//: C07:MemTest.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// Testing the Mem class
//{L} Mem  

//The Mem class is designed to be used as a tool within other classes to simplify their 
//memory management (it could also be used to hide a more sophisticated memory-management 
//system provided, for example, by the operating system). Appropriately, it is tested here 
//by creating a simple “string” class:

#include "Mem.h"
#include <cstring>
#include <iostream>
using namespace std;

class MyString {
  Mem* buf;
public:
  MyString();
  MyString(char* str);
//MyString(char* str = "");
  ~MyString();
  void concat(char* str);
  void print(ostream& os);
};

MyString::MyString() {  buf = 0; }

MyString::MyString(char* str) {
  buf = new Mem(strlen(str) + 1);
  strcpy((char*)buf->pointer(), str);
}

//不建議使用,用funcation overloading will result in easier maintainability, especially if the functions are large.

/*
MyString::MyString(char* str) {
  if(!*str) { // Pointing at an empty string
    buf = 0;
    return;
  }
  buf = new Mem(strlen(str) + 1);
  strcpy((char*)buf->pointer(), str);
} 
*/


void MyString::concat(char* str) {
  if(!buf) buf = new Mem;
  strcat((char*)buf->pointer(
    buf->msize() + strlen(str) + 1), str);
}

void MyString::print(ostream& os) {
  if(!buf) return;
  os << buf->pointer() << endl;
}

MyString::~MyString() { delete buf; }

void main() 
{
  MyString s("My test string");
  s.print(cout);
  s.concat(" some additional stuff");
  s.print(cout);
  MyString s2;
  s2.concat("Using default constructor");
  s2.print(cout);
} ///:~