OS/2 Shareware BBS: 10 Tools/10-Tools.zip/ctdemo.zip/classes/@CLSLIB1.ZIP/cls/tutorial/string.cpp

C/C++ Source or Header | 1995-03-30 | 5KB | 259 lines

#ifndef INC_STRING
#define INC_STRING

#ifndef __FIRST__
#define __FIRST__
#define __IMPL__STRING
#endif

/////V String PCM f:\cls_ibm\cls\tutorial 10  PM 30.03.95 10:25:25
/*
/////H
20.10.94 19:37 PM 0 copied from: String TOS f:\cls_ibm\cls\tutorial 0 PM 19.10.94 00:26:00
30.03.95 10:34 PM 10 archived: String PCM f:\cls_ibm\cls\tutorial 10  PM 30.03.95 10:25:25
/////
*/

/////1
#undef inline

#include <bsa.h>

/////I IOSTREAM.H @ @ @ @ pre
#include <IOSTREAM.H>

/////I STRING.H @ @ @ @ pre
#include <STRING.H>

/////I stdlib.h @ @ @ @ pre
#include <stdlib.h>


#ifndef __INLINE__
#define inline
#endif

/////C String @ @ app level0
class String

{
/////N >> @ >>
friend istream & operator >> (istream & s, String & x);

/////N << @ <<
friend ostream & operator << ( ostream  & s, const String & x );

/////N != @ !=
friend int operator != ( const String & x, const String & y );

/////N != @ !=
friend int operator != ( const String & x, const char * s );

/////N == @ ==
friend int operator == ( const String & x, const String & y );

/////N == @ ==
friend int operator == ( const String & x, const char * s );

/////T struct srep inside
struct srep {
    char *    s;    // pointer to data
    int         n;    // reference count
    srep() { n = 1; }
};
/////


private:
/////D P @  @ instance private
    srep *  P;


public:
    String & operator   = (const String&);
    String & operator   = (const char*);
    String ();
    String (const char*);
    String (const String&);
    char & operator   [] (int);
    virtual ~String ();
};

    inline int operator   != (const String&,const char*);
    inline int operator   != (const String&,const String&);
    ostream & operator   << (ostream&,const String&);
    inline int operator   == (const String&,const char*);
    inline int operator   == (const String&,const String&);
    istream & operator   >> (istream&,String&);
    void   error (const char*);

/////2
#undef inline


#if (defined __INLINE__) || (defined __IMPL__STRING)

#ifndef __INLINE__
#define inline
#endif

/////F != @ @ global inline
inline
int operator != ( const String & x, const String & y )
{
    return strcmp(x.P->s, y.P->s) != 0;
}

/////F != @ @ global inline
inline
int operator != ( const String & x, const char * s )
{
    return strcmp(x.P->s, s) != 0;
}

/////F == @ @ global inline
inline
int operator == ( const String & x, const String & y )
{
    return strcmp(x.P->s, y.P->s) == 0;
}

/////F == @ @ global inline
inline
int operator == ( const String & x, const char * s )
{
    return strcmp(x.P->s, s) == 0;
}

/////
#endif

/////3
#undef inline

#ifdef __IMPL__STRING
/////F << @ @ global
ostream & operator << ( ostream  & s, const String & x )
{
//    return s << x.P->s << " [" << x.P->n << "] \n";
    return s << x.P->s;
}

/////F = @ @ instance public
String & String:: operator = ( const char * s )
{
    if (P->n > 1) {                        // dissconnect self
        P->n--;
        P = new srep;
    }
    else
        delete[] P->s;                    // free old string

    P->s = new char[ strlen(s) + 1 ];
    strcpy(P->s, s);

    return * this;
}

/////F = @ @ instance public
String & String:: operator = ( const String & x )
{
    x.P->n++;    // protecct against "st = st "
    if (--P->n == 0) {
        delete[] P->s,
        delete P;
    }
    P = x.P;
    return * this;
}

/////F >> @ @ global
istream & operator >> (istream & s, String & x)
{
    char buf[256];
    s >> buf; // unsafe, might overflow
    x = buf;
    cout << "echo: " << x << "\n";
    return s;
}

/////F error @ @ global
void error ( const char * p )
{
    cerr << p << "\n";
        exit(1);
}

/////
#ifdef __APPCLASS__
/////F main @ @ global
int main ()
{
    String x[5];
    int n;

    cout << "here we go (type in a few chars, 'done' to terminate)\n";
    for (n = 0; cin >> x[n]; n++) {
        if (n==4) {
            error("too many strings");
            return 99;
        }
        String y;
        y = x[n];
        cout << y << '\n';
        if (y=="done")
            break;
        cout << "next string please\n";
    }
    cout << "\nhere we go back again\n";
    for (int i=n-1; 0<=i; i--)
        cout << x[i] << '\n';
    return 0;
}
/////
#endif

/////F String @ @ instance public
String:: String (const String & x)
{
    x.P->n++;
    P = x.P;
}

/////F String @ @ instance public
String:: String (const char * s)
{
    P = new srep;
    P->s = new char[ strlen(s)+1 ];
    strcpy(P->s, s);
}

/////F String @ @ public instance docu
String:: String ()
{
    P = new srep;
    P->s = 0;
}

/////F [] @ @ instance public
char & String:: operator [] ( int i )
{
    if (i<0 || strlen(P->s)<i)
        error ("index out of range");
    return P->s[i];
}

/////F ~String @ @ terminal public instance
String:: ~String ()
{
    if (--P->n == 0) {
        delete[] P->s;
        delete P;
    }
}

/////
#endif

#endif