Delphi中压缩字符串中的空格，只保留一个空格【CompressWhiteSpace】

函数代码

function CompressWhiteSpace(const S: string): string;
var
  Idx: Integer;      // loops thru all characters in string
  ResCount: Integer; // counts number of characters in result string
  PRes: PChar;       // pointer to characters in result string
begin
  // Set length of result to length of source string and set pointer to it
  SetLength(Result, Length(S));
  PRes := PChar(Result);
  // Reset count of characters in result string
  ResCount := 0;
  // Loop thru characters of source string
  Idx := 1;
  while Idx <= Length(S) do
  begin
    if IsWhiteSpace(S[Idx]) then
    begin
      // Current char is white space: replace by space char and count it
      PRes^ := ' ';
      Inc(PRes);
      Inc(ResCount);
      // Skip past any following white space
      Inc(Idx);
      while IsWhiteSpace(S[Idx]) do
        Inc(Idx);
    end
    else
    begin
      // Current char is not white space: copy it literally and count it
      PRes^ := S[Idx];
      Inc(PRes);
      Inc(ResCount);
      Inc(Idx);
    end;
  end;
  // Reduce length of result string if it is shorter than source string
  if ResCount < Length(S) then
    SetLength(Result, ResCount);
end;