C/C++ Users Group Library 1996 July/C-C++ Users Group Library July 1996.iso/vol_300/328_02/whelp.c

C/C++ Source or Header | 1991-03-22 | 4.4 KB | 228 lines

/* whelp
 *        Context-sensitive help system.
 *        The help system is installed with a file reference.
 *        The program looks for help files with the extension .HLP and .HX
 *            in the 'home directory' specified by whome_dir
 *
 *        HELP is displayed until ESCAPE is pressed.
 *        F1 again displays a list of HELP topics.
 *
 */
#include "wsys.h"

#ifndef __TURBOC__
    /* this is MSC */
    #include "direct.h"
    #define MAXPATH  80
#else
    /* __TURBOC__ */
    #include <dir.h>
#endif


#include "whelp.h"



static void help(void);


static char hname[MAXPATH] = {0};
static char xname[MAXPATH] = {0};


static char NOHELP[] = "Not available";





void whelp_install ( char *fn )
    {
    if ( strlen ( fn ) > 8 )
        {
        werror ('H', "Helpfile name > 8");
        }


    if ( ! *hname )
        {
        /* not yet installed
         */
        whotkey_install ( FKEY(1), help );
        }

    strcpy ( hname, whome_dir );
    strcat ( hname, fn );
    strcat ( hname, ".HLP" );

    strcpy ( xname, whome_dir );
    strcat ( xname, fn );
    strcat ( xname, ".HX" );



    return;        /* whelp_install */
    }


static void help(void)
    {

    /* a list of ptrs into the file topics
     */
    char **hxlist;
    int  key, n, ntopics, nbytes, complen, l_marg, t_marg;

    char *topic, *text;

    HX  *hx;

    FILE *hfile;

    topic = whelp_ptr;

    /* read the index file
     */
    if ( NULL == (hfile =fopen (xname, "rb") ))
        {
        werror ('H', "HELP- open index");
        }
    if ( 1 != fread ( &ntopics, sizeof(ntopics), 1, hfile ) )
        {
        werror ('H', "HELP- read index");
        }
    hx = wmalloc ( sizeof (HX) * (1+ntopics), " HELP ");

    if ( ntopics != fread (hx, sizeof(HX), ntopics, hfile) )
        {
        werror ('H', "HELP- read index");
        }
    fclose (hfile);



    /* run through the topics and create list of ptrs to the strings
     */
    hxlist = wmalloc ( sizeof (char *) * (ntopics+1), " HELP " );
    for ( n=0; n<ntopics; ++n )
        {
        hxlist[n] = hx[n].hxtopic;
        }
    hxlist[n] = NULL;




    wopen (10, 5, 60, 15, whelpattr, DOUBLE_BORDER, whelpattr,
            WSAVE2RAM);
    wtitle ( " HELP " );

    wbutton_add ("ESCAPE",     6, 13, 7, ESCAPE, WBTN_BOX );
    wbutton_add ("F1 TOPICS", 46, 13,10, FKEY(1),WBTN_BOX );

    do
        {
        /* find the topic in the index
         */
        for ( n=0; n<ntopics; ++n )
            {
            /* shorten comparison lenght to exclude terminal
             * spaces, punctuation chars, newline chars etc...
             * required because of method of generating help
             * for WFORM and WMENU
             */
            complen = min ( strlen(topic), TOPIC_SIZE );
            while ( (complen > 0)
                  && (strchr ( " :-.=?+\n\r", topic[complen-1] ) != NULL ) )
                {
                --complen;
                }

            if ( memicmp (hxlist[n], topic, complen )==0 )
                {
                /* found the topic - read in from file.
                 */
                nbytes = hx[n].hxsize;
                text = wmalloc ( nbytes+1, " HELP " );

                if ( NULL == (hfile = fopen ( hname, "rb" )))
                    {
                    werror ('H', "HELP -helpfileO");
                    }
                if (0!=fseek (hfile, hx[n].hxpos, SEEK_SET) )
                    {
                    werror ('H', "HELP -helpfileS");
                    }

                if (1!= fread (text, nbytes, 1, hfile))
                    {
                    werror ('H', "HELP -helpfileR");
                    }
                fclose (hfile);

                text[nbytes] =0;

                break;
                }

            }
        if ( n == ntopics )
            {
            /* topic not found
             * NOTE that 'text' is freed later, so must alloc
             *     even though we know exactly what to put.
             */
            text = wmalloc (sizeof (NOHELP), " HELP ");
            strcpy (text,NOHELP);
            }



        /* print the help text
         *        NOTE recalc position each time in case window is wmsdrag()'d
         */
        l_marg = w0-> winleft + 5;
        t_marg = w0-> wintop  + 3;

        /* define a small window to create left and top margins for text.
         * also, this clears previous text.
         */
        wopen ( l_marg, t_marg, 50, 8, whelpattr, NO_BORDER, 0, WSAVE2NULL );
        wputs (text);
        free  (text);
        wabandon();

        wgoto ( 5, 1 );
        wclearline();
        wputs ("TOPIC: ");
        wputs (topic);

        key = wgetc ();

        if ( key == FKEY(1) )
            {
            /* set location for list of topics above the "F1" button.
             */
            wsetlocation ( WLOC_ATWIN, 46, 1 );

            topic = hxlist [ wpicklist ("help topics",
                            hxlist ) ];

            if ( topic == NULL )  /* ESCAPE pressed */
                {
                topic = whelp_ptr;
                }
            }

        }
    while ( key != ESCAPE );

    wclose ();

    free (hx);

    return;        /* help */
    }
/*------------------ end of whelp.c ----------------------*/