如何在Delphi 7中手动模拟`TStringBuilder`的功能?
时间: 2024-09-20 18:11:50 浏览: 35
在 Delphi 7 中,由于 `TStringBuilder` 是从 Delphi 2009 开始引入的一个类,如果你需要在不支持该类型的早期版本中模拟类似功能,你可以创建一个自定义的动态数组字符串容器,并手动实现一些常见的字符串操作。这里是一个简单的模拟示例:
1. 首先,定义一个 `TSimpleStringBuilder` 类:
```delphi
type
TSimpleStringBuilder = class
private
FBuffer: array of WideChar;
FLength, Capacity: Integer;
public
constructor Create(ACapacity: Integer);
function Length(): Integer;
procedure Append(const AValue: WideString);
function ToString: WideString;
end;
constructor TSimpleStringBuilder.Create(ACapacity: Integer);
begin
SetLength(FBuffer, ACapacity);
FLength := 0;
FCapacity := ACapacity;
end;
function TSimpleStringBuilder.Length(): Integer;
begin
Result := FLength;
end;
procedure TSimpleStringBuilder.Append(const AValue: WideString);
var
i: Integer;
begin
if FLength + Length(AValue) > FCapacity then
begin
Inc(FCapacity, Max(10, FLength * 2)); // 动态增加容量
ResizeBuffer;
end;
for i := 1 to Length(AValue) do
FBuffer[FLength + i] := AValue[i];
Inc(FLength);
end;
function TSimpleStringBuilder.ToString: WideString;
begin
Result := Copy(PWideChar(@FBuffer[0]), 0, FLength); // 返回副本,避免修改原始数组
end;
procedure TSimpleStringBuilder.ResizeBuffer;
var
Temp: array of WideChar;
begin
SetLength(Temp, FLength);
Move(FBuffer[0], Temp[0], FLength);
SetLength(FBuffer, FCapacity);
Move(Temp[0], FBuffer[0], FLength);
end;
```