分析带分隔符的字符串

真是烦，每次遇到要分析带分隔符字符串的代码时，都要把下面全部重写一遍，费时又费力，可气的是Delphi手册中居然没有此类函数，唉！动手自己写吧，然后加到代码模板里，按Ctrl+j随叫随到，呵呵。想必还有很多人也常遇到这种情况吧。

至于用法就不用我多说了吧，开头的注释很清楚了，您的英文不好可别怪我哟。

---

// Description: Extract a field of value from Source string delimited by
// somewhat delimitor.
// Parameters:
// [in] Source: specifies the source data;
// [in] Delim: specifies a charactor as delimitor;
// [in] Index: specifies a serial number of field you need, which started by zero.
// Return Value:
// returns the valid string of that field you need if succeeded, otherwise
// empty string. if Index you passed is more than the maximum number of fields,
// it also returns empty string.
// Remark: None.
function T|.ExtractDelimitedStr(Source: string; Delim: Char;
Index: Integer): string;
var
Src: string;
ix: Integer;
PPrev, PNext: PChar;
begin
if Length (Source) = 0 then Exit;

Src := Source;
ix := 0;
PPrev := PChar (Src);
PNext := StrScan (PPrev, Delim);

if PNext = nil then
begin
Result := Src;
Exit;
end;

while not ((PNext = nil) and (PPrev = nil)) do
begin
if ix = Index then
begin
if Assigned (PNext) then
Result := Copy (StrPas (PPrev), 1, PNext - PPrev)
else
Result := StrPas (PPrev);
Exit;
end;

if PNext = nil then Exit;

Delete (Src, 1, PNext - PPrev + 1);
Inc (ix);
PPrev := PChar (Src);
PNext := StrScan (PPrev, Delim);
end; // end while
end;