Simtel MSDOS - Coast to Coast/simteldosarchivecoasttocoast2.iso/ddjmag/ddj8910.zip/STEVENS.LST

File List | 1989-09-07 | 18KB | 677 lines

_C Programming_
by Al Stevens

[LISTING ONE]


// ------------ menus.h

#ifndef MENUS
#define MENUS

#include "window.h"

#define MAXSELECTIONS 12
#define CHECK '\xfb' // IBM Graphics character set check mark

#define MENUFG CYAN
#define MENUBG BLUE
#define SELECTFG BLACK
#define SELECTBG WHITE
#define DISABLEFG LIGHTGRAY
#define DISABLEBG BLUE

//
//   SLIDING BAR MENUS
//
class SlideBar    {
    int row;                       // menu screen row
    void (**mfunc)(SlideBar&);     // selection functions
    char **mtext;                  // selection titles
    int selections;                // number of selections
    int quitflag;                  // flag for appl to say quit
    unsigned *msave;               // save area for menu bar
    int selection;                 // selection position
    int dispatch(int sel, int titlewidth);
public:
    SlideBar(int line, char **text, int sel,
        void (**func)(SlideBar&));
    ~SlideBar();
    void terminate(void)
        { quitflag = 1; }
    int current_selection(void)
        { return selection; }
};

//
//    POPDOWN MENUS
//
class PopdownMenu : Window    {
    int selections;               // number of selections
    void (**mfunc)(PopdownMenu&); // selection functions
    char **text;                  // address of menu text
    int quitflag;                 // flag for appl to say quit
    int selection;                // current selection position
    // --- private methods
    int get_selection(int sel);
    int dispatch(int sel);
    int menuheight(char **text);
    int menuwidth(char **text);
    void operator<<(char **text);
public:
    PopdownMenu(unsigned left, unsigned top,
            char **text, int sel, void (**func)(PopdownMenu&));
    ~PopdownMenu(){};
    void terminate(void)
        { quitflag = 1; }
    void disable_selection(int sel)
        { *text[sel-1] = '-'; }
    void enable_selection(int sel)
        { *text[sel-1] = ' '; }
    int test_toggle(int selection);
    int current_selection(void)
        { return selection; }
};

#endif



[LISTING TWO]

// ----------- menus.c

#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <conio.h>
#include "menus.h"
#include "console.h"

static void select(int row,int sel, char *ttl,int set,int wd);
#define ON  1
#define OFF 0

//
//   SLIDING BAR MENUS
//

// ----------- constructor for a sliding menu bar
SlideBar::SlideBar(int line, char **text, int sel,
        void (**func)(SlideBar&))
{
    savecursor();
    hidecursor();
    initconsole();
    // ------ menu variables
    quitflag = 0;
    mfunc = func;
    mtext = text;
    // -------- save video memory
    msave = new unsigned[SCREENWIDTH];
    row = min(line-1, 24);
    savevideo(msave, row, 0, row, SCREENWIDTH-1);
    // --------- display the menu bar
    colors(MENUFG, MENUBG);
    setcursor(0, row);
    int cols = SCREENWIDTH;
    while (cols--)
        window_putc(' ');
    // ---- compute the width of the selection texts
    int titlewidth = 0;
    for (int i = 0; mtext[i] && i < MAXSELECTIONS; i++)
        titlewidth = max(titlewidth, strlen(mtext[i]));
    // ----- save the selection count
    selections = i;
    // ------ display the selection texts
    for (i = 0; i < selections; i++)
        select(row, i+1, mtext[i], OFF, titlewidth);
    // ------- dispatch the menu's selections
    dispatch(sel, titlewidth);
}

// ----------- destructor for a menu bar
SlideBar::~SlideBar(void)
{
    restorevideo(msave, row, 0, row, SCREENWIDTH-1);
    delete msave;
    restorecursor();
    unhidecursor();
}

// ------ navigate the menu and dispatch a chosen function
int SlideBar::dispatch(int sel, int titlewidth)
{
    savecursor();
    int sliding = 1;
    if (sel)
        selection = sel;
    while (sliding)    {
        // ---- highlight the menu bar selection
        select(row, selection, mtext[selection-1],
                                        ON,titlewidth);
        // ----- read a selection key
        int c = getkey();
        switch (c)    {
            case ESC:
                // ----- ESC key quits
                sliding = 0;
                break;
            case FWD:
                // ------ right-arrow cursor key
                select(row, selection, mtext[selection-1],OFF,
                    titlewidth);
                if (selection++ == selections)
                    selection = 1;
                break;
            case BS:
                // ------ left-arrow cursor key
                select(row, selection, mtext[selection-1],OFF,
                    titlewidth);
                if (--selection == 0)
                    selection = selections;
                break;
            default:
                // ---- test for 1st letter match
                for (int i = 0; i < selections; i++)
                    if (tolower(c) == tolower(mtext[i][1]))   {
                        // -- match, turn off current selection
                        select(row, selection,
                            mtext[selection-1],
                            OFF,titlewidth);
                        // --- turn on new selection
                        selection = i+1;
                        select(row, selection,
                            mtext[selection-1],
                            ON,titlewidth);
                        break;
                    }
                if (i == selections)
                    break;
            case '\r':
                // ------- ENTER key = user selection
                if (mfunc[selection-1])
                    (*mfunc[selection-1])(*this);
                    sliding = !(quitflag == 1);
                break;
        }
    }
    restorecursor();
    select(row,selection,mtext[selection-1],OFF,titlewidth);
    return quitflag ? 0 : selection;
}

// --- set or clear the highlight on a menu bar selection
static void select(int row,int sel,char *ttl,int set,int wd)
{
    setcursor(5+(sel-1)*wd, row);
    if (set == OFF)
        colors(MENUFG, MENUBG);
    else
        colors(SELECTFG, SELECTBG);
    window_printf(ttl);
}

//
//    POPDOWN MENUS
//

// -------- constructor for the PopdownMenu
PopdownMenu::PopdownMenu(unsigned left, unsigned top,
            char **mtext, int sel, void (**func)(PopdownMenu&))
                : (left, top, left+1+menuwidth(mtext),
                    top+1+menuheight(mtext), MENUFG, MENUBG)
{
    *this << mtext;
    mfunc = func;
    text = mtext;
    selection = sel;
    selections = menuheight(text);
    // ------ dispatch the menu selection
    dispatch(sel);
}

// ------- write text selections into the popdown menu
void PopdownMenu::operator<<(char **mtext)
{
    hidecursor();
    int y = 0;
    // ----- a NULL-terminated array of character pointers
    text = mtext;
    while (*mtext != NULL)    {
        cursor(0, y++);
        char hold = **mtext;
        if (**mtext == '-')    {
            set_colors(DISABLEFG, DISABLEBG);
            **mtext = ' ';
        }
        *this << *mtext;
        **mtext++ = hold;
        set_colors(MENUFG, MENUBG);
    }
    unhidecursor();
}

// ------------ get a popdown menu selection
int PopdownMenu::get_selection(int sel)
{
    // ---- set the initial selection
    if (sel)
        selection = sel;
    int selecting = 1;
    int c;
    while (selecting)    {
        // ------- display the menu's selection texts
        *this << text;
        // ------ watch for disabled selections
        if (**(text+selection-1)=='-')
            c = DN;        // force a key to
                        // bypass a disabled selection
        else    {
            // ---- highlight the current selection
            cursor(0, selection-1);
            set_colors(SELECTFG, SELECTBG);
            *this << *(text + selection - 1);
            set_colors(MENUFG, MENUBG);
            hidecursor();
            c = getkey();    // --- read the next keystroke
        }
        switch (c)    {
            case ESC:
            case FWD:
            case BS:
                // ---- ESC,FWD, or BS will terminate selection
                selecting = 0;
                break;
            case UP:
                // ------- up-arrow cursor key
                do
                    if (--selection == 0)
                        selection = selections;
                while (**(text+selection-1) == '-');
                break;
            case DN:
                // ------- down-arrow cursor key
                do
                    if (selection++ == selections)
                        selection = 1;
                while (**(text+selection-1) == '-');
                break;
            default:
                // ----- other key, test first letter match
                for (int i = 0; i < selections; i++) {
                    if (tolower(c) == tolower(text[i][1]) &&
                             *(text[i]) != '-')   {
                        selection = i+1;
                        selecting = 0;
                    }
                }
                break;
            case '\r':
                // ---- ENTER key is a selection
                selecting = 0;
                break;
        }
    }
    return c == '\r' ? selection : c;
}

// ------------ get and dispatch a popdown menu selection
int PopdownMenu::dispatch(int sel)
{
    int upanddown = 1;
    while (upanddown)    {
          // ---------- read a user selection
        sel = get_selection(sel);
        switch (sel)    {
               // -------- these keys exit the menu
            case FWD:
            case BS:
            case ESC:
                upanddown = 0;
                break;
            default:
                // -------- user has made a menu selection
                if (mfunc[selection-1]) {
                    // ----- execute a menu selection function
                    hidewindow();
                    (*mfunc[selection-1])(*this);
                    upanddown = !(quitflag == 1);
                    restorewindow();
                }
                else    {
                    // ----- no function, must be a toggle
                    char *cp = text[selection-1];
                    cp += strlen(cp)-1;
                    if (*cp == ' ')
                        *cp = CHECK;
                    else if ((*cp & 255) == CHECK)
                        *cp = ' ';
                }
                break;
        }
    }
    return sel == ESC ? ESC : 0;
}

// --------- compute the height of a popdown menu
int PopdownMenu::menuheight(char **text)
{
    int height = 0;
    while (text[height])
        height++;
    return height;
}

// --------- compute the width of a popdown menu
int PopdownMenu::menuwidth(char **text)
{
    int width = 0;
    while (*text)    {
        width = max(width, strlen(*text));
        text++;
    }
    return width;
}

// ----- test the setting of a toggle selection
int PopdownMenu::test_toggle(int sel)
{
    char *cp = text[sel-1];
    cp += strlen(cp)-1;
    return (*cp & 255) == CHECK;
}


[LISTING THREE]

// ---------- demoslid.c

#include <stddef.h>
#include <conio.h>
#include <stdio.h>
#include "menus.h"
#include "console.h"

// ----------- File menu
static char *fmenu[] = {
    " Load ",
    " Save ",
    " New  ",
    " Quit ",
    NULL
};

static void load(SlideBar&);
static void save(SlideBar&);
static void newfile(SlideBar&);
static void quit(SlideBar&);

static void (*ffuncs[])(SlideBar&)={load,save,newfile,quit};

void main(void)
{
    SlideBar menu(1, fmenu, 1, ffuncs);
}

static void load(SlideBar& menu)
{
    Window wnd(20,10,40,20,BLACK,CYAN);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n   LOAD A FILE";
    getkey();
}

static void save(SlideBar &menu)
{
    Window wnd(20,10,40,20,YELLOW,RED);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n  SAVE A FILE";
    getkey();
}

static void newfile(SlideBar &menu)
{
    Window wnd(20,10,40,20,YELLOW,RED);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n   NEW FILE";
    getkey();
}

static void quit(SlideBar& menu)
{
    YesNo yn("Quit");
    if (yn.answer)
        menu.terminate();
}



[LISTING FOUR]

// ---------- demopop.c

#include <stddef.h>
#include <conio.h>
#include <stdio.h>
#include "menus.h"
#include "console.h"

// ----------- File menu
static char *fmenu[] = {
    " Load    ",
    "-Save    ",
    " New     ",
    " Option  ",
    " Quit    ",
    NULL
};

static void load(PopdownMenu&);
static void save(PopdownMenu&);
static void newfile(PopdownMenu&);
static void quit(PopdownMenu&);

static void (*ffuncs[])(PopdownMenu&) =
    { load, save, newfile, NULL, quit };

void main(void)
{
    PopdownMenu menu(20, 10, fmenu, 1, ffuncs);
}

static void load(PopdownMenu& menu)
{
    Window wnd(20,10,40,20,BLACK,CYAN);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n   LOAD A FILE";
    menu.enable_selection(2);    // enable the save command
    getkey();
}

static void save(PopdownMenu &menu)
{
    Window wnd(20,10,40,20,YELLOW,RED);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n  SAVE A FILE";
    menu.disable_selection(2);    // disable the save command
    getkey();
}

static void newfile(PopdownMenu &menu)
{
    Window wnd(20,10,40,20,YELLOW,RED);
    wnd.title("(Stub Function)");
    wnd << "\n\n\n\n   NEW FILE";
    menu.enable_selection(2);    // enable the save command
    getkey();
}

static void quit(PopdownMenu& menu)
{
    if (menu.test_toggle(4))
        menu.terminate();
    else    {
        YesNo yn("Quit");
        if (yn.answer)
            menu.terminate();
    }
}



[LISTING FIVE]


// -------- strings.h

#ifndef STRINGS
#define STRINGS

#include <string.h>

class string    {
    char *sptr;
public:
    //          CONSTRUCTORS
    // -------- construct a null string
    string(void);
    // ------- construct with a char * initializer
    string(char *s);
    // ------- construct with another string as initializer
    string(string& s);
    // -------- construct with just a size
    string(int len);

    //          DESTRUCTOR
    ~string(void) { delete sptr; }

    //          MEMBER FUNCTIONS
    // ------ return the address of the string
    const char *stradr(void) { return sptr; }

    //          SUBSTRINGS
    // ------ substring: right len chars
    string right(int len);
    // ------ substring: left len chars
    string left(int len);
    // ------ substring: middle len chars starting from where
    string mid(int len, int where);

    //          ASSIGNMENTS
    // -------- assign a char array to a string
    void operator=(char *s);
    // ---------- assign a string to a string
    void operator=(string& s) { *this = s.sptr; }

    //          CONCATENATORS
    // ------- 1st concatenation operator (str1 += char *)
    void operator+=(char *s);
    // ------- 2nd concatenation operator (str1 += str2;)
    void operator+=(string& s) { *this += s.sptr; }
    // ------- 3rd concatenation operator (str1 = str2+char*;)
    string operator+(char *s);
    // ------- 4th concatenation operator (str1 = str2 + str3;)
    string operator+(string& s) { return *this + s.sptr; }

    //          RELATIONAL OPERATORS
    int operator==(string& s) { return strcmp(sptr,s.sptr)==0;}
    int operator!=(string& s) { return strcmp(sptr,s.sptr)!=0;}
    int operator<(string& s)  { return strcmp(sptr,s.sptr)< 0;}
    int operator>(string& s)  { return strcmp(sptr,s.sptr)> 0;}
    int operator<=(string& s) { return strcmp(sptr,s.sptr)<=0;}
    int operator>=(string& s) { return strcmp(sptr,s.sptr)>=0;}
    int operator==(char *s)   { return strcmp(sptr,s)==0; }
    int operator!=(char *s)   { return strcmp(sptr,s)!=0; }
    int operator<(char *s)    { return strcmp(sptr,s)< 0; }
    int operator>(char *s)    { return strcmp(sptr,s)> 0; }
    int operator<=(char *s)   { return strcmp(sptr,s)<=0; }
    int operator>=(char *s)   { return strcmp(sptr,s)>=0; }

    //          SUBSCRIPTORS
    char operator[](int n) { return *(sptr + n); }
    char* operator+(int n) { return sptr + n; }
};

#endif



[LISTING SIX]

// -------- strings.c

#include <stddef.h>
#include <stream.hpp>
#include "strings.h"

// -------- construct a null string
string::string(void)
{
    sptr = new char;
    *sptr = '\0';
}
// ------- construct with a char * initializer
string::string(char *s)
{
    sptr = new char[strlen(s)+1];
    strcpy(sptr, s);
}
// ------- construct with another string as initializer
string::string(string& s)
{
    sptr = new char[strlen(s.sptr)+1];
    strcpy(sptr, s.sptr);
}
// -------- construct with just a size
string::string(int len)
{
    sptr = new char[len+1];
    memset(sptr, 0, len+1);
}
// -------- assign a char array to a string
void string::operator=(char *s)
{
    delete sptr;
    sptr = new char[strlen(s)+1];
    strcpy(sptr, s);
}
// ------- 1st concatenation operator (str1 += char *;)
void string::operator+=(char *s)
{
    char *sp = new char[strlen(sptr) + strlen(s) + 1];
    strcpy(sp, sptr);
    strcat(sp, s);
    delete sptr;
    sptr = sp;
}
// ------- 3rd concatenation operator (str1 = str2 + char*;)
string string::operator+(char *s)
{
    string tmp(*this);
    tmp += s;
    return tmp;
}
// ------ substring: right len chars
string string::right(int len)
{
    string tmp(sptr + strlen(sptr) - len);
    return tmp;
}
// ------ substring: left len chars
string string::left(int len)
{
    string tmp(len+1);
    strncpy(tmp.stradr(), sptr, len);
    return tmp;
}
// ------ substring: middle len chars starting from where
string string::mid(int len, int where)
{
    string tmp(len+1);
    strncpy(tmp.stradr(),sptr+where-1,len);
    return tmp;
}