = StrTwo then ...
(where both StrOne and StrTwo are String types that is) but
sometimes that works and sometimes it doesn't. Converting
string to PChar types and using StrComp() DOES work though}
var
userWordPC,dictWordPC: PChar;
compResult: Integer;
begin
userWordPC := 'tree';
dictWordPC := PChar(dictWord);
compResult := StrComp(userWordPC,dictWordPC);
if (compResult = 0) then
begin
ShowMessage('match found for tree');
end;
end;
procedure TForm1.CapitalButtonClick(Sender: TObject);
{gubbins code... NOTE ye have te be REALLY careful with PChar variables...}
{-the 'memo' type is one such. PChars are pointers to characters, so many of}
{the normal low-level string-handling routines (like substituting each instance}
{of a particular character for another, for instance) are potentially dangerous}
{if you screw up with the syntax (which is easily done, as the compiler may}
{well let you get away with it. Best strategy is to 1) convert your PChar}
{variable to a string (using a simple assignment), 2) perform what operations}
{you must on the string variable, 3) overwrite the old PChar variable with the}
{new string (using a simple assignment statement again)...}
var
TotalLines : Integer;
LineLength : Integer;
x, y, LeftPos, RightPos : Integer;
TempString : String;
begin
TotalLines := Memo1.Lines.Count;
for x := 0 to TotalLines do
begin
LineLength := Length(Memo1.Lines[x]);
TempString := Memo1.Lines[x];
y := 0;
while (y < LineLength) do
begin
Inc(y);
if (y >= LineLength) then break;
if (TempString[y] = '<') then
begin
Inc(y);
repeat
TempString[y] := UpCase(TempString[y]);
Inc(y);
until ((y >= LineLength) or (TempString[y] = '>'));
end; {end if}
end; {end while}
Memo1.Lines[x] := TempString;
TempString := '';
end;
end;
function TForm1.GetWordsEnd: Integer;
var
len: Integer;
textEnd: Boolean;
begin
len := 1;
textEnd := False;
while ((textEnd = False) and (len < bufSize)) do
begin
if (((dictBuf[len] >= 'A') and (dictBuf[len] <= 'Z')) or
((dictBuf[len] >= 'a') and (dictBuf[len] <= 'z')) or
(dictBuf[len] = ',' )) then
begin
Inc(len);
end
else
begin
textEnd := True;
end;
end;
Result := len;
end;
procedure TForm1.ExtractWords;
{parse out one word at a time from the (comma-delimited) text file...
this procedure also involves some 'low-level' stuff -it's necessary
to work chunks of text in the form of a 'null-terminated string' in
the form of a character array, and then convert that to Delphi's
kind of string...}
var
i,pos,x,y: Integer;
charsLen: Integer;
thisChunk: array [1..30] of Char;
thisWord: String;
begin
i := 1;
pos := 1;
for x := 1 to 30 do
begin
thisChunk[x] := #0;
end;
charsLen := GetWordsEnd;
while (i < charsLen) do
begin
while ((not(dictBuf[i] = ',') and (i < charsLen))) do
begin
Inc(i);
end;
y := 1;
for x := pos to (i - 1) do
begin
thisChunk[y] := dictBuf[x];
Inc(y);
end;
{use a typecast to convert from character array to string...}
thisWord := string(thisChunk);
TempFindMatch(thisWord);
{skip a comma by incrementing i...}
Inc(i);
pos := i;
for x := 1 to 30 do
begin
thisChunk[x] := #0;
end;
end; {outer while}
end;
*****************************************************************
{reverse a sequence of characters...}
patt is a string
tempArray is an array
j := (pattLen - 1);
for i := 1 to pattLen do
begin
tempArray[j] := patt[i];
Dec(j);
end;