menu/libmenu/help.c

   1 /* -*- c -*- ------------------------------------------------------------- *
   2  *
   3  *   Copyright 2004-2005 Murali Krishnan Ganapathy - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 #include "help.h"
  14 #include <stdio.h>
  15 #include "string.h"
  16 #include "com32io.h"
  17 #include <loadfile.h> // to read entire file into memory
  18
  19 char helpbasedir[HELPDIRLEN]; // name of help directory limited to HELPDIRLEN
  20
  21 // Find the occurence of the count'th \n in buffer (or NULL) if not found
  22 char * findline(char*buffer,int count)
  23 {
  24    int ctr;
  25    char *p= buffer-1;
  26
  27    if (count < 1) return buffer;
  28    for (ctr=0; ctr < count; ctr++) {
  29        p = strchr(p+1,'\n');
  30        if (p==NULL) return NULL;
  31    }
  32    return p;
  33 }
  34
  35 // return the number of lines in buffer
  36 int countlines(char*buffer)
  37 {
  38   int ans;
  39   const char *p;
  40
  41   p = buffer-1;
  42   ans = 1;
  43   while(p) {p = strchr(p+1,'\n'); ans++; }
  44   return ans;
  45 }
  46
  47
  48 // Print numlines of text starting from buf
  49 void printtext(char*buf, int from)
  50 {
  51   char *p,*f;
  52   char right,bot,nlines;
  53
  54   // clear window to print
  55   right = getnumcols() - HELP_RIGHT_MARGIN;
  56   bot = getnumrows() - HELP_BOTTOM_MARGIN;
  57   nlines = bot-HELP_BODY_ROW+1;
  58   scrollupwindow(HELP_BODY_ROW,HELP_LEFT_MARGIN,bot,right,0x07,nlines);
  59
  60   f  = findline(buf,from);
  61   if (!f) return; // nothing to print
  62   if (*f=='\n') f++; // start of from+1st line
  63   p = findline(f,nlines);
  64   if (p && (*p=='\n')) *p = '\0'; // change to NUL
  65   gotoxy(HELP_BODY_ROW,HELP_LEFT_MARGIN,HELPPAGE);
  66   cswprint(f,0x07,HELP_LEFT_MARGIN);
  67   if (p) *p = '\n'; // set it back
  68 }
  69
  70 void showhelp(const char *filename)
  71 {
  72    char nc,nr,ph;
  73    char *title,*text;
  74    union { char *buffer; void *vbuf; } buf; // This is to avoild type-punning issues
  75
  76    char line[512];
  77    size_t size;
  78    char scan;
  79    int rv,numlines,curr_line;
  80
  81    nc = getnumcols();
  82    nr = getnumrows();
  83    ph = nr - HELP_BOTTOM_MARGIN - HELP_BODY_ROW - 1;
  84    cls();
  85    drawbox(0,0,nr,nc-1,HELPPAGE,0x07,HELPBOX);
  86
  87    drawhorizline(2,0,nc-1,HELPPAGE,0x07,HELPBOX,0); // dumb==0
  88    if (filename == NULL) { // print file contents
  89      gotoxy(HELP_BODY_ROW,HELP_LEFT_MARGIN,HELPPAGE);
  90      cswprint("Filename not given",0x07,HELP_LEFT_MARGIN);
  91      while (1) {
  92        inputc(&scan);
  93        if (scan == ESCAPE) break;
  94      }
  95      cls();
  96      return;
  97    }
  98
  99    rv = loadfile(filename,(void **)&buf.vbuf, &size); // load entire file into memory
 100    if (rv < 0) { // Error reading file or no such file
 101       sprintf(line, "Error reading file or file not found\n file=%s",filename);
 102       gotoxy(HELP_BODY_ROW,HELP_LEFT_MARGIN,HELPPAGE);
 103       cswprint(line,0x07,HELP_LEFT_MARGIN);
 104       while (1) {
 105         inputc(&scan);
 106         if (scan == ESCAPE) break;
 107       }
 108       cls();
 109       return;
 110    }
 111
 112    title = buf.buffer;
 113    text = findline(title,1); // end of first line
 114    *text++='\0'; // end the title string and increment text
 115
 116    // Now we have a file just print it.
 117    gotoxy(1,(nc-strlen(title))/2,HELPPAGE);
 118    csprint(title,0x07);
 119    numlines = countlines(text);
 120    curr_line = 0;
 121    scan = ESCAPE+1; // anything except ESCAPE
 122
 123    while(scan != ESCAPE) {
 124        printtext(text,curr_line);
 125        gotoxy(HELP_BODY_ROW-1,nc-HELP_RIGHT_MARGIN,HELPPAGE);
 126        if (curr_line > 0)
 127           putch(HELP_MORE_ABOVE,0x07,HELPPAGE);
 128        else putch(' ',0x07,HELPPAGE);
 129        gotoxy(nr-HELP_BOTTOM_MARGIN+1,nc-HELP_RIGHT_MARGIN,HELPPAGE);
 130        if (curr_line < numlines - ph)
 131           putch(HELP_MORE_BELOW,0x07,HELPPAGE);
 132        else putch(' ',0x07,HELPPAGE);
 133
 134        inputc(&scan); // wait for user keypress
 135
 136        switch(scan) {
 137          case HOMEKEY:
 138              curr_line = 0;
 139              break;
 140          case ENDKEY:
 141              curr_line = numlines;
 142              break;
 143          case UPARROW:
 144              curr_line--;
 145              break;
 146          case DNARROW:
 147              curr_line++;
 148              break;
 149          case PAGEUP:
 150              curr_line -= ph;
 151              break;
 152          case PAGEDN:
 153              curr_line += ph;
 154              break;
 155          default:
 156            break;
 157        }
 158        if (curr_line > numlines - ph) curr_line = numlines-ph;
 159        if (curr_line < 0) curr_line = 0;
 160    }
 161    cls();
 162    return;
 163 }
 164
 165 void runhelp(const char *filename)
 166 {
 167    char dp;
 168    char fullname[HELPDIRLEN+16];
 169
 170    dp = getdisppage();
 171    if (dp != HELPPAGE) setdisppage(HELPPAGE);
 172    cursoroff();
 173    if (helpbasedir[0] != 0) {
 174       strcpy(fullname,helpbasedir);
 175       strcat(fullname,"/");
 176       strcat(fullname,filename);
 177       showhelp(fullname);
 178    }
 179    else showhelp (filename); // Assume filename is absolute
 180    if (dp != HELPPAGE) setdisppage(dp);
 181 }
 182
 183 void runhelpsystem(unsigned int helpid)
 184 {
 185    char filename[15];
 186
 187    sprintf(filename,"hlp%5d.txt",helpid);
 188    runhelp(filename);
 189 }
 190
 191 void init_help(const char *helpdir)
 192 {
 193    if (helpdir != NULL)
 194       strcpy(helpbasedir,helpdir);
 195    else helpbasedir[0] = 0;
 196 }
 197
 198 void close_help(void)
 199 {
 200 }