gnu/lib/libdialog/help.c

   1 /***************************************************************
   2  *
   3  * Program:     help.c
   4  * Author:      Marc van Kempen
   5  * Desc:        get help
   6  *
   7  *
   8  * Copyright (c) 1995, Marc van Kempen
   9  *
  10  * All rights reserved.
  11  *
  12  * This software may be used, modified, copied, distributed, and
  13  * sold, in both source and binary form provided that the above
  14  * copyright and these terms are retained, verbatim, as the first
  15  * lines of this file.  Under no circumstances is the author
  16  * responsible for the proper functioning of this software, nor does
  17  * the author assume any responsibility for damages incurred with
  18  * its use.
  19  *
  20  ***************************************************************/
  21
  22 #include <stdlib.h>
  23 #include <sys/param.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <string.h>
  27 #include <dialog.h>
  28
  29 static char     _helpfilebuf[MAXPATHLEN];
  30 static char     _helplinebuf[77];         /* limit the helpline to 76 characters */
  31 static char     *_helpfile = NULL;
  32 static char     *_helpline = NULL;
  33
  34 /******************************************************************
  35  *
  36  *      helpfile routines
  37  *
  38  ******************************************************************/
  39
  40 void
  41 use_helpfile(char *hfile)
  42 /*
  43  * desc: set the helpfile to be opened on pressing F1 to <helpfile>
  44  */
  45 {
  46     if (hfile != NULL) {
  47         _helpfile = _helpfilebuf;
  48         strcpy(_helpfile, hfile);
  49     } else {
  50         _helpfile = NULL;
  51     }
  52
  53     return;
  54 } /* use_helpfile() */
  55
  56 void
  57 display_helpfile(void)
  58 /*
  59  * desc: display the current helpfile in a window
  60  */
  61 {
  62     WINDOW      *w;
  63     FILE        *f;
  64     struct stat sb;
  65     char        msg[80], *buf;
  66     static int  in_help = FALSE;
  67     char        *savehline = NULL;
  68
  69     if (in_help) return;        /* dont call help when you're in help */
  70
  71     if (_helpfile != NULL) {
  72         if ((w = dupwin(newscr)) == NULL) {
  73             dialog_notify("No memory to dup previous screen\n");
  74             return;
  75         }
  76         if ((f = fopen(_helpfile, "r")) == NULL) {
  77             sprintf(msg, "Can't open helpfile : %s\n", _helpfile);
  78             dialog_notify(msg);
  79             return;
  80         }
  81         if (fstat(fileno(f), &sb)) {
  82             sprintf(msg, "Can't stat helpfile : %s\n", _helpfile);
  83             dialog_notify(msg);
  84             return;
  85         }
  86         if ((buf = (char *) malloc( sb.st_size )) == NULL) {
  87             sprintf(msg, "Could not malloc space for helpfile : %s\n", _helpfile);
  88             dialog_notify(msg);
  89             return;
  90         }
  91         if (fread(buf, 1, sb.st_size, f) != sb.st_size) {
  92             sprintf(msg, "Could not read entire help file : %s", _helpfile);
  93             dialog_notify(msg);
  94             free(buf);
  95             return;
  96         }
  97         buf[sb.st_size] = 0;
  98         in_help = TRUE;
  99         savehline = get_helpline();
 100         use_helpline("Use arrowkeys, PgUp, PgDn, Home and End to move through text");
 101         dialog_mesgbox("Online help", buf, LINES-4, COLS-4);
 102         restore_helpline(savehline);
 103         in_help = FALSE;
 104         touchwin(w);
 105         wrefresh(w);
 106         delwin(w);
 107         free(buf);
 108     } else {
 109         /* do nothing */
 110     }
 111
 112     return;
 113 } /* display_helpfile() */
 114
 115
 116 /******************************************************************
 117  *
 118  *      helpline routines
 119  *
 120  ******************************************************************/
 121
 122 void
 123 use_helpline(char *hline)
 124 /*
 125  * desc: set the helpline to printed in dialogs
 126  */
 127 {
 128     if (hline) {
 129         _helpline = _helplinebuf;
 130         if (strlen(hline) > 76) {
 131             /* only display the first 76 characters in the helpline */
 132             strncpy(_helpline, hline, 76);
 133             _helpline[76] = 0;
 134         } else {
 135             strcpy(_helpline, hline);
 136         }
 137     } else {
 138         _helpline = NULL;
 139     }
 140
 141     return;
 142 } /* use_helpline() */
 143
 144 void
 145 display_helpline(WINDOW *w, int y, int width)
 146 /*
 147  * desc: display the helpline at the given coordinates <y, x> in the window <w>
 148  */
 149 {
 150     if (_helpline != NULL) {
 151         if (strlen(_helpline) > width - 6) {
 152             _helpline[width - 6] = 0;
 153         }
 154         wmove(w, y, (int) (width - strlen(_helpline)- 4) / 2);
 155         wattrset(w, title_attr);
 156         waddstr(w, "[ ");
 157         waddstr(w, _helpline);
 158         waddstr(w, " ]");
 159     } else {
 160         /* do nothing */
 161     }
 162
 163     return;
 164 }
 165
 166 char *
 167 get_helpline(void)
 168 /*
 169  * desc: allocate new space, copy the helpline to it and return a pointer to it
 170  */
 171 {
 172     char *hlp;
 173
 174     if (_helpline) {
 175         hlp = (char *) malloc( strlen(_helpline) + 1 );
 176         strcpy(hlp, _helpline);
 177     } else {
 178         hlp = NULL;
 179     }
 180
 181     return(hlp);
 182 } /* get_helpline() */
 183
 184 void
 185 restore_helpline(char *helpline)
 186 /*
 187  * Desc: set the helpline to <helpline> and free the space allocated to it
 188  */
 189 {
 190     use_helpline(helpline);
 191     free(helpline);
 192
 193     return;
 194 } /* restore_helpline() */